WO2020078286A1 - 电解液及二次电池、电池模块、电池包、装置 - Google Patents

电解液及二次电池、电池模块、电池包、装置 Download PDF

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WO2020078286A1
WO2020078286A1 PCT/CN2019/110849 CN2019110849W WO2020078286A1 WO 2020078286 A1 WO2020078286 A1 WO 2020078286A1 CN 2019110849 W CN2019110849 W CN 2019110849W WO 2020078286 A1 WO2020078286 A1 WO 2020078286A1
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electrolyte
battery
lithium
carbonate
mass ratio
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PCT/CN2019/110849
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English (en)
French (fr)
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唐代春
张小细
姜玲燕
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宁德时代新能源科技股份有限公司
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Publication of WO2020078286A1 publication Critical patent/WO2020078286A1/zh

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • 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
    • H01M10/0567—Liquid materials characterised by the additives
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2300/00—Electrolytes
    • H01M2300/0017—Non-aqueous electrolytes
    • H01M2300/0025—Organic electrolyte
    • 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

Definitions

  • the invention relates to the technical field of batteries, in particular to an electrolyte, a secondary battery, a battery module, a battery pack, and a device.
  • the main methods are: improving the dynamics of the negative electrode and reducing the impedance of the cell; improving the conductivity of the electrolyte; limiting the user to charge large currents.
  • these methods can extend the service life of the battery pack, they cannot fundamentally solve the problem of diving or even safety during the use of the battery cell, mainly because the dynamics of the negative electrode will inevitably decrease during the use of the battery cell, and the electrolyte It will be gradually consumed, and the local dynamics are insufficient during use, which leads to the inevitable lithium evolution. Users are charging and discharging electric vehicles for a long time, and the safety risk caused by lithium precipitation is high.
  • the object of the present invention is to provide an electrolyte and a secondary battery, the secondary battery has a low impedance during use, and can take into account both excellent cycle performance and long cycle Life and safety performance.
  • the first aspect of the present invention provides an electrolyte, which includes a lithium salt, an organic solvent, and an additive, and the additive includes nitrogen.
  • a second aspect of the present invention provides a secondary battery including a positive electrode sheet, a negative electrode sheet, a separator disposed between the positive electrode sheet and the negative electrode sheet, and the electrolyte of the first aspect of the present invention.
  • a third aspect of the present invention provides a battery module including the secondary battery according to the second aspect of the present invention.
  • a fourth aspect of the present invention provides a battery pack including the battery module described in the third aspect of the present invention.
  • a fifth aspect of the present invention provides a device including the secondary battery according to the second aspect of the present invention, the secondary battery being used as a power source for the device.
  • Oxygen and carbon dioxide are usually present in the electrolyte. These gases will undergo side reactions on the surface of the positive and negative electrodes to form compounds such as lithium carbonate. The formation of these compounds will increase the impedance of the cell and affect the service life of the battery. Adding nitrogen to the electrolyte of the present invention can effectively exclude oxygen and carbon dioxide, which solves this problem from the root cause and reduces the impedance of the battery.
  • Li 3 N is an electronic insulator, which will prevent direct contact between electrons and lithium ions due to the low potential of the lithium deposition area, prevent the diffusion of lithium deposition, and thereby passivate lithium deposition, prolonging the life of the battery during use. It also avoids the safety problems caused by prolonging the generation of lithium dendrites during long-term use.
  • the battery module, battery pack and device of the present invention include the aforementioned secondary battery, and thus have at least the same advantages as the secondary battery.
  • FIG. 1 is a schematic diagram of an embodiment of the secondary battery of the present invention.
  • FIG. 2 is a schematic diagram of an embodiment of the battery module of the present invention.
  • FIG. 3 is a schematic diagram of an embodiment of the battery pack of the present invention.
  • Fig. 4 is an exploded view of Fig. 3.
  • FIG. 5 is a schematic diagram of an embodiment of a device in which the secondary battery of the present invention is used as a power source.
  • the electrolyte of the first aspect of the present invention includes: a lithium salt, an organic solvent, and an additive, where the additive includes nitrogen.
  • Li 3 N is an electronic insulator, which will prevent direct contact between electrons and lithium ions due to the low potential of the lithium deposition area, prevent the diffusion of lithium deposition, and thereby passivate lithium deposition, prolonging the life of the battery during use. It also avoids the safety problems caused by prolonging the generation of lithium dendrites during long-term use.
  • nitrogen is used as the additive.
  • the mass ratio of the nitrogen in the electrolyte is 0.01% -1.2%, 0.2% -0.5%, 0.01% -0.05%, 0.05% -0.1%, 0.1% -0.2%, 0.2% -0.3%, 0.3% -0.5%, 0.5% -0.7%, 0.7% -1.2%.
  • the mass ratio of nitrogen in the electrolyte is 0.2% -0.5%.
  • Low amount of nitrogen added the lithium precipitated in the battery during the cycle reacts with nitrogen, and the generated lithium nitride content is small, which cannot play the role of passivation of lithium precipitation; the high amount of nitrogen added, due to the solubility limit of the electrolyte, nitrogen is easy overflow.
  • the electrolyte further includes oxygen and / or carbon dioxide, the mass ratio of oxygen in the electrolyte is less than or equal to 0.04%, and the mass ratio of carbon dioxide in the electrolyte is 0.02% or less.
  • Oxygen and carbon dioxide are usually present in the electrolyte. These gases will undergo side reactions on the surface of the positive and negative electrodes to form compounds such as lithium carbonate. The formation of these compounds will increase the impedance of the cell and affect the service life of the battery.
  • the inventors found that adding nitrogen to the electrolyte can effectively eliminate oxygen and carbon dioxide, which solves this problem from the root cause and reduces the impedance of the battery.
  • the mass ratio of oxygen / carbon dioxide in the electrolyte of the present invention refers to the mass ratio of oxygen / carbon dioxide remaining in the electrolyte after adding nitrogen to the electrolyte.
  • the mass ratio of the oxygen in the electrolyte is 0% -0.04%, 0% -0.01%, 0.01% -0.02%, 0.02% -0.03%, 0.03% -0.04% .
  • the mass ratio of the oxygen in the electrolyte is 0% -0.01%.
  • the mass ratio of the carbon dioxide in the electrolyte is 0% -0.02%, 0% -0.01%, 0.01% -0.02%.
  • the mass ratio of carbon dioxide in the electrolyte is 0% -0.01%.
  • the additive further includes one or more of amine compounds, lithium azide, or diazo compounds.
  • the amine compound is selected from primary amines, and the amine compound is preferably selected from one or more of methylamine, ethylenediamine, and aniline.
  • the mass ratio of the amine compound in the electrolyte is 0.01% -10%, 1% -3%, 0.01% -0.05%, 0.05% -1%, 1%- 3%, 3% -5%, 5% -7%, 7% -10%.
  • the mass ratio of the amine compound in the electrolyte is 1% -3%.
  • the amount of amine compound added is low, the lithium precipitated in the cell during the cycle reacts with the amine compound, and the generated lithium nitride content is small, which can not play the role of passivation of lithium precipitation. Core performance has an impact, resulting in poor cycling or power performance.
  • the mass ratio of the lithium azide in the electrolyte is 0.01% -10%, 1% -3%, 0.01% -0.05%, 0.05% -1%, 1% -3%, 3% -5%, 5% -7%, 7% -10%.
  • the mass ratio of the lithium azide in the electrolyte is 1% -3%.
  • Low addition of lithium azide and low amount of nitrogen produced The added amount is high, and the added amount of generated nitrogen is high. Due to the limitation of the solubility of the electrolyte, nitrogen easily overflows.
  • the mass ratio of the diazo compound in the electrolyte is 0.01% -10%, 1% -3%, 0.01% -0.05%, 0.05% -1%, 1%- 3%, 3% -5%, 5% -7%, 7% -10%.
  • the mass ratio of the diazo compound in the electrolyte is 1% -3%.
  • the amount of diazo compound added is low, the lithium precipitated in the battery during the cycle reacts with the diazo compound, and the generated lithium nitride content is small, which can not play the role of passivation of lithium precipitation; Core performance has an impact, resulting in poor cycling or power performance.
  • a person skilled in the art may select a lithium salt concentration suitable for the electrolyte in the art.
  • the lithium salt may be an organic lithium salt or an inorganic lithium salt.
  • the lithium salt may further contain one or more of fluorine element, boron element, and phosphorus element.
  • the lithium salt may be selected from LiPF 6 and / or LiN (SO 2 R F ) 2 .
  • the electrolyte further includes an organic solvent, and those skilled in the art can select an organic solvent suitable for the electrolyte in the art.
  • the organic solvent is an ester solvent. More specifically, the organic solvent may be selected from C1-C8 ester solvents.
  • the organic solvent may be selected from ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate, ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate, dipropyl carbonate, carbonic acid One or more of methylpropyl ester, ethylpropyl carbonate, 1,4-butyrolactone, methyl propionate, methyl butyrate, ethyl acetate, ethyl propionate, ethyl butyrate, etc.
  • the electrolyte provided in the first aspect of the present invention can be prepared by a method known in the art, for example, the organic solvent, lithium salt, and additives may be mixed evenly.
  • a second aspect of the present invention provides a secondary battery.
  • the secondary battery further includes a positive electrode tab, a negative electrode tab, a separator, and an electrolyte, and the electrolyte is selected from the electrolyte of the first aspect of the present invention.
  • the battery of the present invention may be a lithium ion battery, a sodium ion battery, and any other secondary battery using the electrolyte of the first aspect of the present invention.
  • the positive electrode sheet includes a positive electrode current collector and a positive electrode active material layer provided on at least one surface of the positive electrode current collector.
  • the positive active material layer includes a positive active material, and the positive active material layer may further include a conductive agent and a binder.
  • the positive electrode active material may be selected from one or more of lithium cobalt oxide (LiCoO 2 ), nickel cobalt lithium manganate ternary material, lithium iron phosphate (LiFePO 4 ), lithium manganate (LiMnO 2 ), wherein
  • the lithium manganate ternary material can be specifically selected from one or more of LiNi 1/3 Co 1/3 Mn 1/3 O 2 , LiNi 0.5 Co 0.2 Mn 0.3 O 2 , LiNi 0.6 Co 0.2 Mn 0.2 O 2, etc. .
  • a person skilled in the art may select a conductive agent and a binder suitable for secondary batteries in the art.
  • the negative electrode tab includes a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector.
  • the negative active material layer includes a negative active material, and the negative active material layer may further include a plasticizer, a conductive agent, and a binder.
  • the negative electrode active material may be selected from one or more of natural graphite, artificial graphite, mesophase microcarbon balls (abbreviated as MCMB), hard carbon, soft carbon, silicon-based materials, and tin-based materials.
  • MCMB mesophase microcarbon balls
  • the amount of the negative electrode active material is 90% -99%.
  • the amount of negative electrode binder is 0.1% -5%.
  • the negative electrode coating weight of 0.1g / 1540.25mm 2 -0.25g / 1540.25mm 2 .
  • the negative electrode density is 1.4g / cc–1.8g / cc.
  • the secondary battery provided by the second aspect of the present invention can be prepared by a method known in the art. For example, stack the positive pole piece, the separator and the negative pole piece in order, so that the separator is placed between the positive and negative pole pieces to play the role of isolation, and then wound to obtain the bare cell; place the bare cell outside In the packaging case, the electrolyte is injected after drying, and the secondary battery is obtained through the steps of vacuum sealing, standing, forming, and shaping.
  • the secondary battery 5 includes a case 6 with an upper opening, an electrode assembly provided in the case 6, and an upper opening with the case 6 ⁇ ⁇ ⁇ ⁇ ⁇ ⁇ 7 ⁇ Mouth seal connected top cover assembly 7.
  • the housing 6 of this embodiment may have a quadrangular prism shape or other shapes.
  • the top cover assembly 7 includes a top cover plate 8 and a pole 9.
  • the top cover assembly 7 is hermetically connected to the housing 6 through the top cover plate 8.
  • the pole 9 is provided on the top cover plate 8 and is electrically connected to the electrode assembly.
  • the electrode assembly includes more than two electrode units, and the electrode unit at least includes a layer of positive pole pieces, a layer of separator and a layer of negative pole pieces.
  • a third aspect of the present invention provides a battery module including any one or more of the secondary batteries described in the second aspect of the present invention.
  • the number of secondary batteries in the battery module can be adjusted according to the application and capacity of the battery module.
  • a plurality of secondary batteries 5 as shown in FIG. 1 may be arranged in sequence along the length direction of the battery module 4. Of course, it can also be arranged in any other way. Further, the plurality of secondary batteries 5 can be fixed by fasteners.
  • the battery module 4 may further include a case having an accommodation space, and the plurality of secondary batteries 5 are accommodated in the accommodation space.
  • a fourth aspect of the present invention provides a battery pack including any one or more of the battery modules described in the third aspect of the present invention. That is, the battery pack includes any one or more of the secondary batteries described in the first aspect of the present invention.
  • the number of battery modules in the battery pack can be adjusted according to the application and capacity of the battery pack.
  • the battery pack 1 may include a battery box and a plurality of battery modules 4 disposed in the battery box.
  • the battery box includes an upper box body 2 and a lower box body 3.
  • the upper box body 2 can be covered on the lower box body 3 and forms an enclosed space for accommodating the battery module 4.
  • the plurality of battery modules 4 can be arranged in the battery box in any manner.
  • a fifth aspect of the present invention provides an apparatus including any one or more of the secondary batteries described in the first aspect of the present invention.
  • the secondary battery can be used as a power source for the device.
  • the device may be, but not limited to, mobile equipment (such as mobile phones, notebook computers, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, Electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.
  • FIG. 5 shows a device including the secondary battery of the present invention
  • the device is a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.
  • the secondary battery of the present invention supplies power to the device.
  • one or more of the method steps mentioned in the present invention does not exclude that there may be other method steps before or after the combination step or that other method steps may be inserted between these explicitly mentioned steps unless otherwise Explained; It should also be understood that the combined connection relationship between one or more devices / devices mentioned in the present invention does not exclude that there may be other devices / devices or those mentioned explicitly in these before and after the combined device / device Other devices / apparatuses can also be inserted between the two devices / apparatuses unless otherwise stated.
  • each method step is only a convenient tool to identify each method step, not to limit the order of each method step or to limit the scope of the present invention, the relative relationship changes or adjustments, in If the technical content is not substantially changed, it should be regarded as the scope of the invention.
  • the positive electrode active material NCM523, the conductive agent acetylene black, and the binder polyvinylidene fluoride (PVDF) are mixed at a mass ratio of 96: 2: 2, the solvent N-methylpyrrolidone (NMP) is added, and the mixture is stirred under the action of a vacuum mixer
  • NMP solvent N-methylpyrrolidone
  • the system is uniform and the positive electrode slurry is obtained; the positive electrode slurry is evenly coated on both surfaces of the positive electrode current collector aluminum foil, dried at room temperature and transferred to a 120 ° C oven to continue drying, and then subjected to cold pressing and slitting to obtain the positive electrode sheet.
  • the negative electrode active material graphite, the conductive agent conductive carbon black (Super-P), the thickener carboxymethyl cellulose (CMC), and the binder styrene-butadiene rubber (SBR) are mixed in a mass ratio of 96.4: 1: 1.2: 1.4 , Add solvent deionized water and stir under the action of a vacuum mixer until the system is uniform to obtain a negative electrode slurry; apply the negative electrode slurry evenly on both surfaces of the negative electrode current collector copper foil, dry it at room temperature and transfer to 120 Continue drying in an oven at °C, and then obtain the negative pole piece after cold pressing and slitting.
  • the above positive pole pieces, separators and negative pole pieces are stacked in order, so that the separation membrane is placed between the positive and negative pole pieces to play the role of isolation, and then wound to obtain the bare battery core;
  • the electrolyte is injected after drying, and the battery is obtained through the steps of vacuum sealing, standing, forming, and shaping.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • Example 1 The difference from Example 1 is that the preparation of the electrolyte is different, and only the preparation method of the electrolyte is described below.
  • EMC Ethylene carbonate
  • EMC ethyl methyl carbonate
  • DEC diethyl carbonate
  • the lithium ion batteries prepared in the examples and comparative examples were fully charged at 1C and fully charged at 1C for 500 times, the lithium ion batteries were fully charged at 1C, and then the negative pole pieces were disassembled and observed Lithium deposition on the surface of the negative pole piece.
  • the area of lithium deposition on the surface of the negative electrode is less than 5%, which is considered to be slight lithium deposition, the area of lithium deposition on the surface of the negative electrode is 5% -40%, which is considered to be moderate lithium deposition, and the area of negative electrode surface is greater than 40% is considered to be serious lithium deposition .

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Abstract

一种电解液及二次电池、电池模块、电池包、装置。所述电解液包括锂盐、有机溶剂以及添加剂，所述添加剂包括氮气。电解液中加入氮气，可以有效排除氧气和二氧化碳，减小了电池的阻抗。同时，电池使用过程中析出的锂由于活性较高，可以和电解液中的氮气发生反应生成Li 3N，Li 3N会阻止由于析锂区域的电位较低而引起电子和锂离子直接接触，阻止析锂的扩散，从而钝化析锂，延长电池在使用过程中的寿命，另一方面，也避免了延长在长期使用过程中生成锂枝晶导致的安全问题。所述电池模块、电池包和装置包括所述二次电池，因而至少具有与所述二次电池相同的优势。

Description

电解液及二次电池、电池模块、电池包、装置 技术领域
本发明涉及电池技术领域，特别是涉及一种电解液及二次电池、电池模块、电池包、装置。
背景技术
随着电动汽车的发展，人们对锂离子电池的能量密度要求越来越高，三元电芯由于其高克容量逐渐成为电动汽车生产厂家关注的焦点。但由于电芯中电解液分布不均，循环过程中膨胀力增大导致局部动力学不均，负极局部开始析锂，析出的锂进一步在充放电过程中和电解液发生副反应导致电解液的消耗和局部阻抗增加，负极进一步发生析锂，最终析锂面积逐渐增大，导致电芯跳水，影响电动汽车的使用寿命。如果析出的锂形成锂枝晶，锂枝晶刺穿隔离膜，导致电芯负极短路，甚至会威胁到用户的生命安全。
目前为了避免电芯在使用过程中跳水甚至出现安全问题，主要方法是：提高负极动力学，降低电芯阻抗；提高电解液电导率；限制用户进行大电流的充电。虽然这些方法能够延长电池包的使用寿命，但却不能根本解决电芯在使用过程中发生跳水甚至安全的问题，主要是由于电芯在使用过程中，负极动力学不可避免会降低，电解液也会逐渐消耗，使用过程中局部动力学不足，导致析锂是不可避免的。用户长时间在进行电动汽车的充放电，析锂导致的安全风险高。因此，需要有一种方法能够钝化析出的锂，提高电芯在使用过程中的寿命；另一方面，需要钝化锂枝晶，避免锂枝晶刺穿隔离膜从而引起安全问题。
发明内容
鉴于以上所述现有技术的缺点，本发明的目的在于提供一种电解液及二次电池，所述二次电池在使用过程中阻抗较小，可同时兼顾优良的循环性能、较长的循环寿命及安全性能。
为实现上述目的及其他相关目的，本发明的第一方面提供一种电解液，包括锂盐、有机溶剂以及添加剂，添加剂包括氮气。
本发明的第二方面提供一种二次电池，包括正极片、负极片、间隔设置于正极片和负极片之间的隔离膜、以及本发明第一方面的电解液。
本发明的第三方面提供一种电池模块，包括本发明第二方面所述的二次电池。
本发明的第四方面提供一种电池包，包括本发明第三方面所述的电池模块。
本发明的第五方面提供一种装置，包括本发明第二方面所述的二次电池，所述二次电池用作所述装置的电源。
相对于现有技术，本发明的有益效果为：
电解液中通常会存在氧气和二氧化碳等气体，这些气体在正负极表面会发生副反应生成碳酸锂等化合物，这些化合物的生成会导致电芯阻抗增加，从而影响电池的使用寿命。本发明的电解液中加入氮气，可以有效排除氧气和二氧化碳，从根源上解决了此问题，减小了电池的阻抗。
同时，电池在使用过程中由于电芯膨胀力或者电解液消耗问题，可能会出现局部阻抗增大并出现析锂情况，析出的锂由于活性较高，可以和电解液中的氮气、胺类化合物或重氮化合物发生反应生成Li 3N，而如果在电解液中添加叠氮化锂，可以生成氮气，然后氮气再与析出的锂反应生成Li 3N。Li 3N是电子绝缘体，会阻止由于析锂区域的电位较低而引起电子和锂离子直接接触，阻止析锂的扩散，从而钝化析锂，延长电池在使用过程中的寿命，另一方面，也避免了延长在长期使用过程中生成锂枝晶导致的安全问题。
本发明的电池模块、电池包和装置包括所述的二次电池，因而至少具有与所述二次电池相同的优势。
附图说明
图1是本发明二次电池的一实施方式的示意图。
图2是本发明电池模块的一实施方式的示意图。
图3是本发明电池包的一实施方式的示意图。
图4是图3的分解图。
图5是本发明二次电池用作电源的装置的一实施方式的示意图。
其中，附图标记说明如下：
1、电池包
2、上箱体
3、下箱体
4、电池模块
5、二次电池
6、壳体
7、顶盖组件
8、顶盖板
9、极柱
具体实施方式
下面详细说明根据本发明的电解液、二次电池、电池模块、电池包及装置。
本发明第一方面的电解液包括：锂盐、有机溶剂以及添加剂，所述添加剂包括氮气。
电池在使用过程中由于电芯膨胀力或者电解液消耗问题，可能会出现局部阻抗增大并出现析锂情况。发明人研究发现，析出的锂由于活性较高，容易和电解液中的氮气发生反应生成Li 3N。Li 3N是电子绝缘体，会阻止由于析锂区域的电位较低而引起电子和锂离子直接接触，阻止析锂的扩散，从而钝化析锂，延长电池在使用过程中的寿命，另一方面，也避免了延长在长期使用过程中生成锂枝晶导致的安全问题。
在本发明的一些实施方式中，所述添加剂采用氮气。所述氮气在电解液中的质量占比是0.01％-1.2％，0.2％-0.5％，0.01％-0.05％，0.05％-0.1％，0.1％-0.2％，0.2％-0.3％，0.3％-0.5％，0.5％-0.7％，0.7％-1.2％。
优选地，所述氮气在电解液中的质量占比是0.2％-0.5％。氮气添加量低，电芯在循环过程中析出的锂和氮气反应，生成的氮化锂含量较少，不能起到钝化析锂的作用；氮气添加量高，由于电解液溶解度限制，氮气容易溢出。
在本发明的一些实施方式中，所述电解液中还包括氧气和/或二氧化碳，所述氧气在电解液中的质量占比小于等于0.04％，所述二氧化碳在电解液中的质量占比为小于等于0.02％。电解液中通常会存在氧气和二氧化碳等气体，这些气体在正负极表面会发生副反应生成碳酸锂等化合物，这些化合物的生成会导致电芯阻抗增加，从而影响电池的使用寿命。发明人研究发现，向电解液中加入氮气，可以有效排除氧气和二氧化碳，从根源上解决了此问题，减小了电池的阻抗。本发明的氧气/二氧化碳在电解液中的质量占比均是指向电解液中加入氮气后剩余的氧气/二氧化碳在电解液中的质量占比。
在本发明的一些实施方式中，所述氧气在电解液中的质量占比是0％-0.04％，0％-0.01％，0.01％-0.02％，0.02％-0.03％，0.03％-0.04％。
优选地，所述氧气在电解液中的质量占比为0％-0.01％。
在本发明的一些实施方式中，所述二氧化碳在电解液中的质量占比为0％-0.02％，0％-0.01％，0.01％-0.02％。
优选地，所述二氧化碳在电解液中的质量占比为0％-0.01％。
在本发明的一些实施方式中，所述添加剂还包括胺类化合物、叠氮化锂或重氮化合物中的一种或几种。
在本发明的一些实施方式中，所述胺类化合物选自伯胺，所述胺类化合物优选选自甲胺、乙二胺、苯胺中的一种或几种。
在本发明的一些实施方式中，所述胺类化合物在电解液中的质量占比为0.01％-10％，1％-3％，0.01％-0.05％，0.05％-1％，1％-3％，3％-5％，5％-7％，7％-10％。
优选地，所述胺类化合物在电解液中的质量占比为1％-3％。胺类化合物添加量低，电芯在循环过程中析出的锂和胺类化合物反应，生成的氮化锂含量较少，不能起到钝化析锂的作用；胺类化合物添加量高，对电芯性能会产生影响，导致循环或功率性能差。
在本发明的一些实施方式中，所述叠氮化锂在电解液中的质量占比是0.01％-10％，1％-3％，0.01％-0.05％，0.05％-1％，1％-3％，3％-5％，5％-7％，7％-10％。
优选地，所述叠氮化锂在电解液中的质量占比是1％-3％。叠氮化锂添加量低，生成的氮气量低，电芯在循环过程中析出的锂和氮气反应，生成的氮化锂含量较少，不能起到钝化析锂的作用；叠氮化锂添加量高，生成的氮气添加量高，由于电解液溶解度限制，氮气容易溢出。
在本发明的一些实施方式中，所述重氮化合物在电解液中的质量占比是0.01％-10％，1％-3％，0.01％-0.05％，0.05％-1％，1％-3％，3％-5％，5％-7％，7％-10％。
优选地，所述重氮化合物在电解液中的质量占比是1％-3％。重氮化合物添加量低，电芯在循环过程中析出的锂和重氮化合物反应，生成的氮化锂含量较少，不能起到钝化析锂的作用；重氮化合物添加量高，对电芯性能会产生影响，导致循环或功率性能差。
在本发明的一些实施方式中，本领域技术人员可以选择本领域适用于电解液的锂盐的浓度。
优选地，所述锂盐的浓度为0.5M-2M(M＝mol/L -1)。
在本发明的一些实施方式中，所述锂盐可为有机锂盐，也可为无机锂盐。所述锂盐还可含有氟元素、硼元素、磷元素中的一种或几种。具体地，所述锂盐可选自LiPF 6、LiBF 4、LiClO 4、LiAsF 6、LiTFOP、LiN(SO 2R F) 2、LiN(SO 2F)(SO 2R F)、LiN(CF 3SO 2) 2、Li(N(SO 2F) 2、LiB(C 2O 4) 2、LiBF 2(C 2O 4)等中的一种或几种，其中，取代基R F＝C nF 2n+1的饱和全氟烷基，n为1～10的整数。
优选地，所述锂盐可选自LiPF 6和/或LiN(SO 2R F) 2。
在本发明的一些实施方式中，所述电解液中还包括有机溶剂，本领域技术人员可以选择本领域适用于电解液的有机溶剂。具体地，所述有机溶剂为酯类溶剂，更具体地，所述有机溶剂可选自C1～C8的酯类溶剂。
优选地，所述有机溶剂可选自碳酸乙烯酯、碳酸丙烯脂、碳酸丁烯酯、氟代碳酸乙烯 酯、碳酸甲乙酯、碳酸二甲酯、碳酸二乙酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、1,4-丁内酯、丙酸甲酯、丁酸甲酯、乙酸乙酯、丙酸乙酯、丁酸乙酯等中的一种或几种。
本发明第一方面提供的电解液可以采用本领域的公知方法进行制备，例如可将有机溶剂、锂盐和添加剂混合均匀即可。
本发明的第二方面提供一种二次电池，所述二次电池还包括正极极片、负极极片、隔离膜以及电解液，所述电解液选自本发明第一方面的电解液。
需要说明的是，本发明的电池可为锂离子电池、钠离子电池以及任何其他使用本发明第一方面电解液的二次电池。
所述正极片包括正极集流体和设置于正极集流体至少一个表面上的正极活性物质层。所述正极活性物质层包括正极活性材料，所述正极活性物质层还可包括导电剂和粘结剂。正极活性材料可选自钴酸锂(LiCoO 2)、镍钴锰酸锂三元材料、磷酸铁锂(LiFePO 4)、锰酸锂(LiMnO 2)中的一种或几种，其中，镍钴锰酸锂三元材料具体可选自LiNi 1/3Co 1/3Mn 1/3O 2、LiNi 0.5Co 0.2Mn 0.3O 2、LiNi 0.6Co 0.2Mn 0.2O 2等中的一种或几种。本领域技术人员可以选择本领域适用于二次电池的导电剂和粘结剂。
所述负极极片包括负极集流体和设置于负极集流体至少一个表面上的负极活性物质层。所述负极活性物质层包括负极活性材料，所述负极活性物质层还可包括增塑剂、导电剂和粘结剂。负极活性材料可选自天然石墨、人造石墨、中间相微碳球(简称为MCMB)、硬碳、软碳、硅基材料、锡基材料中的一种或几种。本领域技术人员可以选择本领域适用于二次电池的增塑剂、导电剂和粘结剂。
为了进一步提高电池的循环性能，负极活性物质的用量为90％-99％。
负极粘结剂的用量在0.1％-5％。
负极涂布重量为0.1g/1540.25mm 2–0.25g/1540.25mm 2。
负极压密为1.4g/cc–1.8g/cc。
本领域技术人员可以选择本领域适用于二次电池的正极活性物质、导电剂和粘结剂的用量、正极涂布重量和正极压密。
本发明第二方面提供的二次电池可以采用本领域的公知方法进行制备。例如，将正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正负极极片之间起到隔离的作用，然后卷绕得到裸电芯；将裸电芯置于外包装壳体中，干燥后注入电解液，经过真空封装、静置、化成、整形等工序，获得二次电池。
在一些实施例中，请参照图1，在二次电池5中，所述二次电池5包括上敞口的壳体6、设置于壳体6内的电极组件以及与壳体6的上敞口密封连接的顶盖组件7。本实施例的壳体6 可以是四棱柱体形状或其他形状。顶盖组件7包括顶盖板8和极柱9。顶盖组件7通过顶盖板8密封连接于壳体6。极柱9设置于顶盖板8并且与电极组件电连接。电极组件包括两个以上的电极单元，所述电极单元至少包括一层正极极片、一层隔离膜和一层负极极片。
本发明第三方面提供一种电池模块，其包括本发明第二方面所述的任意一种或几种二次电池。所述电池模块中的二次电池的数量可以根据电池模块的应用和容量进行调节。
在一些实施例中，请参照图2，在电池模块4中，多个如图1所示的二次电池5可以是沿电池模块4的长度方向依次排列设置。当然，也可以按照其他任意的方式进行排布。进一步可以通过紧固件将该多个二次电池5进行固定。
可选地，电池模块4还可以包括具有容纳空间的壳体，多个二次电池5容纳于该容纳空间。
本发明第四方面提供一种电池包，其包括本发明第三方面所述的任意一种或几种电池模块。也就是，该电池包包括本发明第一方面所述的任意一种或几种二次电池。
所述电池包中电池模块的数量可以根据电池包的应用和容量进行调节。
在一些实施例中，请参照图3和图4，在电池包1中可以包括电池箱和设置于电池箱中的多个电池模块4。电池箱包括上箱体2和下箱体3，上箱体2能够盖设于下箱体3，并形成用于容纳电池模组4的封闭空间。多个电池模块4可以按照任意的方式排布于电池箱中。
本发明第五方面提供一种装置，其包括本发明第一方面所述的任意一种或几种二次电池。所述二次电池可以用作所述装置的电源。优选地，所述装置可以但不限于是移动设备(例如手机、笔记本电脑等)、电动车辆(例如纯电动车、混合动力电动车、插电式混合动力电动车、电动自行车、电动踏板车、电动高尔夫球车、电动卡车等)、电气列车、船舶及卫星、储能系统等。
在一些实施例中，请参照图5，图5所示为一种包含本发明的二次电池的装置，该装置为纯电动车、混合动力电动车、或插电式混合动力电动车等，本发明的二次电池为该装置供电。
以下结合实施例进一步说明本发明的有益效果。
为了使本发明的发明目的、技术方案和有益技术效果更加清晰，以下结合实施例进一步详细描述本发明。但是，应当理解的是，本发明的实施例仅仅是为了解释本发明，并非为了限制本发明，且本发明的实施例并不局限于说明书中给出的实施例。实施例中未注明具体实验条件或操作条件的按常规条件制作，或按材料供应商推荐的条件制作。
此外应理解，本发明中提到的一个或多个方法步骤并不排斥在所述组合步骤前后还可以 存在其他方法步骤或在这些明确提到的步骤之间还可以插入其他方法步骤，除非另有说明；还应理解，本发明中提到的一个或多个设备/装置之间的组合连接关系并不排斥在所述组合设备/装置前后还可以存在其他设备/装置或在这些明确提到的两个设备/装置之间还可以插入其他设备/装置，除非另有说明。而且，除非另有说明，各方法步骤的编号仅为鉴别各方法步骤的便利工具，而非为限制各方法步骤的排列次序或限定本发明可实施的范围，其相对关系的改变或调整，在无实质变更技术内容的情况下，当亦视为本发明可实施的范畴。
在下述实施例中，所使用到的试剂、材料以及仪器如没有特殊的说明，均可商购获得。
一、用于测试的电池的制备
实施例1
(1)正极极片的制备
将正极活性材料NCM523、导电剂乙炔黑、粘结剂聚偏氟乙烯(PVDF)按质量比96:2:2进行混合，加入溶剂N-甲基吡咯烷酮(NMP)，在真空搅拌机作用下搅拌至体系呈均一状，获得正极浆料；将正极浆料均匀涂覆在正极集流体铝箔的两个表面上，室温晾干后转移至120℃烘箱继续干燥，然后经过冷压、分切得到正极极片。
(2)负极极片的制备
将负极活性材料石墨、导电剂导电炭黑(Super-P)、增稠剂羧甲基纤维素(CMC)、粘结剂丁苯橡胶(SBR)按质量比96.4:1:1.2:1.4进行混合，加入溶剂去离子水，在真空搅拌机作用下搅拌至体系呈均一状，获得负极浆料；将负极浆料均匀涂覆在负极集流体铜箔的两个表面上，室温晾干后转移至120℃烘箱继续干燥，然后经过冷压、分切得到负极极片。
(3)电解液的制备
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气，氮气的质量占比为0.01％。
(4)隔离膜的制备
选自聚乙烯膜作为隔离膜。
(5)电池的制备
将上述正极极片、隔离膜、负极极片按顺序叠好，使隔离膜处于正、负极极片之间起到隔离的作用，然后卷绕得到裸电芯；将裸电芯置于外包装壳中，干燥后注入电解液，经过真空封装、静置、化成、整形等工序，获得电池。
实施例2
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气，氮气的质量占比为0.05％。
实施例3
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气，氮气的质量占比为0.1％。
实施例4
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气，氮气的质量占比为0.2％。
实施例5
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气，氮气的质量占比为0.3％。
实施例6
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气，氮气的质量占比为0.5％。
实施例7
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为 EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气，氮气的质量占比为0.7％。
实施例8
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气，氮气的质量占比为1％。
实施例9
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气，氮气的质量占比为0.005％。
实施例10
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气，氮气的质量占比为1.2％。
实施例11
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气并加入乙二胺，其中氮气的质量占比为0.3％，乙二胺的质量占比为0.01％。
实施例12
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气并加入乙二胺，其中氮气的质量占比为0.3％，乙二胺的质量占比为0.50％。
实施例13
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气并加入乙二胺，其中氮气的质量占比为0.3％，乙二胺的质量占比为1％。
实施例14
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气并加入乙二胺，其中氮气的质量占比为0.3％，乙二胺的质量占比为2％。
实施例15
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气并加入乙二胺，其中氮气的质量占比为0.3％，乙二胺的质量占比为3％。
实施例16
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气并加入乙二胺，其中氮气的质量占比为0.3％，乙二胺的质量占比为5％。
实施例17
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气并加入乙二胺，其中氮气的质量占比为0.3％，乙二胺的质量占比为7％。
实施例18
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气并加入乙二胺，其中氮气的质量占比为0.3％，乙二胺的质量占比为10％。
实施例19
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中，之后通入氮气并加入甲胺，其中氮气的质量占比为0.3％，甲胺的质量占比为3％。
对比例1
与实施例1的区别是电解液的制备不同，下面仅描述电解液的制备方法。
将碳酸亚乙酯(EC)、碳酸甲乙酯(EMC)、碳酸二乙酯(DEC)按照体积比为EC:EMC:DEC＝1:1:1进行混合，接着将充分干燥的锂盐LiPF6溶解于混合有机溶剂中。
二、电池性能测试方式
按照实施例1-19和对比例1制备出电池后，按照下列方法测试各项电池性能。测试结果详见表1。
循环性能测试和析锂测试
在25℃下，将实施例和对比例制备得到的锂离子电池以1C满充、以1C满放重复500次后，再将锂离子电池以1C满充，然后拆解出负极极片并观察负极极片表面的析锂情况。其中，负极表面析锂区域面积小于5％认为是轻微析锂，负极表面析锂区域面积为5％～40％认为是中度析锂，负极表面析锂区域面积大于40％认为是严重析锂。
表1
Figure PCTCN2019110849-appb-000001
Figure PCTCN2019110849-appb-000002
从表1的结果可以看出，在电解液中添加适量的氮气、乙二胺或甲胺，电芯在进行1C/1C循环500周后拆解电芯显示析锂有明显改善。从500周的容量保持率来看，随着添加剂含量的增加，容量保持率先增加后减小，这是由于电芯在循环过程中添加过多的添加剂，电芯析锂生成的Li 3N过多，容易导致电芯极化增加，导致1C/1C容量保持率反而下降，优选地，采用在电解液中添加质量占比是0.3％的氮气和3％的甲胺作为电解液添加剂时，电芯容量保持率最高，达到93％。
以上所述，仅为本发明的较佳实施例，并非对本发明任何形式上和实质上的限制，应当指出，对于本技术领域的普通技术人员，在不脱离本发明方法的前提下，还将可以做出若干改进和补充，这些改进和补充也应视为本发明的保护范围。凡熟悉本专业的技术人员，在不 脱离本发明的精神和范围的情况下，当可利用以上所揭示的技术内容而做出的些许更动、修饰与演变的等同变化，均为本发明的等效实施例；同时，凡依据本发明的实质技术对上述实施例所作的任何等同变化的更动、修饰与演变，均仍属于本发明的技术方案的范围内。

Claims (13)

  1. 一种电解液，包括锂盐、有机溶剂以及添加剂，其特征在于，所述添加剂包括氮气。
  2. 根据权利要求1所述的电解液，其特征在于，所述氮气在电解液中的质量占比为0.01％-1.2％，优选为0.2％-0.5％。
  3. 根据权利要求1所述的电解液，其特征在于，所述电解液中还包括氧气和/或二氧化碳，所述氧气在电解液中的质量占比小于等于0.04％，所述二氧化碳在电解液中的质量占比小于等于0.02％。
  4. 根据权利要求1所述的电解液，其特征在于，所述添加剂还包括胺类化合物、叠氮化锂或重氮化合物中的一种或几种。
  5. 根据权利要求4所述的电解液，其特征在于，所述胺类化合物选自伯胺，所述胺类化合物优选选自甲胺、乙二胺、苯胺中的一种或几种。
  6. 根据权利要求4所述的电解液，其特征在于，所述胺类化合物在电解液中的质量占比为0.01％-10％，优选为1％-3％。
  7. 根据权利要求4所述的电解液，其特征在于，所述叠氮化锂在电解液中的质量占比为0.01％-10％，优选为1％-3％。
  8. 根据权利要求4所述的电解液，其特征在于，所述重氮化合物在电解液中的质量占比为0.01％-10％，优选为1％-3％。
  9. 根据权利要求1所述的电解液，其特征在于，所述锂盐选自LiPF 6、LiBF 4、LiClO 4、LiAsF 6、LiTFOP、LiN(SO 2R F) 2、LiN(SO 2F)(SO 2R F)、LiN(CF 3SO 2) 2、Li(N(SO 2F) 2、LiB(C 2O 4) 2、LiBF 2(C 2O 4)中的一种或几种，所述取代基R F为C nF 2n+1的饱和全氟烷基，n为1～10的整数；所述有机溶剂为酯类溶剂，所述酯类溶剂选自C1-C8的酯类溶质，优选选自碳酸乙烯酯、碳酸丙烯脂、碳酸丁烯酯、氟代碳酸乙烯酯、碳酸甲乙酯、碳酸二甲酯、碳酸二乙酯、碳酸二丙酯、碳酸甲丙酯、碳酸乙丙酯、1,4-丁内酯、丙酸甲酯、丁酸甲酯、乙酸乙酯、丙酸乙酯、丁酸乙酯中的一种或几种。
  10. 一种二次电池，包括正极片、负极片、间隔设置于正极片和负极片之间的隔离膜、以及电解液，其特征在于，所述电解液为权利要求1～9任一项所述的电解液。
  11. 一种电池模块，包括根据权利要求10所述的二次电池。
  12. 一种电池包，包括根据权利要求11所述的电池模块。
  13. 一种装置，包括根据权利要求10所述的二次电池，所述二次电池用作所述装置的电源；优选地，所述装置包括移动设备、电动车辆、电气列车、卫星、船舶及储能系统。
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CN114421010B (zh) * 2020-10-28 2024-08-27 陕西泽邦环境科技有限公司 一种补锂型锂离子电池电解液及其应用
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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN105789704A (zh) * 2014-12-22 2016-07-20 远景能源（江苏）有限公司 可抑制锂枝晶的非水溶剂、非水电解液及锂离子二次电池
CN107078355A (zh) * 2014-09-30 2017-08-18 Nec能源元器件株式会社 锂离子二次电池及其制造方法
CN207320253U (zh) * 2017-08-21 2018-05-04 中航锂电（洛阳）有限公司 锂电池生产系统及其电解液供液系统
KR20180109520A (ko) * 2017-03-28 2018-10-08 서울대학교산학협력단 리튬 이차전지용 전해질 및 이를 포함하는 리튬 이차전지
CN109786870A (zh) * 2018-12-25 2019-05-21 上海力信能源科技有限责任公司 一种减少锂电池析锂的方法

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103326065B (zh) * 2013-06-08 2015-06-03 宁德新能源科技有限公司 钛酸锂电池及其电解液
CN105428718B (zh) * 2015-12-29 2018-01-16 珠海市赛纬电子材料股份有限公司 一种电解液添加剂的制备方法
JP7003394B2 (ja) * 2016-09-06 2022-01-20 株式会社村田製作所 二次電池用電解液、二次電池、電池パック、電動車両、電力貯蔵システム、電動工具および電子機器
CN108400381A (zh) * 2018-01-29 2018-08-14 江苏理文化工有限公司 一种锂电池电解液的配制方法

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107078355A (zh) * 2014-09-30 2017-08-18 Nec能源元器件株式会社 锂离子二次电池及其制造方法
CN105789704A (zh) * 2014-12-22 2016-07-20 远景能源（江苏）有限公司 可抑制锂枝晶的非水溶剂、非水电解液及锂离子二次电池
KR20180109520A (ko) * 2017-03-28 2018-10-08 서울대학교산학협력단 리튬 이차전지용 전해질 및 이를 포함하는 리튬 이차전지
CN207320253U (zh) * 2017-08-21 2018-05-04 中航锂电（洛阳）有限公司 锂电池生产系统及其电解液供液系统
CN109786870A (zh) * 2018-12-25 2019-05-21 上海力信能源科技有限责任公司 一种减少锂电池析锂的方法

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