CN110676514A

Movatterモバイル変換

Info

Publication number: CN110676514A
Application number: CN201810711661.3A
Authority: CN
Inventors: 康利斌; 唐堃; 张开周; 潘广宏; 康丹苗; 王璐璘
Original assignee: China Energy Investment Corp Ltd; National Institute of Clean and Low Carbon Energy
Current assignee: China Energy Investment Corp Ltd; National Institute of Clean and Low Carbon Energy
Priority date: 2018-07-03
Filing date: 2018-07-03
Publication date: 2020-01-10
Anticipated expiration: 2038-07-03
Also published as: CN110676514B

Abstract

Translated fromChinese

本发明涉及锂电池技术领域，公开了一种锂离子电池单体及其化成方法，其中，所述锂离子电池单体包括阳极、阴极、隔膜、电解液和封装材料，阳极容量A与阴极容量B的比值为0.7‑1。该锂离子电池单体具有高能量密度、高功率密度、电池内阻低、优异快充性能和长循环寿命，适合高倍率工况下长期使用；采用该化成方法在电池化成时最高截止容量按阳极容量截止，其能够有效地提高了电池化成过程的安全性；以及经该化成方法后的锂离子电池的内阻小，在5C充放电循环500次容量保持80％以上，以及5C快充结束后电池表面温度低，能够有效减少快充过程中的发热。

The invention relates to the technical field of lithium batteries, and discloses a lithium ion battery cell and a chemical synthesis method thereof, wherein the lithium ion battery cell comprises an anode, a cathode, a diaphragm, an electrolyte and a packaging material, and the anode capacity A and the cathode capacity The ratio of B is 0.7‑1. The lithium-ion battery cell has high energy density, high power density, low battery internal resistance, excellent fast charging performance and long cycle life, and is suitable for long-term use under high-rate conditions; using this formation method, the maximum cut-off capacity of the battery is determined by The anode capacity is cut off, which can effectively improve the safety of the battery formation process; and the internal resistance of the lithium-ion battery after the formation method is small, and the capacity remains more than 80% after 500 charge-discharge cycles at 5C, and the end of 5C fast charge The surface temperature of the rear battery is low, which can effectively reduce the heat generated during the fast charging process.

Description

Translated fromChinese

锂离子电池单体及其化成方法Lithium-ion battery cell and method for forming the same

技术领域technical field

本发明涉及锂电池技术领域，具体涉及一种锂离子电池单体及其化成方法。The invention relates to the technical field of lithium batteries, in particular to a lithium ion battery cell and a chemical synthesis method thereof.

背景技术Background technique

随着新能源汽车的快速发展，近年来市场对锂离子电池快充性能需求日益强烈。With the rapid development of new energy vehicles, the demand for fast charging performance of lithium-ion batteries has become increasingly strong in recent years.

传统锂离子电池在较低倍率下进行充电时，阴极材料中的锂离子可以充分脱出，并嵌入到阳极材料结构中。在电池设计时，为防止充电过程中阳极表面锂枝晶析出，阳极容量与阴极容量平衡比大于1。以无定形碳或包含无定形碳的材料为阳极的锂离子电池适合在大倍率下充电，在大倍率充电条件下，电池的极化不可避免，因此阴极材料中的锂离子不可全部脱出，并嵌入到阳极材料结构中。按传统电池设计以无定形碳或包含无定形碳的材料为阳极的快充型锂离子电池时，阳极容量与阴极容量平衡比大于1会造成电极厚度增加、电池温升高、快充效果减弱等弊端。When traditional lithium-ion batteries are charged at lower rates, the lithium ions in the cathode material can be fully extracted and intercalated into the anode material structure. In battery design, in order to prevent the precipitation of lithium dendrites on the anode surface during charging, the balance ratio of anode capacity to cathode capacity is greater than 1. Lithium-ion batteries using amorphous carbon or materials containing amorphous carbon as anodes are suitable for charging at high rates. Under high-rate charging conditions, the polarization of the battery is unavoidable, so the lithium ions in the cathode material cannot be completely released, and Embedded in the anode material structure. According to the traditional battery design, when the fast-charging lithium-ion battery uses amorphous carbon or materials containing amorphous carbon as the anode, the balance ratio of the anode capacity to the cathode capacity is greater than 1, which will cause the electrode thickness to increase, the battery temperature to rise, and the fast charging effect to weaken. and other disadvantages.

锂离子电池化成过程，也叫预充过程或首次充电过程，是指将电池在无电状态下充电，使之成为带电的原电池。化成是锂电池生产过程中必不可少的一道工序，其对锂电池性能的优劣起着至关重要的作用。特别是对于软包锂电池，化成不但有激活电池材料、改善锂电池界面、自放电、循环等作用，还具有增强电芯硬度、整形等功能。传统的热压化成工艺存在发软、析锂等问题。The lithium-ion battery formation process, also known as the pre-charging process or the first charging process, refers to charging the battery in an uncharged state to make it a charged primary battery. Formation is an indispensable process in the production process of lithium batteries, which plays a crucial role in the performance of lithium batteries. Especially for soft-pack lithium batteries, chemical formation not only has the functions of activating battery materials, improving the interface of lithium batteries, self-discharging, and cycling, but also enhancing the hardness and shaping of battery cells. The traditional hot pressing process has problems such as softening and lithium precipitation.

CN102916224A公开了一种锂离子电池化成方法，所述锂离子电池所使用的阳极活性物质包括无定形碳材料，所述化成方法至少包括充电和静置两个步骤，其特征在于：所述锂离子电池的电池平衡比为(1.04-1)：1，所述电池平衡比的计算公式为(A_c×A_w)/(C_c×C_w×C_f×A_f)，其中，A_c为阳极活性物质的首次充电克容量，单位为mAh/g，A_w为阳极活性物质的质量，单位为g，C_c为阴极活性物质设计电压下的首次放电克容量，单位为mAh/g，C_w为阴极活性物质的质量，单位为g，C_f为阴极活性物质的首次充放电效率，A_f为阳极活性物质的首次充放电效率；首次充电化成结束时阳极电位在0.03-0V之间。CN102916224A discloses a lithium ion battery formation method, the anode active material used in the lithium ion battery includes amorphous carbon material, and the formation method includes at least two steps of charging and standing, characterized in that: the lithium ion battery The cell balance ratio of the battery is (1.04-1): 1, and the calculation formula of the cell balance ratio is (A_c ×A_w )/(C_c ×C_w ×C_f ×A_f ), where A_c is The first charge gram capacity of the anode active material, in mAh/g, A_w is the mass of the anode active material, in g, C_c is the first discharge gram capacity at the design voltage of the cathode active material, in mAh/g, C_w is the mass of the cathode active material in g, C_f is the first charge-discharge efficiency of the cathode active material, and A_f is the first charge-discharge efficiency of the anode active material; the anode potential is between 0.03-0V at the end of the first charge formation.

CN102916224A首次化成结束时阳极电位控制在0.03-0V之间，能够提前将无定形碳材料的一些不可逆活性点充分消耗，在阳极表面形成完整的SEI膜，改善电池的高温存储性能。但是在电池设计时，阳极容量与阴极容量平衡比大于1，更加适应较低倍率充电，用于高倍率快速充电时，会带来电极厚度增加、内阻增加、快充效果减弱等弊端。The anode potential of CN102916224A is controlled between 0.03-0V at the end of the first formation, which can fully consume some irreversible active points of the amorphous carbon material in advance, form a complete SEI film on the anode surface, and improve the high-temperature storage performance of the battery. However, in battery design, the balance ratio of anode capacity to cathode capacity is greater than 1, which is more suitable for lower-rate charging. When used for high-rate fast charging, it will bring disadvantages such as increased electrode thickness, increased internal resistance, and weakened fast charging effect.

因此，为了克服传统高功率锂离子电池设计带来的电极厚度增加、内阻增加、快充效果减弱的缺陷问题，有必要研究和开发适用于高倍率快速充电的锂离子电池和化成方法。Therefore, in order to overcome the defects of increased electrode thickness, increased internal resistance, and weakened fast charging effect caused by traditional high-power lithium-ion battery design, it is necessary to research and develop lithium-ion batteries and formation methods suitable for high-rate fast charging.

发明内容SUMMARY OF THE INVENTION

本发明的目的是为了克服传统高功率锂离子电池设计带来的电极厚度增加、内阻增加、快充效果减弱的缺陷问题，提供一种锂离子电池单体及其化成方法，该锂离子电池单体的阳极容量A与阴极容量B的比值为0.7-1，具有优异快充性能和长循环寿命；采用该化成方法在电池化成时最高截止容量按阳极容量截止，其能够有效地提高了电池化成过程的安全性；以及经该化成方法后的锂离子电池的内阻小，5C充电容量保持率75％以上，在5C充放电循环500次容量保持80％以上，以及5C快充结束后电池表面温度低，能够有效减少快充过程中的发热。The purpose of the present invention is to overcome the defects of increased electrode thickness, increased internal resistance, and weakened fast charging effect caused by the design of traditional high-power lithium-ion batteries, and provides a lithium-ion battery cell and a method for forming the same. The lithium-ion battery The ratio of the anode capacity A to the cathode capacity B of the monomer is 0.7-1, which has excellent fast charging performance and long cycle life; the highest cut-off capacity of the battery is cut off according to the anode capacity when the battery is formed, which can effectively improve the battery. The safety of the formation process; and the internal resistance of the lithium-ion battery after the formation method is small, the 5C charging capacity retention rate is more than 75%, the capacity is maintained at more than 80% after 500 charge-discharge cycles at 5C, and the battery after the 5C fast charge is completed. The surface temperature is low, which can effectively reduce the heat generation during the fast charging process.

为了实现上述目的，本发明第一方面提供一种锂离子电池单体，所述锂离子电池单体包括阳极、阴极、隔膜、电解液和封装材料，其中，阳极容量A与阴极容量B的比值为0.7-1。In order to achieve the above object, a first aspect of the present invention provides a lithium ion battery cell, the lithium ion battery cell includes an anode, a cathode, a separator, an electrolyte and a packaging material, wherein the ratio of the anode capacity A to the cathode capacity B is is 0.7-1.

本发明第二方面提供了一种锂离子电池单体的化成方法，其中，该方法至少包括：将前述所述的锂离子电池单体进行充电和充电截止。A second aspect of the present invention provides a method for forming a lithium ion battery cell, wherein the method at least includes: charging and cutting off the above-mentioned lithium ion battery cell.

通过上述技术方案，由于该锂离子电池单体的阳极容量与阴极容量平衡比小于1，负极极片厚度减小，快充性能提高；电池内阻降低，减少快充过程中发热，电池的能量效率提高；可以补充电池长期快充循过程中消耗的锂，电池寿命增加；负极材料使用量减少，电池重量减轻，同时成本相对降低。另外，采用该化成方法在电池化成时最高截止容量按阳极容量截止，其能够有效地提高了电池化成过程的安全性；以及经该化成方法后的锂离子电池的内阻小，在5C充放电循环500次容量保持80％以上，以及5C快充结束后电池表面温度低，能够有效减少快充过程中的发热。Through the above technical solution, because the balance ratio of the anode capacity to the cathode capacity of the lithium ion battery is less than 1, the thickness of the negative electrode plate is reduced, and the fast charging performance is improved; the internal resistance of the battery is reduced, and the heat generated during the fast charging process is reduced. The efficiency is improved; the lithium consumed during the long-term fast charge cycle of the battery can be supplemented, and the battery life is increased; the use of negative electrode materials is reduced, the weight of the battery is reduced, and the cost is relatively reduced. In addition, the highest cut-off capacity is cut off according to the anode capacity when the battery is formed by this chemical formation method, which can effectively improve the safety of the battery formation process; and the internal resistance of the lithium-ion battery after this chemical formation method is small, and it can be charged and discharged at 5C. The capacity is maintained at more than 80% after 500 cycles, and the surface temperature of the battery is low after the 5C fast charge, which can effectively reduce the heat generated during the fast charge.

附图说明Description of drawings

图1是石墨阳极大倍率(5C)充电后电极表面状态图；Fig. 1 is a graph showing the state of the electrode surface after the graphite anode is charged at a high rate (5C);

图2是无定形碳阳极大倍率(5C)充电后电极表面状态图；Fig. 2 is the state diagram of the electrode surface after high-rate (5C) charging of the amorphous carbon anode;

图3是实施例1-3制备的锂离子电池S1-S3与对比例1制备的锂离子电池D1在阳极大倍率(5C)充放循环寿命对比图。3 is a comparison diagram of the charge-discharge cycle life of the lithium ion batteries S1-S3 prepared in Examples 1-3 and the lithium ion battery D1 prepared in Comparative Example 1 in the anode high rate (5C).

具体实施方式Detailed ways

在本文中所披露的范围的端点和任何值都不限于该精确的范围或值，这些范围或值应当理解为包含接近这些范围或值的值。对于数值范围来说，各个范围的端点值之间、各个范围的端点值和单独的点值之间，以及单独的点值之间可以彼此组合而得到一个或多个新的数值范围，这些数值范围应被视为在本文中具体公开。The endpoints of ranges and any values disclosed herein are not limited to the precise ranges or values, which are to be understood to encompass values proximate to those ranges or values. For ranges of values, the endpoints of each range, the endpoints of each range and the individual point values, and the individual point values can be combined with each other to yield one or more new ranges of values that Ranges should be considered as specifically disclosed herein.

本发明第一方面提供了一种锂离子电池单体，所述锂离子电池单体包括阳极、阴极、隔膜、电解液和封装材料，其中，阳极容量A与阴极容量B的比值为0.7-1。A first aspect of the present invention provides a lithium ion battery cell, the lithium ion battery cell includes an anode, a cathode, a separator, an electrolyte and a packaging material, wherein the ratio of the anode capacity A to the cathode capacity B is 0.7-1 .

根据本发明，所述阳极容量A与所述阴极容量B的比值优选为0.85-1；在本发明中，将所述阳极容量A与所述阴极容量B的比值限定为上述范围之内，能够使负极极片厚度减小，提高快充性能；能够降低电池内阻，减少快充过程中发热，提高电池的能量效率；能够补充电池长期快充循过程中消耗的锂，电池寿命增加；以及负极材料使用量减少，电池重量减轻，同时成本相对降低。According to the present invention, the ratio of the anode capacity A to the cathode capacity B is preferably 0.85-1; It can reduce the thickness of the negative pole piece and improve the fast charging performance; it can reduce the internal resistance of the battery, reduce the heat during the fast charging process, and improve the energy efficiency of the battery; it can supplement the lithium consumed during the long-term fast charging cycle of the battery, and the battery life is increased; and The amount of negative electrode material used is reduced, the weight of the battery is reduced, and the cost is relatively reduced.

优选情况下，所述阳极容量A为阳极活性材料总容量，所述阴极容量B为阴极活性材料总容量。Preferably, the anode capacity A is the total capacity of the anode active material, and the cathode capacity B is the total capacity of the cathode active material.

根据本发明，所述阳极包括无定形碳材料；优选地，所述无定形碳材料占阳极活性物质总质量的5-99％，优选为50-99％；优选地，所述无定形碳材料包括软碳和硬碳中的至少一种，优选地，所述无定形碳材料包括软碳。According to the present invention, the anode includes an amorphous carbon material; preferably, the amorphous carbon material accounts for 5-99%, preferably 50-99%, of the total mass of the anode active material; preferably, the amorphous carbon material Comprising at least one of soft carbon and hard carbon, preferably, the amorphous carbon material comprises soft carbon.

根据本发明，所述阴极可以为钴酸锂、锰酸锂、镍锰酸锂、镍钴锰酸锂、镍钴铝酸锂和磷酸铁锂中一种或几种。According to the present invention, the cathode can be one or more of lithium cobalt oxide, lithium manganate, lithium nickel manganate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate and lithium iron phosphate.

根据本发明，所述电解液可以包括有机溶剂、添加剂和锂盐。According to the present invention, the electrolyte may include an organic solvent, an additive and a lithium salt.

其中，优选情况下，所述有机溶剂可以为碳酸丙烯酯PC(Propylene Carbonate)、碳酸乙烯酯EC(Ethylene Carbonate)和碳酸二甲酯DEC(Dimethyl Carbonate)中的一种或多种。Wherein, preferably, the organic solvent may be one or more of propylene carbonate PC (Propylene Carbonate), ethylene carbonate EC (Ethylene Carbonate) and dimethyl carbonate DEC (Dimethyl Carbonate).

其中，优选情况下，所述添加剂可以包括碳酸亚乙烯酯VC(Vinylene Carbonate)、亚硫酸丙烯酯PS(propylene sulfite)和氟代碳酸乙烯酯FEC(FluoroethyleneCarbonate)中的一种或者多种；并且，在本发明中，以所述电解液的总重量为基准，所述添加剂的用量为0.5-5重量％。Wherein, preferably, the additive may include one or more of vinylene carbonate VC (Vinylene Carbonate), propylene sulfite PS (propylene sulfite) and fluoroethylene carbonate FEC (Fluoroethylene Carbonate); and, In the present invention, based on the total weight of the electrolyte, the additive is used in an amount of 0.5-5% by weight.

其中，优选情况下，所述锂盐可以为六氟磷酸锂、四氟硼酸锂和六氟砷酸锂中的一种或多种，且所述锂盐的浓度可以为1.2-2M，优选为1.2-1.4M。Wherein, preferably, the lithium salt can be one or more of lithium hexafluorophosphate, lithium tetrafluoroborate and lithium hexafluoroarsenate, and the concentration of the lithium salt can be 1.2-2M, preferably 1.2-1.4 M.

根据本发明，所述隔膜可以为PP膜(聚丙烯Polypropylene，简称PP)、PE膜(聚乙烯Polyethylene，简称PE)和PP/PE/PP复合膜中的一种或多种，优选情况下，所述隔膜的厚度可以为16-26μm，在本发明中，更优选情况下，所述隔膜为厚度为20-25μm的PP/PE/PP复合膜；最优选情况下，所述隔膜为厚度为25um的PP/PE/PP复合膜；在本发明中，PP/PE/PP表示第一PP膜、PE膜和第二PP膜复合而成的复合膜，其中，第一PP膜和第二PP膜可以为相同的PP膜。According to the present invention, the separator can be one or more of PP film (Polypropylene, PP for short), PE film (Polyethylene, PE for short) and PP/PE/PP composite film, preferably, The thickness of the separator can be 16-26 μm. In the present invention, more preferably, the separator is a PP/PE/PP composite film with a thickness of 20-25 μm; 25um PP/PE/PP composite film; in the present invention, PP/PE/PP represents the composite film formed by the composite of the first PP film, the PE film and the second PP film, wherein the first PP film and the second PP film The membrane can be the same PP membrane.

所述封装材料可以为铝塑膜封装材料、铝壳和钢壳中的一种或多种，优选为铝塑膜封装材料。The packaging material may be one or more of an aluminum-plastic film packaging material, an aluminum case and a steel case, preferably an aluminum-plastic film packaging material.

根据本发明，所述充电包括第一恒流充电和第二恒流充电截止；According to the present invention, the charging includes the first constant current charging and the second constant current charging being turned off;

根据本发明，所述第一恒流充电的条件包括：充电电流为0.01-1C，优选为0.01-0.05C；时间为100-1h，优选为50-10h。According to the present invention, the conditions of the first constant current charging include: the charging current is 0.01-1C, preferably 0.01-0.05C; the time is 100-1h, preferably 50-10h.

根据本发明，所述第二恒流充电的条件包括：充电电流为0.01-2C，优选为0.1-2C，更优选为0.1-1C；当锂离子电池容量达到阳极容量A时停止充电。According to the present invention, the conditions for the second constant current charging include: the charging current is 0.01-2C, preferably 0.1-2C, more preferably 0.1-1C; charging is stopped when the lithium-ion battery capacity reaches the anode capacity A.

根据本发明，采用该化成方法在电池化成时按阳极容量A截止，其能够有效地提高了电池化成过程的安全性。According to the present invention, the formation method is used to cut off according to the anode capacity A during the formation of the battery, which can effectively improve the safety of the formation process of the battery.

根据本发明，经该化成方法后的锂离子电池的内阻小；在5C充放电循环500次容量保持80％以上，以及5C快充结束后电池表面温度低，能够有效减少快充过程中的发热。According to the present invention, the internal resistance of the lithium ion battery after the formation method is small; the capacity is maintained at more than 80% after 500 charge-discharge cycles at 5C; fever.

以下将通过实施例对本发明进行详细描述。The present invention will be described in detail below by means of examples.

以下实施例和对比例中，性能参数测定如下：In the following examples and comparative examples, the performance parameters are determined as follows:

(1)电池性能测试(内阻测试)：将化成结束后的锂电池用交流阻抗仪测试电池内阻，其中，交流阻抗仪购自Tonghui，型号为TH9310B；(1) Battery performance test (internal resistance test): The internal resistance of the lithium battery after the formation is tested with an AC impedance meter, wherein the AC impedance meter is purchased from Tonghui, and the model is TH9310B;

(2)5C快充容量保持率、5C充电结束电池表面温度测试：将化成结束后的锂电池以1C恒电流放电至截止电压2.5V，再以5C恒电流充电至截止电压4.2V，同时记录电池表面中心点温度；按以上程序进行5次循环测试，得到5C充电平均容量，充电结束时测试表面中心点平均温度。(2) 5C fast charging capacity retention rate, battery surface temperature test after 5C charging: discharge the lithium battery after formation with a 1C constant current to a cut-off voltage of 2.5V, and then charge it with a 5C constant current to a cut-off voltage of 4.2V, and record at the same time The temperature of the center point of the battery surface; 5 cycle tests are carried out according to the above procedure, and the average charging capacity of 5C is obtained, and the average temperature of the center point of the surface is tested at the end of charging.

(3)5C充放循环测试：将化成结束后的锂电池以5C恒电流放电至截止电压2.5V，再以5C恒电流充电至截止电压4.2V，按以上程序进行500次循环测试，记录每次循环的充放电容量。(3) 5C charge-discharge cycle test: discharge the lithium battery after formation with a 5C constant current to a cut-off voltage of 2.5V, and then charge it with a 5C constant current to a cut-off voltage of 4.2V, and perform 500 cycle tests according to the above procedure, and record each charge-discharge capacity per cycle.

实施例1Example 1

本实施例在于说明本发明的锂离子电池单体及化成方法。This embodiment is to illustrate the lithium ion battery cell and the formation method of the present invention.

(1)采用快充型1Ah软包装锂离子电池，按阳极容量A与阴极容量B的比值为0.9进行电池设计；(1) Adopt fast-charging 1Ah flexible packaging lithium-ion battery, and design the battery according to the ratio of anode capacity A and cathode capacity B to 0.9;

其中，阳极材料为无定形碳材料，所述无定形碳材料占阳极活性物质总质量的95％；Wherein, the anode material is an amorphous carbon material, and the amorphous carbon material accounts for 95% of the total mass of the anode active material;

其中，阴极材料为333型镍钴锰酸锂，所述阴极材料占阳极活性物质总质量的94％；Among them, the cathode material is 333 type nickel cobalt manganate lithium, and the cathode material accounts for 94% of the total mass of the anode active material;

其中，隔膜为25μm厚三层PP/PE/PP复合膜；Among them, the diaphragm is a 25μm thick three-layer PP/PE/PP composite film;

其中，电解液的浓度为1.3M(其中，2％FEC添加剂)；Wherein, the concentration of the electrolyte is 1.3M (wherein, 2% FEC additive);

其中，电池采用铝塑膜封装。Among them, the battery is packaged with aluminum plastic film.

(2)将制作好的电池进行化成：(2) Convert the fabricated battery into:

第一步：0.02C恒流充电20小时；The first step: 0.02C constant current charging for 20 hours;

第二步：0.1C恒流充电，充电容量等于阳极设计容量4.2V时停止充电。The second step: 0.1C constant current charging, stop charging when the charging capacity is equal to the anode design capacity of 4.2V.

将化成后的锂电池记为S1，且对其进行性能测试，结果如表1所示。The formed lithium battery is denoted as S1, and its performance is tested, and the results are shown in Table 1.

另外，图2是无定形碳阳极大倍率(5C)充电后电极表面状态图；In addition, Figure 2 is a diagram of the electrode surface state after the amorphous carbon anode is charged at a high rate (5C);

从图2可以看出：由于采用无定形碳材料结构异于石墨，无定形碳材料层间距大，有序度低，锂离子传输路径短、方向多，锂离子输运速度快，因此以无定形碳材料为阳极电池在大倍率下充电(5C)可以有效避免因大电流充电而导致的阳极析锂，无定形碳阳极大倍率(5C)充电后表面没有析锂现象。It can be seen from Figure 2 that due to the structure of amorphous carbon material is different from that of graphite, the interlayer spacing of amorphous carbon material is large, the degree of order is low, the transport path of lithium ions is short, the directions are many, and the transport speed of lithium ions is fast. The shaped carbon material is used for the anode battery to be charged at a high rate (5C), which can effectively avoid the anode lithium deposition caused by high current charging, and the amorphous carbon anode does not have lithium deposition on the surface after high rate (5C) charging.

因而无定形碳材料非常适合的应用在对快速充电有着较高要求的锂离子电池阳极上。Therefore, amorphous carbon materials are very suitable for the application of lithium-ion battery anodes that have high requirements for fast charging.

实施例2Example 2

按照与实施例1相同的化成方法制备锂离子电池，所不同之处在于：所提供的锂离子电池单体的阳极容量A与阴极容量B的比值为0.7。A lithium ion battery was prepared according to the same chemical synthesis method as in Example 1, except that the ratio of the anode capacity A to the cathode capacity B of the provided lithium ion battery cell was 0.7.

将化成后的锂电池记为S2，且对其进行性能测试，结果如表1所示。The formed lithium battery is denoted as S2, and its performance is tested, and the results are shown in Table 1.

实施例3Example 3

本实施例在于说明本发明的锂离子电池单体及化成方法和锂离子电池。This embodiment is to illustrate the lithium ion battery cell and its formation method and the lithium ion battery of the present invention.

按照与实施例1相同的化成方法制备锂离子电池，所不同之处在于：所提供的锂离子电池单体的阳极容量A与阴极容量B的比值为1。A lithium ion battery was prepared according to the same chemical synthesis method as in Example 1, except that the ratio of the anode capacity A to the cathode capacity B of the provided lithium ion battery cell was 1.

将化成后的锂电池记为S3，且对其进行性能测试，结果如表1所示。The formed lithium battery is denoted as S3, and its performance is tested, and the results are shown in Table 1.

实施例4Example 4

按照与实施例1相同的化成方法制备锂离子电池，所不同之处在于：所提供的锂离子电池单体的阳极容量A与阴极容量B的比值为0.8。The lithium ion battery was prepared according to the same chemical synthesis method as in Example 1, except that the ratio of the anode capacity A to the cathode capacity B of the provided lithium ion battery cell was 0.8.

将化成后的锂电池记为S4，且对其进行性能测试，结果如表1所示。The formed lithium battery is denoted as S4, and its performance is tested, and the results are shown in Table 1.

实施例5Example 5

按照与实施例1相同的化成方法制备锂离子电池，所不同之处在于：The lithium ion battery was prepared according to the same chemical synthesis method as in Example 1, except that:

将制作好的电池进行化成：Convert the fabricated battery into:

第一步：0.01C恒流充电50小时；The first step: 0.01C constant current charging for 50 hours;

第二步：0.1C恒流充电，充电容量等于阳极容量时停止充电。The second step: 0.1C constant current charging, stop charging when the charging capacity is equal to the anode capacity.

将化成后的锂电池记为S5，且对其进行性能测试，结果如表1所示。The formed lithium battery is denoted as S5, and its performance is tested, and the results are shown in Table 1.

实施例6Example 6

将制作好的电池进行化成：Convert the fabricated battery into:

第二步：2C恒流充电，充电容量等于4.2V阳极容量时停止充电。The second step: 2C constant current charging, stop charging when the charging capacity is equal to the 4.2V anode capacity.

将化成后的锂电池记为S6，且对其进行性能测试，结果如表1所示。The formed lithium battery is denoted as S6, and its performance is tested, and the results are shown in Table 1.

实施例7Example 7

按照与实施例1相同的化成方法制备锂离子电池，所不同之处在于：所述无定型碳为硬碳。A lithium ion battery was prepared according to the same chemical synthesis method as in Example 1, except that the amorphous carbon was hard carbon.

将化成后的锂电池记为S7，且对其进行性能测试，结果如表1所示。The formed lithium battery is denoted as S7, and its performance is tested, and the results are shown in Table 1.

对比例1Comparative Example 1

按照与实施例1相同的化成方法制备锂离子电池，所不同之处在于：所提供的锂离子电池单体的阳极容量A与阴极容量B的比值为1.1。A lithium ion battery was prepared according to the same chemical synthesis method as in Example 1, except that the ratio of the anode capacity A to the cathode capacity B of the provided lithium ion battery cell was 1.1.

化成后的锂电池记为D1，且对其进行性能测试，结果如表1所示。The formed lithium battery is denoted as D1, and its performance is tested, and the results are shown in Table 1.

对比例2Comparative Example 2

按照与实施例1相同的化成方法制备锂离子电池，所不同之处在于：所提供的锂离子电池单体的阳极采用石墨。A lithium ion battery was prepared according to the same chemical synthesis method as in Example 1, except that the anode of the provided lithium ion battery cell was made of graphite.

化成后的锂电池记为D2，且对其进行性能测试，结果如表1所示。The formed lithium battery was recorded as D2, and its performance was tested. The results are shown in Table 1.

另外，图1是石墨阳极大倍率(5C)充电后电极表面的状态图；In addition, Figure 1 is a state diagram of the electrode surface after the graphite anode is charged at a high rate (5C);

从图1中可以看出：由于采用石墨为阳极，由于层间距较小、扩散路径长，锂离子输运速度慢，因此限制了锂离子电池的充电速度，以石墨为阳极的电池一般在较低倍率下进行充电(小于2C)，一旦充电速度加大，阳极就面临表面析锂的安全隐患，石墨阳极大倍率(5C)充电后表面析锂，且容量迅速衰减。It can be seen from Figure 1 that due to the use of graphite as the anode, due to the small interlayer spacing, long diffusion path and slow lithium ion transport speed, the charging speed of lithium ion batteries is limited. When charging at a low rate (less than 2C), once the charging speed is increased, the anode will face the safety hazard of lithium deposition on the surface. After the graphite anode is charged at a high rate (5C), lithium will be deposited on the surface, and the capacity will decay rapidly.

对比例3Comparative Example 3

将制作好的电池进行化成：Convert the fabricated battery into:

第二步：0.1C恒流充电，充电容量等于阴极容量时停止充电。The second step: 0.1C constant current charging, stop charging when the charging capacity is equal to the cathode capacity.

将化成后的锂电池记为D3，且对其进行性能测试，结果如表1所示。The formed lithium battery was recorded as D3, and its performance was tested. The results are shown in Table 1.

对比例4Comparative Example 4

按照与实施例1相同的化成方法制备锂离子电池，所不同之处在于：所提供的锂离子电池单体的阳极容量A与阴极容量B的比值为0.6。The lithium ion battery was prepared according to the same chemical synthesis method as in Example 1, except that the ratio of the anode capacity A to the cathode capacity B of the provided lithium ion battery cell was 0.6.

化成后的锂电池记为D4，且对其进行性能测试，结果如表1所示。The formed lithium battery was denoted as D4, and its performance was tested. The results are shown in Table 1.

表1Table 1

编号Numbering内阻(mΩ)Internal resistance (mΩ)5C快充容量保持率5C fast charge capacity retention rate5C充电结束电池表面温度(℃)5C charging end battery surface temperature (℃)实施例1Example 110.3710.3777％77%35.135.1实施例2Example 29.659.6580％80%34.334.3实施例3Example 310.5810.5875％75%35.635.6实施例4Example 410.1210.1277％77%34.834.8实施例5Example 510.2910.2976％76%35.335.3实施例6Example 610.3110.3176％76%35.635.6实施例7Example 710.1510.1580％80%34.134.1对比例1Comparative Example 111.2711.2771％71%37.337.3对比例2Comparative Example 212.5112.5165％65%38.238.2对比例3Comparative Example 310.6110.6174％74%39.139.1对比例4Comparative Example 410.6910.6951％51%35.735.7

通过表1的结果可以看出，采用本发明的方法制备的实施例S1-S7锂离子电池5C充电容量保持75％以上，说明按照本发明方法能够有效提高电池快充容量；S1-S7锂离子电池的内阻为9.65-10.37，说明按照本发明的化成方法能够降低电池内阻；以及S1-S7锂离子电池的表面温度为34.1-35.6℃，说明按照本发明的化成方法能够有效减少快充过程中的发热。It can be seen from the results in Table 1 that the 5C charging capacity of the S1-S7 lithium ion battery prepared by the method of the present invention maintains more than 75%, indicating that the method of the present invention can effectively improve the battery fast charge capacity; S1-S7 lithium ion battery The internal resistance of the battery is 9.65-10.37, indicating that the chemical synthesis method according to the present invention can reduce the internal resistance of the battery; and the surface temperature of the S1-S7 lithium-ion battery is 34.1-35.6 °C, indicating that the chemical forming method according to the present invention can effectively reduce fast charging. heat during the process.

另外，图3是实施例1-3制备的锂离子电池S1-S3与对比例1制备的锂离子电池D1在大倍率(5C)充放循环寿命对比图，从图3中可以看出：采用本发明的方法制备的电池能有效提高电池循环寿命，大倍率(5C)充放循环500次后容量保持率大于80％。In addition, Figure 3 is a comparison chart of the charge-discharge cycle life of lithium-ion batteries S1-S3 prepared in Example 1-3 and lithium-ion battery D1 prepared in Comparative Example 1 at a large rate (5C). It can be seen from Figure 3 that: The battery prepared by the method of the invention can effectively improve the cycle life of the battery, and the capacity retention rate is greater than 80% after 500 high-rate (5C) charge-discharge cycles.

以上详细描述了本发明的优选实施方式，但是，本发明并不限于此。在本发明的技术构思范围内，可以对本发明的技术方案进行多种简单变型，包括各个技术特征以任何其它的合适方式进行组合，这些简单变型和组合同样应当视为本发明所公开的内容，均属于本发明的保护范围。The preferred embodiments of the present invention have been described above in detail, however, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, a variety of simple modifications can be made to the technical solutions of the present invention, including the combination of various technical features in any other suitable manner. These simple modifications and combinations should also be regarded as the content disclosed in the present invention. All belong to the protection scope of the present invention.

Claims

1. A lithium ion battery monomer comprises an anode, a cathode, a diaphragm, electrolyte and a packaging material, and is characterized in that the ratio of the anode capacity A to the cathode capacity B is 0.7-1.

2. The lithium ion battery cell of claim 1, wherein the ratio of the anode capacity a to the cathode capacity B is 0.85-1; preferably, the anode capacity a is a total anode active material capacity, and the cathode capacity B is a total cathode active material capacity.

3. The lithium ion battery cell of claim 1, wherein the anode comprises an amorphous carbon material; preferably, the amorphous carbon material accounts for 5-99%, preferably 50-99% of the total mass of the anode active material; preferably, the amorphous carbon material includes at least one of soft carbon and hard carbon.

4. The lithium ion battery cell of claim 1, wherein the cathode is one or more of lithium cobaltate, lithium manganate, lithium nickel cobalt aluminate, and lithium iron phosphate.

5. The lithium ion battery cell of claim 1, wherein the electrolyte comprises an organic solvent, an additive, and a lithium salt; preferably, the organic solvent is one or more of propylene carbonate, ethylene carbonate and dimethyl carbonate; the additive comprises one or more of vinylene carbonate, propylene sulfite and fluoroethylene carbonate; the lithium salt is one or more of lithium hexafluorophosphate, lithium tetrafluoroborate and lithium hexafluoroarsenate, and the concentration of the lithium salt is 1.2-2M.

6. The lithium ion battery cell of claim 1, wherein the separator is one or more of a PP film, a PE film and a PP/PE/PP composite film, preferably the separator has a thickness of 16-26 μ ι η, more preferably the separator is a PP/PE/PP composite film having a thickness of 20-25 μ ι η.

7. A method for forming a lithium ion battery cell is characterized by at least comprising the following steps: charging and charge-blocking the lithium-ion battery cell of any of claims 1-6.

8. The chemical formation method of claim 7, wherein the charging comprises a first constant current charging and a second constant current charging being off.

9. The formation method according to claim 8, wherein the condition of the first constant current charging includes: the charging current is 0.01-1C, and the time is 100-1 h; the second constant current charging condition includes: the charging current is 0.01-2C, and the charging is stopped when the capacity of the lithium ion battery reaches the anode capacity A.

10. The formation method according to claim 9, wherein the conditions of the first constant current charging include: the charging current is 0.01-0.05C, and the time is 50-10 h; the second constant current charging condition includes: the charging current is 0.1-2C.