CN115498274A - Preparation method of battery core with electrolyte rapid infiltration structure and battery - Google Patents
Preparation method of battery core with electrolyte rapid infiltration structure and battery Download PDFInfo
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- CN115498274A CN115498274A CN202211158738.1A CN202211158738A CN115498274A CN 115498274 A CN115498274 A CN 115498274A CN 202211158738 A CN202211158738 A CN 202211158738A CN 115498274 A CN115498274 A CN 115498274A
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- 239000003792 electrolyte Substances 0.000 title claims abstract description 24
- 230000008595 infiltration Effects 0.000 title claims abstract description 19
- 238000001764 infiltration Methods 0.000 title claims abstract description 19
- 238000002360 preparation method Methods 0.000 title claims abstract description 10
- 238000000034 method Methods 0.000 claims abstract description 23
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 17
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 17
- 238000013329 compounding Methods 0.000 claims abstract description 7
- 239000007773 negative electrode material Substances 0.000 claims description 8
- 239000007774 positive electrode material Substances 0.000 claims description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 3
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 claims description 3
- 239000010439 graphite Substances 0.000 claims description 3
- 229910002804 graphite Inorganic materials 0.000 claims description 3
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 claims description 3
- 239000000463 material Substances 0.000 claims description 3
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 229910000314 transition metal oxide Inorganic materials 0.000 claims description 3
- 229910052751 metal Inorganic materials 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims description 2
- 230000007547 defect Effects 0.000 abstract description 3
- 210000004027 cell Anatomy 0.000 description 37
- 230000000052 comparative effect Effects 0.000 description 14
- 238000004080 punching Methods 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 6
- 238000013461 design Methods 0.000 description 5
- 238000010586 diagram Methods 0.000 description 4
- 239000011267 electrode slurry Substances 0.000 description 4
- 230000014759 maintenance of location Effects 0.000 description 4
- 239000000203 mixture Substances 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000003475 lamination Methods 0.000 description 2
- 229910001416 lithium ion Inorganic materials 0.000 description 2
- 238000003825 pressing Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000009736 wetting Methods 0.000 description 2
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 1
- 239000002033 PVDF binder Substances 0.000 description 1
- 229920002125 Sokalan® Polymers 0.000 description 1
- 239000006183 anode active material Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 229910021641 deionized water Inorganic materials 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000004806 packaging method and process Methods 0.000 description 1
- 239000004584 polyacrylic acid Substances 0.000 description 1
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 1
- 238000009715 pressure infiltration Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 229920003048 styrene butadiene rubber Polymers 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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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
- H01M10/052—Li-accumulators
-
- 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
-
- 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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- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
The application provides a battery core preparation method with an electrolyte rapid infiltration structure and a battery. The preparation method of the battery cell comprises the following steps: s1, providing a positive plate, a diaphragm and a negative plate; s2, respectively forming holes on the positive plate and the negative plate to respectively form a first through hole and a second through hole; and S3, sequentially superposing the positive plate in the step S2, the diaphragm in the step S1 and the negative plate in the step S2, and carrying out thermal compounding to form the dry cell, wherein the area of the first through hole is larger than that of the second through hole, and the first through hole and the second through hole are eccentrically arranged. According to the method provided by the embodiment of the invention, the size and the position of each through hole are designed, so that the area of the positive plate after the hole is opened is still smaller than that of the negative plate, more lithium embedding positions are arranged on the negative plate, the defect that the mechanical property of the battery is poor due to the hole opening in the axial direction of the battery can be effectively improved, and the performance and the mechanical strength of the battery are improved.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a battery core preparation method with an electrolyte rapid infiltration structure and a battery.
Background
With the development of science and technology, the requirements on the performance and the service life of the lithium battery are higher and higher, and besides the quality problems of pole pieces and raw materials, whether the electrolyte is fully soaked and uniformly dispersed in the lithium battery is also important. The lithium ion transmission medium can be used as a homogeneous lithium ion transmission medium only when the electrolyte is fully infiltrated into the positive and negative pole pieces and the diaphragm, and if the electrolyte is not fully infiltrated, the lithium battery can have a phenomenon of partial lack of electrolyte in the middle and later stages of the cycle, even in the initial stage, so that the cycle life of the lithium battery is influenced.
In the prior art, in order to ensure that a pole core is not loose and a positive pole, a negative pole and a diaphragm are not staggered in a production process, dry pressing is carried out on a laminated core after lamination to form a battery core, and particularly for a power type lithium battery, the surface density of the positive pole and the negative pole is high, the compaction density is high, the steric hindrance of electrolyte infiltration is large, and the uniform infiltration of the battery core is not facilitated.
In order to solve the problem, methods such as vacuum injection, high-pressure infiltration and the like can be adopted to improve the infiltration performance of the electrolyte, but the method has higher production difficulty and high production cost.
Disclosure of Invention
In view of this, the present invention provides a method for preparing a battery cell, which can improve the wettability of an electrolyte in the battery.
The invention also provides a battery.
The preparation method of the battery cell with the electrolyte rapid infiltration structure according to the embodiment of the first aspect of the invention comprises the following steps:
s1, providing a positive plate, a diaphragm and a negative plate;
s2, respectively forming holes in the positive plate and the negative plate to respectively form a first through hole and a second through hole;
s3, sequentially superposing the positive plate in the step S2, the diaphragm in the step S1 and the negative plate in the step S2, and compounding to form a dry cell,
the area of the first through hole is larger than that of the second through hole, and the first through hole and the second through hole are arranged eccentrically to each other.
Further, in the step S2, the first through hole and the second through hole are independently formed in a circular shape, a triangular shape, a square shape, a polygonal shape, or a special shape.
Further, in the step S2, a distance from any center of the first through hole and the second through hole to an edge of the layer where the center is located is greater than or equal to 0.1mm.
Further, the step S3 includes:
s31, sequentially overlapping the perforated positive plate, the perforated diaphragm and the perforated negative plate to form an electrode group, wherein the first through hole and the second through hole in each electrode group are eccentrically arranged;
s32, stacking a plurality of electrode groups with the separator interposed therebetween;
and S33, carrying out thermal compounding on the stacked electrode groups to form the dry cell.
Further, in step S31, the second through hole of each electrode group is located in the first through hole in a projection in the stacking direction.
Furthermore, the centers of the through holes in the battery core are sequentially connected to form a sawtooth line, an oblique line or an unordered broken line.
Further, in the step S32, the center of the first via hole in each of the electrode groups is offset by the same distance with respect to the center of the second via hole in the first/second direction, and the offset distance Δ satisfies formula 1):
wherein x is a larger vertical distance from the center of the first through hole/the second through hole to the edge of a pole piece in the first direction/the second direction, k is a ratio of a smaller vertical distance from the center of the first through hole/the second through hole to the edge of the pole piece in the first direction/the second direction to a distance from the two edges of the pole piece in the first direction/the second direction, m is the number of layers of negative pole pieces in the electrode group, and n is the number of layers of positive pole pieces in the electrode group; and the offset distance Δ satisfies formula 2):
Δ＜R 2)
wherein R is the distance between the center of the second through hole and the edge of the second through hole;
the first direction and the second direction are along the width direction and the length direction of the pole piece.
Further, in step S33, in two adjacent electrode groups, the deviation direction of the connecting line between the center of the first through hole and the center of the second through hole is opposite.
The battery according to the second aspect of the embodiment of the invention comprises a plurality of battery cells prepared by the method.
Further, a positive active layer is formed on a positive plate of the battery, the positive active layer contains a positive active material, and the positive active material is selected from one or more of lithium iron phosphate, lithium cobaltate, lithium manganate and ternary materials;
a negative electrode active layer is formed on a negative electrode sheet of the battery, the negative electrode active layer contains a negative electrode active material, and the negative electrode active material is selected from one or more of graphite, silicon base, transition metal oxide and metal lithium.
The technical scheme of the invention has at least one of the following beneficial effects:
according to the preparation method of the battery cell with the electrolyte rapid infiltration structure, the positive plate and the negative plate are respectively provided with the holes to respectively form the first through hole and the second through hole, and the first through hole and the second through hole are sequentially overlapped and then pressed to form the battery cell, so that the electrolyte can be infiltrated to the corresponding positive plate and the negative plate through the first through hole and the second through hole, the infiltration path of the electrolyte is shortened, the infiltration speed is improved, the area of the first through hole is larger than that of the second through hole, and the first through hole and the second through hole are eccentrically arranged with each other, namely, the size of each through hole is designed, the area of the first through hole formed in the positive plate is larger than that of the second through hole formed in the negative plate, so that the area of the positive plate after the holes are formed can be still smaller than that of the negative plate, more lithium embedding positions are formed in the negative plate, lithium separation caused by lithium separation during charging is avoided, and the performance and the service life of the battery are improved; through designing the positions of the through holes, namely the first through hole and the second through hole are eccentrically arranged, compared with a through hole, the defect that the mechanical property of the battery is poor due to the fact that holes are formed in the axial direction of the battery can be effectively overcome, and the mechanical strength of the battery is improved.
Drawings
Fig. 1 is a flowchart of a method for manufacturing a battery cell according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a battery cell according to an embodiment of the present invention;
fig. 3 is a schematic structural diagram of a battery cell according to another embodiment of the present invention;
fig. 4 is a schematic diagram of a positional relationship between through holes in a projection of an electrode group in a battery cell in a stacking direction according to an embodiment of the present invention;
fig. 5 is a schematic diagram illustrating a position of a first through hole of an electrode assembly according to an embodiment of the invention.
Reference numerals: 100. a positive plate; 110. a first through hole; 200. a diaphragm; 300. a negative plate; 310. a second via.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the described embodiments of the invention, are within the scope of the invention.
Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention belongs. The use of "first," "second," and the like, herein does not denote any order, quantity, or importance, but rather the terms "first," "second," and the like are used to distinguish one element from another. Also, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one. The terms "connected" or "coupled" and the like are not restricted to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "upper", "lower", "left", "right", and the like are used merely to indicate relative positional relationships, and when the absolute position of the object being described is changed, the relative positional relationships are changed accordingly.
First, a method for manufacturing a battery cell with a rapid electrolyte infiltration structure according to an embodiment of the first aspect of the present invention is specifically described below.
As shown in fig. 1, the method for preparing a battery cell according to the embodiment of the present invention includes the following steps:
s1, a positive electrode sheet 100, a separator 200, and a negative electrode sheet 300 are provided.
The positive plate 100, the diaphragm 200 and the negative plate 300 can be prepared by a conventional preparation method, wherein a positive active layer is formed on the positive plate 100, the positive active layer contains a positive active material, and the positive active material is selected from one or more of lithium iron phosphate, lithium cobaltate, lithium manganate and ternary materials; the negative electrode sheet 300 has a negative electrode active layer formed thereon, and the negative electrode active layer contains a negative electrode active material selected from one or more of graphite, silicon, transition metal oxide, and metallic lithium.
S2, holes are respectively formed in the positive plate 100 and the negative plate 300 to respectively form a first through hole 110 and a second through hole 310, the area of the first through hole 110 is larger than that of the second through hole 310, and the first through hole 110 and the second through hole 310 are arranged in an eccentric mode.
And S3, sequentially overlapping the positive plate 100 in the step S2, the diaphragm 200 in the step S1 and the negative plate 300 in the step S2, and compounding to form the dry battery core.
That is to say, firstly, the first through hole 110 and the second through hole 310 are respectively formed by respectively forming holes on the positive plate 100 and the negative plate 300, then the first through hole 110 and the second through hole 310 are eccentrically arranged with each other during lamination, finally, the dry cell is formed by pressing, and then when the dry cell is injected, the electrolyte can be infiltrated into each layer of the positive plate 100 and the negative plate 300 corresponding to the through holes through the first through hole 110 and the second through hole 310, so that the infiltration path of the electrolyte is shortened, and the infiltration speed is increased.
And, the area of the first via 110 in the cell is larger than the area of the second via 310. That is to say, through designing the size of each through-hole for the first through-hole 110 area that offers on positive plate 100 > second through-hole 310 area on the negative plate 300, thereby can guarantee that the area of positive plate 100 after the trompil still is less than the area of negative plate 300, make to have more lithium-inserting positions on the negative plate 300, can avoid analyzing lithium and the lithium dendrite short circuit that leads to when charging, improve the performance and the life-span of battery.
Moreover, by designing the positions of the through holes, that is, the first through hole 110 and the second through hole 310 are arranged eccentrically to each other, that is, by adjusting the transverse position between the positive plate 100 and the negative plate 300 in the process of stacking the positive plate 100, the separator 200, and the negative plate 300 in sequence, the first through hole 110 on the positive plate 100 and the second through hole 310 on the negative plate 300 are arranged eccentrically to each other, compared with a through hole, the defect of poor mechanical performance of the battery caused by the hole opening in the axial direction of the battery can be effectively improved, and the mechanical strength of the battery is improved.
In addition to the above design of the sizes of the first through hole 110 and the second through hole 310, the shape and the positional relationship of the through holes may be further limited in step S2 to further improve the mechanical strength of the battery.
As for the shape of each through hole, corresponding to step S2, the first through hole 110 and the second through hole 310 are each independently formed in a circular shape, a triangular shape, a square shape, a polygonal shape, or a special shape. That is, the shapes of the first through hole 110 and the second through hole 310 may be determined according to the difficulty of machining and the shape of the tool bit in the actual punching process, so as to improve the production efficiency.
Regarding the positional relationship of each through hole in the layer where each through hole is located, the distance from any center of the first through hole 110 and the second through hole 310 to the edge of the layer where each through hole is located in step S2 is greater than or equal to 0.1mm. That is, the distance from the center of the first through hole 110 to the edge of the positive plate 100 and the distance from the second through hole 310 to the edge of the negative plate 300 are both greater than or equal to 0.1mm, so as to ensure the mechanical performance of the battery. As a preferred embodiment, the distance from the center of the first through hole 110 to the edge of the positive electrode tab 100 and the distance from the second through hole 310 to the edge of the negative electrode tab 300 may also be greater than or equal to 0.5mm, so as to further improve the mechanical strength of the battery.
Further, as shown in fig. 2 and 3, the negative electrode sheet 300, the separator 200 and the positive electrode sheet 100 are an electrode group, and the battery cell includes a plurality of electrode groups connected in series, wherein two adjacent electrode groups are separated by the separator 200, and the first through hole 110 and the second through hole 310 in each electrode group are arranged eccentrically to each other. That is, on the basis of the eccentric arrangement of each through hole, the electrode group can be kept to have high mechanical strength as much as possible, and further, each through hole in each electrode group is eccentrically arranged, so that the battery cell obtained by connecting a plurality of electrode groups in series also keeps high mechanical strength.
Furthermore, the centers of all the through holes in the battery cell are sequentially connected to form a sawtooth line, an oblique line or an unordered broken line. That is, the eccentric distance, the eccentric direction of the center of each through hole may be the same or different from one layer to another.
Specifically, when the eccentricity directions of two adjacent electrode groups are different, the centers of the through holes in the battery cell are connected in sequence, so that a sawtooth line as shown in fig. 2 can be formed; when the eccentric directions of the through holes are the same and the eccentric distances are the same between two adjacent electrode groups, the centers of the through holes in the battery cell are sequentially connected to form oblique lines as shown in fig. 3; when the eccentric distance and the eccentric direction of each through hole in two adjacent electrode groups are randomly the same or different, the centers of the through holes in the battery cell are sequentially connected to form a disordered fold line (not shown in the figure).
In some embodiments, in each electrode group, the center of the first through hole 110 is offset from the center of the second through hole 310 by the same distance in the first direction/the second direction, which is the width direction and the length direction along the pole piece. That is, in each electrode group of the battery cell, the center of the first through hole 110 is equidistantly offset from the center of the second through hole 310. The structure is convenient for controlling the processing of punching. Specifically, when the punching process is performed, the offset distance Δ of the center of the first through hole 110 from the center of the second through hole 310 satisfies formula 1):
wherein x is the larger vertical distance from the center of the first through hole 110/the second through hole 310 to the edge of the pole piece in the first direction/the second direction, k is the ratio of the smaller vertical distance from the center of the first through hole 110/the second through hole 310 to the edge of the pole piece in the first direction/the second direction to the distance from the two edges of the pole piece in the first direction/the second direction, m is the number of layers of the negative pole piece 300 in the electrode group, and n is the number of layers of the positive pole piece 100 in the electrode group. And the offset distance Δ satisfies formula 2): Δ < R, where R is the distance from the center of the second via 310 to the edge of the via. That is to say, as long as the number of electrode groups in the battery cell and the overall eccentric distance are determined, the plane coordinates of the centers of the first through hole 110 and the second through hole 310 of each layer in the first direction and the second direction can be calculated through the above formulas 1) and 2), and then the electrolyte can be fully infiltrated among the layers after the punching process by the punching device, so that the performance and the service life of the battery are further improved.
Specifically, as shown in fig. 5, taking the example of calculating the offset distance of the centers of two through holes in the first direction (corresponding to the up-down direction in fig. 5), assuming that the distance between the two edges of the pole piece in the first direction is 5, and the vertical distance y that the center of the first through hole 110 of the first layer positive pole piece is smaller from the edge in the first direction is 2, the vertical distance x that the center of the first through hole 110 of the first layer positive pole piece is larger from the edge of the pole piece in the first direction is 3, so that for the second through hole 310 of the second layer negative pole piece, the ratio of the vertical distance that the center of the first through hole 110 is smaller from the edge of the pole piece in the first direction to the distance z that the center of the pole piece is from the edge in the first direction is: k =2/5=0.4, the number of positive electrode sheets n in the electrode group is 1, the number of negative electrode sheets m is 1, and the deviation distance Δ =0.4 × 3/2=0.6 from the center of the first through hole of the first positive electrode sheet in the first direction, that is, the coordinate of the center of the second through hole 310 of the second negative electrode sheet in the first direction is 2.6 =2.6, that is, the center of the second through hole 310 of the second negative electrode sheet in the first direction is 2.4 away from the edge, and the larger vertical distance x is 2.6, then, for the first through hole of the positive electrode sheet in the third layer, k =2.4/5=0.48, that is, the number n of positive electrode sheets in the electrode sheet group is 2, the number m of negative electrode sheets is 1, the deviation distance Δ =0.48 = 0.6/016 from the center of the second through hole of the negative electrode sheet in the first layer is 2.416, and the distance Δ 983.416 from the center of the first through hole of the negative electrode sheet in the first direction is 2.6.
According to the design, the deviation directions of connecting lines of the centers of the first through holes 110 and the centers of the second through holes 310 in two adjacent electrode groups are the same, and after the punching processing of the punching device, the centers of the through holes are connected in sequence to form oblique lines.
In some embodiments, the offset direction of the line connecting the center of the first through hole 110 and the center of the second through hole 310 in two adjacent electrode sets is opposite. That is, on the basis of the above design, the deviation directions of the connecting lines of the centers of the first through hole 110 and the second through hole 310 adjacent to each other between two adjacent electrode groups of the battery cell are opposite, so that the centers of the through holes are sequentially connected to form a zigzag line or a disordered zigzag line, thereby fully wetting the electrolyte among the layers, and further improving the performance and the service life of the battery.
As a specific example, taking fig. 2 as an example, in each electrode group, the center of the first through hole 110 and the center of the second through hole 310 are on a diagonal line (i.e., the eccentric direction between the layers is the same, and the eccentric distance is also the same), and the diagonal line has different inclination directions between two adjacent electrode groups (i.e., the eccentric direction between the electrode groups is different), thereby forming a regular zigzag line.
After each layer is perforated, the perforated positive plate, the diaphragm and the perforated negative plate are sequentially overlapped and then compounded to form a dry battery core, namely step S3.
In some embodiments of the present application, step S3 may include:
s31, respectively stacking the perforated positive electrode sheet 100, the diaphragm 200 and the perforated negative electrode sheet 300 in sequence to form electrode groups, wherein the first through hole 110 and the second through hole 310 in each electrode group are eccentrically arranged;
s32, stacking a plurality of electrode groups with a separator 200 interposed therebetween;
and S33, thermally compounding the plurality of superposed electrode groups to form a dry battery core.
That is, in step S31, the positive electrode sheet 100, the separator 200, and the negative electrode sheet 300 are sequentially stacked, and by performing a corresponding design of the punching position in the punching stage (step S2), or by adjusting the lateral position between the positive electrode sheet 100 and the negative electrode sheet 300 during the stacking process, the first through-hole 110 of the positive electrode sheet 100 and the second through-hole 310 of the negative electrode sheet 300 may be eccentrically disposed from each other, thereby further improving the mechanical strength of the electrode group.
Further, in step S32, the second through hole 310 of each electrode group is located within the first through hole 110 in projection in the stacking direction. As shown in fig. 4, the area of the first through-hole 110>On the basis of the area of the second through hole 310, the first through hole 110 and the second through hole 310 correspond to two circular holes gradually decreasing from the outside to the inside in fig. 4, and under the projection in the stacking direction of any one electrode group, any point O in the overlapped area of the first through hole 110 and the second through hole 310 is arbitrarily taken and extends from the point O to the edge of the negative electrode sheet 300 and the line segment L at the edge of the positive electrode sheet 100 along any direction 1 、L 2 Then L is 1 Length of (2) < L 2 Length of (d). That is, the centers of the respective through holes of each electrode group are eccentrically arranged with respect to each other by designing the positions of the respective through holes.
It should be noted that the relative positions of the holes may be realized by drilling holes at corresponding positions in the punching stage after designing in advance, or may be realized by adjusting the transverse positions of the layers during stacking in step S3 and performing corresponding cutting after stacking.
And after obtaining the dry battery cell, injecting liquid, packaging and the like to obtain the battery cell for the battery.
The battery as an embodiment of the second aspect of the invention comprises a plurality of battery cells obtained by the preparation method of the first aspect. That is to say, the battery cell is obtained by the method for preparing the battery cell with the electrolyte rapid infiltration structure according to the embodiment of the first aspect, and then the battery cells are connected in series to form the battery. Since the battery cell of any of the above embodiments is provided, the battery also has similar effects to the battery cell, and a detailed description thereof is omitted here.
In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in further detail below.
First, the composition ratios of the positive electrode slurry and the negative electrode slurry, the ratio of the negative electrode active material to the negative electrode slurry, and the structures of the first through-hole 110 and the second through-hole 310, the shapes, sizes, offset distances Δ, and offset directions of the respective through-holes of examples 1 to 24 and comparative examples 1 to 3 will be described in detail.
Firstly, adding 95wt% of positive electrode active material, 2wt% of superconducting carbon and 3wt% of polyvinylidene fluoride into N-methyl pyrrolidone, and uniformly stirring to form positive electrode slurry; adding 90wt% of negative active material, 2wt% of superconducting carbon, 7wt% of polyacrylic acid and 1wt% of styrene butadiene rubber into deionized water, and uniformly stirring to form negative slurry.
Next, table 1 shows the proportions of the anode active materials in the anode pastes of examples 1 to 24 and comparative examples 1 to 3, and the structures of the first through-holes 110 and the second through-holes 310 of examples 1 to 24, the shapes, sizes, offset distances, and offset directions of the respective through-holes.
TABLE 1 negative electrode compositions and respective through-hole structure designs of examples 1 to 24 and comparative examples 1 to 3
The cells of examples 1 to 24 and comparative examples 1 to 3 were prepared according to the process parameters in table 1, and then assembled into the batteries of examples 1 to 24 and comparative examples 1 to 3 by stacking the cells, and the batteries of examples 1 to 24 and comparative examples 1 to 3 were subjected to the internal resistance test. The results are shown in Table 2.
TABLE 2 internal resistance of the batteries of examples 1-24 and comparative examples 1-3
| Number of | Internal resistance/m omega | Numbering | Internal resistance/m omega | Numbering | Internal resistance/m omega |
| Example 1 | 43 | Example 2 | 36.2 | Example 3 | 24 |
| Example 4 | 41.5 | Example 5 | 35 | Example 6 | 23.7 |
| Example 7 | 40.9 | Example 8 | 34.3 | Example 9 | 22.5 |
| Example 10 | 39.5 | Example 11 | 33 | Example 12 | 21 |
| Example 13 | 43.6 | Example 14 | 35.8 | Example 15 | 23.8 |
| Example 16 | 41.8 | Example 17 | 34.9 | Example 18 | 23.5 |
| Example 19 | 40.7 | Example 20 | 33.6 | Example 21 | 22 |
| Example 22 | 39.9 | Example 23 | 32 | Example 24 | 21.5 |
| Comparative example 1 | 45 | Comparative example 2 | 38 | Comparative example 3 | 25 |
As can be seen from tables 1 to 2, the internal resistances of the batteries of examples 1 to 24 of the present invention were significantly reduced as compared with the batteries of comparative examples 1 to 3, that is, the internal resistances of the batteries of examples 1 to 24 of the present invention were significantly lower than those of the comparative examples of the same composition for different negative electrode active material ratios. The first through hole 110 and the second through hole 310 formed on the positive plate 100 and the negative plate 300 in the battery cell enable the electrolyte to be infiltrated into each layer of the battery cell through each through hole, so that the infiltration path of the electrolyte is shortened, the infiltration speed is increased, the infiltration effect is remarkably improved, and meanwhile, the mechanical strength of the battery is improved due to the eccentric arrangement of the first through hole 110 and the second through hole 310.
Then, the normal-temperature long-cycle capacity retention rate of the battery is measured under the conditions that the charging and discharging rates are 1C and 1C respectively at normal temperature and 800 times of charging and discharging cycles; the high-temperature long-cycle capacity retention rate of the battery was measured under the conditions of 55 ℃ and charge and discharge rates of 1C and 1c, respectively, and 600 charge and discharge cycles, and the results are shown in table 3 below.
TABLE 3 Battery capacity retention after ordinary-temperature and high-temperature cycles of examples and comparative examples
As can be seen from table 3, the batteries of examples 3, 6, 9, 12, 15, 18, 21, and 24 according to the present invention have improved capacity retention rates under the conditions of charge and discharge rates of 1C and 1C, respectively, and charge and discharge cycles of 800 times at room temperature and 600 times at 55 ℃, respectively, compared to the battery of comparative example 3, which indicates that good wetting property is maintained and no local lean phenomenon is generated inside the battery in the middle and later stages of the charge and discharge cycles.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (10)
1. A preparation method of a battery cell with an electrolyte rapid infiltration structure is characterized by comprising the following steps:
s1, providing a positive plate, a diaphragm and a negative plate;
s2, respectively forming holes in the positive plate and the negative plate to respectively form a first through hole and a second through hole;
s3, sequentially superposing the positive plate in the step S2, the diaphragm in the step S1 and the negative plate in the step S2, and compounding to form a dry battery core,
the area of the first through hole is larger than that of the second through hole, and the first through hole and the second through hole are arranged eccentrically to each other.
2. The method according to claim 1, wherein in the step S2, the first through hole and the second through hole are each independently formed in a circular shape, a triangular shape, a square shape, a polygonal shape, or a special shape.
3. The method according to claim 1, wherein in step S2, a distance from any center of the first through hole and the second through hole to an edge of a layer where the first through hole and the second through hole are located is greater than or equal to 0.1mm.
4. The method according to claim 1, wherein the step S3 comprises:
s31, sequentially overlapping the perforated positive plate, the perforated diaphragm and the perforated negative plate to form an electrode group, wherein the first through hole and the second through hole in each electrode group are eccentrically arranged;
s32, stacking a plurality of electrode groups with the separator interposed therebetween;
and S33, carrying out thermal compounding on the stacked electrode groups to form the dry cell.
5. The method of claim 4, wherein the second via of each of the electrode sets is located within the first via as projected in a stacking direction.
6. The method of claim 4, wherein centers of the through holes in the battery cells are sequentially connected to form a zigzag line, an oblique line or a disordered fold line.
7. The method according to claim 4, wherein the centers of the first through holes in each of the electrode groups are offset from the center of the second through hole by the same offset distance in the first/second direction, and the offset distance Δ satisfies formula 1):
wherein x is a larger vertical distance from the center of the first through hole/the second through hole to the edge of a pole piece in the first direction/the second direction, k is a ratio of a smaller vertical distance from the center of the first through hole/the second through hole to the edge of the pole piece in the first direction/the second direction to a distance between two edges of the pole piece in the first direction/the second direction, m is the number of layers of negative pole pieces in the electrode group, and n is the number of layers of positive pole pieces in the electrode group;
and the offset distance Δ satisfies formula 2):
Δ＜R 2)
wherein R is the distance between the center of the second through hole and the edge of the second through hole;
the first direction and the second direction are along the width direction and the length direction of the pole piece.
8. The method according to claim 4, wherein in step S33, in two adjacent electrode sets, the deviation directions of the connecting lines of the centers of the first through holes and the centers of the second through holes are opposite.
9. A battery, comprising: a plurality of cells prepared by the method of any of claims 1 to 8.
10. The battery according to claim 9, wherein a positive electrode active layer is formed on the positive electrode sheet of the battery, the positive electrode active layer contains a positive electrode active material, and the positive electrode active material is selected from one or more of lithium iron phosphate, lithium cobaltate, lithium manganate and ternary materials;
a negative electrode active layer is formed on a negative electrode sheet of the battery, the negative electrode active layer contains a negative electrode active material, and the negative electrode active material is selected from one or more of graphite, silicon base, transition metal oxide and metal lithium.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116231103A (en) * | 2023-03-03 | 2023-06-06 | 深圳市神通天下科技有限公司 | Laminated lithium ion battery and preparation method thereof |
| CN116565128A (en) * | 2023-07-07 | 2023-08-08 | 宁德新能源科技有限公司 | Electrochemical device and electric equipment |
| CN116722102A (en) * | 2023-08-07 | 2023-09-08 | 宁德时代新能源科技股份有限公司 | Positive electrode plate, preparation method, battery cell, battery and electricity utilization device |
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2022
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116231103A (en) * | 2023-03-03 | 2023-06-06 | 深圳市神通天下科技有限公司 | Laminated lithium ion battery and preparation method thereof |
| CN116565128A (en) * | 2023-07-07 | 2023-08-08 | 宁德新能源科技有限公司 | Electrochemical device and electric equipment |
| CN116565128B (en) * | 2023-07-07 | 2023-11-03 | 宁德新能源科技有限公司 | Electrochemical device and electric equipment |
| CN116722102A (en) * | 2023-08-07 | 2023-09-08 | 宁德时代新能源科技股份有限公司 | Positive electrode plate, preparation method, battery cell, battery and electricity utilization device |
| CN116722102B (en) * | 2023-08-07 | 2024-05-28 | 宁德时代新能源科技股份有限公司 | Positive electrode plate, preparation method, battery cell, battery and electricity utilization device |
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