JPS63294665A - Non-liquid active material battery - Google Patents

Abstract

PURPOSE:To achieve explosion-proof function within a safety pressure range by forming a groove shaped in a letter W in section and flattened in its bottom by multipying the thicknes of a portion at the cross point of the groove of an explosion-proof thin portion specific times in comparison with other portions. CONSTITUTION:On a projection portion 2a at the center of the bottom 2 of a battery case 1, a crosslike groove 3 in plane view is formed. The groove 3 is shaped in an inverse trapezoid section having a flat bottom. Namely, an explosion-proof thin portion 4 which is partially thinned due to the formation of the groove 3 is flattened over a large portion 4b except a cross point 3b of the groove 3, while a portion 4a at the cross point 3b protrudes and the thickness t1 of the portion 4a is set larger 1.05 to 1.5 times than that of the flat part 4b. The section of the groove cut by a line Y-Y is shaped approximately as the letter W, and a central portion 3a2 of a groove bottom portion 3a is slightly higher than ends 3a1, 3a1 of both side. When internal pressure rises, it concentrates on the ends 3a1, 3a1 to cut or break same. It is thus possible to give a battery explosion-proof function within a pressure range where safety at the initial stage of internal pressure is ensured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a non-aqueous liquid active material battery with explosion-proof function.

[Conventional technology]

Non-aqueous liquid active materials, such as thionyl chloride-lithium batteries, use oxyhalide-based liquids such as thionyl chloride, sulfuryl chloride, and phosphoryl chloride as the positive electrode active material, and use alkali metals such as lithium, sodium, and potassium for the negative electrode. In material batteries, the cathode active material and alkali metals are highly reactive with water, so a completely sealed structure is used in which the battery container is sealed with a hermetic seal.

Non-aqueous liquid active material batteries that use such hermetic seals have the advantage of being highly hermetic (and have excellent storage stability), but on the other hand, because of their high hermetic sealing, they cannot be exposed to high-temperature heating, - When an abnormal situation occurs, such as being charged at a high voltage, the internal pressure of the battery increases abnormally, causing the battery to burst, making a loud bursting sound, and causing the contents of the battery to scatter all over the place, causing the battery to become unusable. There is a risk of contaminating the equipment.

Therefore, it is proposed to equip the battery with an explosion-proof function by forming a cross-shaped groove at the bottom of the battery container and providing a thin wall part at the bottom of the battery container, as has been proposed for alkaline batteries that similarly have a sealed structure. However, it is necessary to incorporate this into this non-aqueous liquid active material battery as well.

However, the explosion-proof groove proposed for alkaline batteries has a V-shaped cross-section, and the tip, or bottom of the groove, is sharp (for example,
(Japanese Utility Model Publication No. 17332), or a V-shaped cross section with a groove bottom rounded by 0.1 to 0.2 +mmH (for example, Japanese Utility Model Publication No. 58-26460), which are detailed below. As such, the groove-forming punch cannot be applied to non-aqueous liquid active material batteries due to its durability and explosion-proof performance.

In other words, the cross-sectional shape proposed for alkaline batteries is V
A groove with a sharp groove bottom can be expected to have a notch effect, but when forming the groove by press molding, the tip of the groove forming punch is easily damaged, especially in batteries with residual water liquid active material. In order to withstand the strong corrosivity of the positive electrode active material, hard and corrosion-resistant metals such as stainless steel are used for battery containers, so damage to the punch becomes more and more severe, resulting in damage to the punch and durability. Due to the variation in the shape of the V-shaped groove due to the
It is thought that damage to the punch will be reduced, but if the bottom of the groove is rounded like this, the effect of making the groove thinner will only be achieved, and additional effects such as the notch effect will hardly be added. Unless the thickness of the thin wall part is made extremely thin, the thin wall part will not break within a safe pressure range, and if the thickness of the thin wall part is made thin, there is a risk that the thin wall part will be corroded during storage and the battery function will be lost. be.

Therefore, the shape of the groove formed at the bottom of the battery container is made into a truncated cross-sectional truncated shape with a flat bottom, and the tensile force due to the internal pressure of the battery and the tensile force due to bending are combined at the end of the groove bottom. A new technology has been developed to give batteries highly safe explosion-proof functionality by allowing rupture to occur from the edge of the bottom of the groove at a relatively low pressure even if the thickness of the thin wall part is maintained to a certain degree. The present applicant has already filed a patent application (Japanese Patent Application No. 228760/1983).

However, from the viewpoint of battery users, there is a desire to operate the explosion-proof function within a pressure range where safety can be more reliably ensured at a lower pressure while maintaining the thickness of the thin part to a certain degree.

[Problem that the invention seeks to solve]

This invention eliminates the problems that the conventional products had, such as when exposed to high temperature heating or charged at high voltage, the internal pressure of the battery rises abnormally and causes the battery to burst, producing a loud bursting sound. This solves the problem of battery contents scattering around and causing damage to equipment using batteries, and even when the thickness of the explosion-proof thin section formed at the bottom of the battery container is maintained to a certain degree, the battery When a battery is placed in a situation where its internal pressure is likely to rise abnormally, part of the battery container will definitely break and break within the relatively low initial pressure range, causing the battery to explode. The purpose of the present invention is to provide a non-aqueous liquid active material battery that has a highly safe explosion-proof function that prevents the battery from bursting under high pressure by releasing the contents to the outside of the battery.

[Means for solving problems]

According to the present invention, the shape of the groove formed at the bottom of the battery container is made into a truncated cross-sectional truncated shape with a flat bottom, and a plurality of grooves are formed so that they have at least one intersection point, and by forming the groove, By making the thickness of the part located at the intersection of the grooves of the thin explosion-proof part provided at the bottom of the battery container 1.05 to 1.5 times the thickness of the part located at a place other than the intersection of the grooves. , when the internal pressure of the battery increases, the tensile force due to the internal pressure of the battery and the tensile force due to bending are more sharply combined and applied to the edge of the groove bottom near the intersection, and the groove bottom is increased at a lower pressure. Even if the thin wall part is kept thick to a certain extent by causing a large amount of rupture at the end, the explosion-proof function is activated within the pressure range that ensures safety when the battery's internal pressure rises in the early stages. be.

In the present invention, the thickness of the portion of the thin wall portion located at the intersection of the grooves is defined as the portion located at a location other than the intersection of the grooves (hereinafter, for simplicity, may be expressed as "other portion").
The thickness should be 1.05 to 1.5 times the thickness of the groove bottom near the groove intersection if the thickness of the thin part at the groove intersection is less than 1.05 times the thickness of the other part. On the other hand, the effect of causing tearing failure at the edge of the thin section at a lower pressure cannot be sufficiently exhibited, and on the other hand, the thickness of the part located at the intersection of the grooves of the thin part becomes thicker than the thickness of the other part. The lower the pressure becomes, the lower the pressure will be required to cause tearing failure at the end of the groove bottom near the intersection of the grooves, but if the thickness of the thin-walled part located at the intersection of the grooves is made smaller than the thickness of the other parts. This is because it is technically difficult to produce a size larger than 1.5 times.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is an enlarged sectional view of the groove formed at the bottom of the battery container, the explosion-proof thin wall part, and the vicinity thereof in the present invention;
Fig. 2 shows the battery container used in the battery of the present invention in an inverted state; Fig. 2(a) is a plan view thereof;
Figure (b) is a sectional view taken along the line X--X in Figure 2 (a). Note that FIGS. 1 and 2 show the battery container upside down, so the bottom is on the top, and the plan view in FIG. 2(a) is a view from the bottom side of the battery container. It is.

Before the battery is assembled, the battery container 1 has a cylindrical shape with a bottom as shown in FIG. The protrusion 2a at the center of the bottom 2 is formed with a groove 3 having a cross-shaped planar shape as shown in FIG. As shown in Figure 3, the cross-sectional shape is an inverted trapezoidal shape with a flat bottom 3a (υ shape, and the term "inverted trapezoidal" refers to the shape when the groove bottom 3a is placed on the lower side). , and the portion partially made thin due to the formation of the groove 3, that is, the explosion-proof thin wall portion 4 provided on the bottom 2 of the battery container 1 due to the formation of the groove 3, is mostly The portion 4b of the groove 3 located outside the intersection 3b is flat.However,
As shown in FIG. 1, a portion 4a of the thin wall portion 4 located at the intersection 3b of the grooves 3 protrudes, and the thickness of this portion 4a is t.
l is the thickness 1. 11.05 to 1.5 times. A cross-sectional view of the bottom part 2 of the battery container 1 taken along the Y-Y line in FIG. 2, that is, a line that diagonally crosses the intersection 3b of the grooves 3, is as shown in FIG. The cross-sectional shape of the groove 3 is approximately W-shaped, and the groove bottom 3a
The center portion 3az is slightly higher than the end portions 3a+, 3a, on both sides. In addition, in this embodiment, in order to facilitate selection of the mounting position of the lead terminal, as shown in Fig. 2,
Since the protrusion 2a is provided at the center of the bottom 2 of the battery container 1, the groove 3 is formed in the protrusion 2a, but the protrusion 2a is not necessarily necessary. The bottom 2 of the battery container 1 may be flat. In that case, the groove 3 may be formed in the center of the flat bottom 2 of the battery container 1. There is no particular deterioration in the explosion-proof function compared to the case where a

This battery container 1 is used for assembling a thionyl chloride-lithium battery as shown in FIG. 6, for example, but after assembling the battery,
When the internal pressure of the battery increases, this battery container l will
As shown in FIG. 5, due to the internal pressure P1 of the battery, a tensile force Pa due to the internal pressure and a tensile force Pb due to bending are combinedly applied to the end 3a of the groove bottom 3a, and the end 3a of the groove bottom 3a is , the area becomes severely cut and fractured. In particular, since the portion 4a of the thin wall portion 4 located at the intersection 3h of the grooves 3 is formed thicker than the other portion 4b, the cross-sectional shape of the groove 3 has a W-shape in the cross section shown in FIG. When pressure is applied to the battery from the inside, the groove bottom 3
The tensile force Pa due to the internal pressure and the tensile force Pb due to bending are applied more sharply to the end 3a of the thin wall portion 4 so as to tear the end 3a, and the intersection 3 of the groove 3 of the thin wall portion 4 The end portion 3a+ of the groove bottom 3a will be cut and fractured at a lower pressure than when the thickness of the portion 4a located at the groove bottom 3a is the same as that of the other portion 4b.

Table 1 below shows the explosion-proof function tested by introducing air pressure into the battery container.

The material of the battery container 1 is stainless steel, and its thickness is 0.3
It is mm. As shown in FIG. 3, the groove 3 has an upright trapezoidal cross section, the groove forming angle θ is 60', and the bottom 3a of the groove 3
The convergence W is 0.15 m-, and the thin part 4 provided on the bottom part 2 of the battery container l by forming the groove 3 is flat in the part 4b located other than the intersection 3b of the groove 3, and its thickness is Although t8 is 80 pm, as shown in FIG.
The portion 4a located at the intersection 3 of is convex and has a thickness of 1. is a portion 4 located at a location other than the intersection 3b of the groove 3
1.05 times the thickness t2 of b (sample N[Ll), 1.3
0 times (sample fish 2) and 1.50 times (sample magnet 3).

For comparison, we used a battery container (sample 8) with rounded grooves formed in the shape of a cross at the bottom, as used in alkaline batteries.
114) was also tested for its explosion-proof function.

The shape of the groove in the battery container of this sample 4 is as shown in FIG. 9, the forming angle θ of the groove 3 is 90°, and the tip is 0.
The thin part 4 is rounded to 1 mmH, and the thin part 4 is entirely flat, and its thickness t4 is 80 pm.

In addition, as a control product, a battery container (sample Nα5) in which a cross-sectional truncated trapezoidal groove was formed in the shape of a cross and the thickness of the thin wall portion was made almost uniform throughout was also tested for the explosion-proof function. The shape of the groove of the battery container of this sample N115 and its vicinity is as shown in FIG. 8, and the formation angle θ of the groove 3 is 6.
0", the width of the bottom part 3a of the groove 3 is 0.15 m-, and the thickness t of the thin part 4 is the part located at the intersection of the grooves 3, the width of the bottom part 3a of the groove 3
The length of the portions located other than the intersections is also 80 μm.

As shown in Table 1, the battery containers of sample holes 1 to 3 and sample hole 5, in which the cross-sectional shape of the groove is inverted trapezoidal, are used for alkaline batteries even though the thickness of the thin wall part is the same. The operating pressure of the explosion-proof function was lower than that of the battery container of sample Nl12, which had a groove with a V-shaped cross section with a rounded tip. In addition, in the battery case of sample kl~3, where the part located at the intersection of the grooves in the thin wall part was thicker than the other parts, the thickness of the thin wall part was made almost uniform throughout, that is, the part located at the intersection of the grooves. The operating pressure of the explosion-proof function was also lower than that of the battery container of Sample 5, in which the thickness of the portions other than the intersections of the grooves was the same. From this result, as in the present invention, by making the portion located at the intersection of the grooves in the thin wall portion thicker than the other portions, even if the thin wall portion is kept thicker than in the past, the pressure can be lowered. In other words, it can be seen that the explosion-proof function can be activated within a pressure range that more reliably ensures safety.

Figure 6 shows a thionyl chloride-lithium battery assembled using the battery container shown in Figures 1 to 4 above.
Reference numeral 1 denotes a battery container provided with a groove 3 and an explosion-proof thin wall portion 4 as described above. Reference numeral 11 denotes a negative electrode made of an alkali metal, and in this embodiment, it is formed by pressing a lithium plate onto the inner peripheral surface of the battery container 1. Therefore, in this battery, the battery container 1 does not function as a negative electrode terminal. have.

Reference numeral 12 denotes a separator, which is made of glass fiber nonwoven fabric and has a cylindrical shape, separating the cylindrical negative electrode 11 and the cylindrical positive electrode 13. Positive electrode 1
3 is a carbon porous molded body made of carbonaceous material containing acetylene black as a main component; 14 is a positive electrode current collector;
Made of stainless steel rod. Reference numeral 15 denotes a battery lid, which is made of stainless steel, and its raised outer periphery is joined to the open end of the battery container 1 by welding. A layer 16 is interposed. The glass layer 16 insulates the battery cover 15 and the positive terminal 17, and the constituent glass is fused to the inner circumferential surface of the battery cover 15 on its outer peripheral surface, and the constituent glass is fused to the positive terminal 17 on its inner circumferential surface. It is fused to the outer peripheral surface to seal 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 when the battery is assembled, and is used as an electrolyte inlet, and its upper end is connected to the upper part of the positive electrode current collector 14 inserted into the hollow part after the electrolyte is injected. It is welded and sealed. 18 is an electrolytic solution, and this electrolytic solution 18 is made by dissolving 1.2·-o1/l of lithium aluminum tetrachloride as a supporting electrolyte in thionyl chloride, and as mentioned above, thionyl chloride is a solvent for the electrolyte and , which is also a positive electrode active material in this battery, causes a reaction between this thionyl chloride and lithium ions ionized from the negative electrode 11 on the surface of the positive electrode 13, and 19
and 20 are a bottom isolation member and an upper isolation member respectively made of glass fiber nonwoven fabric, and 21 is an air chamber provided at the upper part of the battery.

Table 2 shows the results of throwing the above-mentioned batteries into a fire and examining whether the batteries exploded with a loud bursting sound. Three types of batteries were prepared as shown in Example 1.2.3. , the batteries of Examples 1 to 3 were prepared using sample N [
It is produced using 11 to 3 battery containers. In addition, for comparison, a battery container with the same configuration as above was used, except that a battery container of sample No. 4 was used, which had a groove with a rounded tip and a roughly V-shaped cross section, as used in alkaline batteries. Table 2 also shows the results of putting the battery (Comparative Example 1) into a fire and examining whether the battery would burst with a loud bursting sound. The number of batteries tested was 10 each, and the denominator of the numerical value for the number of batteries that exploded in fire in Table 2 indicates the number of batteries subjected to the test, and the numerator indicates the number of batteries that exploded in fire. .

Table 2 As shown in Table 2, the batteries of Examples 1 to 3 of the present invention were:
All of them exhibited stable explosion-proof functionality, with no material that would explode during fire.

In addition, in the above embodiment, the formation angle θ of the groove 3 is 60@,
Although the width W of the groove bottom 3 was set to 0.15 m, it is generally preferable that the full 3 forming angle θ is in the range of 50 to 80'.
In addition, the radius W of the groove bottom 3 is generally 0.09 to 0.51I1m.
It is preferable that the thickness of the thin part 4 be within the range of 80 μm (however, the thickness of the part located other than the intersection of the grooves) is 80 μm. The thickness of the part located at the
In particular, in the present invention, the operating pressure of the explosion-proof function can be lowered by forming the part located at the intersection of the thin-walled parts thicker than the other parts. It is now possible to activate the explosion-proof function within a pressure range that ensures safety even if the thickness of the groove is as thick as 70 to 100 μm (the thickness of the area other than the intersection of the grooves). .

Further, in the above embodiment, a case where cross-shaped grooves were formed was explained, but the grooves may be a plurality of grooves as long as they intersect at least at one place, and the planar shape of the grooves is different from that in the embodiment. In addition to the cross shape shown, for example, the seventh
As shown in the figure, an (See Figure 7 (B)). Especially when internal pressure is applied to the battery, the center of the bottom of the battery container deforms the most, so a cross shape with an intersection at the center of the bottom of the battery container, Its modification is X-shape, Y
A character shape, an asterisk shape, etc. are preferable, and the grooves do not need to intersect in the middle, but may be such that the ends of the grooves intersect, such as a Y shape, and the above-mentioned 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, but may have various planar shapes similar to the groove.

Note that in the present invention, a plurality of grooves are formed and the plurality of grooves intersect at at least one place. This is because the internal pressure of the battery will be concentrated at the intersection, and the explosion-proof function will be activated in response to the increase in internal pressure of the battery.

〔Effect of the invention〕

As explained above, in the present invention, at the bottom of the battery container,
A groove with a flat bottom and a truncated trapezoidal cross-section is formed, and the thickness of the thin section for explosion protection provided by forming the groove is 1.05 to 1.05 of the thickness of the other portions at the intersection of the grooves. 1.5
By doubling the thickness, it is possible to provide a highly safe non-aqueous liquid active material battery whose explosion-proof function operates within a low pressure range, that is, within a safe pressure range, even if the thickness of the thin part is kept thick to a certain extent. Ta.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of a groove formed at the bottom of a battery container used in the battery of the present invention, a thin wall portion, and the vicinity thereof. Fig. 2 shows the battery container used in the battery of the present invention in an inverted state, and Fig. 2 (b) is a plan view thereof.
FIG. 2(b) is a sectional view taken along the line X--X of FIG. 2(a). FIG. 3 is an enlarged sectional view of the groove formed in the bottom of the battery container and its vicinity in the present invention, and is particularly for explaining the cross-sectional shape of the groove. Figure 4 is similar to Figure 2 (a
) is a partially enlarged sectional view taken along the Y-Y line. FIG. 5 is a partially enlarged sectional view showing a state when pressure is applied to the bottom of the battery container shown in FIG. 4 from inside the battery container. 6th
The figure is a sectional view of a thionyl chloride-lithium battery showing one embodiment of the present invention. FIG. 7 schematically illustrates the planar shape of grooves other than the cross-shaped grooves of the battery container used in the battery of the present invention, and the upper row is a schematic front view of each battery container;
The lower rows are respectively schematic bottom views. 8 and 9 are enlarged cross-sectional views showing grooves, thin-walled portions, and their vicinity formed in the battery case of a battery having a different configuration from that of the present invention. In FIG. This shows a case in which the groove is formed almost uniformly over the entire area, and FIG. 9 shows a case in which the groove is V-shaped in cross section and rounded at the tip, as is used in alkaline batteries. l...Battery container, 2...Bottom, 3...Groove, 3
a...bottom of the groove, 3b...intersection of the groove, 4...
Thin wall portion, 4a...portion located at the intersection of the grooves of the thin wall portion,
4b... Portion located at a location other than the intersection of the grooves of the thin wall portion, 11... Negative electrode, 12... Separator, 13
...Positive electrode, 15...Battery lid, 16...Glass layer, 18...Electrolyte 1st Figure 1...Battery container 2...Bottom 3...Groove 3b...Groove Intersection 4... Thin wall portion 4a... Portion to be placed at the intersection of the grooves of the thin wall portion 3 Fig. 1... Battery container 2... Bottom portion 3... Groove 3a...・Bottom part 4 of the groove... Thin wall part 4a... Portion located at the intersection of the grooves of the thin wall part Fig. 4 Fig. 6 Fig. 7

Claims (1)

[Claims] (1) An oxyhalide liquid such as thionyl chloride, sulfuryl chloride, or phosphoryl chloride is used as the positive electrode active material, an alkali metal such as lithium, sodium, or potassium is used as the negative electrode 11, and the battery container 1 is sealed with a hermetic seal. In the aqueous liquid active material battery, an explosion-proof thin section 4 is provided by forming a plurality of grooves 3 in the bottom section 2 of the battery container 1 in the shape of a truncated trapezoid with a flat bottom section 3a and having at least one intersection point. , the thickness of the portion 4a located at the intersection 3 of the grooves 3 of the thin portion 4 is determined by the thickness of the groove 3 of the thin portion 4.
1 of the thickness of the portion 4b located at a location other than the intersection 3b of
．． 1. A non-aqueous liquid active material battery characterized in that the battery is made up of 0.05 to 1.5 times.