CN112582751A - Diaphragm, lithium battery and preparation method thereof - Google Patents
Diaphragm, lithium battery and preparation method thereof Download PDFInfo
- Publication number
- CN112582751A CN112582751A CN202011509151.1A CN202011509151A CN112582751A CN 112582751 A CN112582751 A CN 112582751A CN 202011509151 A CN202011509151 A CN 202011509151A CN 112582751 A CN112582751 A CN 112582751A
- Authority
- CN
- China
- Prior art keywords
- diaphragm
- lithium battery
- hot pressing
- plate
- base film
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 title claims abstract description 63
- 229910052744 lithium Inorganic materials 0.000 title claims abstract description 63
- 238000002360 preparation method Methods 0.000 title abstract description 11
- 238000007731 hot pressing Methods 0.000 claims abstract description 75
- 229920006231 aramid fiber Polymers 0.000 claims abstract description 36
- 239000011247 coating layer Substances 0.000 claims abstract description 7
- 239000002033 PVDF binder Substances 0.000 claims description 18
- 239000010410 layer Substances 0.000 claims description 18
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 18
- 238000000576 coating method Methods 0.000 claims description 10
- 239000011248 coating agent Substances 0.000 claims description 8
- 238000004804 winding Methods 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 6
- 239000000463 material Substances 0.000 claims description 6
- 238000000034 method Methods 0.000 abstract description 14
- 230000037303 wrinkles Effects 0.000 abstract description 7
- 238000001556 precipitation Methods 0.000 abstract description 3
- 230000000694 effects Effects 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 28
- 229920003235 aromatic polyamide Polymers 0.000 description 16
- 239000004760 aramid Substances 0.000 description 13
- 150000002641 lithium Chemical class 0.000 description 13
- 230000008569 process Effects 0.000 description 12
- 238000009826 distribution Methods 0.000 description 10
- 238000010586 diagram Methods 0.000 description 9
- 239000007788 liquid Substances 0.000 description 9
- 238000010030 laminating Methods 0.000 description 6
- 230000008901 benefit Effects 0.000 description 4
- 239000000835 fiber Substances 0.000 description 3
- 238000005520 cutting process Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 230000006872 improvement Effects 0.000 description 2
- 238000003475 lamination Methods 0.000 description 2
- 230000002035 prolonged effect Effects 0.000 description 2
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 1
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001351 cycling effect Effects 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 239000003063 flame retardant Substances 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 229910001416 lithium ion Inorganic materials 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/052—Li-accumulators
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M10/00—Secondary cells; Manufacture thereof
- H01M10/05—Accumulators with non-aqueous electrolyte
- H01M10/058—Construction or manufacture
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Secondary Cells (AREA)
Abstract
The invention provides a diaphragm, a lithium battery and a preparation method thereof, wherein the diaphragm comprises an aramid fiber base film and a coating layer arranged on at least one surface of the aramid fiber base film, the lithium battery comprises a positive plate, a negative plate and the diaphragm arranged between the positive plate and the negative plate, the high-temperature hot pressing is directly carried out on a multilayer electrode plate, the hot pressing time is short, the diaphragm bonding effect is good, and therefore the efficiency can be improved; in addition, the method can ensure that the diaphragm has no wrinkles after the capacity grading of the battery cell, the surface of the pole piece is smooth, and the surface of the negative pole has no phenomenon of lithium precipitation.
Description
Technical Field
The invention relates to the technical field of lithium batteries, and particularly relates to a diaphragm, a lithium battery and a preparation method thereof.
Background
The lithium battery becomes a main power source of the electric automobile by virtue of high energy density, good rate performance and long-term cycle performance. Along with the continuous improvement of the energy density of the lithium battery, the safety also receives more and more attention from people.
The aramid fiber base film has heat resistance and excellent fireproof and flame-retardant properties, so that the safety performance of the lithium battery can be remarkably improved. In addition, the aramid fiber base film has high affinity to electrolyte, so that the diaphragm has good wetting, liquid absorbing and retaining performances, and the cycle life of the battery can be prolonged. In addition, the aramid fiber base film can improve oxidation resistance, and further realize high potential, so that the energy density is improved. Therefore, the aramid fiber base film can not only improve the safety performance of the battery, but also prolong the cycle life and improve the energy density.
Aramid-based films, however, also present problems in lithium battery applications. After the battery is filled with the aramid fiber base film, the diaphragm is soaked by an organic solvent and is prone to wrinkle. The migration path of lithium ions at the positive electrode and the negative electrode can be prolonged at the folds, polarization is increased, lithium precipitation is easy to cause, and further the electrical property of the battery is reduced and potential safety hazards are increased.
Disclosure of Invention
The invention aims to provide a diaphragm, a lithium battery and a preparation method thereof, which aim to solve the problem that the aramid diaphragm is easy to wrinkle in the prior art; the thickness consistency of the battery and the interface uniformity of the pole piece are improved.
The technical problem to be solved by the invention is realized by adopting the following technical scheme. The invention provides a diaphragm which comprises an aramid fiber base film, wherein a coating is formed on at least one surface of the aramid fiber base film.
The material selection of the aramid fiber substrate is not particularly limited, and common aramid fibers can be used. In one embodiment of the present invention, the material of the aramid-based film is selected from at least one of para-aramid, para-aramid copolymer, meta-aramid, and substituent-containing meta-aramid copolymer.
In one embodiment of the invention, the material of the coating is selected from polyvinylidene fluoride.
The invention also provides a lithium battery, which comprises a positive plate and a negative plate, wherein the diaphragm is arranged between the positive plate and the negative plate, and the diaphragm is arranged between the positive plate and the negative plate.
In one embodiment of the present invention, the separator is bonded to the positive electrode tab and/or the negative electrode tab by hot pressing.
In one embodiment of the invention, the temperature of the hot pressing is 120-150 ℃; further, the hot pressing temperature is 130-150 ℃.
In one embodiment of the invention, the pressure of the hot pressing is 1.0 ton to 4.6 ton; further, the pressure of hot pressing is 1.6 tons to 3.4 tons; further, the pressure of hot pressing is 3.8 tons to 4.6 tons.
In one embodiment of the invention, the hot pressing time is 20 seconds to 60 seconds; further, the hot pressing time is 20 seconds to 40 seconds.
In one embodiment of the invention, the total number of layers of the positive plate and the negative plate is 21-89 layers; further, the total number of layers of the positive plate and the negative plate is 21-59; further, the number of the layers is 41 to 59.
The invention also provides a preparation method of the lithium battery, which comprises the following steps:
stacking or winding at least one positive plate, at least one negative plate and at least one diaphragm to form a naked battery cell;
and the diaphragm is bonded with the positive plate and/or the negative plate by hot-pressing the bare cell. After hot pressing, the battery can be manufactured by assembling, baking, injecting liquid, forming and grading and the like according to the conventional process.
The diaphragm comprises an aramid fiber base film and a coating layer arranged on at least one surface of the aramid fiber base film, and the lithium battery comprises a positive plate, a negative plate and the diaphragm arranged between the positive plate and the negative plate. According to the invention, after the coating is arranged on at least one surface of the aramid fiber base film, high-temperature hot pressing is directly carried out on the multilayer electrode plate, the hot pressing time is short, the diaphragm bonding effect is good, the diaphragm after the capacity grading of the battery cell is free from wrinkles, the surface of the electrode plate is smooth, and the lithium precipitation phenomenon on the surface of the negative electrode is avoided.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and together with the description, serve to explain the principles of the application. In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed to be used in the description of the embodiments will be briefly described below, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
Fig. 1 is a graph of discharge curves at 3C rate for a first comparative example and a first embodiment of the present invention.
Fig. 2 is a charging graph at 3C rate for the first comparative example and the first embodiment of the present invention.
Fig. 3 is a cell thickness distribution diagram of a first comparative example and a first embodiment of the present invention.
Fig. 4 is a graph of a cycle of a second comparative example and a second embodiment of the present invention.
Fig. 5 is a cell thickness distribution diagram of a second comparative example and a second embodiment of the present invention.
Detailed Description
In the following description, reference is made to the accompanying drawings that describe several embodiments of the application. It is to be understood that other embodiments may be utilized and mechanical composition, construction, and operational changes may be made without departing from the spirit and scope of the present invention. The following detailed description is not to be taken in a limiting sense, and the scope of various embodiments of the present invention is defined only by the claims of the issued patent. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
Although the terms first, second, etc. may be used herein to describe various elements in some embodiments, these elements should not be limited by these terms. These terms are only used to distinguish one element from another.
Embodiments of the present invention provide a separator including an aramid base film, wherein a coating layer is formed on at least one surface of the aramid base film, that is, the coating layer may be coated on only one surface of the aramid base film, or may be coated on both surfaces of the aramid base film. The aramid-based film can be made of at least one of para-aramid fiber, para-aramid copolymer fiber, meta-aramid fiber and substituent-containing meta-aramid copolymer fiber. The material of the coating is selected from polyvinylidene fluoride (PVDF).
In one embodiment of the invention, the material of the coating is polyvinylidene fluoride. Furthermore, the hot pressing temperature can reach 120-150 ℃, and the hot pressing time can be controlled within 60s due to the high hot pressing temperature. In other embodiments, the hot pressing temperature may be 130 ℃ to 150 ℃ and the hot pressing time may be 20 seconds to 40 seconds.
The embodiment of the invention also provides a lithium battery, wherein the battery core of the lithium battery is of a winding type and comprises a positive plate and a negative plate, the diaphragm is arranged between the positive plate and the negative plate, and the diaphragm is wound between the positive plate and the negative plate. The diaphragm is bonded with the positive plate and/or the negative plate through hot pressing.
The preparation method of the coiled lithium battery comprises the following steps:
a diaphragm is arranged between the positive plate and the negative plate, and comprises an aramid fiber base film and a coating layer arranged on at least one surface of the aramid fiber base film;
separating the positive plate and the negative plate by a diaphragm, and winding to form a naked electric core;
presetting temperature and pressure, and bonding the diaphragm with the positive plate and/or the negative plate by hot-pressing the bare cell core.
In the preparation method of the coiled lithium battery, the preset temperature is 120-150 ℃, and further, the preset temperature can be 130-150 ℃. The preset pressure is 1.0 ton to 4.6 tons; further, the preset pressure is 1.6 tons to 3.4 tons; further, the preset pressure is 3.8 tons to 4.6 tons. The hot pressing time is 20 seconds to 60 seconds, and further, the hot pressing time can be 20 seconds to 40 seconds. The invention can carry out short-time hot pressing on the naked electric core so as to solve the problem of diaphragm wrinkles generated by subsequent capacity grading.
In the embodiment, the total number of the positive plate and the negative plate is 21-89 layers; furthermore, the total number of layers of the positive plate and the negative plate is 20-44.
The embodiment of the invention also provides another lithium battery, wherein the battery core of the lithium battery is of a laminated type, the lithium battery comprises a plurality of positive plates and a plurality of negative plates which are mutually stacked, and the diaphragm is arranged between each positive plate and each negative plate to form a bare battery core. And (3) hot-pressing the bare cell to bond the diaphragm with the positive plate and/or the negative plate.
In the embodiment, the total number of the positive plate and the negative plate is 21-89 layers; furthermore, the total number of layers of the positive plate and the negative plate is 21-59. The invention can carry out one-time short-time hot pressing on dozens of positive and negative pole pieces, has simple hot pressing process and is suitable for the requirement of large-scale industrial production.
The preparation method of the laminated lithium battery comprises the following steps:
alternately stacking a plurality of positive plates and a plurality of negative plates, and arranging a diaphragm between each positive plate and each negative plate, wherein the diaphragm comprises an aramid fiber base film and a coating layer arranged on at least one surface of the aramid fiber base film;
and (3) presetting temperature and pressure, and bonding the diaphragm with the positive plate and/or the negative plate through hot pressing.
In the preparation method of the laminated lithium battery, the preset temperature is 120-150 ℃, and further, the preset temperature can be 130-150 ℃; the preset pressure is 1.0 ton to 4.6 tons; further, the preset pressure is 1.6 tons to 3.4 tons; further, the preset pressure is 3.8 tons to 4.6 tons. The hot pressing time is 20-60 seconds; further, the hot pressing time may be 20 seconds to 40 seconds.
The performance of the laminated lithium battery and the rolled lithium battery comprising the separator according to the present invention will be described with reference to specific examples.
First embodiment
The embodiment provides a laminated lithium battery, which is manufactured by the following process: repeatedly laminating the positive plate, the diaphragm and the negative electrode to obtain a naked battery core of the laminated lithium battery; the diaphragm comprises an aramid fiber base film and polyvinylidene fluoride (PVDF) arranged on two surfaces of the aramid fiber base film, the number of the negative electrode sheets is 30, and the number of the positive electrode sheets is 29; and placing the bare cell between the two heated press plates for hot pressing, wherein the hot pressing pressure is 4.2-4.6T, the hot pressing temperature is 130 ℃, and the hot pressing time is 60 s. The hardness of the bare cell is improved after hot pressing, and the positive electrode and the negative electrode are well bonded with the diaphragm.
And assembling, baking, injecting liquid, forming and grading the bare cell to prepare the lithium battery with the capacity of 52 Ah. The positive and negative pole pieces can still be tightly adhered with the diaphragm after the capacity of the lithium battery is divided, and the diaphragm has no folds.
Second embodiment
The embodiment provides a laminated lithium battery, which is manufactured by the following process: repeatedly laminating the positive plate, the diaphragm and the negative electrode to obtain a naked battery core of the laminated lithium battery; the diaphragm comprises an aramid fiber base film and polyvinylidene fluoride (PVDF) arranged on two surfaces of the aramid fiber base film, the negative plate is 22 layers, and the positive plate is 21 layers; and placing the bare cell between the two heated press plates for hot pressing, wherein the hot pressing pressure is 4.2-4.6T, the hot pressing temperature is 130 ℃, and the hot pressing time is 30 s. The hardness of the bare cell is improved after hot pressing, and the positive electrode and the negative electrode are well bonded with the diaphragm.
And assembling, baking, injecting liquid, forming and grading the bare cell to prepare the lithium battery with the capacity of 21 Ah. The positive and negative pole pieces can still be tightly adhered with the diaphragm after the capacity of the lithium battery is divided, and the diaphragm has no folds.
Third embodiment
The embodiment provides a laminated lithium battery, which comprises the following manufacturing process: repeatedly laminating the positive plate, the diaphragm and the negative electrode to obtain a naked battery core of the laminated lithium battery; the diaphragm comprises an aramid fiber base film and polyvinylidene fluoride (PVDF) arranged on two surfaces of the aramid fiber base film, the number of the negative electrode sheets is 11, and the number of the positive electrode sheets is 10; and placing the naked electric core between the two heated press plates for hot pressing, wherein the hot pressing pressure is 4.2-4.4T, the hot pressing temperature is 120 ℃, and the hot pressing time is 20 s. The hardness of the bare cell is improved after hot pressing, and the positive electrode and the negative electrode are well bonded with the diaphragm.
And assembling, baking, injecting liquid, forming and grading the bare cell to prepare the lithium battery with the capacity of 14 Ah. The positive and negative pole pieces can still be tightly adhered with the diaphragm after the capacity of the lithium battery is divided, and the diaphragm has no folds.
Fourth embodiment
The embodiment provides a laminated lithium battery, which comprises the following manufacturing process: repeatedly laminating the positive plate, the diaphragm and the negative electrode to obtain a naked battery core of the laminated lithium battery; the diaphragm comprises an aramid fiber base film and polyvinylidene fluoride (PVDF) arranged on two surfaces of the aramid fiber base film, the number of the negative electrode sheets is 45, and the number of the positive electrode sheets is 44; and placing the bare cell between the two heated press plates for hot pressing, wherein the hot pressing pressure is 4.4-4.6T, the hot pressing temperature is 150 ℃, and the hot pressing time is 60 s. The hardness of the bare cell is improved after hot pressing, and the positive electrode and the negative electrode are well bonded with the diaphragm.
And assembling, baking, injecting liquid, forming and grading the bare cell to prepare the lithium battery with the capacity of 52 Ah. The positive and negative pole pieces can still be tightly adhered with the diaphragm after the capacity of the lithium battery is divided, and the diaphragm has no folds.
Fifth embodiment
The embodiment provides a coiled lithium battery, wherein a diaphragm is arranged between a positive plate and a negative plate, the diaphragm comprises an aramid fiber base film and coatings arranged on two surfaces of the aramid fiber base film, and the coatings are polyvinylidene fluoride (PVDF); winding the positive plate and the negative plate by a diaphragm at intervals to form a bare cell, wherein the negative plate is 13 layers, and the positive plate is 12 layers; the preset pressure is 1.4-1.8 tons, the hot pressing temperature is 130 ℃, the hot pressing time is 60s, and the diaphragm is bonded with the positive plate and/or the negative plate through hot pressing. The hardness of the bare cell is improved after hot pressing, and the positive electrode and the negative electrode are well bonded with the diaphragm.
And assembling, baking, injecting liquid, forming and grading the bare cell to prepare the lithium battery with the capacity of 21 Ah. The positive and negative pole pieces can still be tightly adhered with the diaphragm after the capacity of the lithium battery is divided, and the diaphragm has no folds.
First comparative example
The present embodiment is different from the first embodiment in that the bare cell of the lithium battery in the first comparative example is not hot-pressed.
The manufacturing process of the lithium battery in the embodiment is as follows: and repeatedly laminating the positive plate, the diaphragm and the negative electrode to obtain the naked electric core of the laminated lithium battery, wherein the negative plate is 30 layers, and the positive plate is 29 layers. The thickness of the naked electric core which is not hot-pressed is obviously larger than that of the naked electric core in the first embodiment, and the aramid fiber base film cannot be closely adhered to the polyvinylidene fluoride. And assembling, baking, injecting liquid, forming and grading the bare cell to prepare the lithium battery with the capacity of 52 Ah. Obvious wrinkles appear on the surface of the diaphragm after the capacity grading of the lithium battery.
According to the first embodiment and the first comparative example, after the diaphragm is arranged between the positive and negative pole pieces of the lithium battery, if the diaphragm is not subjected to hot pressing, the positive and negative pole pieces after capacity grading of the lithium battery cannot be tightly adhered to the diaphragm, so that the diaphragm is wrinkled after subsequent steps such as capacity grading, and the like, and the problem that the diaphragm is wrinkled after capacity grading of the lithium battery can be solved only by coating PVDF on an aramid fiber base film and hot pressing. In addition, the preparation efficiency can be improved by increasing the hot-pressing temperature to reduce the hot-pressing time.
Second comparative example
The present embodiment is different from the second embodiment in that the bare cell of the lithium battery in the second comparative example is not hot-pressed.
The manufacturing process of the lithium battery in the embodiment is as follows: and repeatedly laminating the positive plate, the diaphragm and the negative electrode to obtain the naked electric core of the laminated lithium battery, wherein the negative plate is 22 layers, and the positive plate is 21 layers. The naked electric core of not being hot pressed, its thickness is obviously less than the thickness of naked electric core in the second embodiment. And assembling, baking, injecting liquid, forming and grading the bare cell to prepare the lithium battery with the capacity of 21 Ah. Obvious wrinkles appear on the surface of the diaphragm after the capacity grading of the lithium battery.
The following compares the rate performance of lithium batteries without and after hot pressing by discharging and charging at the rate of 3C for the lithium batteries in the first example and the first comparative example.
The 3C charging process comprises the following steps: (1) standing for 10 min; (2)17.16A constant current discharge, cut-off voltage 2.7V; (3) standing for 10 min; (4)156A is charged to 4.2V with constant current and constant voltage, and the current is cut off by 2.6A; (5) standing for 30 min.
The 3C discharging process comprises the following steps: (1) standing for 10 min; (2)17.16A constant current discharge, cut-off voltage 2.7V; (3) standing for 10 min; (4) charging to 4.2V at a constant current and a constant voltage of 17.16A, and cutting off the current of 2.6A; (5) standing for 10 min; (6)156A, constant current discharge, cut-off voltage 2.7V. In the above charge and discharge test, a Xinwei 200A test cabinet with model number CT-4008-5V200A-NTFA was used.
Fig. 1 is a graph of discharge curves at 3C rate for a first comparative example and a first embodiment of the present invention. Referring to fig. 1, a curve 3 is a discharge curve of the first embodiment at a 3C rate, and a curve 4 is a discharge curve of the first comparative example at a 3C rate, as can be seen from fig. 1, the discharge curve of the first embodiment at the 3C rate is gentler than the discharge curve of the first comparative example at the 3C rate, and the first embodiment has a rate performance advantage compared to the first comparative example.
Fig. 2 is a charging curve diagram at 3C rate for the first comparative example and the first embodiment, respectively. Referring to fig. 2, a curve 7 is a charging curve of the first embodiment at a 3C rate, and a curve 8 is a charging curve of the first comparative example at a 3C rate, as can be seen from fig. 2, the charging curve of the first embodiment at a 3C rate is gentler than the charging curve of the first comparative example at a 3C rate, and the first embodiment has a rate performance advantage compared with the first comparative example.
Fig. 3 is a diagram of a first comparative example and a bare cell thickness distribution according to a first embodiment of the present invention. Gather naked electric core sample in first embodiment and the first contrast ratio, and naked electric core sample number (naked electric core number) is 100. Through measuring, obtain relevant curve, wherein, curve 9 is the naked electric core thickness distribution diagram of first embodiment, and curve 10 is the naked electric core thickness distribution diagram of first contrast. By curve 9 and curve 10, the naked electric core thickness of the naked electric core of not hot pressing distributes widely, and the naked electric core thickness distribution uniformity after the hot pressing is good, consequently, first embodiment has the higher naked electric core thickness of uniformity than first contrast ratio.
In combination with the first embodiment and the first comparative example, after the diaphragm is arranged between the positive and negative electrode plates of the lithium battery, if hot pressing is not performed, the positive and negative electrode plates after capacity grading of the lithium battery cannot be tightly bonded with the diaphragm, so that the diaphragm is wrinkled after subsequent capacity grading and other steps.
Next, the lithium batteries of the second example and the second comparative example were subjected to cycle tests, respectively, to compare the cycle performance of the lithium batteries without hot pressing and with hot pressing.
The cycle test procedure was as follows: (1) standing for 10 min; (2)21A constant current discharge with cut-off voltage of 2.7V; (3) standing for 10 min; (4) charging to 4.25V at constant current and constant voltage of 42A, and cutting off current of 5.25A; (5) standing for 10 min; (6) the process steps (2) - (5) are cycled 2500 times (the cycling test is stopped with the capacity decaying to 80% of the capacity of the initial cell); (7)21A, constant current discharge, cut-off voltage 2.7V. In the above cycle test, a Xinwei 100A test cabinet, model CT-4016-5V100A-NTFA, was used.
After the above cycle test, a cycle graph of the second embodiment and the second comparative example is obtained. Fig. 4 is a graph of a cycle of a second comparative example and a second embodiment of the present invention. The curve 11 is a cycle curve of the second embodiment, and the curve 12 is a cycle curve of the second comparative example, it is obvious that the curve of the second embodiment is more gentle than the curve of the second comparative example, that is, the second embodiment has a cycle advantage than the second comparative example, that is, the lithium battery coated with polyvinylidene fluoride on the aramid-based film and subjected to hot pressing has a significant cycle advantage.
Fig. 5 is a cell thickness distribution diagram of a second comparative example and a second embodiment of the present invention. The naked electric core sample in second embodiment and the second contrast ratio is gathered, and naked electric core sample number (naked electric core number) is 100. Through measuring, obtain relevant curve, wherein, curve 13 is the naked electric core thickness distribution diagram of second embodiment, and curve 14 is the naked electric core thickness distribution diagram of second contrast ratio. By curve 13 and curve 14, the naked electric core thickness of the naked electric core of not hot pressing distributes widely, and the naked electric core thickness distribution uniformity after the hot pressing is good, consequently, the second embodiment has the higher naked electric core thickness of uniformity than the second opposite ratio.
The diaphragm comprises an aramid fiber base film and a coating arranged on at least one surface of the aramid fiber base film, is arranged between a positive plate and a negative plate, is manufactured into a bare cell through a lamination process or a winding process, and is then subjected to hot pressing to finally manufacture the lithium battery. According to the invention, the aramid fiber base film coated with the adhesive is arranged between the positive plate and the negative plate of the lithium battery, so that a naked battery core can be prepared through a winding process and a lamination process, the process is simple, the problem of low hot-pressing efficiency caused by that a conventional diaphragm can only be hot-pressed at low temperature (the temperature is generally below 80 ℃ and maximally not more than 90 ℃) due to no high temperature resistance in the hot-pressing process can be solved, and the problem that the diaphragm is wrinkled after capacity grading of the battery core can be solved.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.
Claims (9)
1. The diaphragm is characterized by comprising an aramid fiber base film, wherein a coating layer is formed on at least one surface of the aramid fiber base film.
2. The separator of claim 1, wherein the material of the coating is polyvinylidene fluoride.
3. A lithium battery comprising a positive electrode sheet and a negative electrode sheet, wherein the separator according to any one of claims 1 to 2 is provided between the positive electrode sheet and the negative electrode sheet, and the separator is provided between the positive electrode sheet and the negative electrode sheet.
4. The lithium battery according to claim 3, wherein the separator is bonded to the positive electrode sheet and/or the negative electrode sheet by hot pressing.
5. A lithium battery as claimed in claim 4, characterized in that the temperature of the hot pressing is 120 ℃ to 150 ℃.
6. A lithium battery according to claim 4, characterized in that the pressure of the hot pressing is 1.0 ton to 4.6 ton.
7. A lithium battery as claimed in claim 4, characterized in that the hot pressing time is 20 seconds to 60 seconds.
8. The lithium battery according to claim 4, wherein the total number of layers of the positive electrode sheet and the negative electrode sheet is 21 to 89 layers.
9. A method of manufacturing a lithium battery as claimed in any one of claims 3 to 8, characterized in that it comprises the steps of:
stacking or winding at least one positive plate, at least one negative plate and at least one diaphragm to form a naked battery cell;
and the diaphragm is bonded with the positive plate and/or the negative plate by hot-pressing the bare cell.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011509151.1A CN112582751A (en) | 2020-12-18 | 2020-12-18 | Diaphragm, lithium battery and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202011509151.1A CN112582751A (en) | 2020-12-18 | 2020-12-18 | Diaphragm, lithium battery and preparation method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN112582751A true CN112582751A (en) | 2021-03-30 |
Family
ID=75136149
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202011509151.1A Pending CN112582751A (en) | 2020-12-18 | 2020-12-18 | Diaphragm, lithium battery and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN112582751A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114388985A (en) * | 2022-01-18 | 2022-04-22 | 烟台泰和新材料股份有限公司 | Para-aramid lithium battery diaphragm and preparation method thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130199030A1 (en) * | 2012-02-07 | 2013-08-08 | Samsung Sdi Co., Ltd. | Method of preparing lithium secondary battery |
| CN106486703A (en) * | 2016-11-02 | 2017-03-08 | 浙江超威创元实业有限公司 | A kind of soft bag lithium ionic cell manufacture method of use pluralgel barrier film |
| US20180294508A1 (en) * | 2017-04-11 | 2018-10-11 | Hon Hai Precision Industry Co., Ltd. | Lithium ion battery diaphragm and method for manufacturing lithiumion battery diaphragm |
| CN108682895A (en) * | 2018-04-10 | 2018-10-19 | 东莞塔菲尔新能源科技有限公司 | A kind of manufacture craft of lithium-ion electric core |
| CN111313099A (en) * | 2019-10-25 | 2020-06-19 | 江苏丰盈科技有限公司 | Lithium ion battery lamination electric core body, lithium ion battery and lamination method |
| CN111384457A (en) * | 2018-12-28 | 2020-07-07 | 安普瑞斯（南京）有限公司 | Formation method for improving first charge-discharge efficiency of lithium ion battery |
-
2020
- 2020-12-18 CN CN202011509151.1A patent/CN112582751A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130199030A1 (en) * | 2012-02-07 | 2013-08-08 | Samsung Sdi Co., Ltd. | Method of preparing lithium secondary battery |
| CN106486703A (en) * | 2016-11-02 | 2017-03-08 | 浙江超威创元实业有限公司 | A kind of soft bag lithium ionic cell manufacture method of use pluralgel barrier film |
| US20180294508A1 (en) * | 2017-04-11 | 2018-10-11 | Hon Hai Precision Industry Co., Ltd. | Lithium ion battery diaphragm and method for manufacturing lithiumion battery diaphragm |
| CN108682895A (en) * | 2018-04-10 | 2018-10-19 | 东莞塔菲尔新能源科技有限公司 | A kind of manufacture craft of lithium-ion electric core |
| CN111384457A (en) * | 2018-12-28 | 2020-07-07 | 安普瑞斯（南京）有限公司 | Formation method for improving first charge-discharge efficiency of lithium ion battery |
| CN111313099A (en) * | 2019-10-25 | 2020-06-19 | 江苏丰盈科技有限公司 | Lithium ion battery lamination electric core body, lithium ion battery and lamination method |
Non-Patent Citations (2)
| Title |
|---|
| 张涛: "《新经济 新产业》", 31 July 2020 * |
| 蔡再生: "《染整概论》", 31 May 2020 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114388985A (en) * | 2022-01-18 | 2022-04-22 | 烟台泰和新材料股份有限公司 | Para-aramid lithium battery diaphragm and preparation method thereof |
| CN114388985B (en) * | 2022-01-18 | 2024-02-20 | 泰和新材集团股份有限公司 | Para-aramid lithium battery diaphragm and preparation method thereof |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN108390101B (en) | Lithium ion battery cell, preparation method thereof and lithium ion battery | |
| US10135090B2 (en) | Method for manufacturing electrode assembly | |
| CN107810569B (en) | Method for manufacturing bent electrode assembly | |
| KR20100137290A (en) | Manufacturing method of stacked electrodes by winding type electrode stacking and stacked electrode thereby | |
| TWI517476B (en) | Electrode assembly, fabricating method of electrode assembly and electrochemical cell containing the electrode assembly | |
| CZ20001956A3 (en) | Lithium secondary cell and process for producing thereof | |
| CN112750980A (en) | Negative plate, preparation method thereof and diaphragm-free battery cell | |
| CN105261781B (en) | Electrochemical cell and preparation method thereof | |
| CN105895860B (en) | A kind of takeup type laminated batteries electrode assembly production method | |
| CN212136623U (en) | Battery cell structure and lithium ion battery | |
| CN108470874A (en) | Improve method, the preparation process of lithium ion battery and the lithium ion battery of battery core extrusion performance | |
| CN112271340A (en) | Battery cell and preparation method thereof | |
| JP2022506188A (en) | Intermittently coated dry electrodes for energy storage devices and their manufacturing methods | |
| CN112133959A (en) | Manufacturing method of bipolar polymer lithium ion battery and lithium ion battery | |
| CN112582751A (en) | Diaphragm, lithium battery and preparation method thereof | |
| CN113571761B (en) | Clamping and stacking type electrode assembly and manufacturing method thereof | |
| CN111640993A (en) | Negative electrode assembly for lithium metal battery, lithium metal battery prepared therefrom and related methods | |
| CN115117560A (en) | Lithium-supplementing composite isolating membrane and preparation method and application thereof | |
| CN205985229U (en) | Lithium ion battery | |
| CN109244556B (en) | Battery cell forming device and method for improving wrinkle deformation of square lithium ion battery cell | |
| CN114171718A (en) | Pole piece preparation method of composite foil current collector, pole piece and soft package battery | |
| CN105932339A (en) | Fast preparation method of wound lithium-ion laminated battery | |
| CN113644321A (en) | Method and apparatus for stacking laminated batteries | |
| CN109244599B (en) | Composite negative pole piece with rapid heating function, and battery cell and battery adopting composite negative pole piece | |
| KR20200141859A (en) | Electrode-assembly and manufacturing method thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| RJ01 | Rejection of invention patent application after publication |
Application publication date: 20210330 |
|
| RJ01 | Rejection of invention patent application after publication |