CN102306834A - Electrolyte solution capable of improving air expansion of soft roll lithium manganese battery - Google Patents

Abstract

The invention relates to electrolyte solution of a lithium manganese battery, in particular to electrolyte solution capable of improving air expansion of a soft roll lithium manganese battery. The electrolyte solution consists of three components, namely (1) lithium salt, (2) a carbonic ester and/or ether organic solvent and (3) 0.01 to 20 mass percent of additive, wherein the molar concentration of the lithium salt in the electrolyte solution is 0.01 to 2 moles/liter; and the additive is a sulfinyl-containing and/or sulfonyl-containing compound. The additive compound in the electrolyte solution is decomposed before the organic solvent of the electrolyte solution to form a passivation layer on the surface of an electrode, so that gas generation due to the decomposition of the organic solvent of the electrolyte solution is restrained, and the aim of improving the air expansion of the soft roll lithium manganese battery is fulfilled.

Description

A kind of electrolytic solution for improving flatulence of soft-packed lithium-manganese battery

technical field

The invention relates to an electrolyte solution for a lithium-manganese battery, in particular to an electrolyte solution for improving flatulence of a soft-packed lithium-manganese battery.

Background technique

Lithium manganese dioxide battery, hereinafter referred to as lithium manganese battery, belongs to primary lithium battery. Lithium-manganese batteries have the advantages of high discharge current, pulse discharge capability, and no voltage hysteresis, accounting for nearly 50% of primary lithium batteries, and are widely used in smart meters, electronic security and RFID and other fields. The common forms of lithium-manganese batteries are cylindrical lithium-manganese and button-type lithium-manganese batteries. Now lithium-manganese batteries have developed into a new form: soft-pack lithium-manganese batteries. This development has greatly expanded the application fields of lithium-manganese batteries, such as in intelligent transportation (freeway toll collection system, vehicle path and crossing identification system, etc.), electronic locks, electronic keys, active electronic cards and electronic tags And other applications that require lithium-manganese batteries to have a smaller thickness. Since the thickness of the general soft-packed lithium-manganese battery is relatively thin, and its application field is generally used at a relatively high temperature, if a conventional electrolyte system is used, gas will be generated due to the reaction between the electrolyte and the negative electrode, and these gases will further affect the soft battery. The thickness of the lithium-manganese battery makes it impossible to apply.

Contents of the invention

The technical problem to be solved by the present invention is to propose an electrolyte solution for improving flatulence of the soft-packed lithium-manganese battery while ensuring the working capacity of the soft-packed lithium-manganese battery in view of the above shortcomings of the prior art.

The technical scheme that the present invention solves above technical problem is:

An electrolyte solution for improving flatulence of a soft-packed lithium-manganese battery. The electrolyte solution is composed of three types of components: (1) lithium salts, (2) carbonate and/or ether organic solvents, and (3) additives; the mass percentage of additives in the electrolyte solution is 0.01 %-20%, the molar concentration of lithium salt in the electrolyte solution is 0.01-2 mol/liter; the additive is a compound containing sulfinyl and/or sulfonyl; lithium salt is at least one of the following substances: LiPF ₆ , LiBF ₄ , LiClO ₄ , LiCF ₃ SO ₃ , LiN(CF ₃ SO ₂ ) ₂ , LiC ₄ F ₉ SO ₃ , LiN(C _x F _2x+1 SO ₂ )(CyF _2y+1 SO2), where x and y are natural numbers.

The additives are compounds containing sulfinyl and/or sulfonyl groups, and the organic solvents are carbonates and/or ethers. During the initial charging process of lithium-manganese batteries, the additive compounds decompose before the organic solvent of the electrolyte, resulting in The passivation layer is formed, thereby inhibiting the decomposition of the organic solvent of the electrolyte to generate gas, and achieving the purpose of improving the flatulence of the soft-packed lithium-manganese battery.

The mass percentage of the additive in the electrolyte solution is 0.01%-20%. When the amount added is small, an effective protective film cannot be formed and the side reactions between the electrolyte and the negative electrode cannot be prevented; when the amount added is too large, due to the formation of a protective film If it is thicker, the internal resistance will increase, which will affect the electrical performance of lithium-manganese batteries.

The technical scheme further defined in the present invention is:

The aforementioned electrolytic solution for improving flatulence of the soft-packed lithium-manganese battery, the carbonate organic solvent is a cyclic carbonate and/or a chain carbonate compound; the cyclic carbonate compound is selected from ethylene carbonate, propylene carbonate One or more of esters, butylene carbonate, and γ-butyrolactone coexist; chain carbonates are selected from ethyl butyl carbonate, methyl butyl carbonate, dibutyl carbonate, diethyl carbonate, carbonic acid One or more of dimethyl, trifluoromethylethylene carbonate, di-n-propyl carbonate, diisopropyl carbonate, ethyl methyl carbonate, ethyl propyl carbonate, ethyl isopropyl carbonate and methyl propyl carbonate species coexist.

The aforementioned electrolytic solution for improving flatulence of soft-packed lithium-manganese batteries, the ether organic solvent is selected from tetrahydrofuran, 2-methyltetrahydrofuran, 1,3-dioxolane, dimethoxymethane, 1,2-dimethoxyethane One or more of alkane, dimethoxyethane, diethoxyethane, tetrahydrofuran, diethylene glycol dimethyl ether; triethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether kind of coexistence.

The aforementioned electrolyte solution for improving flatulence of soft-packed lithium-manganese batteries, the additive is one or more of the following compounds coexisting: 1,3-propane sultone, 1,4-butyl sultone, dimethyl Sulfite, diethylsulfite, alkylsulfonic anhydride, vinylsulfonate, 1,3-propene sultone, methylene methanedisulfonate.

The structural formula of the aforesaid electrolytic solution for improving flatulence of the soft-packed lithium-manganese battery, thionyl:

The structural formula of the sulfonyl group:

Wherein R1 and R2 are the same or different groups, representing linear (with/without branching) or cyclic oxygen-containing (or non-) aliphatic hydrocarbons, containing 1-6 carbon atoms.

The beneficial effects of the present invention are: the present invention adopts the additive compound to form a passivation layer on the electrode surface, thereby preventing the oxidative decomposition of the electrolyte. During the initial charging process of the lithium-manganese battery, the additive compound is decomposed before the organic solvent of the electrolyte, resulting in A passivation layer is formed on the surface of the electrode, thereby inhibiting the decomposition of the organic solvent of the electrolyte to generate gas, and achieving the purpose of improving the flatulence of the soft-packed lithium-manganese battery. The use of this electrolyte system also ensures the working capacity of the lithium-manganese battery.

Detailed ways

Example 1

A 750mAh 284646 soft-pack lithium-manganese battery was prepared, filled with electrolytes with different additive contents, stored at 60 degrees for 6 weeks, and tested for its thickness change and capacity change at room temperature 0.2C when the relative addition amount was 0%. The standard electrolyte is 1M LiClO4/PC-DME (1:1, vol), and the additive is 1,3 propane sultone.

See Table 1 below for details:

Additive amount Thickness expansion (60°C for 6 weeks) Normal temperature discharge (recorded as 100% when 0% is added) 0% 30% 100.0% 1% 7.8% 99.9% 2% 4.9% 99.7% 3% 2.8% 99.5% 5% 2.6% 98.6% 7% 2.0% 98.0% 10% 1.5% 97.0%

Example 2

A 750mAh 284646 soft-pack lithium-manganese battery was prepared, filled with electrolytes with different additive contents, stored at 60 degrees for 6 weeks, and tested for its thickness change and capacity change at room temperature 0.2C when the relative addition amount was 0%. The standard electrolyte is 1M LiClO4/PC-DME-DXL (1:1:1, vol), and the additive is vinyl sulfate.

See Table 2 below for details:

Additive amount Thickness expansion (60°C for 6 weeks) Normal temperature discharge (recorded as 100% when 0% is added) 0% 35% 100.0% 1% 8.8% 99.8% 2% 5.3% 99.5% 3% 3.2% 99.2% 5% 2.4% 98.5% 7% 2.0% 98.0% 10% 1.8% 97.5%

In addition to the above-mentioned embodiments, the present invention can also have other implementations. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention.

Claims (5)

1. electrolyte solution that improves Soft Roll lithium-manganese cell flatulence, it is characterized in that: this electrolyte solution is made up of three types of compositions: ⑴ lithium salts, ⑵ carbonates and/or ether organic solvent, ⑶ additive; The mass percent that described additive accounts for electrolyte solution is 0.01%-20%, and the molar concentration of said lithium salts in electrolyte solution is the 0.01-2 mol; Described additive is the compound that contains sulfinyl and/or contain sulfonyl; Said lithium salts is at least a in the following material: LiPF ₆, LiBF ₄, LiClO ₄, LiCF ₃SO ₃, LiN (CF ₃SO ₂) ₂, LiC ₄F ₉SO ₃, LiN (C _xF _2x+1SO ₂) (CyF _2y+1SO2), x and y are natural number in the formula.

2. the electrolyte solution that improves Soft Roll lithium-manganese cell flatulence as claimed in claim 1 is characterized in that: carbonates that described carbonates organic solvent is a ring-type and/or linear carbonate compounds; The carbonats compound of described ring-type is selected from one or more coexistences in ethylene carbonate, propene carbonate, butylene, the gamma-butyrolacton; Described linear carbonate compounds be selected from ethyl butyl carbonate, carbonic acid first butyl ester, dibutyl carbonate, diethyl carbonate, dimethyl carbonate, trifluoromethyl ethylene carbonate, carbonic acid di-n-propyl ester, carbonic acid diisopropyl ester, methyl ethyl carbonate, ethyl propyl carbonic acid ester, ethylene isopropyl ester and the carbonic acid first propyl ester one or more and deposit.

3. the electrolyte solution that improves Soft Roll lithium-manganese cell flatulence as claimed in claim 1; It is characterized in that: described ether organic solvent is selected from oxolane, 2-methyltetrahydrofuran, 1; 3-dioxolanes, dimethoxymethane, 1,2-dimethoxy ethane, dimethoxy-ethane, diethoxyethane, oxolane, diglycol ethylene dimethyl ether; Contract triethylene glycol dimethyl ether and one or more coexistences of contracting in the tetraethyleneglycol dimethyl ether.

4. the electrolyte solution that improves Soft Roll lithium-manganese cell flatulence as claimed in claim 1; It is characterized in that: described additive is one or more coexistences in the following compounds: 1; 3-propane sultone, 1; 4-butyl sulfonic acid lactone, dimethyl sulfite, diethyl sulfite, alkyl sulfonic acid acid anhydride, sulfonic acid vinyl acetate, 1,3-propene sulfonic acid lactone, methane-disulfonic acid methylene ester.

5. the electrolyte solution that improves Soft Roll lithium-manganese cell flatulence as claimed in claim 1 is characterized in that: the structural formula of said sulfinyl:

The structural formula of said sulfonyl:

R1 wherein, R2 is identical or different group, that represents straight chain (having/unbranched) or ring-type contains (or not containing) oxygen aliphatic hydrocarbon, contains 1-6 carbon atom.