JPH07101610B2 - Inorganic non-aqueous electrolyte battery - Google Patents

Description

TECHNICAL FIELD The present invention relates to an inorganic non-aqueous electrolyte battery using an oxyhalide as a solvent for a positive electrode active material and an electrolytic solution and an alkali metal as a negative electrode active material.

[Conventional technology]

Thionyl chloride-using oxyhalides such as thionyl chloride, sulfuryl chloride, and phosphoryl chloride, which are typified by lithium batteries, as the solvent of the positive electrode active material and the electrolytic solution, and alkali metals such as lithium, sodium, and potassium as the negative electrode active material. In the inorganic non-aqueous electrolyte battery, a typical battery thereof, thionyl chloride-lithium battery, will be described as an example.Thionyl chloride, which is the positive electrode active material, is in direct contact with the lithium negative electrode, and therefore chloride on the lithium negative electrode. A lithium coating is formed. This lithium chloride coating film is a sparse coating film at the beginning of formation, but when it is stored at high temperature or for a long period of time, it grows into a dense coating film, which causes passivation of the lithium negative electrode. As a result, if this battery is used at high temperature or after being stored for a long period of time, a voltage drop occurs at the initial stage of discharge, and a desired voltage value is not reached, so that there is a problem that a device using this battery as a driving power source cannot operate. . In particular, a mustache-like voltage drop (see the discharge characteristic of Comparative Example 1 in FIG. 2) that appears instantaneously for several 100 μs to several ms immediately after the start of discharge is large, and therefore the range of use of the battery is extremely limited. become. Moreover, such a voltage drop phenomenon at the initial stage of discharge has a peculiarity that it repeatedly appears every time the battery is stored to some extent, not only when the undischarged battery is stored.

Therefore, conventionally, as shown in JP-A-60-249253, chlorinated polypropylene is added to the electrolytic solution to suppress the voltage drop in the initial stage of discharge, and JP-A-61-1908.
As disclosed in Japanese Patent Laid-Open No. 63-63, it has been proposed to add polyethylene oxide to an electrolytic solution to suppress the voltage drop at the initial stage of discharge.

However, even when chlorinated polypropylene or polyethylene oxide is added to the electrolytic solution as described above, there is almost no effect especially on a large whisker-like voltage drop that appears instantaneously for several 100 μs to several ms immediately after the start of discharge. Was not shown.

[Problems to be solved by the invention]

The present invention solves the problem that the conventional products have a high voltage or a large current discharge after long-term storage that causes a voltage drop in the initial stage of discharge, and the initial discharge is also high temperature or a large current discharge after long-term storage. It is an object of the present invention to provide an inorganic non-aqueous electrolyte battery in which no voltage drop occurs.

[Means for solving problems]

According to the present invention, by adding an oxygen-containing organosilane compound to an electrolytic solution, a voltage drop at the initial stage of discharge, particularly a large voltage drop that appears instantaneously immediately after the start of discharge occurs even at high current discharge after high temperature or long-term storage. It was designed so that it would not exist.

That is, by adding the oxygen-containing organosilane compound to the electrolytic solution, the lithium chloride coating film formed by incorporating the organosilane compound on the surface of the lithium negative electrode becomes a very rough film, and a high current discharge after high temperature or long-term storage Even at this time, the transfer of charges from the lithium metal of the negative electrode and the diffusion of lithium ions from the negative electrode into the electrolytic solution can be performed smoothly without being hindered by the lithium chloride film, and the activation polarization and the concentration polarization are small. Therefore, the voltage drop at the initial stage of discharge is prevented.

The reason why the film formed on the lithium negative electrode becomes a rough film by adding the oxygen-containing organic silane compound as described above is not always clear at present, but the oxygen silane in the oxygen-containing organic silane compound is not always clear. The bond has reactivity with lithium, and the oxygen silane bond is cleaved by lithium, whereby the lithium on the negative electrode surface is directly bonded to the organic silane compound, and the organic silane compound is scattered on the negative electrode lithium surface. It is considered that the lithium chloride film becomes rough. In addition, as described above, the organic silane compound is directly bonded and scattered on the surface of the negative electrode lithium to roughen the lithium chloride coating film, thereby suppressing an increase in the interface resistance of the negative electrode lithium.

In particular, when this oxygen-containing organosilane compound is added to the electrolytic solution, other additives that can prevent a large voltage drop that appears momentarily immediately after the start of discharge when discharging a battery after storage at high temperature or for a long time It is considered that this is due to the direct bonding of the organic silane compound with lithium on the surface of the negative electrode, as described above.

In the present invention, as the oxygen-containing organic silane compound added to the electrolytic solution, for example, the general formula Si _W C _X H _Y O _Z (wherein W, X, Y, and Z are as follows: 1 ≦ W
≤ 6, 3 ≤ X ≤ 48, 10 ≤ Y ≤ 60, 1 ≤ Z ≤ 10) are preferred, and specific examples thereof are given along with their structural formulas and English names, for example, trimethoxyvinylsilane _{CH 2 = CHSi (OCH 3)} 3, triethoxy vinyl silane _{(triethoxyvinylsilane) CH 2 = CHSi (} OC 2 H 5) 3, 3- glycidoxypropyltrimethoxysilane (3-Glycidoxypropyltrimethoysilane) 3-Methacryloxypropyltrimethoxysilane Tris (2-methoxyethoxy) vinylsilane (Tris (2-methoxyethoxy) vinylsilane ) CH 2 = CHSi (OC 2 H 4 OCH 3) 3, diethoxy-3-glycidoxypropyl methyl silane (Diethoxy-3-glycidoxypropylmethylsilane) Methyltrimethoxysilane _{(Methyltrimethoxysilane) CH 3 Si (OCH} 3) 3, dimethoxy dimethylsilane (Dimethoxydimethylsilan
_{e) (CH 3) 2 Si} (OCH 3) 2, phenyl trimethoxysilane (Phenyltrimethoxysilan
e) C ₆ H ₅ Si (OCH ₃ ) ₃ , Dimethoxydiphenylsilan
e) (C ₆ H ₅ ) ₂ Si (OCH ₃ ) ₂ , etc. However, it is considered that these oxygen-containing organic silane compounds will be present in the electrolytic solution in a state in which some or all of the hydrogen atoms are replaced with chlorine atoms by the addition of the electrolytic solution. Therefore, the oxygen-containing organic silane compound exemplified above in which some or all of the hydrogen atoms are replaced with chlorine atoms can be used in the same manner as the oxygen-containing organic silane compound exemplified above.

The amount of these oxygen-containing organosilane compounds added to the electrolytic solution is preferably in the range of 1 × 10 ⁻⁶ mol / to 1 × 10 ⁻¹ mol /. That is, when the amount of the oxygen-containing organic silane compound added to the electrolytic solution is less than the above range, the effect of roughening the lithium chloride coating formed on the negative electrode surface is not sufficiently exerted, and the electrolysis of the oxygen-containing organic silane compound is not performed. Even if the amount added to the liquid exceeds the above range, the effect of roughening the lithium chloride coating to prevent the voltage drop at the initial stage of discharge does not change much, but rather the amount of oxygen-containing organosilane compound increases in accordance with the increase of the battery. This is because the positive electrode active material that can be filled inside is reduced, which is not preferable.

In the battery of the present invention, as the positive electrode active material, for example, an oxyhalide that is liquid at room temperature, such as thionyl chloride, phosphoryl chloride, and sulfuryl chloride, is used. These oxyhalides are used as a positive electrode active material and a solvent for the electrolytic solution, and the electrolytic solution is prepared by dissolving a supporting electrolyte such as LiAlCl ₄ , LiAlBr ₄ , LiGaCl ₄ , and LiB ₁₀ Cl _{10 in} these oxyhalides. Is prepared. In addition,
When preparing the electrolyte, the supporting electrolyte such as LiAlCl ₄ should be L
Add iCl and AlCl ₃ to the oxyhalide in the electrolyte
In the form of LiAlCl ₄ (provided that, Li ⁺ and AlCl ₄ to ionize ^-
The oxygen-containing organic silane compound may be added together with the supporting electrolyte at the time of preparing the electrolytic solution or before the supporting electrolyte.

And in the battery of the present invention, as the negative electrode active material,
For example, alkali metals such as lithium, sodium and potassium are used.

〔Example〕

 Next, the present invention will be described in more detail with reference to examples.

Example 1 An AA thionyl chloride-lithium battery was prepared using thionyl chloride as the positive electrode active material and lithium as the negative electrode active material. The electrolytic solution was prepared by dissolving 1.2 mol / mol of LiAlCl ₄ (provided that LiCl and AlCl ₃ were added to thionyl chloride at the time of adding to thionyl chloride) in thionyl chloride as described above. Trimethoxyvinylsilane is dissolved in the solution at 1 × 10 ⁻³ mol / mol.

FIG. 1 shows the above battery, in which 1 is a negative electrode made of lithium. The negative electrode 1 is formed by pressing a lithium sheet onto the inner peripheral surface of a cylindrical battery container 2 having a bottom. There is. Reference numeral 3 is a positive electrode, and this positive electrode 3 is composed of a cylindrical carbon porous molded body containing acetylene black as a main component. 4 is an electrolytic solution, and this electrolytic solution 4 is prepared by dissolving LiAlCl ₄ in thionyl chloride as described above,
In this example, 1 × 10 ⁻³ mol / trimethoxyvinylsilane was added to this electrolytic solution 4, and 3.9 ml was stored in the battery.
Has been injected. Then, in this battery, thionyl chloride is a solvent for the electrolytic solution and a positive electrode active material as described above. Reference numeral 5 denotes a separator made of glass fiber nonwoven fabric, which has a cylindrical shape and separates the cylindrical negative electrode 1 and the cylindrical positive electrode 3 from each other. 6 is a positive electrode current collector,
Made of stainless steel rod. 7 is a battery lid, and this battery lid 7
Is made of stainless steel, and the raised outer peripheral portion is joined to the open end portion of the battery container 2 by welding. A glass layer 8 is provided on the inner peripheral side of the battery lid 7 between the battery lid 7 and the positive electrode terminal 9, and the glass layer 8 serves as the battery lid 7.
And the positive electrode terminal 9 are insulated from each other, the constituent glass is fused to the inner peripheral surface of the battery lid 7 on the outer peripheral surface, and the constituent glass is fused to the outer peripheral surface of the positive electrode terminal 9 on the inner peripheral surface, Battery lid 7
The positive electrode terminal 9 and the positive electrode terminal 9 are sealed, and the opening of the battery container 2 is sealed by a so-called hermetic seal. The positive electrode terminal 9 is made of stainless steel and has a pipe shape at the time of battery assembly and is used as an electrolyte injection port. The upper end portion of the positive electrode current collector 6 is inserted into the hollow portion of the positive electrode current collector 6 after the electrolyte solution is injected. It is welded and sealed. And 10 and
Reference numeral 11 is a bottom separator and a top separator made of glass fiber non-woven fabric, and 12 is an air chamber provided at the top of the battery.

Example 2 A thionyl chloride-lithium battery having the same configuration as in Example 1 was prepared except that an electrolytic solution containing 1 × 10 ⁻³ mol / triethoxyvinylsilane was used instead of trimethoxyvinylsilane.

Example 3 A thionyl chloride-lithium battery having the same configuration as in Example 1 except that an electrolytic solution containing 1 × 10 ⁻³ mol / mol of ³ -glycidoxypropyltrimethoxysilane was used in place of trimethoxyvinylsilane was used. It was made.

Example 4 A thionyl chloride-lithium battery having the same configuration as in Example 1 was prepared except that an electrolytic solution containing 1 × 10 ⁻³ mol / mol of 3-methacryloxypropyltrimethoxysilane was used in place of trimethoxyvinylsilane. did.

Example 5 The addition amount of trimethoxyvinylsilane to the electrolytic solution was 1 × 10 5.
Change to ^-5 mol / and add 1x this trimethoxyvinylsilane
A thionyl chloride-lithium battery having the same configuration as in Example 1 was prepared except that an electrolytic solution containing 10 ⁻⁵ mol / addition was used.

Example 6 The amount of trimethoxyvinylsilane added to the electrolytic solution was 1 × 10 6.
Change to ^-1 mol / and add 1x this trimethoxyvinylsilane
A thionyl chloride-lithium battery having the same structure as in Example 1 except that an electrolytic solution containing 10 ⁻¹ mol / addition was used was prepared.

Comparative Example 1 The same constitution as in Example 1 except that an electrolytic solution containing no oxygen-containing organic silane compound such as trimethoxyvinylsilane, that is, an electrolytic solution containing 1.2 mol / mol of LiAlCl ₄ dissolved in thionyl chloride was used. A thionyl chloride-lithium battery consisting of

Comparative Example 2 A thionyl chloride-lithium battery having the same configuration as in Example 1 was prepared except that an electrolytic solution containing 0.15 g / chlorinated polyethylene instead of trimethoxyvinylsilane was used.

The amount of chlorinated polyethylene added to the electrolytic solution is approximately the same as the amount of trimethoxyvinylsilane added in Example 1 in grams. That is, the amount of trimethoxyvinylsilane added to the electrolytic solution in the battery of Example 1 was 1 × 10 5.
^-3 mol /, but when expressed in g /, it is about 0.15 g /
Is. In this way, the amount added to the chlorinated polyethylene electrolytic solution was set to g / standard because the chlorinated polyethylene is a polymer compound and has a very large molecular weight, so that the same molar (mol /) concentration as in Example 1 was used. This is because when it is added to the electrolytic solution, the amount of addition becomes very large, and the performance is rather deteriorated.

Comparative Example 3 Example 1 except that an electrolytic solution containing 0.15 g / polyethylene oxide was added instead of trimethoxyvinylsilane.
A thionyl chloride-lithium battery having the same structure as in Example 1 was produced.

In this way, also in Comparative Example 3, the amount of polyethylene oxide added to the electrolytic solution was set to g / reference from the same viewpoint as in the case of the chlorinated polyethylene of Comparative Example 2.

The batteries of Examples 1 to 6 and Comparative Examples 1 to 20 were stored at 60 ° C. for 20
1ms when stored for 10ms at 20 ° C and 10Ω after storage for 1 day
The minimum voltage before and after (that is, around 1 ms after the start of discharge) was measured. In other words, the extent of the voltage drop that appeared immediately after the start of discharge with a large current (current equivalent to about 200 mA at a load of 10 Ω) after high temperature storage was investigated. The results are shown in Table 1.

As shown in Table 1, after storage for 20 days at 60 ℃,
When discharged for ms, in the battery of Comparative Example 1 in which no additive was added, the battery voltage dropped to 1.304V, and a large voltage drop was observed, whereas in the batteries of Examples 1 to 6, Although there were some differences due to differences in additives and differences in addition amount, no large voltage drop was observed in the battery voltage range of 2.012V to 2.124V. The battery of Comparative Example 2 in which chlorinated polyethylene was added to the electrolytic solution and the battery of Comparative Example 3 in which polyethylene oxide was added to the electrolytic solution were
The battery voltages were 1.512 V and 1.475 V, respectively, which were close to those of the battery of Comparative Example 1, and such a large current discharge showed almost no effect of preventing the voltage drop that appears immediately after the start of discharge.

FIG. 2 shows the battery of Example 1 and the battery of Comparative Example 1 at 20 ° C.
It is a figure which shows the discharge characteristic at the time of a 10-ohm constant resistance discharge.

As shown in FIG. 2, in the battery of Comparative Example 1 in which no additive was added at all, a large whisker-like voltage drop was observed around 1 ms after the start of discharge, but in the battery of Example 1, No such beard-like voltage drop was observed.
The batteries of Examples 2 to 6 were also discharged under the same conditions as above, and the discharge characteristics were examined.
The battery of No. 2 did not have a whisker-like voltage drop immediately after the start of discharge, and had the same discharge characteristics as the battery of Example 1.

〔The invention's effect〕

As described above, in the present invention, by adding the oxygen-containing organic silane compound to the electrolytic solution, the voltage drop at the initial stage of discharge even in the large-current discharge after storage, especially the large voltage drop that appears momentarily immediately after the start of discharge. Could be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the inorganic non-aqueous electrolyte battery of the present invention. FIG. 2 is a discharge characteristic diagram of the battery of Example 1 and the battery of Comparative Example 1. 1 ... Negative electrode, 3 ... Positive electrode, 4 ... Electrolyte

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ninoyasu Iwamaru 1-188, Tora, Ibaraki-shi, Osaka Inside Hitachi Maxell Co., Ltd. (56) Reference JP-A-61-220279 (JP, A)

Claims (5)

[Claims] 1. An inorganic non-aqueous electrolyte battery using an oxyhalide as a solvent for a positive electrode active material and an electrolytic solution and an alkali metal as a negative electrode active material, wherein an oxygen-containing organosilane compound is added to the electrolytic solution. Inorganic non-aqueous electrolyte battery. 2. An oxygen-containing organic silane compound is trimethoxyvinylsilane, triethoxyvinylsilane, 3-glycidoxypropyltrimethoxysilane, 3-methacryloxypropyltrimethoxysilane, tris (2-methoxyethoxy) vinylsilane, diethoxy-3. -Inorganic non-aqueous electrolysis according to claim 1, which is at least one selected from the group consisting of glycidoxypropylmethylsilane, methyltrimethoxysilane, dimethoxydimethylsilane, phenyltrimethoxysilane and dimethoxydiphenylsilane. Liquid battery. 3. A patent in which the oxygen-containing organic silane compound is at least one selected from the group consisting of trimethoxyvinylsilane, triethoxyvinylsilane, 3-glycidoxypropyltrimethoxysilane and 3-methacryloxypropyltrimethoxysilane. The inorganic non-aqueous electrolyte battery according to claim 1. 4. The inorganic non-aqueous electrolyte battery according to claim 1, wherein a part or all of hydrogen atoms of the oxygen-containing organic silane compound are replaced with chlorine atoms. 5. The inorganic non-aqueous electrolyte battery according to claim 1, wherein the amount of the oxygen-containing organic silane compound added to the electrolytic solution is 1 × 10 ⁻⁶ mol / to 1 × 10 ⁻¹ mol /. .