JPH07105220B2 - Non-aqueous liquid active material battery - Google Patents

Description

The present invention relates to a specific water liquid active material battery having an explosion-proof function.

[Conventional technology]

Thionyl chloride-A non-aqueous liquid active material that uses an oxyhalide-based liquid such as thionyl chloride, sulfuryl chloride, or phosphoryl chloride as a positive electrode active material typified by a lithium battery, and an alkali metal such as lithium, sodium, or potassium in the negative electrode. In a material battery, a positive electrode active material, an alkali metal, and the like are very likely to react with water, so a completely sealed structure in which a battery container is hermetically sealed is adopted.

The non-aqueous liquid active material battery adopting such a hermetic seal has the advantages of high sealing property and excellent storability, but on the other hand, because of its high sealing property, it may be exposed to high temperature heating or high temperature. When an abnormal situation such as charging with voltage is encountered, the internal pressure of the battery rises abnormally and the battery explodes, creating a loud popping sound and the battery contents splashing around and There is a risk of contamination.

Therefore, a battery is provided with an explosion-proof function by forming a cross-shaped groove at the bottom of the battery container and providing a thin portion at the bottom of the battery container, as has been proposed for alkaline batteries having a similar sealed structure. However, it is necessary to incorporate it also in this non-aqueous liquid active material battery.

However, the explosion-proof groove proposed in the alkaline battery has a V-shaped cross-section, and its tip, that is, the groove bottom is sharpened (see, for example, Japanese Utility Model Publication No. 58-17).
No. 332), or a V-shaped cross section with 0.1 to
It has a roundness of 0.2mmR (for example,
No. 26460), these cannot be applied to the non-aqueous liquid active material battery from the viewpoint of durability of the punch for forming the groove and the explosion-proof performance, as described in detail below.

That is, the cross-sectional shape provided by the alkaline battery is V
Although a groove with a sharp shape at the bottom of the groove can be expected to have a notch effect, when the groove is formed by press molding, the tip of the punch for forming the groove is immediately damaged, especially for non-aqueous liquid active material batteries. In order to withstand the strong corrosiveness of the positive electrode active material, the battery container uses corrosion-resistant metal with high hardness such as stainless steel, so the damage to the punch becomes more and more severe, and the durability of the punch and damage to the punch are increased. Due to the variation in the shape of the V-shaped groove, it cannot be industrially adopted. On the other hand, the V-shaped cross-section with rounded groove bottom is
It is thought that the punch will be less damaged, but if the bottom of the groove is rounded, the effect of simply making it thinner will be exhibited, and additional effects such as a notch effect will hardly be added, so Unless the thickness of the thin section is extremely thin, the thin section does not break within the safe pressure range.If the thin section is thin, the thin section may be corroded during storage and the battery function may be lost. is there.

Therefore, the shape of the groove formed in the bottom of the battery container is an inverted trapezoidal cross-section with a flat bottom, and the tensile force due to the internal pressure of the battery and the tensile force due to bending are applied to the ends of the groove bottom. Even if the thickness of the thin wall portion is maintained to some extent, it is possible to develop a highly safe explosion-proof function for the battery by causing a fracture fracture from the end of the groove bottom with a relatively low pressure. The applicant has already applied for a patent (Japanese Patent Application No. 61-228760).

However, from the standpoint of using the battery, there is a demand to operate the explosion-proof function within a pressure range where safety can be more reliably ensured at a lower pressure, while keeping the thickness of the thin portion thick to some extent.

[Problems to be solved by the invention]

This invention is exposed to the high temperature heating that the conventional product has, or when the battery is charged at a high voltage, the internal pressure of the battery abnormally rises to cause the battery to burst and generate a large burst noise, Solved the problem that the battery contents could scatter around and damage the equipment that uses the battery, and even when the thin explosion-proof part formed at the bottom of the battery container was kept thick to some extent, When the battery is placed under conditions where it is likely to cause an abnormal rise in internal pressure, the battery container will rupture without fail within the initial relatively low pressure range, causing battery rupture. An object of the present invention is to provide a non-aqueous liquid active material battery having a highly safe explosion-proof function of releasing the contents to the outside of the battery to prevent the battery from bursting under high pressure.

[Means for solving problems]

According to the present invention, the shape of the groove formed in the bottom of the battery container is an inverted trapezoidal cross-section with a flat bottom, and a plurality of the grooves are provided so that they have at least one intersection point. By making the thickness of the part located at the intersection of the groove of the explosion-proof thin wall provided at the bottom of the battery container 1.05 to 1.5 times the thickness of the part other than the intersection of the groove, When the pressure rises, the tensile force due to the internal pressure of the battery and the tensile force due to bending are applied more sharply to the edge of the groove bottom near the intersection, and the edge of the groove bottom is applied with lower pressure. Even if the thickness of the thin-walled portion is kept to some extent by performing a large fracture and breakage, the explosion-proof function operates within a pressure range where safety can be secured at the initial stage of internal pressure rise of the battery.

In the present invention, the thickness of the portion of the thin-walled portion located at the intersection of the grooves is located at a portion other than the intersection of the grooves (hereinafter, may be referred to as "other portion" for simplification).
The thickness of the groove is 1.05 to 1.5 times as large as the thickness of the thin part at the intersection of the groove is less than 1.05 times the thickness of the other part, the cut at the end of the groove bottom near the intersection of the groove. The effect of causing destruction at a lower pressure cannot be fully exerted, while the thickness of the portion located at the intersection of the grooves of the thin portion becomes thicker than the thickness of other portions, the vicinity of the intersection of the grooves The fracture of the end of the bottom of the groove will occur at a lower pressure, but the thickness of the part located at the intersection of the grooves of the thin part will be made larger than 1.5 times the thickness of the other parts. It is technically difficult.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is an enlarged cross-sectional view of a groove formed in a bottom portion of a battery container in the present invention, a thin wall portion for explosion-proof and its vicinity, and FIG. 2 is a state in which a battery container used in the battery of the present invention is inverted. , And FIG. 2 (a) is a plan view thereof,
FIG. 2 (b) is a sectional view taken along line XX of FIG. 2 (a). Since FIGS. 1 and 2 show the battery container in an inverted state, the bottom part is located on the upper side, and the plan view of FIG. 2 (a) is a view seen from the bottom part side of the battery container. Is.

Before the battery is assembled, the battery container 1 has a cylindrical shape with a bottom as shown in FIG. 2 (however, since the battery container is shown in an inverted state in FIG. 2 as described above, the bottom 2 Is located on the upper side), and the protrusion 2a at the center of the bottom 2 has a second
As shown in FIG. 3A, a groove 3 having a cross shape in a plan view is formed. As shown in FIG. 3, the groove 3 has an inverted trapezoidal cross-sectional shape with a flat bottom 3a ( In the shape, the expression "inverted trapezoidal shape" represents the shape when the groove bottom portion 3a is arranged on the lower side), and the portion partially thinned by the formation of the groove 3 That is, most of the explosion-proof thin-walled portion 4 provided on the bottom portion 2 of the battery container 1 by forming the groove 3, that is, the groove 3
The portion 4b located at a position other than the intersection 3b of is flattened. However, as shown in FIG. 1, the groove 3 of the thin portion 4
The portion 4a located at the intersection 3b of is protruding, and this portion 4a
Thickness t ₁ is the 1.05 to 1.5 times the thickness t ₂ of a portion 4b which is located outside the intersection 3b of the grooves 3 of the thin portion. A sectional view of the bottom portion 2 of the battery container 1 taken along line YY in FIG. 2, that is, a line diagonally crossing the intersection 3b of the groove 3 is as shown in FIG. Groove 3
The cross-sectional shape of the groove is substantially W-shaped, and the center part 3a of the groove bottom part 3a is
₂ is slightly higher than the ends 3a ₁ and 3a ₁ on both sides.
In this embodiment, since the protrusion 2a is provided at the center of the bottom portion 2 of the battery case 1 as shown in FIG. 2 so that the mounting position of the lead terminal can be easily selected, the groove 3 is formed. Is formed on the protruding portion 2a, but the protruding portion 2a is not always necessary, and the bottom portion 2 of the battery container 1 may be flat. In that case, the groove 3 may be formed in the central portion of the flat bottom portion 2 of the battery container 1, but even in such a case, the protruding portion is formed.
Compared with the case where the groove 3 is formed in 2a, the explosion-proof function is not particularly deteriorated.

The battery container 1 is used for assembling a thionyl chloride-lithium battery as shown in FIG. 6, for example.
When the internal pressure of the battery rises, the battery container 1
As shown in FIG. 5, the internal pressure P ₁ of the battery causes the bottom of the groove to
Tensile force Pa due to internal pressure and tensile force P due to bending at end 3a ₁ of 3a
This is combined with b, and the end 3a ₁ of the groove bottom 3a is greatly fractured. In particular, the groove 3 of the thin portion 4
Since the portion 4a located at the intersection point 3b is formed thicker than the other portions 4b, in the cross section as shown in FIG.
Has a W-shaped cross-section, and when pressure is applied to the battery from the inside, the end 3a ₁ of the groove bottom 3a has a tensile force Pa caused by internal pressure so as to cut the end 3a _1. Tensile force due to bending Pb
And so as to concentrate more sharply, and the thickness of the portion 4a located at the intersection 3b of the groove 3 of the thin portion 4 is the other portion 4b.
As compared with the case where the groove is formed to have the same thickness as the above, the edge 3a ₁ of the groove bottom 3a is fractured at a lower pressure.

The following Table 1 shows the operation test of the explosion-proof function by introducing air pressure into the battery container. The material of the battery container 1 is stainless steel, and its thickness is 0.3 mm. The groove 3 has an inverted trapezoidal cross section as shown in FIG. 3, the groove forming angle θ is 60 °, and the width W of the bottom portion 3a of the groove 3 is 0.15 mm.
The thin portion 4 provided on the bottom portion 2 of the battery container 1 by the formation of the groove 3 is a portion other than the intersection 3b of the groove 3.
4b is flat and has a thickness t ₂ of 80 μm, but as shown in FIG. 1, the portion 4a located at the intersection 3b of the groove 3 is convex, and the thickness t ₁ thereof is other than the intersection 3b of the groove 3. The thickness t ₂ of the portion 4b located at 1.05 times (Sample No. 1) and 1.30 times (Sample N)
o.2) and 1.50 times (Sample No. 3).

For comparison, a battery container with a rounded groove in the shape of a cross as used in alkaline batteries (Sample N
Regarding o.4), the operation test of the explosion proof function was also conducted. The shape of the groove of the battery container of this sample No. 4 is as shown in FIG. 9, the forming angle θ of the groove 3 is 90 °, the tip is rounded by 0.1 mmR, and the thin portion 4 is entirely Flat and its thickness t ₄ is 80 μm
Is.

Further, as a control product, a battery container (Sample No. 5) in which a groove having an inverted trapezoidal cross-section was formed in a cross shape and the thickness of the thin portion was substantially uniform over the whole was also subjected to an operation test of explosion-proof function. The groove of the battery container of this sample No. 5 and the shape in the vicinity thereof are as shown in FIG. 8, and the formation angle θ of the groove 3 is 60 °.
The width of the bottom portion 3a of the groove 3 is 0.15 mm, and the thickness t of the thin portion 4 is t.
₃ is 80 μm for both the portion located at the intersection of the grooves 3 and the portion located at a place other than the intersection of the grooves 3.

As shown in Table 1, the battery containers of Sample Nos. 1 to 3 and Sample No. 5 in which the groove has an inverted trapezoidal cross section are used for alkaline batteries even if the thin-walled parts have the same thickness. The working pressure of the explosion-proof function was lower than that of the battery container of Sample No. 2 having a V-shaped groove with a rounded tip as described above. Also, in the battery containers of Sample Nos. 1 to 3 in which the portion located at the intersection of the grooves of the thin portion was made thicker than the other portions, the thickness of the thin portion was made almost uniform as a whole, that is, it was located at the intersection of the grooves. The operating pressure of the explosion-proof function was lower than that of the battery container of Sample No. 5 in which the portions to be filled and the portions other than the intersections of the grooves had the same thickness. From this result, as in the present invention, by making the portion located at the intersection of the groove of the thin portion thicker than the other portions, than the conventional one, even if the thin portion is kept thick, lower pressure, In other words, it can be seen that the explosion-proof function can be operated within the pressure range where safety can be more reliably ensured.

FIG. 6 shows a thionyl chloride-lithium battery assembled using the battery container shown in FIGS. 1 to 4 above.
Reference numeral 1 is a battery container provided with the groove 3 and the explosion-proof thin portion 4 as described above. Reference numeral 11 denotes a negative electrode made of an alkali metal, which is formed by pressing a lithium plate onto the inner peripheral surface of the battery container 1 in this embodiment. Therefore, in this battery, the battery container 1 functions as a negative electrode terminal. Have
12 is a separator, and this separator 12 is made of glass fiber nonwoven fabric and has a cylindrical shape, and the cylindrical negative electrode.
11 and the cylindrical positive electrode 13 are separated. The positive electrode 13 is made of a carbon porous molded body formed of carbonaceous material containing acetylene black as a main component, and 14 is a positive electrode current collector made of a stainless steel rod. Reference numeral 15 denotes a battery lid, which is formed of stainless steel, and the raised outer peripheral portion is joined to the open end of the battery container 1 by welding, and the positive electrode terminal is provided on the inner peripheral side of the battery lid 15.
A glass layer 16 is provided between the glass layer 16 and The glass layer 16 insulates the battery lid 15 and the positive electrode terminal 17 from each other, and its constituent glass is fused to the inner peripheral surface of the battery lid 15 on the outer peripheral surface thereof, and the constituent glass of the positive electrode terminal 17 on the inner peripheral surface thereof. The outer peripheral surface is fused and sealed between the battery lid 15 and the positive electrode terminal 17, and the opening of the battery container 1 is sealed by a so-called hermetic seal. The positive electrode terminal 17 is made of stainless steel and has a pipe shape at the time of battery assembly, and is used as an electrolyte injection port. It is welded and sealed. 18 is an electrolytic solution, and this electrolytic solution 18 is thionyl chloride in which 1.2 mol / mol of lithium aluminum tetrachloride is dissolved as a supporting electrolyte, and thionyl chloride is the solvent of the electrolytic solution as described above, and the positive electrode active material in this battery. It is also a substance, and on the surface of the positive electrode 13, this thionyl chloride reacts with the lithium ions ionized from the negative electrode 11. Further, 19 and 20 are a bottom separator and an upper separator made of glass fiber non-woven fabric, respectively, and 21 is an air chamber provided in the upper part of the battery.

Table 2 shows the results of investigating whether or not the battery bursts with a loud popping noise when the battery was placed in a fire. Three types of batteries were prepared as in Examples 1, 2 and 3, and the batteries of Examples 1 to 3 were each the sample No. 1 as described above.
It is manufactured using the battery containers of 3 to 3. For comparison, the same construction as above was used except that the battery container of Sample No. 4 having a rounded V-shaped groove with a rounded tip as used in alkaline batteries was used. Table 2 also shows the results of investigating whether or not the battery (Comparative Example 1) was put into a fire and ruptured with a loud breaking sound. The number of samples tested was 10 for each battery. The denominator of the number of fire burst batteries in Table 2 indicates the number of batteries used in the test, and the numerator indicates the number of batteries that burst during fire. .

As shown in Table 2, the batteries of Examples 1 to 3 of the present invention were
None of them caused a burst in the fire, and demonstrated stable explosion-proof function.

Although the forming angle θ of the groove 3 is 60 ° and the width W of the groove bottom 3 is 0.15 mm in the above embodiment, the forming angle θ of the groove 3 is preferably in the range of 50 to 80 °. Also, the groove bottom 3
The width W is generally preferably in the range of 0.09 to 0.5 mm. And, the thickness of the thin portion (however, the thickness of the portion located other than the intersection of the groove) is set to 80 μm, but the thickness of the thin portion 4 (however, the thickness of the portion located other than the intersection of the groove is Generally, the thickness is preferably in the range of 30 to 100 μm. In particular, in the present invention, since the operating pressure of the explosion-proof function can be lowered by forming the portion located at the intersection of the thin-walled portion thicker than the other portions, the thickness of the thin-walled portion (however, other than the intersection of the groove Even if the thickness of the portion located there) is increased to 70-100 μm, the explosion-proof function can be activated within the pressure range where safety can be secured.

Further, in the above-mentioned embodiment, the case where the cross-shaped groove is formed has been described. However, as long as there are a plurality of grooves and those grooves intersect at at least one location, the planar shape is the same as in the embodiment. In addition to the cross shape shown, for example, the seventh
As shown in the figure, an X shape (see FIG. 7A), a Y shape (see FIG. 7B), an asterisk (*) shape (see FIG. 7C), an H shape (See FIG. 7 (d)). In particular, when the internal pressure is applied to the battery, the center of the bottom of the battery container is most deformed.
A letter shape, an asterisk shape and the like are preferable. Further, the groove is not required to intersect at the middle portion thereof, and the end portions of the groove may intersect, such as a Y shape. The explosion-proof thin-walled portion provided at the bottom of the battery container by forming the groove is not limited to the cross shape illustrated in the embodiment, and may have various planar shapes similar to the groove.

In addition, in the present invention, a plurality of grooves are formed and the plurality of grooves intersect at at least one place. However, this is because the plurality of grooves are formed so that the grooves have intersections. This is because the internal pressure of the battery concentrates on the intersection, and the explosion-proof function operates in accordance with the increase in the internal pressure of the battery.

〔The invention's effect〕

As described above, in the present invention, the bottom of the battery container,
Form a groove with an inverted trapezoidal cross-section with a flat bottom, and make the thickness of the part located at the intersection of the groove of the thin wall part for explosion protection provided by forming the groove 1.05 to 1.5 times the thickness of the other part By this, it was possible to provide a highly safe non-aqueous liquid active material battery in which the explosion-proof function operates in a low pressure range, that is, in a pressure range where safety can be secured, even if the thickness of the thin portion is kept to a certain degree. .

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view of a groove formed in a bottom portion of a battery container used for the battery of the present invention, a thin wall portion and the vicinity thereof. FIG. 2 shows an inverted state of the battery container used for the battery of the present invention, FIG. 2 (a) is a plan view thereof, and FIG. 2 (b) is X of FIG. 2 (a). It is a sectional view taken along the line X-. FIG. 3 is an enlarged cross-sectional view of the groove formed in the bottom of the battery container and the vicinity thereof in the present invention, particularly for explaining the cross-sectional shape of the groove. FIG. 4 is a partially enlarged sectional view taken along line YY of FIG. Fifth
The figure is a partially enlarged cross-sectional view showing a state where pressure is applied from the inside of the battery container to the bottom portion of the battery container shown in FIG.
FIG. 6 is a sectional view of a thionyl chloride-lithium battery showing an embodiment of the present invention. FIG. 7 schematically illustrates a planar shape of a groove other than the cross-shaped groove of the battery container used for the battery of the present invention. The upper stage is a schematic front view of each battery container, and the lower stage is a schematic bottom face of each. It is a figure. 8 to 9 are enlarged cross-sectional views showing a groove, a thin-walled portion and its vicinity formed in a battery container of a battery having a configuration different from that of the present invention, and FIG. 8 shows a groove having an inverted trapezoidal cross-section and a thin-walled portion. FIG. 9 shows a case where the groove is V-shaped in cross section and has a rounded tip as used in an alkaline battery. 1 ... Battery container, 2 ... bottom, 3 ... groove, 3a ... groove bottom, 3b ... groove intersection, 4 ... thin-walled portion, 4a ... portion located at thin-walled groove intersection, 4b …… Parts other than the intersections of the grooves in the thin wall,
11 …… Negative electrode, 12 …… Separator, 13 …… Positive electrode, 15 …… Battery lid, 16 …… Glass layer, 18 …… Electrolyte

Claims (1)

[Claims] 1. A positive electrode active material comprising an oxyhalide liquid such as thionyl chloride, sulfuryl chloride or phosphoryl chloride, an anode 11 made of an alkali metal such as lithium, sodium or potassium, and a hermetically sealed battery container 1. In the non-aqueous liquid active material battery described above, a plurality of grooves 3 having an inverted trapezoidal cross section with a flat bottom 3a and having at least one intersection are formed in the bottom 2 of the battery container 1 to form a thin portion 4 for explosion protection. And the groove 3 of the thin portion 4 is provided.
The thickness of the portion 4a located at the intersection point 3b of 1 is 1.05 to 1 of the thickness of the portion 4b located at a position other than the intersection point 3b of the groove 3 of the thin portion 4.
A non-aqueous liquid active material battery characterized by being multiplied by 5.