CN114678535A - Lithium battery structure and battery pack - Google Patents

Lithium battery structure and battery pack Download PDF

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Publication number
CN114678535A
CN114678535A CN202011552401.XA CN202011552401A CN114678535A CN 114678535 A CN114678535 A CN 114678535A CN 202011552401 A CN202011552401 A CN 202011552401A CN 114678535 A CN114678535 A CN 114678535A
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positive
pole piece
negative
lithium battery
current collector
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CN202011552401.XA
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乔璐璐
焦晓朋
江正福
李娜
谭义江
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BYD Co Ltd
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BYD Co Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/02—Electrodes composed of, or comprising, active material
    • H01M4/64—Carriers or collectors
    • H01M4/70—Carriers or collectors characterised by shape or form
    • H01M4/80—Porous plates, e.g. sintered carriers
    • 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
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Abstract

The application discloses lithium battery structure and battery package. The lithium battery structure includes: the repeating unit comprises a negative pole piece and a plurality of positive pole pieces matched with the negative pole piece, and a diaphragm is arranged between the negative pole piece and the positive pole piece adjacent to the negative pole piece; the positive pole piece comprises a positive current collector and a positive active material coated on the surface of the positive current collector, and the positive current collector is a porous electrode current collector; the negative pole piece comprises a negative current collector and a negative active material coated on the surface of the negative current collector; the double-sided surface density of the negative pole piece is A, the specific capacity of the negative active material is B, the double-sided surface density of the positive pole piece is C, the specific capacity of the positive active material is D, the negative excess ratio N/P is E, and the repeated single sheet is made of a material with a specific surface area density of A, a specific surface area density of B, a specific surface area density of C, a specific surface area density of D, a specific surface area density of P, a specific surface area density of N/P and a specific surface area density of EThe number of the positive pole pieces in the element
Figure DDA0002858056070000011
The lithium battery structure can improve the energy density of the lithium battery structure.

Description

Lithium battery structure and battery pack
Technical Field
The application relates to the field of batteries, in particular to a lithium battery structure and a battery pack.
Background
The theoretical capacity of the positive electrode material in the conventional battery is lower, in order to pursue higher energy density, the surface loading capacity of the positive electrode plate gradually reaches the limit value, and the compaction density is continuously improved and is close to the maximum value. The current demand for energy density of batteries is still severe.
Disclosure of Invention
In order to improve the energy density of a lithium battery structure, the present application provides a lithium battery structure comprising: the repeating unit comprises a negative pole piece and a plurality of positive pole pieces matched with the negative pole piece, and a diaphragm is arranged between the negative pole piece and the positive pole piece adjacent to the negative pole piece;
the positive pole piece comprises a positive current collector and a positive active material coated on the surface of the positive current collector, and the positive current collector is a porous electrode current collector;
the negative pole piece comprises a negative current collector and a negative active material coated on the surface of the negative current collector;
the specific capacity of the positive electrode active material is D, the negative electrode excess ratio N/P is E, and the number of the positive electrode plates in the repeating unit is E
Figure BDA0002858056050000011
Optionally, in the repeating unit, the capacity of the negative electrode sheet is greater than the sum of the capacities of the plurality of positive electrode sheets.
Alternatively, the anode excess ratio E ranges from 1.1 to 1.3.
Optionally, the areal density A is in the range of 10mg/cm2-100mg/cm2B is 200mAh/g-500mAh/g, and the double-sided surface density C is 10mg/cm2-60mg/cm2(ii) a D is in the range of 150mAh/g to 300 mAh/g.
Optionally, the positive electrode piece includes a first positive electrode piece, a second positive electrode piece, and a third positive electrode piece that are sequentially disposed.
Optionally, in the repeating unit, the first positive electrode tab, the second positive electrode tab, and the third positive electrode tab are sequentially disposed on two surfaces of the negative electrode tab disposed opposite to each other.
Optionally, a separator is disposed between adjacent positive electrode plates.
Optionally, the lithium battery structure comprises a plurality of the repeating units, and the plurality of the repeating units are longitudinally stacked and/or transversely arranged.
The application also provides a battery pack, the battery pack comprises at least two battery structures, and the battery structures are the lithium battery structures described in the foregoing.
In order to solve the technical problem that exists at present, the application provides a lithium battery structure and battery package, lithium battery structure contain negative pole piece and with the corresponding multi-disc positive pole piece of negative pole piece to positive pole piece adopts porous mass flow body, can realize the free mobility of lithium ion, through increasing negative pole piece coating capacity, can realize that a negative pole piece matches with multi-disc positive pole piece, negative pole piece's two-sided surface density is A, negative pole active material's specific capacity is B, positive pole piece's two-sided surface density is C, positive pole active material's specific capacity is D, negative pole excess ratio N/P is E, in the lithium battery structure with the figure of the multi-disc positive pole piece that negative pole piece matches
Figure BDA0002858056050000021
Under the condition of the same capacity, the use of a negative electrode current collector and a diaphragm can be reduced through the improvement, and the energy density of the lithium battery structure is improved.
Drawings
The following drawings of the present application are included to provide an understanding of the present application. The drawings illustrate embodiments of the application and their description, serve to explain the principles and apparatus of the application. In the drawings, there is shown in the drawings,
fig. 1 is a schematic structural diagram of an arrangement mode of a negative electrode plate of a lithium battery structure and a plurality of positive electrode plates corresponding to the negative electrode plate in an embodiment of the present application;
FIG. 2 is a schematic diagram of a longitudinal stack of lithium battery structures in a battery pack according to the present application;
fig. 3 is a schematic structural diagram of the lateral arrangement of the lithium battery structure in the battery pack of the present application.
Detailed Description
In the following description, numerous specific details are set forth in order to provide a more thorough understanding of the present application. It will be apparent, however, to one skilled in the art, that the present application may be practiced without one or more of these specific details. In other instances, well-known features have not been described in order to avoid obscuring the present application.
It is to be understood that the present application is capable of implementation in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the application to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity. Like reference numerals refer to like elements throughout.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of the associated listed items.
In order to provide a thorough understanding of the present application, a detailed structure will be presented in the following description in order to explain the technical solutions presented in the present application. The following detailed description of the preferred embodiments of the present application, however, will suggest that the present application may have other embodiments in addition to these detailed descriptions.
In order to solve the technical problem of the application, from the perspective of a pole piece, the surface loading capacity of a negative pole piece is still improved due to the fact that the theoretical capacity of a negative pole active material is higher than that of a positive pole active material, and the surface loading capacity of the negative pole piece can be greatly improved along with the rise of a novel negative pole material; however, the space for increasing the surface loading of the positive electrode plate is limited, so that the capacity of the positive electrode plate cannot be matched with the capacity of the negative electrode plate with high surface loading. Thus, to further increase the energy density of a lithium battery structure, the present application provides a lithium battery structure comprising:
the repeating unit comprises a negative pole piece and a plurality of positive pole pieces matched with the negative pole piece, and a diaphragm is arranged between the negative pole piece and the positive pole piece adjacent to the negative pole piece;
the positive pole piece comprises a positive current collector and a positive active material coated on the surface of the positive current collector, and the positive current collector is a porous electrode current collector;
the negative pole piece comprises a negative current collector and a negative active material coated on the surface of the negative current collector;
the specific capacity of the positive electrode active material is D, the negative electrode excess ratio N/P is E, and the number of the positive electrode plates in the repeating unit is E
Figure BDA0002858056050000031
Wherein the negative electrode excess ratio N/P refers to the excess ratio of the capacity of one negative electrode sheet in the repeating unit to the sum of the capacities of all positive electrode sheets in the repeating unit.
In this application, the negative pole piece can be single-sided coating or two-sided coating, for example in a specific embodiment, at the two surfaces that the negative current collector set up relatively coat negative active material, in order to improve the utilization ratio of negative current collector and negative active material, improve the capacity of negative pole piece, and then improve the energy density of lithium battery structure.
The surface density of the two surfaces of the positive pole piece and the negative pole piece is the same when the two surfaces are coated, and the surface density of the two surfaces is twice of that of the single surface. When the positive pole piece and/or the negative pole piece are coated on one side, in the calculation formula of the number n of the positive pole pieces, the single-sided density (which is half of the double-sided density) can be converted into the double-sided density, and the double-sided density is substituted into the formula for calculation, so that the accurate number of the positive pole pieces can be obtained.
For example, in an embodiment of the present application, when the negative electrode sheet is coated on one side, the number of the positive electrode sheets is the number of layers of the coating layer for coating the positive electrode sheet. When the positive pole piece and the negative pole piece are coated on two sides, the number of the positive pole pieces is half of the number of layers of the coating of the positive pole piece.
The capacity of the negative pole piece is increased by increasing the coating amount of the negative pole piece, so that the negative pole piece has the capacity capable of being matched with a plurality of positive pole pieces, namely the surface loading amount of the negative pole piece can reach the maximum value of the coating of the negative pole piece, and the capacity of the negative pole piece can also reach the maximum value; in order to match the capacity of the negative pole piece, a plurality of positive pole pieces need to be prepared with the negative pole piece, the surface loading capacity of each positive pole piece reaches the maximum value of the coating of the positive pole piece, and the capacity of each positive pole piece also can reach the maximum value, so that the sum of the capacities of the positive pole pieces is matched with the capacity of the negative pole piece. In the repeating unit, the use of the negative electrode current collector and the separator is reduced while ensuring the capacity design, so that the energy density of the lithium battery structure can be improved.
Specifically, in the present application, the capacity of the negative electrode plate is matched with the capacities of the plurality of positive electrode plates, so as to improve the energy density of the lithium battery structure.
In order to realize that a negative pole piece matches with the multiple-disc positive pole piece in this application, the positive current collector sets up to porous electrode mass collector, through adopt porous current collector, can realize the free removal of lithium ion to realize lithium battery structure's basic function.
In an embodiment of the present application, the positive electrode current collector may use a porous aluminum foil, but is not limited to this example.
Similarly, the positive electrode sheet may be coated on a single side or coated on both sides, for example, in a specific embodiment, a positive active material is coated on two opposite surfaces of the positive current collector, so as to improve the utilization rate of the positive current collector and the positive active material, improve the capacity of the positive electrode sheet, and further improve the energy density of the lithium battery structure.
The number of the positive pole pieces matched with the negative pole piece in the repeating unit is not set arbitrarily, and the capacity of the positive pole pieces is required to be matched with the capacity of the negative pole piece. The capacity of the positive pole piece is related to the surface density of the positive pole piece and the specific capacity of the positive active material, and the capacity of the negative pole piece is related to the surface density of the positive pole piece and the specific capacity of the negative active material. In addition, the number of the plurality of positive pole pieces is also related to the negative electrode excess ratio N/P of the lithium battery structure.
In an embodiment of the present application, in order to better match the positive electrode plate and the negative electrode plate, the present application further provides a calculation method for calculating the number of the positive electrode plates, taking double-sided coating as an example: the cathode excess ratio N/P is E, and the double-sided surface density of the cathode pole piece is A mg/cm2The specific capacity of the negative active material is B mAh/g, and the density of the two sides of the positive pole piece is C mg/cm2(ii) a The specific capacity of the positive active material is D mAh/g, and the number of the positive pole pieces in the repeating unit
Figure BDA0002858056050000051
By the method, the number of the positive pole pieces can be more accurately determined, so that the positive pole pieces and the negative pole pieces are better matched, and the energy density of the lithium battery structure is further improved.
In an embodiment of the present application, the double-sided surface density a of the negative electrode tab ranges from 10mg/cm2-100mg/cm2Optionally 20mg/cm2-60mg/cm2(ii) a The specific capacity B of the negative active material is in the range of 200mAh/g-500mAh/g, and the density of the two surfaces of the positive pole piece is in the range of 10mg/cm2-60mg/cm2Optionally 20mg/cm2-50mg/cm2(ii) a The specific capacity D of the positive electrode active material is in the range of 150mAh/g-300 mAh/g.
The above numerical range is an example of the present application, is not limited to this example, and may be selected according to actual needs.
In an embodiment of the present application, the positive electrode sheet includes three electrode sheets, for example, the positive electrode sheet includes a first positive electrode sheet, a second positive electrode sheet, and a third positive electrode sheet that are sequentially disposed.
In an embodiment of the present application, adjacent ones of the first positive electrode tab, the second positive electrode tab, and the third positive electrode tab are spaced apart from each other by a separator.
In another embodiment of the present application, no separator may be disposed between the first positive electrode sheet, the second positive electrode sheet, and the third positive electrode sheet.
Further, a separator 105 is provided between the negative electrode tab 101 and the first positive electrode tab 102, as shown in fig. 1.
Wherein the separator comprises any one of a PP-based film, a PE-based film, and a PP/PE-based film.
In an embodiment of this application, negative pole piece includes relative first surface and the second surface that sets up, only when the first surface coating negative pole active material of negative pole piece, set gradually first positive pole piece, second positive pole piece and third positive pole piece on the first surface of negative pole piece.
In another embodiment of the present application, when the first surface and the second surface of the negative electrode tab are both coated with a negative active material, the first positive electrode tab 102, the second positive electrode tab 103, and the third positive electrode tab 104 are symmetrically disposed on the first surface and the second surface of the negative electrode tab 101 from near to far in sequence, as shown in fig. 1.
In an embodiment of the present application, the negative electrode current collector may be a conventional non-porous current collector or a porous current collector, which is not limited herein.
The negative electrode plate and the plurality of positive electrode plates may be horizontally stacked, and the negative electrode plate and the plurality of positive electrode plates may be wound, which is not limited to a specific type.
The cathode active material comprises at least one of lithium cobaltate, lithium manganate, lithium iron phosphate and ternary materials; and/or the negative active material comprises at least one of a graphite material, a hard carbon material, a soft carbon material, a silicon carbon material, and a lithium titanate material.
The positive pole piece and the negative pole piece are prepared by coating positive and negative pole slurry on a positive current collector and a negative current collector.
The positive and negative electrode slurry contains a conductive agent and a binder, wherein the conductive agent comprises at least one of carbon black, ketjen carbon, acetylene black, Super P, graphene, single-walled or multi-walled carbon nanotubes;
the binder comprises at least one of carboxymethyl cellulose, sodium carboxymethyl cellulose, lithium carboxymethyl cellulose, polyacrylic acid, sodium polyacrylate, lithium polyacrylate, styrene-butadiene rubber, polyethylene oxide, polyester, polyamide and polymethyl methacrylate.
The preparation method of the anode slurry comprises the steps of mixing an anode active substance, a conductive agent and a binder according to a certain proportion, adding a proper amount of solvent into a mixer, dissolving the binder in the solvent through high-speed dispersion to obtain the anode slurry, and coating. The preparation of the anode slurry is similar and is not described in detail herein.
The repeating unit comprises a positive electrode lug and a negative electrode lug, the positive electrode lug is connected with the plurality of positive electrode pieces, and the negative electrode lug is connected with the negative electrode pieces. Each repeating unit comprises an independent positive electrode lug and an independent negative electrode lug, and the internal resistance is favorably reduced.
In this application, lithium battery structure includes electric core, and electric core includes at least one repeating unit, wherein, electric core is lamination electricity core or coiling electricity core, and wherein, positive pole piece, negative pole piece and diaphragm stack and form lamination electricity core, and positive pole piece, negative pole piece and diaphragm coiling then form coiling electricity core, thereby improve and set up the use that reduces negative pole mass flow body and diaphragm, further improve lithium battery structure's energy density.
The application provides a lithium battery structure, lithium battery structure contains negative pole piece, a plurality of positive pole pieces such as the first positive pole piece corresponding with this negative pole piece, second positive pole piece, third positive pole piece to and the diaphragm between the adjacent electrode pole piece. The negative pole piece comprises a negative current collector and negative active materials coated on two sides of the negative current collector; the positive pole piece comprises a porous electrode current collector and positive active materials coated on two sides of the porous electrode current collector.
The positive pole piece adopts a porous current collector, so that the lithium ions can freely move, and one negative pole piece can be matched with a plurality of positive pole pieces by increasing the coating amount of the negative pole piece. In addition, the lithium battery structure is provided with a positive electrode tab and a negative electrode tab independently, so that the reduction of internal resistance is facilitated, and the improvement and the arrangement reduce the use of a negative electrode current collector and a diaphragm, so that the energy density of the lithium battery structure is improved.
It should be noted that the lithium battery structure can be used for power batteries, consumer electronics batteries, and energy storage batteries.
The present application further provides a battery pack, the battery pack includes at least two of the foregoing lithium battery structures, the lithium battery structure includes:
the device comprises at least one repeating unit, a plurality of electrode plates and a plurality of insulating layers, wherein the repeating unit comprises a negative electrode plate and a plurality of positive electrode plates, and a diaphragm is arranged between the negative electrode plate and the positive electrode plate;
the positive pole piece comprises a positive current collector and a positive active material coated on the surface of the positive current collector, and the positive current collector is a porous electrode current collector;
the negative pole piece comprises a negative current collector and a negative active material coated on the surface of the negative current collector;
the double-sided surface density of the negative pole piece is A, the specific capacity of the negative active material is B, the double-sided surface density of the positive pole piece is C, the specific capacity of the positive active material is D, the negative excess ratio N/P is E, and the number of the positive pole pieces matched with the negative pole piece in the lithium battery structure
Figure BDA0002858056050000071
In the battery pack, the lithium battery structure comprises battery cells including at least one repeating unit, and the battery cells may be stacked longitudinally as shown in fig. 2, or arranged transversely as shown in fig. 3.
The battery pack has all the advantages of the lithium battery structure due to the adoption of the lithium battery structure, such as: the lithium battery structure comprises a negative pole piece and a plurality of positive pole pieces corresponding to the negative pole piece, the positive pole piece adopts a porous current collector, free movement of lithium ions can be realized, and matching of one negative pole piece and the plurality of positive pole pieces can be realized by increasing the coating amount of the negative pole piece, so that the use of the negative current collector and a diaphragm is reduced, and the energy density of the lithium battery structure is improved.
Example 1
Coating a commercial lithium ion battery LFP positive electrode material on a porous current collector (double-sided coating), wherein the double-sided surface density C is 40mg/cm2The specific capacity D is 150 mAh/g. The graphite negative electrode material is coated on a conventional nonporous current collector (double-sided coating), and the surface density A of the graphite negative electrode material is 55mg/cm2The specific capacity D is 360 mAh/g. The N/P ratio is 1.1, the number of the anode layers corresponding to the cathode
Figure BDA0002858056050000081
And cutting into corresponding sizes after rolling, winding the obtained product in the order of negative electrode/diaphragm/first positive electrode/diaphragm/second positive electrode/diaphragm/third positive electrode to obtain cells containing the repeating units, and longitudinally stacking 36 cells containing the repeating units to obtain the lithium ion secondary battery S1 containing 36 repeating unit chains. The positive and negative pole piece preparation and battery manufacturing methods are well known to those skilled in the art and are not described in detail.
Example 2
A cell was prepared in the same manner as in example 1, and two cells comprising 36 repeating units were arranged laterally together to produce a lithium ion secondary battery S2 comprising a chain of 72 repeating units. The positive and negative pole piece preparation and battery manufacturing methods are well known to those skilled in the art and are not described in detail.
Example 3
Coating the LCO anode material of a commercial lithium ion battery on a porous current collector (double-sided coating), wherein the double-sided surface density C is 40mg/cm2The specific capacity D is 180 mAh/g. The graphite negative electrode material is coated on a conventional nonporous current collector (double-sided coating), and the area density A of the graphite negative electrode material is 66mg/cm2The specific capacity D is 360 mAh/g. The N/P ratio is 1.1, the number of the anode layers corresponding to the cathode
Figure BDA0002858056050000082
A cell containing a repeating unit was fabricated by stacking in the order of negative electrode/separator/first positive electrode/separator/second positive electrode/separator/third positive electrode, and 40 cells containing a repeating unit were stacked longitudinally to fabricate a lithium ion secondary battery S3 containing 40 repeating unit chains. The positive and negative pole piece preparation and battery manufacturing methods are well known to those skilled in the art and are not described in detail.
Example 4
Positive and negative electrode sheets with corresponding sizes are obtained in the manner of example 3, then cells containing the repeating units are manufactured by laminating the negative electrode/the diaphragm/the first positive electrode/the second positive electrode/the third positive electrode in sequence, and 40 cells containing the repeating units are longitudinally stacked to manufacture the lithium ion secondary battery S4 containing 40 repeating unit chains. The positive and negative pole piece preparation and battery manufacturing methods are well known to those skilled in the art and are not described in detail.
Comparative example 1
Coating the LFP anode material of the commercial lithium ion battery on a conventional nonporous current collector (double-sided coating), wherein the double-sided surface density C is 40mg/cm2The specific capacity D is 150 mAh/g. The graphite negative electrode material is coated on a conventional nonporous current collector (double-sided coating), and the surface density A of the graphite negative electrode material is 18.33mg/cm2The specific capacity D is 360 mAh/g. The N/P ratio is 1.1, the capacities of the two are matched, the two are cut into corresponding sizes after rolling, the two are wound into cells according to the sequence of negative electrode/diaphragm/first positive electrode/diaphragm/second positive electrode/diaphragm/third positive electrode, 36 cells are longitudinally stacked, and the lithium ion secondary battery Sc1 is manufactured. The positive and negative pole piece preparation and battery manufacturing methods are well known to those skilled in the art and are not described in detail.
Comparative example 2
Coating the LFP anode material of the commercial lithium ion battery on a conventional nonporous current collector (double-sided coating), wherein the double-sided surface density C is 40mg/cm2The specific capacity D is 150 mAh/g. The graphite negative electrode material is coated on a conventional nonporous current collector (double-sided coating), and the surface density A of the graphite negative electrode material is 18.33mg/cm2The specific capacity D is 360 mAh/g. The N/P ratio is 1.1, the capacities of the two are matched, the two are cut into corresponding sizes after rolling, cells are manufactured by winding according to the sequence of negative electrode/diaphragm/positive electrode/diaphragm, 36 cells are longitudinally stacked, and the lithium ion secondary battery Sc2 is manufactured. The positive and negative pole piece preparation and battery manufacturing methods are well known to those skilled in the art and are not described in detail.
The prepared batteries S1, S2, S3, S4, Sc1 and Sc2 were subjected to normal-temperature electrochemical charge and discharge tests, and the number of cycles was 500.
The cycle test results of the present application are:
Figure BDA0002858056050000091
the table above shows the cycle performance evaluation of the prepared batteries S1, S2, S3, S4 and Sc1 under different multiplying power (0.2C, 1C, 2C, 3C, 5C). As can be seen from the comparison between example 1 and comparative examples 1 and 2, the appropriate capacity design (i.e., satisfying the formula) and the use of porous current collectors still maintain good battery performance with reduced use of negative current collectors (saving space and mass of negative current collectors compared to conventional batteries), so the use of "one negative electrode plate corresponds to multiple positive electrode plates" is effective for increasing the energy density of batteries, and by improving the amount of electricity per unit volume/mass, the volume/mass energy density is increased.
Examples 2 and 3 show that the lithium battery structure containing the repeating unit formed by different stacking modes and different electrode materials can reduce the use of the negative current collector and improve the energy density, and simultaneously ensure the good performance of the battery. Example 4 shows that whether the diaphragm between the positive electrode plates is used or not is flexible, and if the diaphragm is not used, more space or quality can be saved, and the energy density of the lithium battery structure can be effectively improved.
Although the example embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the above-described example embodiments are merely illustrative and are not intended to limit the scope of the present application thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the scope or spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as claimed in the appended claims.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the implementation. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. For example, the above-described device embodiments are merely illustrative, and for example, the division of the units is only one logical functional division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another device, or some features may be omitted, or not executed.
In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the application may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.
Similarly, it should be appreciated that in the description of exemplary embodiments of the present application, various features of the application are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the application and aiding in the understanding of one or more of the various inventive aspects. However, the method of the present application should not be construed to reflect the intent: this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this application.
It will be understood by those skilled in the art that all of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or elements of any method or apparatus so disclosed, may be combined in any combination, except combinations where such features are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.
Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features included in other embodiments, rather than other features, combinations of features of different embodiments are meant to be within the scope of the application and form different embodiments. For example, in the claims, any of the claimed embodiments may be used in any combination.
It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The application may be implemented by means of hardware comprising several distinct elements, and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by one and the same item of hardware. The usage of the words first, second and third, etcetera do not indicate any ordering. These words may be interpreted as names.

Claims (9)

1. A lithium battery cell structure, comprising:
the repeating unit comprises a negative pole piece and a plurality of positive pole pieces matched with the negative pole piece, and a diaphragm is arranged between the negative pole piece and the positive pole piece adjacent to the negative pole piece;
the positive pole piece comprises a positive current collector and a positive active material coated on the surface of the positive current collector, and the positive current collector is a porous electrode current collector;
the negative pole piece comprises a negative current collector and a negative active material coated on the surface of the negative current collector;
the specific capacity of the positive electrode active material is D, the negative electrode excess ratio N/P is E, and the number of the positive electrode plates in the repeating unit is E
Figure FDA0002858056040000011
2. The lithium battery structure of claim 1, wherein the capacity of the negative electrode tab in the repeating unit is greater than the sum of the capacities of the plurality of positive electrode tabs.
3. The lithium battery structure as claimed in claim 1, wherein the negative electrode excess ratio E is in a range of 1.1 to 1.3.
4. The lithium battery structure of claim 1, wherein the double sided areal density a is in the range of 10mg/cm2-100mg/cm2B is 200mAh/g-500mAh/g, and the double-sided surface density C is 10mg/cm2-60mg/cm2(ii) a D is in the range of 150mAh/g to 300 mAh/g.
5. The lithium battery structure as claimed in one of claims 1 to 4, wherein the positive electrode sheet comprises a first positive electrode sheet, a second positive electrode sheet and a third positive electrode sheet which are arranged in sequence.
6. The lithium battery structure according to claim 5, wherein in the repeating unit, the first positive electrode tab, the second positive electrode tab, and the third positive electrode tab are provided in this order on both surfaces where the negative electrode tabs are provided oppositely.
7. The lithium battery structure as claimed in claim 1, wherein a separator is disposed between adjacent positive electrode sheets.
8. The lithium battery structure as claimed in claim 1, wherein the lithium battery structure comprises a plurality of the repeating units, and a plurality of the repeating units are stacked longitudinally and/or arranged laterally.
9. A battery pack, characterized in that the battery pack comprises a lithium battery construction according to one of claims 1 to 8.
CN202011552401.XA 2020-12-24 2020-12-24 Lithium battery structure and battery pack Pending CN114678535A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1874041A (en) * 2005-05-31 2006-12-06 深圳市比克电池有限公司 System and method for designing electricity core of batteries
CN110165289A (en) * 2019-06-21 2019-08-23 中天储能科技有限公司 Lithium ion battery and preparation method
CN210224192U (en) * 2019-06-13 2020-03-31 深圳市深远大科技有限公司 Multi-pole pair cylindrical battery

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1874041A (en) * 2005-05-31 2006-12-06 深圳市比克电池有限公司 System and method for designing electricity core of batteries
CN210224192U (en) * 2019-06-13 2020-03-31 深圳市深远大科技有限公司 Multi-pole pair cylindrical battery
CN110165289A (en) * 2019-06-21 2019-08-23 中天储能科技有限公司 Lithium ion battery and preparation method

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