CN221201269U - Reel core and battery - Google Patents
Reel core and battery Download PDFInfo
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- CN221201269U CN221201269U CN202322621098.XU CN202322621098U CN221201269U CN 221201269 U CN221201269 U CN 221201269U CN 202322621098 U CN202322621098 U CN 202322621098U CN 221201269 U CN221201269 U CN 221201269U
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- 238000006138 lithiation reaction Methods 0.000 claims abstract description 171
- 238000004804 winding Methods 0.000 claims abstract description 119
- 238000005452 bending Methods 0.000 claims abstract description 73
- 239000011248 coating agent Substances 0.000 claims abstract description 23
- 238000000576 coating method Methods 0.000 claims abstract description 23
- 239000000126 substance Substances 0.000 claims description 37
- 238000000034 method Methods 0.000 abstract description 20
- 229910052744 lithium Inorganic materials 0.000 abstract description 17
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 abstract description 16
- 239000003792 electrolyte Substances 0.000 abstract description 11
- 238000000926 separation method Methods 0.000 abstract description 6
- 239000007788 liquid Substances 0.000 abstract description 3
- 238000012360 testing method Methods 0.000 description 12
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 9
- 229910001416 lithium ion Inorganic materials 0.000 description 9
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- 238000005520 cutting process Methods 0.000 description 4
- 238000001556 precipitation Methods 0.000 description 4
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 239000011889 copper foil Substances 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 125000004122 cyclic group Chemical group 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 230000008595 infiltration Effects 0.000 description 2
- 238000001764 infiltration Methods 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 239000012634 fragment Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000005215 recombination Methods 0.000 description 1
- 230000006798 recombination Effects 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
Classifications
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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
-
- 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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Abstract
The application discloses a winding core and a battery; the winding core comprises a straight section and a bending section; the winding core comprises a negative plate; a first pre-lithiation area and a second pre-lithiation area are sequentially and circularly connected to the negative electrode active coating on at least one side surface of the negative electrode plate; the thickness dimension of the second pre-lithiation zone is larger than that of the first pre-lithiation zone along the thickness direction of the negative electrode plate; the second pre-lithiation area is positioned at the bending section of the winding core; the first prelithiation zone is located in the straight section of the winding core. As above, after the liquid is injected, the pre-lithiation zone reacts with the negative electrode plate to disappear, and the area of the bending section opposite to the second pre-lithiation zone forms a cavity relative to other areas of the winding core, wherein the cavity can provide a release space for stress generated by the expansion of the negative electrode plate in the circulation process, so that the problems of deformation and fracture of the bending section of the winding core are improved; meanwhile, the cavity of the bending section of the winding core can store more electrolyte, so that the lithium separation risk is reduced.
Description
Technical Field
The application relates to the technical field of batteries, in particular to a winding core and a battery comprising the winding core.
Background
With the rapid development of 5G, the requirements of people on the endurance time of electronic products are higher and higher, and the silicon-based negative electrode is the key point of current research due to higher gram capacity. Compared with a graphite negative electrode plate, the silicon-based negative electrode plate has the problem of relatively larger expansion in the cyclic process; the silicon-based negative electrode plate is wound to obtain a winding core, and in the recycling process of the battery comprising the winding core, bending sections on two sides of the winding core deform due to expansion of the silicon-based negative electrode plate, so that lithium precipitation and even fracture risks are generated.
Disclosure of utility model
In view of the above, the present application provides a winding core, and also provides a battery including the winding core, which solves the problems of deformation, lithium precipitation, and even fracture of the bending section of the winding core.
In order to achieve the above purpose, the present application provides the following technical solutions:
a winding core comprising a straight section and a bending section;
The winding core comprises a negative plate; the negative plate comprises a negative current collector and a negative active coating coated on the surface of the negative current collector;
a first pre-lithiation area and a second pre-lithiation area are sequentially and circularly connected to the negative electrode active coating on at least one side surface of the negative electrode plate;
The thickness dimension of the second pre-lithiation region is larger than that of the first pre-lithiation region along the thickness direction of the negative electrode plate;
The second pre-lithiation zone is positioned at the bending section of the winding core; the first prelithiation zone is located at a straight section of the winding core.
Optionally, in the foregoing winding core, the second prelithiation area has a width dimension along a long axis direction of the negative electrode sheet;
The bending section comprises a plurality of bending section layers; and the width dimension of the second prelithiation areas on the plurality of bending segment layers is increased along the direction from the center of the winding core to the edge of the winding core.
Optionally, the bending section comprises a plurality of bending section layers; and the width sizes of the second prelithiation areas on the plurality of bending segment layers are the same along the direction from the center of the winding core to the edge of the winding core.
Optionally, in the foregoing winding core, the second prelithiation area has a length dimension along a short axis direction of the negative electrode sheet; the length dimension of the second pre-lithiation region is the same as the width dimension of the negative electrode sheet.
Optionally, in the foregoing winding core, along a thickness direction of the negative electrode sheet, a thickness dimension of the first pre-lithiation region is H1, and a thickness dimension of the second pre-lithiation region is H2;
HI. H2 satisfies: h2 = (1.01-4.0) H1.
Optionally, in the above-mentioned winding core,
The first pre-lithiation zone comprises a first pre-lithiation substance and a first gap which are sequentially and circularly connected along the long axis direction of the negative electrode plate;
and the second pre-lithiation zone comprises a second pre-lithiation substance and a second gap which are sequentially and circularly connected along the long axis direction of the negative electrode plate.
Optionally, in the winding core, an area ratio of the second pre-lithiation substance to the second pre-lithiation region is greater than an area ratio of the first pre-lithiation substance to the first pre-lithiation region.
Optionally, in the above-mentioned winding core,
The area ratio of the first pre-lithiation substance to the first pre-lithiation region is S1;
the area ratio of the second pre-lithiation substance to the second pre-lithiation region is S2;
s1 and S2 satisfy the following conditions: s2= (1.05-4.3) S1.
Optionally, in the winding core, a first pre-lithiation layer is disposed on the negative electrode active coating; a second pre-lithiation layer is arranged on the first pre-lithiation layer on at least one side surface of the negative electrode plate at intervals;
And a second pre-lithiation area is formed in a region where the second pre-lithiation layer and the first pre-lithiation layer are overlapped, and a first pre-lithiation area is formed in a region where the first pre-lithiation layer is not overlapped with the second pre-lithiation layer.
A battery comprising a jellyroll as described above.
In the winding core and the battery provided by the application, a first pre-lithiation area and a second pre-lithiation area are sequentially and circularly connected on a negative electrode active coating on at least one side surface of a negative electrode sheet of the winding core; the thickness dimension of the second pre-lithiation zone is larger than that of the first pre-lithiation zone, the second pre-lithiation zones are both positioned at the bending section of the winding core, and the first pre-lithiation zone is positioned at the straight section of the winding core; as described above, the plurality of second prelithiation areas can be arranged in the bending sections on the two sides of the winding core in sequence from inside to outside, so that thicker prelithiation areas are formed in the areas, opposite to the second prelithiation areas, of the bending sections on the two sides of the winding core relative to other areas of the winding core; after the electrolyte is injected into the winding battery comprising the winding core, the pre-lithiated substance on the pre-lithiated region reacts with the negative electrode plate to disappear, and the thickness dimension of the pre-lithiated region of the area, opposite to the second pre-lithiated region, of the bending section of the winding core is larger than that of the pre-lithiated region of other areas of the winding core, so that a certain cavity is formed in the area, opposite to the second pre-lithiated region, of the bending section of the winding core; the cavity formed by the bending section of the winding core can provide a release space for stress generated by the expansion of the negative plate in the circulation process, so that the problems of deformation and fracture of the bending section of the winding core are improved; meanwhile, the cavity formed in the bending section of the winding core can store more electrolyte, so that the dynamic performance of lithium ions is improved, and the lithium separation risk is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present application, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural view of a negative electrode sheet in the prior art;
FIG. 2 is a schematic view of the structure of the negative plate of the present application;
Fig. 3 is a schematic structural view of a negative electrode sheet according to another embodiment of the present application;
FIG. 4 is a schematic diagram of the structure of the first and second pre-lithiation regions according to the present application;
FIG. 5 is a schematic view of the winding core of the present application;
Fig. 6 is a schematic structural view of a bending section of the winding core of the present application.
In fig. 1-6:
1. A negative electrode current collector; 2. a negative electrode active coating; 3. a first pre-lithiation zone; 4. a second prelithiation zone; 5. a first prelithiation layer; 6. a second prelithiation layer; 7. a straight section; 8. a bending section; 9. a negative electrode sheet; 10. a positive plate; 11. a diaphragm.
Detailed Description
The application provides a winding core and a battery comprising the winding core.
The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
As shown in fig. 2-6, a winding core comprises a straight section 7 and bent sections 8 located on both sides of the straight section 7. The winding core comprises a negative plate 9; the negative electrode sheet 9 includes a negative electrode current collector 1 and a negative electrode active coating 2 coated on the surface of the negative electrode current collector 1. Along the long axis direction of the negative electrode plate 9, a first pre-lithiation zone 3 and a second pre-lithiation zone 4 are sequentially and circularly connected to the negative electrode active coating 2 on at least one side surface of the negative electrode plate 9; as described above, a plurality of second pre-lithiated regions 4 are formed on the negative electrode sheet 9 at intervals, and the first pre-lithiated regions 3 are provided between adjacent second pre-lithiated regions 4. The first pre-lithiation region 3 and the second pre-lithiation region 4 are formed on the side of the anode active coating 2 remote from the anode current collector 1. The thickness dimension of the second pre-lithiation zone 4 is larger than that of the first pre-lithiation zone 3 along the thickness direction of the negative electrode sheet 9, and the second pre-lithiation zone 4 is positioned at the bending section 8 of the winding core; the first prelithiation zone 3 is located at the straight section 7 of the winding core.
The thickness direction of the negative electrode sheet 9 is indicated by an arrow in fig. 1 to 3.
Referring to fig. 2 of the specification, the second prelithiation areas 4 are formed at intervals on only one side of the negative electrode sheet 9.
Referring to fig. 3 of the specification, a plurality of second prelithiation areas 4 are formed on both sides of the negative electrode sheet 9 at intervals.
The negative electrode active coating 2 on at least one side surface of the negative electrode sheet 9 is sequentially and circularly connected with a first pre-lithiation zone 3 and a second pre-lithiation zone 4; the thickness dimension of the second pre-lithiation region 4 is greater than that of the first pre-lithiation region 3, when the negative electrode sheet 9 is wound into a roll core, the plurality of second pre-lithiation regions 4 can be respectively arranged on the bending sections 8 on two sides of the roll core from inside to outside in sequence, so that thicker pre-lithiation regions are formed in the regions of the bending sections 8 on two sides of the roll core, which are opposite to the second pre-lithiation region 4, relative to other regions of the roll core. When the electrolyte is injected into the wound battery including the winding core, the pre-lithiated substance of the pre-lithiated region reacts with the negative electrode sheet 9 to disappear; because the thickness dimension of the pre-lithiation area of the area, opposite to the second pre-lithiation area 4, of the bending section 8 of the winding core is larger than that of the other areas of the winding core, after the pre-lithiation area reacts with the negative electrode sheet 9, a certain cavity is formed in the area, opposite to the second pre-lithiation area 4, of the bending section 8 of the winding core; the cavity formed by the bending section 8 of the winding core can provide a release space for stress generated by expansion of the negative electrode sheet 9 in the circulation process, so that the deformation and the sheet breakage problem of the bending section 8 of the winding core are improved; meanwhile, the cavity formed in the bending section 8 of the winding core can store more electrolyte, so that the dynamic performance of lithium ions is improved, and the lithium separation risk is reduced.
In some embodiments of the present application, the second pre-lithiated region 4 has a width dimension along the long axis of the negative electrode sheet 9. The bending section 8 comprises a plurality of bending section layers; the width dimension of the second prelithiation zone 4 on the plurality of folded segment layers increases in the direction from the center of the winding core to the edge of the winding core.
It should be noted that the winding core has a center point, and the direction from the center of the winding core to the edge of the winding core is the direction extending outwards from the center point of the winding core, specifically, referring to the direction indicated by the arrow in fig. 6.
The width direction of the first pre-lithiation zone 3 and the width direction of the second pre-lithiation zone 4 are parallel to the long axis direction of the negative electrode sheet 9; the long axis direction of the negative electrode sheet 9 is the direction indicated by the arrow in fig. 1 to 4.
The length dimension of the bending segment layer is increased gradually along the direction from the center of the winding core to the edge of the winding core; therefore, the width dimension of the second pre-lithiation zone 4 is controlled, so that the width dimension of a plurality of second pre-lithiation zones 4 which are arranged at intervals is increased; as described above, when the negative electrode sheet 9 is wound into a winding core, the plurality of second pre-lithiation areas 4 can be sequentially arranged on each bending segment layer in the bending segments 8 on both sides of the winding core, and at least part of the regions of each bending segment layer are opposite to the positions of the second pre-lithiation areas 4, so that the bending segments 8 of the winding core are accurately ensured to have the pre-lithiation areas with larger thickness dimensions.
Further, the width sizes of the second pre-lithiation areas 4 are increased gradually along the direction from the center of the winding core to the edge of the winding core, and the width sizes of the second pre-lithiation areas 4 are matched with the length sizes of the bending segment layers; at this time, the width dimensions of the plurality of first prelithiation zones 3 are all the same. As above, in the winding process of the negative electrode sheet 9, the plurality of second pre-lithiation areas 4 are ensured to be sequentially arranged on each bending segment layer in the bending segments 8 at the two sides of the winding core, and the whole bending segment layer is opposite to the second pre-lithiation areas 4 in position; meanwhile, the plurality of first pre-lithiation areas 3 are sequentially arranged on each flat segment layer of the flat section 7 of the winding core, and the positions of the whole flat segment layers and the first pre-lithiation areas 3 are opposite, so that the bending section 8 of the winding core is accurately ensured to be a pre-lithiation area with a larger thickness dimension compared with the flat section 7.
Or the width dimension of the second prelithiation zone 4 on the plurality of folded segment layers is the same along the direction from the center of the winding core to the edge of the winding core.
The second pre-lithiation zone 4 is arranged in an equal width mode, so that the production and the processing are convenient; at this time, the interval distance between two adjacent second pre-lithiation areas 4 is controlled, that is, the length sizes of the first pre-lithiation areas 3 which are sequentially arranged are further ensured in the winding process of the negative electrode sheet 9, so that the second pre-lithiation areas 4 are sequentially arranged on each bending segment layer in the bending segments 8 at two sides of the winding core, at least part of the regions of each bending segment layer are opposite to the positions of the second pre-lithiation areas 4, and the bending segments 8 of the winding core are ensured to have the pre-lithiation areas with larger thickness sizes.
In some embodiments of the application, the length direction of the second prelithiation zone 4 is parallel to the short axis direction of the negative electrode sheet 9. Along the short axis direction of the negative plate, the second pre-lithiation zone 4 has a length dimension; the length dimension of the second prelithiation zone 4 is the same as the width dimension of the negative electrode sheet 9.
The short axis direction of the negative electrode sheet 9 is the direction indicated by the arrow in fig. 4.
In the short axis direction of the negative electrode sheet 9, the maximum setting of the length dimension of the second prelithiation zone 4 is realized, and further, the prelithiation zone with a larger thickness dimension of the bending section 8 of the winding core is ensured.
In some embodiments of the present application, the thickness dimension of the first pre-lithiated region 3 is H1 along the thickness direction of the negative electrode 9 sheet. The thickness dimension of the second prelithiation zone 4 is H2 in the thickness direction of the negative electrode sheet 9. HI. H2 satisfies: h2 = (1.01-4.0) H1.
It should be noted that, the thickness dimension H2 of the second prelithiation zone 4 of the bending section 8 of the winding core is controlled within the above range, so that the thickness dimension of the prelithiation zone in the area opposite to the bending section 8 and the second prelithiation zone 4 can be ensured to be larger than the thickness dimension of the prelithiation zone in other areas of the winding core, and further, the area opposite to the bending section 8 and the second prelithiation zone 4 forms a cavity relative to other areas of the winding core, and the cavity of the bending section 8 is enough to resist the problems of deformation, lithium precipitation and even fracture of the bending section 8 of the winding core caused by the expansion of the negative electrode sheet 9; at the same time, the size of the bending section 8 is ensured not to be excessively large, so that the energy density of the battery is ensured.
In some embodiments of the present application, the first pre-lithiation region 3 includes a first pre-lithiation substance and a first gap connected in a sequentially cyclic arrangement along the long axis direction of the negative electrode sheet 9. Along the long axis direction of the negative electrode sheet 9, the second pre-lithiation zone 4 comprises a second pre-lithiation substance and a second gap which are sequentially and circularly arranged and connected.
The first pre-lithiation substance and the second pre-lithiation substance are the same in material; the main components are all lithium metal.
The first gap refers to an empty coating region between two adjacent first prelithiation substances, i.e. no first prelithiation substances are provided at the first gap. The second gap refers to an empty coating region between two adjacent second prelithiation substances, i.e. no second prelithiation substances are provided at the second gap.
Along the short axis direction of the negative electrode sheet 9, the first prelithiation substance extends in a corrugated shape (i.e., white corrugations in both side areas in fig. 4 of the specification); the first gaps also extend in a corrugated shape (i.e., black corrugations in both side areas in fig. 4 of the specification) along the short axis direction of the negative electrode sheet 9.
Along the short axis direction of the negative electrode sheet 9, the second prelithiation substance extends in a corrugated shape (i.e., white corrugations in the middle area in fig. 4 of the specification); along the short axis direction of the negative electrode sheet 9, the second gap also extends in a wavy shape (i.e., black waves in the middle area in fig. 4 of the specification).
And a first gap is arranged between the adjacent first pre-lithiated substances, so that the contact area of the first pre-lithiated substances and the electrolyte is increased, the infiltration of the electrolyte to the negative electrode plate 9 is accelerated, and the reaction of the negative electrode plate 9 and the first pre-lithiated substances is accelerated. And a second gap is arranged between the adjacent second pre-lithiated substances, so that the contact area of the second pre-lithiated substances and the electrolyte is increased, the infiltration of the electrolyte to the negative electrode plate 9 is accelerated, and the reaction of the negative electrode plate 9 and the second pre-lithiated substances is accelerated.
In certain embodiments of the present application, the area ratio of the first prelithiation species to the first prelithiation zone 3 is S1. The area ratio of the second pre-lithiation substance to the second pre-lithiation zone 4 is S2; s2 > S1.
In summary, the content density of the prelithiation species in the second prelithiation zone 4 is greater than the content density of the prelithiation species in the first prelithiation zone 3; therefore, more lithium is pre-embedded in the bending section 8 of the winding core, and therefore, the bending section 8 of the winding core has larger surface capacity compared with the straight section 7 of the winding core.
Further, S1 and S2 satisfy: s2= (1.05-4.3) S1.
The area ratio of the second pre-lithiation substance to the second pre-lithiation zone 4 is limited in the above range, so that the bending section 8 of the winding core can be ensured to have a larger lithium separation window, and lithium separation is avoided; at the same time, the effective contact area of the second prelithiation compound of the bending section 8 with the electrolyte can be ensured.
Referring to fig. 2-3 of the drawings, in some embodiments of the present application, a first prelithiation layer 5 is disposed on the negative electrode active coating 2. The first pre-lithiation layer 5 on at least one side of the negative electrode sheet 9 is provided with second pre-lithiation layers 6 at intervals. On the side of the negative electrode sheet 9 where the second pre-lithiated layer 6 is provided, the region where the second pre-lithiated layer 6 and the first pre-lithiated layer 5 overlap forms the second pre-lithiated region 4. The areas of the first prelithiation layer 5 not overlapping the second prelithiation layer 6 form the first prelithiation zone 3.
First, a first pre-lithiation layer 5 is compounded on the negative electrode active coating 2 of the negative electrode sheet 9; a second prelithiation layer 6 is then laminated onto the first prelithiation layer 5. At this time, the overlapping area of the second pre-lithiation layer 6 and the first pre-lithiation layer 5 is the second pre-lithiation area 4 with larger thickness dimension of the pre-lithiation area; the region including only one first pre-lithiation layer 5 is the first pre-lithiation region 3 with smaller thickness dimension.
As above, the molding process of the first pre-lithiation zone 3 and the second pre-lithiation zone 4 is convenient and quick, and each size is easy to control.
It should be noted that, the second prelithiation areas 4 with larger thickness dimension may be arranged on the anode active coating 2 of the anode sheet 9 at intervals; and then the first pre-lithiation zone 3 with smaller thickness dimension is compounded in the gap between the adjacent second pre-lithiation zones 4.
Referring to fig. 5-6 of the drawings, the application further provides a battery; the battery includes the winding core described above.
Since the battery of the present application has the winding core, the beneficial effects of the battery caused by the winding core are referred to above, and will not be described herein.
The above winding core is used to make a battery. After the battery is discharged, the negative electrode plate 9 and the area aligned with the first pre-lithiation area 3 form a buckling half battery for discharge test; and forming a buckling half battery by the positive area of the negative plate 9 and the second pre-lithiation area 4 for discharge test. Wherein, the discharge capacity of the positive area of the negative electrode sheet 9 and the second pre-lithiation zone 4 is higher.
Because the positive area of the negative electrode plate 9 and the second pre-lithiation area 4 is more pre-embedded with lithium, more lithium ions are extracted in the discharging process of the electricity buckling half-cell formed by the negative electrode plate, so that the capacity is higher.
Further, after the battery is full, the positive plate and the area aligned by the first pre-lithiation area 3 form a power-on half battery for charging test; and forming a buckling half battery by the positive plate and the area aligned by the second pre-lithiation area 4 for charging test. The charge capacity of the positive electrode sheet and the second prelithiation zone 4 in the alignment area is lower.
Because the positive area of the negative plate 9 and the second pre-lithiation area 4 is pre-embedded with more lithium, after the battery is full, partial lithium ions still remain in the positive area of the positive plate and the second pre-lithiation area 4 and are not separated from and embedded into the negative electrode, the vacancy for containing the lithium ions is reduced, and the lithium ions which can be embedded are reduced in the charging process of the buckling half battery formed by the lithium ion storage battery, so that the capacity is lower.
Further, after the battery is fully charged, the Li/Co ratio R1 of the area where the positive plate and the first pre-lithiation area 3 are aligned is smaller than the Li/Co ratio R2 of the area where the positive plate 9 and the second pre-lithiation area 4 are aligned.
After the battery is fully charged, part of lithium ions are not separated from and embedded into the negative electrode in the area where the positive electrode plate is aligned with the second pre-lithiation area 4, so that the Li/Co ratio of the area is high.
The positive electrode is a lithium cobaltate positive electrode, and the negative electrode is a silicon-based negative electrode. The width dimension of the negative electrode sheet 9 was 86mm, and the first pre-lithiation zone 3 was striped.
The positive plate is subjected to the working procedures of coating, rolling, die cutting and the like, the positive lug is die-cut according to the technological requirements, and then the sequence is switched to the winding working procedure for standby.
Control group
After the negative electrode sheet is subjected to a die cutting process, the negative electrode sheet is converted into a pre-lithiation process;
The negative current collector selects copper foil; a first pre-lithiation layer 5 is compounded on the anode active coating 2 on both sides of the anode current collector, and the main component of the first pre-lithiation layer 5 is metal lithium; the thickness dimension of the first prelithiation layer 5, i.e. the thickness dimension Hz of the first prelithiation zone 3, is 5um.
Experiment group 1
After the negative electrode is subjected to a die cutting process, the process is switched to a pre-lithiation process;
The negative current collector selects copper foil; a first pre-lithiation layer 5 is compounded on the anode active coating 2 on both sides of the anode current collector;
A second pre-lithiation layer 6 is compounded on a specific position of the first pre-lithiation layer 5 on one side surface of the negative electrode sheet 9 through secondary pre-lithiation process; on the side of the negative electrode sheet 9, a second pre-lithiated region 4 having a large thickness dimension is formed in the region where the second pre-lithiated layer 6 overlaps the first pre-lithiated layer 5; only the region having the first prelithiation layer 5 forms the first prelithiation region 3 having a small thickness dimension;
The thickness dimension H1 of the first prelithiation zone 3 is 5um; the thickness dimension H2 of the second prelithiation zone 4 is 10um;
The area ratio of the first pre-lithiation substance to the first pre-lithiation zone 3 is 0.461; the area ratio of the second prelithiation substance to the second prelithiation zone 4 is 0.87.
Experiment group 2
After the negative electrode is subjected to a die cutting process, the process is switched to a pre-lithiation process;
The negative current collector selects copper foil; a first pre-lithiation layer 5 is compounded on the anode active coating 2 on both sides of the anode current collector;
The second pre-lithiation layer 6 is compounded on specific positions of the first pre-lithiation layer 5 on both sides of the negative electrode sheet 9 through secondary pre-lithiation process; in each side of the negative electrode sheet 9, the region where the second pre-lithiation layer 6 overlaps the first pre-lithiation layer 5 forms a second pre-lithiation region 4 of large thickness dimension; only the region having the first prelithiation layer 5 forms the first prelithiation region 3 having a small thickness dimension;
The thickness dimension H1 of the first prelithiation zone 3 is 5um; the thickness dimension H2 of the second prelithiation zone 4 is 10um;
The area ratio of the first pre-lithiation substance to the first pre-lithiation zone 3 is 0.47; the area ratio of the second prelithiation substance to the second prelithiation zone 4 is 0.89.
The length dimension of the second pre-lithiated region 4 in the experimental group 1 and the experimental group 2 was the same as the width dimension of the negative electrode sheet 9, and the length dimension of the second pre-lithiated region 4 was 86mm. The width dimensions of the plurality of second prelithiation zones 4 are all the same, all 4mm. The width dimension of the first pre-lithiation zone 3 increases progressively along the long axis direction of the negative electrode sheet 9; the width of the first prelithiation zone 3 can be adjusted correspondingly according to the length of each bending segment layer.
The positive electrode sheet 10, the negative electrode sheet 9 and the diaphragm 11 of the comparison group and the experimental group are wound to form a winding core, wherein the second pre-lithiation areas 4 on the negative electrode sheet 9 of the experimental group are positioned on the bending sections on two sides of the winding core. And (5) normal sequence conversion after packaging and liquid injection.
Testing the batteries of the comparison group and the experimental group; the test results are shown in Table 1.
TABLE 1
The battery is subjected to a cycle test after capacity division, and the ratio of lithium and fragments in the bending section is confirmed by disassembling after 500 cycles.
From the above table 1, the experimental group can effectively avoid lithium precipitation in the bending section relative to the comparative group; the occurrence of the fracture phenomenon does not exist; the surface capacity of the negative plate 9 is effectively improved, and the Li/Co ratio of the positive plate 10 is also improved to a certain extent.
In the winding process, under the action of tension, the positive electrode sheet 10, the negative electrode sheet 9 and the diaphragm 11 form close fit at the bending section 8, and the pre-lithiated substances in the first pre-lithiated area 3 and the second pre-lithiated area 4 react with the negative electrode sheet 9 after liquid injection and are embedded into the negative electrode active coating 2 to form a certain gap. However, in the experimental group, due to the existence of the second prelithiation zone 4 with larger thickness, an extra cavity is formed in the bending section 8 of the winding core, so that a larger space is provided for the expansion of the negative electrode sheet 9 in the later period of circulation, the damage of the expansion stress to the negative electrode sheet 9 is reduced, and the deformation of the bending section 8 of the winding core is improved; and after the second pre-lithiation zone 4 disappears, more electrolyte can be stored in the second pre-lithiation zone, so that the dynamic performance of lithium ions is improved, and the lithium separation risk is reduced.
After the battery is discharged to 3.0V, the battery is disassembled, and the negative electrode plate 9 and the first pre-lithiation area 3 are aligned to form a buckling half battery, and the buckling half battery is discharged to 0.05V, wherein the discharge capacity is 0.2mAh. And (3) performing discharge test on the negative plate 9 and the second pre-lithiation zone 4, wherein the positive region forms a buckling half-cell, and the discharge capacity is 1.6mAh after the buckling half-cell is discharged to 0.05V.
After the battery is fully charged to 4.4V, the battery is disassembled, and the element content test is carried out on the positive plate 10 and the area aligned to the first pre-lithiation area 3, so as to obtain the Li/Co ratio R1. And (3) carrying out element content test on the positive plate 10 and the area aligned with the second pre-lithiation area 4, wherein the Li/Co ratio is R2. Wherein: r1 is less than R2.
And forming a buckling half battery by the positive plate 10 and the region aligned with the first pre-lithiation region 3 for charging test, wherein the charging capacities are 6.8mAh respectively. And forming a buckling half battery by the positive plate 10 and the region aligned by the second pre-lithiation region 4 for charging test, wherein the charging capacities are 5.4mAh respectively.
The components, arrangements, etc. referred to in this disclosure are only illustrative examples and are not intended to require or imply that the connections, arrangements, configurations must be made in the manner shown in the drawings. These components, devices, may be connected, arranged, configured in any manner, as will be appreciated by those skilled in the art. Words such as "including," "comprising," "having," and the like are words of openness and mean "including but not limited to," and are used interchangeably therewith. The terms "or" and "as used herein refer to and are used interchangeably with the term" and/or "unless the context clearly indicates otherwise. The term "such as" as used herein refers to, and is used interchangeably with, the phrase "such as, but not limited to.
It should also be noted that in the device of the present application, the components may be disassembled and/or reassembled. Such decomposition and/or recombination should be considered as equivalent aspects of the present application.
The previous description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects without departing from the scope of the application. Thus, the present application is not intended to be limited to the aspects shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
The foregoing description has been presented for purposes of illustration and description. Furthermore, this description is not intended to limit embodiments of the application to the form disclosed herein. Although a number of example aspects and embodiments have been discussed above, a person of ordinary skill in the art will recognize certain variations, modifications, alterations, additions, and subcombinations thereof.
The foregoing description of the preferred embodiments of the application is not intended to be limiting, but rather is to be construed as including any modifications, equivalents, and alternatives falling within the spirit and principles of the application.
Claims (10)
1. The winding core is characterized by comprising a straight section (7) and a bending section (8);
The winding core comprises a negative plate (9); the negative electrode sheet (9) comprises a negative electrode current collector (1) and a negative electrode active coating (2) coated on the surface of the negative electrode current collector (1);
The negative electrode active coating (2) on at least one side surface of the negative electrode sheet (9) is sequentially and circularly connected with a first pre-lithiation zone (3) and a second pre-lithiation zone (4);
Wherein, along the thickness direction of the negative electrode sheet (9), the thickness dimension of the second pre-lithiation region (4) is larger than the thickness dimension of the first pre-lithiation region (3);
The second pre-lithiation zone (4) is positioned at a bending section (8) of the winding core; the first prelithiation zone (3) is located in a straight section (7) of the winding core.
2. The winding core according to claim 1, characterized in that the second prelithiation zone (4) has a width dimension along the long axis direction of the negative electrode sheet (9);
The bending section (8) comprises a plurality of bending section layers; the width dimension of the second prelithiation zone (4) on the plurality of folded segment layers increases progressively in the direction from the center of the winding core to the edge of the winding core.
3. The winding core according to claim 1, characterized in that the second prelithiation zone (4) has a width dimension along the long axis direction of the negative electrode sheet (9);
The bending section (8) comprises a plurality of bending section layers; the width dimensions of the second prelithiation areas (4) on the plurality of folded segment layers are the same along the direction from the center of the winding core to the edge of the winding core.
4. The winding core according to claim 1, characterized in that the second prelithiation zone (4) has a length dimension along the short axis direction of the negative electrode sheet (9); the length dimension of the second pre-lithiation zone (4) is the same as the width dimension of the negative electrode sheet (9).
5. The winding core according to claim 1, characterized in that the thickness dimension of the first pre-lithiated region (3) is H1 and the thickness dimension of the second pre-lithiated region (4) is H2 in the thickness direction of the negative electrode sheet (9);
HI. H2 satisfies: h2 = (1.01-4.0) H1.
6. The winding core according to claim 1, wherein,
Along the long axis direction of the negative electrode sheet (9), the first pre-lithiation zone (3) comprises a first pre-lithiation substance and a first gap which are sequentially and circularly connected;
Along the long axis direction of the negative electrode sheet (9), the second pre-lithiation zone (4) comprises a second pre-lithiation substance and a second gap which are sequentially and circularly connected.
7. A winding core according to claim 6, characterized in that the area ratio of the second pre-lithiated substance to the second pre-lithiated region (4) is greater than the area ratio of the first pre-lithiated substance to the first pre-lithiated region (3).
8. The winding core according to claim 7, wherein,
The area ratio of the first pre-lithiation substance to the first pre-lithiation region (3) is S1;
The area ratio of the second pre-lithiation substance to the second pre-lithiation region (4) is S2;
s1 and S2 satisfy the following conditions: s2= (1.05-4.3) S1.
9. The winding core according to any one of claims 1 to 8, characterized in that the negative active coating (2) is provided with a first prelithiation layer (5); a second pre-lithiation layer (6) is arranged on the first pre-lithiation layer (5) on at least one side surface of the negative electrode plate (9) at intervals;
And one side of the second pre-lithiation layer (6) is arranged on the negative electrode sheet (9), the second pre-lithiation region (4) is formed in the overlapping area of the second pre-lithiation layer (6) and the first pre-lithiation layer (5), and the first pre-lithiation region (3) is formed in the area where the first pre-lithiation layer (5) is not overlapped with the second pre-lithiation layer (6).
10. A battery comprising a winding core according to any one of claims 1-9.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322621098.XU CN221201269U (en) | 2023-09-26 | 2023-09-26 | Reel core and battery |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322621098.XU CN221201269U (en) | 2023-09-26 | 2023-09-26 | Reel core and battery |
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| CN221201269U true CN221201269U (en) | 2024-06-21 |
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