CN114883576B - Electric core, battery module and battery package - Google Patents

Electric core, battery module and battery package Download PDF

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Publication number
CN114883576B
CN114883576B CN202210503308.2A CN202210503308A CN114883576B CN 114883576 B CN114883576 B CN 114883576B CN 202210503308 A CN202210503308 A CN 202210503308A CN 114883576 B CN114883576 B CN 114883576B
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current collector
thickness
positive
active material
battery
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CN114883576A (en
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赖林聪
王汭
於洪将
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Jiangsu Zenio New Energy Battery Technologies Co Ltd
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Jiangsu Zenergy Battery Technologies 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
    • H01M4/66—Selection of materials
    • H01M4/665—Composites
    • H01M4/667—Composites in the form of layers, e.g. coatings
    • 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
    • H01M10/056—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes
    • H01M10/0564—Accumulators with non-aqueous electrolyte characterised by the materials used as electrolytes, e.g. mixed inorganic/organic electrolytes the electrolyte being constituted of organic materials only
    • H01M10/0566—Liquid materials
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/50—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese
    • H01M4/505—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of manganese of mixed oxides or hydroxides containing manganese for inserting or intercalating light metals, e.g. LiMn2O4 or LiMn2OxFy
    • 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
    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/48—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525—Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • 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
    • H01M2004/021—Physical characteristics, e.g. porosity, surface area
    • 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
    • H01M2004/026—Electrodes composed of, or comprising, active material characterised by the polarity
    • H01M2004/028—Positive electrodes
    • 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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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Inorganic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Composite Materials (AREA)
  • Materials Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Secondary Cells (AREA)
  • Battery Electrode And Active Subsutance (AREA)

Abstract

The invention discloses a battery cell, a battery module and a battery pack, and relates to the technical field of battery cells; the battery cell comprises a shell, a winding core and electrolyte, wherein the winding core and the electrolyte are arranged in the shell, and the winding core is formed by laminating positive plates, isolating films and negative plates; the positive plate comprises a positive current collector and a nickel-containing positive active material coated on the positive current collector, wherein the positive current collector is a composite current collector comprising an insulating support layer and a conductive layer at least arranged on one side of the insulating support layer, the thickness of the insulating support layer is A, the unit is um, the weight percentage of nickel element in the positive active material is I, and the unit is; the thickness of the winding core is C, and the unit is mm; the thickness A of the insulating supporting layer, the weight percentage I of nickel element in the positive electrode active material and the thickness C of the battery core winding core are more than or equal to 0.70 and less than or equal to A/(C/100+I) and less than or equal to 110. The battery cell has the advantages of high energy density and high safety performance.

Description

Electric core, battery module and battery package
Technical Field
The invention relates to the technical field of electric cores, in particular to an electric core, a battery module and a battery pack.
Background
The current positive current collector used by the pole piece of the lithium ion battery core is aluminum foil, and the current collector of the negative electrode is copper foil. Copper foil and aluminum foil have excellent conductivity, but when the cell is damaged by needling, extrusion, etc., the inside of the cell is easily shorted, causing thermal runaway of the cell.
In view of this, the present invention has been made.
Disclosure of Invention
The invention aims to provide a battery cell, a battery module and a battery pack, which have high energy density and high safety performance.
Embodiments of the invention may be implemented as follows:
in a first aspect, the present invention provides a cell comprising:
The lithium ion battery comprises a shell, a winding core and electrolyte, wherein the winding core and the electrolyte are arranged in the shell, and the winding core is formed by laminating positive plates, isolating films and negative plates; the positive plate comprises a positive current collector and a nickel-containing positive active material coated on the positive current collector, wherein the positive current collector is a composite current collector comprising an insulating support layer and a conductive layer at least arranged on one side of the insulating support layer, the thickness of the insulating support layer is A, the unit is um, the weight percentage of nickel element in the positive active material is I, and the unit is; the thickness of the winding core is C, and the unit is mm;
The thickness A of the insulating supporting layer, the weight percentage I of nickel element in the positive electrode active material and the thickness C of the battery core winding core are more than or equal to 0.70 and less than or equal to A/(C/100+I) and less than or equal to 110.
In an alternative embodiment, the thickness A of the insulating support layer, the weight percentage I of nickel element in the positive electrode active material, and the thickness C of the winding core satisfy 2.07.ltoreq.A/(C/100+I.ltoreq.37.5.
In an alternative embodiment, the thickness A of the insulating support layer is in the range of 1-30um;
preferably, the thickness A of the insulating support layer is in the range of 5-15um.
In an alternative embodiment, the weight percentage of nickel element in the positive electrode active material is in the range of 20-60%; preferably, the weight percentage I of the nickel element in the positive electrode active material ranges from 30 to 45%.
In an alternative embodiment, the thickness C of the winding core is in the range of 10-80mm;
preferably, the thickness D of the winding core ranges from 13 to 30mm.
In an alternative embodiment, the active particles of the positive electrode active material are lithium nickel cobalt manganate.
In an alternative embodiment, the negative electrode sheet is copper foil;
Or alternatively
The negative plate comprises a negative current collector and a negative active material coated on the negative current collector, the negative current collector is a composite current collector comprising an insulating support layer and a conductive layer at least arranged on one side of the insulating support layer, the insulating support layer is an organic polymer material layer or a ceramic-doped polymer layer, and the conductive layer is a copper foil layer.
In an alternative embodiment, the composite current collector comprises two conductive layers, wherein the two conductive layers have the same thickness and are respectively arranged at two sides of the insulating support layer.
In a second aspect, the present invention provides a battery module comprising a cell according to any of the preceding embodiments.
In a third aspect, the present invention provides a battery pack comprising the cells of any of the preceding embodiments; or includes the battery module of the foregoing embodiment.
The embodiment of the invention has at least the following advantages or beneficial effects:
The embodiment of the invention provides a battery cell, which comprises a shell, a winding core and electrolyte, wherein the winding core and the electrolyte are arranged in the shell, and the winding core is formed by laminating positive plates, isolating films and negative plates; the positive plate comprises a positive current collector and a nickel-containing positive active material coated on the positive current collector, wherein the positive current collector is a composite current collector comprising an insulating support layer and a conductive layer at least arranged on one side of the insulating support layer, the thickness of the insulating support layer is A, the unit is um, the weight percentage of nickel element in the positive active material is I, and the unit is; the thickness of the winding core is C, and the unit is mm; the thickness A of the insulating supporting layer, the weight percentage I of nickel element in the positive electrode active material and the thickness C of the winding core are more than or equal to 0.70 and less than or equal to A/(C/100+I) and less than or equal to 110.
On one hand, the positive current collector of the battery core is a composite current collector, and the composite current collector is a composite structure obtained by compositing an insulating supporting layer and a conducting layer, so that the weight of the current collector can be reduced, and the weight energy density of the battery core can be improved; meanwhile, the deformation resistance of the electric core during penetration of foreign matters can be improved by increasing the thickness of the insulating layer, so that burrs generated by the conducting layer during penetration are smaller, the short circuit resistance is increased, the generated heat is smaller, the internal short circuit is not easy to occur, the risk of out-of-control short circuit in the electric core can be reduced, and the safety of the electric core is improved; on the other hand, through limiting the relation among the thickness A of the insulating supporting layer, the weight percent I of nickel element in the positive electrode active material and the thickness C of the battery core winding core, the thickness of the battery core winding core can be thinned under the condition of the same capacity and battery core volume, so that the surface area of the battery core is increased, the number of layers of short circuits when the battery core is internally short-circuited can be reduced, the number of through holes is reduced, and further short-circuit points are fewer; meanwhile, the thermal diffusion surface area during needling can be increased, so that the short-circuit current is smaller, thermal runaway is not easy to occur, and the safety performance of the battery cell can be further improved.
The embodiment of the invention also provides a battery module and a battery pack, which both comprise the battery cells. Therefore, the battery module also has the advantages of high energy density and high safety performance.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of a composite current collector of a battery cell according to an embodiment of the present invention;
Fig. 2 is a schematic structural diagram of a winding core of a battery cell according to an embodiment of the present invention.
Icon: 20-a composite current collector; 211-an insulating support layer; 212-a conductive layer; 213-winding core.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that: like reference numerals and letters denote like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
In the description of the present invention, it should be noted that, directions or positional relationships indicated by terms such as "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., are directions or positional relationships based on those shown in the drawings, or are directions or positional relationships conventionally put in use of the inventive product, are merely for convenience of describing the present invention and simplifying the description, and are not indicative or implying that the apparatus or element to be referred to must have a specific direction, be constructed and operated in a specific direction, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.
Furthermore, the terms "horizontal," "vertical," and the like do not denote a requirement that the component be absolutely horizontal or overhang, but rather may be slightly inclined. As "horizontal" merely means that its direction is more horizontal than "vertical", and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.
In the description of the present invention, it should also be noted that, unless explicitly specified and limited otherwise, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
In the related art, the positive current collector used for the pole piece of the lithium ion battery core is aluminum foil, and the negative current collector is copper foil. Copper foil and aluminum foil have excellent conductivity, but when the cell is damaged by needling, extrusion, etc., the inside of the cell is easily shorted, causing thermal runaway of the cell.
In view of this, the embodiment of the invention provides a battery cell with a composite current collector for the positive plate, and the relationship among the thickness A of the insulating support layer, the weight percentage I of nickel element in the positive active material and the thickness C of the winding core is limited, so that the energy density and the safety of the battery cell can be effectively improved. The battery cell can be square aluminum shell, soft package, lamination and cylinder, and the embodiment of the invention adopts square aluminum shell battery cells. The structure and performance of the cell are described in detail below.
Fig. 1 is a schematic structural diagram of a composite current collector 20 of a battery cell according to an embodiment of the present invention; fig. 2 is a schematic structural diagram of a winding core 213 of a battery cell according to an embodiment of the present invention. The battery cell provided in this embodiment is an aluminum-shell battery cell, and includes a housing, a winding core 213 shown in fig. 2, and an electrolyte. Wherein, the casing is the aluminum hull, and roll up core 213 and electrolyte and set up in the casing, roll up core 213 through positive plate, barrier film (PE and/or PP material) and the negative plate lamination of range upon range of setting or winding shaping, positive plate connection is provided with the positive tab, and the negative plate connection is provided with the negative tab, has positive post and negative post on the casing, and positive tab is connected (e.g. welded) with positive post electricity, and the negative post is connected (e.g. welded) with the negative tab electricity to guarantee the normal clear of electric core charge-discharge operation.
Meanwhile, in the embodiment of the invention, the positive electrode sheet and the negative electrode sheet are both of the composite structure shown in fig. 1. The positive electrode sheet includes a positive electrode current collector and a positive electrode active material coated on the positive electrode current collector, and active particles of the positive electrode active material may be selected to be a nickel-containing positive electrode material, for example, active particles of the positive electrode active material may be selected to be nickel cobalt lithium manganate (ternary lithium). The negative electrode sheet comprises a negative electrode current collector and a negative electrode active material coated on the negative electrode current collector, wherein active particles of the negative electrode active material can be selected from graphite, graphene, titanium-based materials, tin-based materials, silicon-based materials or nitride materials and the like. Of course, in other embodiments, only the positive electrode current collector of the positive electrode sheet may be set as the composite current collector, and the negative electrode current collector of the negative electrode sheet may be set as the copper foil, which is not limited.
In addition, in the embodiment of the present invention, the composite current collector 20 includes an insulating support layer 211 and two conductive layers 212 disposed on both sides of the insulating support layer 211, respectively, regardless of whether it is a positive electrode sheet or a negative electrode sheet. Of course, only one conductive layer 212 may be disposed on one side of the insulating support layer 211, which is not described in detail in this embodiment.
The thickness of the insulating support layer 211 of the positive plate and the thickness of the insulating support layer 211 of the negative plate can be the same or different, and in the embodiment of the invention, the thicknesses of the insulating support layers 211 of the positive plate and the negative plate are the same, and the unit is um. The thicknesses of the two conductive layers 212 of the positive electrode sheet and the negative electrode sheet may be set to be the same or different, and the thicknesses of the conductive layers 212 of the positive electrode sheet and the negative electrode sheet in the embodiment of the present invention may be set to be the same. And the weight percentage of nickel element in the positive electrode active material is I. The type of the isolating film is PE or PP, or a compound of PE and PP. The thickness of the winding core 213 (i.e., the dimension of the winding core 213 in the direction perpendicular to the positive and negative electrode sheets) is C in mm. Whether the thickness of the insulating support layer 211 and the thickness of the conductive layer 212 of the positive and negative electrode sheets are the same or not, in the embodiment of the invention, the thickness A of the insulating support layer 211, the weight percentage I of nickel element in the positive electrode active material and the thickness C of the winding core 213 satisfy 0.70 < A/(C/100+I) 110.
On one hand, the positive current collector of the battery core is a composite current collector 20, and the composite current collector 20 is a composite structure obtained by compositing an insulating support layer 211 and a conductive layer 212, so that the weight of the current collector can be reduced, and the weight energy density of the battery core can be improved; meanwhile, by increasing the thickness of the insulating layer, the deformation resistance of the battery cell when the foreign matters in the battery cell are pierced can be improved, burrs generated by the conductive layer 212 are smaller when the battery cell is pierced, so that the short circuit resistance is increased, the generated heat is smaller, the internal short circuit is not easy to occur, the risk of out-of-control short circuit in the battery cell can be reduced, and the safety of the battery cell is improved; on the other hand, through the limitation of the relation among the thickness A of the insulating support layer 211, the weight percentage I of nickel element in the positive electrode active material and the thickness C of the battery core winding 213, the thickness of the battery core winding 213 can be thinned under the condition of the same capacity and battery core volume, so that the surface area of the battery core is increased, the number of layers of short circuits when the battery core is internally short-circuited can be reduced, the number of through holes is reduced, and further, the short circuit points are fewer; meanwhile, the thermal diffusion surface area during needling can be increased, so that the short-circuit current is smaller, thermal runaway is not easy to occur, and the safety performance of the battery cell can be further improved.
In other embodiments, the material of the insulating support layer 211 of the positive electrode current collector and the negative electrode current collector may be an organic polymer material (such as PET) or a ceramic-doped polymer. The conductive layer 212 of the positive current collector may be selected to be an aluminum foil layer. The conductive layer 212 of the negative current collector may be selected to be a copper foil layer. Meanwhile, the positive electrode active material layer and the negative electrode active material layer are all coatings prepared by mixing and rolling auxiliary agents such as active particles (active particles of positive electrode active materials are nickel cobalt lithium manganate and active particles of negative electrode active materials are graphite), conductive agents (such as carbon black, carbon nano tubes and the like) and binders (such as styrene-butadiene rubber, PVDF and the like).
In this embodiment of the present invention, the method for testing the weight percentage I of the nickel element in the positive electrode active material is performed by using an IPC elemental analysis method, and the device for testing may be IPC-OES. That is, in the test, aqua regia is added to the sample to dissolve the sample, and then the inductively coupled plasma emission spectrometer is used for the test.
Meanwhile, the thickness of the insulating support layer 211, the conductive layer 212 and the isolation film can be measured by a micrometer. The thickness of the winding core 213 refers to the thickness of the bare cell, and does not include the outer case thickness, which can also be measured by a micrometer. In addition, there is a slight difference in thickness measurement modes of the winding cores 213 with different shapes, if the winding cores 213 of square aluminum cases, soft packages or laminated battery cores are used, the thickness of the central position of the large surface of the winding core 213 is usually measured after hot pressing, and a specific test method is that the winding cores 213 are placed between two measuring anvils of a micrometer at room temperature, so that the axis of a micrometer screw coincides with the central line in the thickness direction of the winding cores 213, a knob is rotated to enable the surface of the winding cores 213 to be close to the measuring anvils, and then a ratchet disc is rotated until a ratchet wheel emits 2-3 sound of 'click', and at this time, the indication numerical value of the micrometer is the thickness dimension of the measured winding cores 213. If the core 213 is a cylindrical cell, the diameter of the core 213 is the thickness of the core 213. The embodiment mainly takes the winding core 213 of the square aluminum-shell battery cell as an example for testing and explanation.
Alternatively, in the embodiment of the invention, the thickness A of the insulating support layer 211, the weight percentage I of the nickel element in the positive electrode active material, and the thickness C of the winding core 213 satisfy 2.07.ltoreq.A/(C/100+I.ltoreq.37.5. The selection relation among the thickness A of the insulating supporting layer 211, the weight percentage I of nickel element in the positive electrode active material and the thickness C of the battery core winding 213 is controlled within the range, so that the thickness of the battery core winding 213 can be thinned under the condition of the same capacity and battery core volume to increase the surface area of the battery core, thereby reducing the number of layers of short circuit when the battery core is internally short-circuited, further reducing the short circuit point and improving the safety performance of the battery core; the thermal diffusion surface area during needling can be improved, so that the short-circuit current is smaller, and the safety performance of the battery cell is further improved.
Further alternatively, in an embodiment of the present invention, the thickness a of the insulating support layer 211 ranges from 1 to 30um; preferably, the thickness A of the insulating support layer 211 is in the range of 5-15um. The thickness of the insulating supporting layer 211 of the positive plate and the thickness of the insulating supporting layer 211 of the negative plate are controlled within the range, so that the thickness of the conductive layer 212 of the positive plate and the thickness of the conductive layer 212 of the negative plate can be set between 0.03 um and 3um, and the thickness of the conductive layer 212 is relatively thin, so that burrs generated by the conductive layer 212 are small when the conductive layer is needled, the short circuit resistance is large, the generated heat is small, thermal runaway is not easy to occur, the thermal runaway problem of the battery cell under the internal short circuit condition can be relieved to a certain extent, and the safety performance of the battery cell can be improved.
Further, in the embodiment of the present invention, the weight percentage I of the nickel element in the positive electrode active material ranges from 20 to 60%; preferably, the weight percentage I of the nickel element in the positive electrode active material ranges from 30 to 45%. Since the thermal runaway risk degree of the battery core is positively related to the proportion of nickel element in the positive electrode material, namely, the higher the nickel element content is, the worse the stability of the positive electrode active material is, and the easier the safety accident is caused. The degree of thermal runaway risk of the cell is inversely related to the thickness of the insulating layer in the composite substrate. Therefore, in one aspect, the embodiment of the present invention controls the weight percentage of nickel element within this range, and can cooperate with the thickness a of the insulating support layer 211 and the thickness C of the battery core 213, so as to effectively ensure the energy density of the battery core on the premise of ensuring the safety of the whole battery core.
The thickness C of the winding core 213 ranges from 10 to 80mm; preferably, the thickness D of the cell core 213 ranges from 13-30mm. By controlling the thickness D of the cell winding core 213, the problem of thermal runaway of the cell can be improved while ensuring the capacity and thickness of the cell.
The embodiment of the invention also provides a battery module which comprises a plurality of battery cells arranged in series or in parallel. The thickness A of the insulating support layer 211 of each cell, the weight percentage I of nickel element in the positive electrode active material and the thickness C of the winding core 213 all satisfy 2.07 & ltoreq.A/(C/100+I) & ltoreq.37.5. Therefore, the battery module also has the advantages of high energy density and high safety performance.
The embodiment of the invention also provides a battery pack which comprises a plurality of the battery modules. The plurality of battery modules are arranged in series or in parallel to form a battery pack. The thickness A of the insulating support layer 211 of each cell, the weight percentage I of nickel element in the positive electrode active material and the thickness C of the cell winding core 213 are all 2.07-A/(C/100+I) 37.5. Therefore, the battery module also has the advantages of high energy density and high safety performance. Of course, in other embodiments of the present invention, the battery pack may also be assembled directly by a plurality of the above-mentioned battery cells to form a battery pack without modules, so as to ensure energy density.
The battery cell, the battery module and the battery pack provided by the embodiment of the invention are described in detail below with reference to specific embodiments:
Examples 1 to 20
Examples 1 to 20 respectively provide 20 kinds of cells (cells 1 to 20), and the relationship among the thickness a of the insulating support layer 211 of the 20 kinds of cells, the weight percentage I of nickel element in the positive electrode active material, and the thickness C of the cell winding core 213 is shown in table 1. Meanwhile, the insulating support layers 211 of the positive current collector and the negative current collector of the 20 battery cores are made of PET, the conductive layer 212 of the positive current collector is made of aluminum foil, and the conductive layer 212 of the negative current collector is made of copper foil. The thickness of the two sides of the positive electrode active material layer coated on the positive electrode current collector is 105um, and the active particles of the positive electrode active material are nickel cobalt lithium manganate. The thickness of the two sides of the anode active material layer coated on the anode current collector is 120um, and the active particles of the anode active material are artificial stone. The isolating film material of 20 cells is PE base film, ceramic and PVDF coating. The electrolyte comprises an organic solvent and an electrolyte salt dissolved in the organic solvent, wherein the organic solvent comprises methyl ethyl carbonate (EMC) and Ethylene Carbonate (EC), the electrolyte salt is LiPF 6, and the electrolyte salt is: the mass ratio of the organic solvent is 1:6, and the organic solvent (EC): the mass ratio of (EMC) was 3:7.
TABLE 1 parameters of examples 1-20 cells
As can be seen from the data of Table 1, the thickness A of the insulating support layer 211, the weight percentage I of the nickel element in the positive electrode active material, and the thickness C of the winding core 213 of the 20 kinds of cells provided in examples 1 to 20 of the present invention satisfy 0.70.ltoreq.A/(C/100+I). Ltoreq.110.
Comparative examples 1 to 2
Comparative examples 1-2 provided 2 cells (cells 21-22), with specific parameters for the 2 cells shown in table 2.
TABLE 2 parameters of comparative examples 1-2 cells
Experimental example 1
The 20 cells provided in examples 1-20 and the 4 cells provided in comparative examples 1-2 were subjected to needling experiments according to the procedure in national standard GBT31485 under the test conditions of 25+ -5deg.C, full-charged to 4.2V,3mm steel needle, and 25mm/s speed to pierce into the cell explosion-proof valve (with fixture), and the experimental results after observation for 1h are shown in Table 3.
TABLE 3 needling experimental data for cells
Type(s) Needling experiment results
Cell 1 #) No smoke, no fire or explosion
Cell 2 #) No smoke, no fire or explosion
Cell 3 #) No smoke, no fire or explosion
Cell 4 #) No smoke, no fire or explosion
Cell 5 #) No smoke, no fire or explosion
Cell 6 #) No smoke, no fire or explosion
Cell 7 #) No smoke, no fire or explosion
Cell 8 #) No smoke, no fire or explosion
Cell 9 #) No smoke, no fire or explosion
Cell 10 #) No smoke, no fire or explosion
Cell 11 #) No smoke, no fire or explosion
Cell 12 #) No smoke, no fire or explosion
Cell 13 #) No smoke, no fire or explosion
Cell 14 #) No smoke, no fire or explosion
Cell 15# No smoke, no fire or explosion
Cell 16 #) No smoke, no fire or explosion
Cell 17 #) No smoke, no fire or explosion
Cell 18 #) No smoke, no fire or explosion
Cell 19 #) No smoke, no fire or explosion
Cell 20 #) No smoke, no fire or explosion
Cell 21 #) Smoke and fire
Cell 22 #) Smoke and fire
As can be seen from the data tested in Table 3, in examples 1-20 of the present invention, compared with comparative examples 1-2, the relationship among the thickness A of the insulating support layer 211, the weight percentage I of the nickel element in the positive electrode active material, and the thickness C of the battery core 213 was controlled within the range of 0.70. Ltoreq.A/(C/100+I). Ltoreq.110, so that the safety performance of the battery core was ensured without smoke, fire or explosion in the needling test.
Experimental example 2
The 20 cells provided in examples 1-20 of the present invention were subjected to temperature rise and voltage test under the same conditions as the 2 cells provided in comparative examples 1-2. Wherein the charging strategy is: at the ambient temperature of 25+/-5 ℃, wrapping 10mm thick insulating glass wool outside the battery cell, charging to 4.1V with a constant current of 100A1C, and standing for 30min; meanwhile, the temperature rise record condition is that the temperature of the battery cell is monitored by adopting a plurality of temperature measuring instruments in the charging process, one section of the temperature sensing wire is connected with the plurality of temperature measuring instruments, the other end of the temperature sensing wire is attached to the center point of the large surface of the battery cell, and the temperature of the battery cell is recorded every 1 s. The condition of voltage record is that voltage testing equipment is adopted to monitor the voltage of the positive and negative poles of the battery cell in the charging process, the testing end of the voltage testing equipment is connected with the pole of the battery cell in the testing process, voltage data are recorded every 1s, and the testing result is shown in table 4.
TABLE 4 test data for cells
Type(s) Temperature rise/°c of battery cell Cell voltage/V
Cell 1 #) 2.50 4.10
Cell 2 #) 4.12 4.05
Cell 3 #) 5.56 4.00
Cell 4 #) 6.84 3.96
Cell 5 #) 7.60 3.94
Cell 6 #) 7.90 3.93
Cell 7 #) 8.18 3.92
Cell 8 #) 8.43 3.92
Cell 9 #) 8.67 3.91
Cell 10 #) 8.88 3.90
Cell 11 #) 9.08 3.90
Cell 12 #) 9.26 3.89
Cell 13 #) 9.43 3.89
Cell 14 #) 9.59 3.88
Cell 15# 7.14 3.96
Cell 16 #) 7.33 3.95
Cell 17 #) 7.50 3.95
Cell 18 #) 7.65 3.94
Cell 19 #) 7.78 3.94
Cell 20 #) 7.89 3.93
Cell 21 #) 4.50 4.02
Cell 22 #) 4.67 4.01
According to the data in table 4, compared with the 21-22 cells provided in the prior art, the 1-20 cells provided in this embodiment have relatively low temperature rise, relatively stable voltage, less thermal runaway, and higher safety performance.
Experimental example 3
The 20 cells provided in examples 1-20 of the present invention were subjected to energy density testing under the same conditions as the 2 cells provided in comparative examples 1-2. Wherein, the discharge energy of 1C is represented by E1, and the unit is Wh; the mass of the battery cell is represented by m, the unit kg, and the weight energy density of the battery cell is represented by W, and the unit Wh/kg. The test conditions of E1 were that the discharge energy E1 was obtained by constant-current charging at a rate of 1C to a voltage of 4.4V, then constant-voltage charging at a rate of 4.4V to a current of 0.05C, and then constant-current discharging at a rate of 1C to a voltage of 2.8V in an incubator at 25 ℃. The weight test condition of the battery cells is that the mass m of each battery cell can be obtained through an electronic scale in an environment of 25 ℃. The weight energy density of the cells was calculated by the formula p=e1/m, and the specific results are shown in table 5.
TABLE 5 energy Density test results
From the data shown in Table 5, it is understood that the energy density of the battery cell can be effectively improved by controlling the relationship among the thickness A of the insulating support layer, the weight percentage I of the nickel element in the positive electrode active material, and the thickness C of the battery cell winding core 213 to be within the range of 0.70A/(C/100+I) 110. Meanwhile, as can be seen from the data of tables 1 to 5, the embodiments of the present invention can maximize the energy density of the battery cells while ensuring the safety of the battery cells.
The following describes in detail the installation process, the working principle and the beneficial effects of the battery pack provided by the embodiment of the invention:
The battery pack can be directly integrated into the battery pack box body through a plurality of battery cells, or the battery cells can be assembled into a battery module first, and then the battery module is assembled into the battery pack. When the battery cell is manufactured, the positive plate, the negative plate and the diaphragm can be wound to obtain the electrode core, the electrode core is arranged in the shell, the positive lug connected with the positive plate is welded with the positive pole post on the shell, the negative lug connected with the negative plate is welded with the negative pole post on the shell, and finally the electrolyte is injected into the shell. In the process of selecting the positive plate and the negative plate, the positive plate is obtained by coating a positive active material on a positive current collector, the negative plate is obtained by coating a negative active material on a negative current collector, the positive current collector and the negative current collector are both composite current collectors 20, the composite current collectors 20 are obtained by coating conductive layers 212 on two sides of an insulating support layer 211, the conductive layers 212 of the positive current collector are aluminum foils, the conductive layers 212 of the negative current collector are copper foils, and the thickness A of the insulating support layer 211, the weight percentage I of nickel element in the positive active material and the thickness C of a winding core 213 are less than or equal to 0.70 and less than or equal to A/(C/100+I) are less than or equal to 110.
In the above process, on one hand, the positive current collector of the battery core is the composite current collector 20, and the composite current collector 20 is a composite structure obtained by compositing the insulating support layer 211 and the conductive layer 212, which can reduce the weight of the current collector and improve the weight energy density of the battery core; meanwhile, by increasing the thickness of the insulating layer, the deformation resistance of the battery cell when the foreign matters in the battery cell are pierced can be improved, burrs generated by the conductive layer 212 are smaller when the battery cell is pierced, so that the short circuit resistance is increased, the generated heat is smaller, the internal short circuit is not easy to occur, the risk of out-of-control short circuit in the battery cell can be reduced, and the safety of the battery cell is improved; on the other hand, by limiting the relation among the thickness a of the insulating support layer 211, the weight percentage I of nickel element in the positive electrode active material and the thickness C of the winding core 213, the thickness of the winding core 213 of the battery core can be thinned under the condition of the same capacity and volume of the battery core, so that the surface area of the battery core is increased, the number of layers of short circuit during internal short circuit of the battery core can be reduced, the number of through holes is reduced, and further, the short circuit points are fewer; meanwhile, the thermal diffusion surface area during needling can be increased, so that the short-circuit current is smaller, thermal runaway is not easy to occur, and the safety performance of the battery cell can be further improved.
In summary, the embodiment of the invention provides a battery cell, a battery module and a battery pack with high energy density and high safety performance.
The present invention is not limited to the above embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention. Therefore, the protection scope of the invention is subject to the protection scope of the claims.

Claims (5)

1. A cell, comprising:
The lithium ion battery comprises a shell, a winding core and electrolyte, wherein the winding core and the electrolyte are arranged in the shell, and the winding core is formed by laminating positive plates, isolating films and negative plates or winding; the positive plate comprises a positive current collector and a nickel-containing positive active material coated on the positive current collector, active particles of the positive active material are nickel cobalt lithium manganate, and the positive current collector is a composite current collector comprising an insulating support layer and a conductive layer at least arranged on one side of the insulating support layer; the negative electrode plate comprises a negative electrode current collector and a negative electrode active material coated on the negative electrode current collector, and the negative electrode current collector is a composite current collector comprising an insulating support layer and a conductive layer at least arranged on one side of the insulating support layer; the insulating support layers of the positive current collector and the negative current collector are both made of PET, the conducting layer of the positive current collector is made of aluminum foil, and the conducting layer of the negative current collector is made of copper foil; the thickness of the two sides of the positive electrode active material layer coated on the positive electrode current collector is 105um, the thickness of the two sides of the negative electrode active material layer coated on the negative electrode current collector is 120um, and the active particles of the negative electrode active material are artificial graphite; the isolating membrane is made of PE base membrane, ceramic and PVDF coating; the electrolyte comprises an organic solvent and electrolyte salt dissolved in the organic solvent, wherein the organic solvent comprises methyl ethyl carbonate and ethylene carbonate, the electrolyte salt is LiPF 6, the mass ratio of the electrolyte salt to the organic solvent is 1:6, and the mass ratio of the ethylene carbonate to the methyl ethyl carbonate in the organic solvent is 3:7; the thickness of the insulating supporting layer is A, the unit is um, the weight percentage of nickel element in the positive electrode active material is I, and the unit is um; the thickness of the winding core is C, and the unit is mm;
The thickness A of the insulating supporting layer, the weight percentage I of nickel element in the positive electrode active material and the thickness C of the winding core are 2.07-less than or equal to A/(C/100+I) less than or equal to 37.5;
the thickness A of the insulating supporting layer is in the range of 3-30um;
the weight percentage I of nickel element in the positive electrode active material ranges from 30% to 45%;
the thickness C of the winding core is in the range of 50-80mm.
2. The cell of claim 1, wherein:
the thickness A of the insulating support layer is in the range of 5-15um.
3. The cell according to any one of claims 1 to 2, characterized in that:
the composite current collector comprises two layers of conductive layers, wherein the thickness of the two layers of conductive layers is the same, and the two layers of conductive layers are respectively arranged on two sides of the insulating supporting layer.
4. A battery module comprising the cell of any one of claims 1 to 3.
5. A battery pack comprising the cell of any one of claims 1 to 3; or includes the battery module according to claim 4.
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JPH01143140A (en) * 1987-11-27 1989-06-05 Matsushita Electric Ind Co Ltd Nonaqueous electrolyte secondary cell
JPH0845500A (en) * 1994-07-29 1996-02-16 Sanyo Electric Co Ltd Manufacture of electrode
CN101771167A (en) * 2010-02-05 2010-07-07 九江天赐高新材料有限公司 High-capacity lithium-ion electrolyte, battery and preparation method of battery
CN104993121A (en) * 2015-05-21 2015-10-21 中信国安盟固利电源技术有限公司 Nickel and manganese blended lithium ion battery positive material and preparation method thereof
CN110611102A (en) * 2019-10-21 2019-12-24 瑞浦能源有限公司 Current collector, pole piece, preparation method of pole piece and electrochemical energy storage device
CN110943215A (en) * 2019-05-31 2020-03-31 宁德时代新能源科技股份有限公司 Lithium ion secondary battery
CN212230513U (en) * 2020-07-13 2020-12-25 北京小米移动软件有限公司 Isolating membrane for battery core, battery core and battery
CN113745523A (en) * 2020-05-29 2021-12-03 比亚迪股份有限公司 Lithium ion battery, power battery module, battery pack, electric automobile and energy storage device

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01143140A (en) * 1987-11-27 1989-06-05 Matsushita Electric Ind Co Ltd Nonaqueous electrolyte secondary cell
JPH0845500A (en) * 1994-07-29 1996-02-16 Sanyo Electric Co Ltd Manufacture of electrode
CN101771167A (en) * 2010-02-05 2010-07-07 九江天赐高新材料有限公司 High-capacity lithium-ion electrolyte, battery and preparation method of battery
CN104993121A (en) * 2015-05-21 2015-10-21 中信国安盟固利电源技术有限公司 Nickel and manganese blended lithium ion battery positive material and preparation method thereof
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CN110611102A (en) * 2019-10-21 2019-12-24 瑞浦能源有限公司 Current collector, pole piece, preparation method of pole piece and electrochemical energy storage device
CN113745523A (en) * 2020-05-29 2021-12-03 比亚迪股份有限公司 Lithium ion battery, power battery module, battery pack, electric automobile and energy storage device
CN212230513U (en) * 2020-07-13 2020-12-25 北京小米移动软件有限公司 Isolating membrane for battery core, battery core and battery

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