JPH0637567Y2 - Non-aqueous liquid active material battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a non-aqueous 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, due to 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, similarly, a battery is provided with an explosion-proof function by forming a cross-shaped groove in the bottom of the battery container and providing a thin portion at the bottom of the battery container, as has been proposed for a sealed alkaline battery. 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 (for example, Japanese Utility Model Publication 58-173).
No. 32), or with a V-shaped cross section at the bottom of the groove of 0.1 to
It has a roundness of 0.2mmR (for example
As described in detail below, these cannot be applied to a non-aqueous liquid active material battery in view of the durability of the punch for forming the groove and the explosion-proof performance.

That is, the cross-sectional shape proposed for alkaline batteries is V
Although a groove with a sharp groove bottom can be expected to have a notch effect, the tip of the groove-forming punch is immediately damaged when the groove is formed by press molding, 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 a 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 due to the above, it cannot be industrially adopted.
On the other hand, a punch with a V-shaped cross section and rounded groove bottom is considered to be less likely to damage the punch. However, when the groove bottom is rounded, the effect of simply reducing the thickness is exhibited. However, the additional effect such as the notch effect is hardly added.Therefore, unless the thickness of the thin-walled part is made extremely thin, the thin-walled part does not break within the safe pressure range, and the thin-walled part is thinned. Then, there is a possibility that the thin wall portion may be corroded during storage and the electrical function may be lost.

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 a battery, there is a demand for operating 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 thicker.

[Problems to be solved by the invention]

This device is exposed to the high temperature heating that the conventional product has, or when it is charged with a high voltage, the internal pressure of the battery rises abnormally and the battery bursts, causing a loud popping sound. Solved the problem that the battery contents could scatter around and damage the equipment using the battery, and even if the thickness of the thin explosion-proof part formed at the bottom of the battery container is kept 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, a groove formed in a bottom portion of a battery container is formed such that a central portion of W having a W-shaped cross section is lower than both ends and an end portion thereof has an arc shape, and by forming the groove, the battery container is formed. By making the explosion-proof thin-walled part at the bottom of the battery arc-shaped in cross section, when the internal pressure of the battery rises, the tensile force due to the internal pressure of the battery and the tensile force due to bending become sharper at the end of the groove bottom. Even if the thin part is kept thick to a certain extent by applying a combined pressure so that a lower pressure causes a large fracture at the end of the groove bottom.
The explosion-proof function operates within the pressure range where the initial safety of the internal pressure rise of the battery can be secured.

〔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 at the bottom of the battery container, a thin explosion-proof portion and its vicinity in the present invention, and FIG. 2 is a state in which the 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 detail in FIG. 1, the groove 3 has a shape in which the central portion of W having a W-shaped cross section is lower than both ends and the tip portion thereof has an arc shape (the central portion of W having a W-shaped cross section). Is lower than both ends and the tip is arcuate in shape represents the shape when the groove bottom 3a is arranged on the lower side), and A partially thinned portion, that is, an explosion-proof thin portion 4 provided on the bottom portion 2 of the battery container 1 by forming the groove 3.
Has an arcuate cross section. 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,
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 electric container 1, but even in that case, the explosion-proof function is particularly improved as compared with the case where the groove 3 is formed in the protruding portion 2a. There is no such thing as a drop.

The battery container 1 is used for assembling a thionyl chloride-lithium battery as shown in FIG. 4, for example.
When the internal pressure of the battery rises, the battery container 1 having the groove 3 in which the central portion of the W having a W-shaped cross section is lower than both ends and the tip portion thereof is arcuate is shown in FIG. As shown, the internal pressure P ₁ of the battery causes the end 3a of the groove bottom 3a to
_The tensile force Pa and the tensile force Pb due to bending are applied to ₁ by a combination of the internal pressure, and the end portion 3a ₁ of the groove bottom portion 3a is greatly fractured. In particular, the groove 3 has a W-shaped cross section in which the central portion of the W is lower than both ends and the tip portion thereof is arcuate, and the thin portion 4 has an arcuate cross-sectional shape. When the internal pressure is applied, the central portion of the arc-shaped thin portion 4 is largely deformed, so that the end portion 3a ₁ of the groove bottom portion 3a has a tensile force Pa due to the internal pressure and a tensile force Pb due to the bending.
Is more sharply concentrated than in the case of forming the inverted cross-section trapezoidal groove filed earlier, and the groove bottom portion is lower in pressure than in the case of forming the inverted trapezoid cross-section groove.
At the end 3a ₁ of 3a, a large fracture occurs.

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. Groove 3
Is a shape having a W-shaped cross-section as shown in FIG. 1, in which the central portion of W is lower than both ends and the tip portion is arc-shaped,
The groove forming angle θ is 60 °, and the width D (however in the horizontal direction) of the bottom of the groove 3 is 0.15 mm. The thin portion 4 has an arcuate cross section as shown in FIG. 1, and the lower surface height h of the central portion is
The thickness t is 50 μm, and the thickness t of the thin portion 4 is 80 μm. This battery container is referred to as Sample No. 1.

For comparison, an explosion proof operation test was also performed on a battery container (Sample No. 2) having a rounded groove at the bottom as used in alkaline batteries. The shape of the groove of the battery container of this sample No. 2 is as shown in FIG.
The forming angle θ is 90 °, and the tip has a roundness of 0.1 mmR,
The thickness t of the thin portion 4 is 80 μm.

In addition, as a control product, a battery container with a groove having an inverted trapezoidal cross section as in the case where the applicant previously applied (Sample No. 3)
Also, the operation test of the explosion-proof function was conducted. This sample No.3
The shape of the groove of the battery container and its vicinity are as shown in FIG. 6, the formation angle θ of the groove 3 is 60 °, the width D of the bottom 3a of the groove 3 is 0.15 mm, and the thickness of the thin portion 4 is t is 80 μm.

As shown in Table 1, the cross-sectional shape of the groove is sample No. 1 in which the central portion of the W-shaped W is lower than both ends and the tip is arcuate, and the thin-walled portion is arcuate in cross-section. The battery container of No. 2 has a lower explosion-proof operating pressure than the battery container of Sample No. 2 which has a groove with a rounded V-shaped cross section, which is used in alkaline batteries. The explosion-proof function was lower than that of the battery container of Sample No. 3, which had an inverted trapezoidal cross section and a flat thin wall. From this result, as in the present invention, the cross-sectional shape of the groove is such that the central portion of the W-shaped W is lower than both ends and the tip portion thereof is arcuate, and the cross-sectional shape of the thin portion is arcuate. It can be seen that the explosion-proof function can be operated at a lower pressure, that is, within a pressure range where safety can be more reliably ensured, even if the thinner portion is kept thicker than the conventional one.

FIG. 4 shows a thionyl chloride-lithium battery assembled using the battery container shown in FIGS. 1-2 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 made 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 the outer peripheral surface thereof is fused to the inner peripheral surface of the constituent glass battery lid 15, and the inner peripheral surface of the constituent glass is the outer periphery of the positive electrode terminal 17. It is fused to the 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 at the time of battery assembly, and is used as an electrolyte injection port, 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 a solution of lithium aluminum tetrachloride 1.2 mol / l dissolved in thionyl chloride as a supporting electrolyte.Thionyl chloride is a solvent of the electrolytic solution as described above, and in this battery, it is a positive electrode. It is also an active material, and on the surface of the positive electrode 13, this thionyl chloride reacts with the lithium ions ionized and eluted from the negative electrode 11. And 19
Reference numerals 20 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 portion 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. In the battery container of the other battery, a groove having a shape in which the center portion of W having a W-shaped cross section is lower than both ends and the tip is arcuate at the bottom as described above is formed, and the cross-sectional shape of the thin wall portion is formed. It is the battery container of sample No. 1 in which the arc is formed. For comparison, the same construction as above was used except that the battery container of Sample No. 2 in which a groove with a rounded V-shaped cross section was formed as in the case of using an alkaline battery was used. Table 2 also shows the results of investigating whether or not the battery (comparative product) was put into a fire and exploded with a loud popping noise. The number of samples tested was 10 for each battery. The denominator of the number of burst batteries in fire in Table 2 indicates the number of batteries used in the test, and the numerator is the number of batteries that burst during fire. Indicates.

As shown in Table 2, the battery of the present invention has no explosion in the fire and exhibits a stable explosion-proof function.

In the present invention, the cross-sectional shape of the thin portion is expressed as an arc shape, but this arc shape may be such that the central upper surface of the thin portion projects and the central lower surface of the thin portion projects. , In this expression of arcuate shape, for example, inverted V shape or inverted U shape
It also includes some deformed shapes such as a letter shape.

Further, in the above embodiment, the forming angle θ of the groove 3 is set to 60 °, and the width D of the thin portion 4 is set to 0.15 mm. However, it is preferable that the forming angle of the groove 3 is generally in the range of 50 to 90 °. Generally, the width D of the thin portion 4 is preferably in the range of 0.09 to 0.5 mm.
The thickness t of the thin portion 4 is set to 80 μm.
In general, the thickness is preferably in the range of 30 to 100 μm. In particular, in the present invention, the explosion-proof function is achieved by making the groove shape such that the central portion of W having a W-shaped cross section is lower than both end portions and the tip end portion thereof is arcuate, and the thin-walled portion is arcuate in cross-sectional shape. Since we were able to lower the operating pressure of
Even if the thickness of the thin portion 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, in view of the explosion-proof function, it is preferable that a plurality of grooves are formed and the grooves intersect at at least one place, and the planar shape is Besides the cross shape shown in the example,
For example, as shown in FIG. 5, an X shape (see FIG. 5A), a Y shape (see FIG. 5B), an asterisk (*) shape (see FIG. 5C), H shape (Fig. 5 (d)
See) can be used. Especially when the internal pressure is applied to the battery, the deformation of the center of the bottom of the battery container becomes the largest,
A cross shape having an intersection at the center of the bottom of the battery container, and variations thereof such as an X shape, a Y shape, and an asterisk shape are preferable.
Further, it is not required that the middle portions of the grooves intersect each other, and the ends of the grooves 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 the present invention, it is preferable that a plurality of grooves are formed and the plurality of grooves intersect at at least one place, and the reason is that there are a plurality of grooves and 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.

[Effect of device]

As described above, in the present invention, at the bottom of the battery container,
A cross section of a thin wall portion for explosion proof provided at the bottom of the battery container is formed by forming a groove having a shape in which the center portion of W having a W-shaped cross section is lower than both end portions and the tip end portion thereof has an arc shape. To provide a highly safe non-aqueous liquid active material battery in which the explosion-proof function operates within a pressure range that is low, that is, safety can be maintained even if the thickness of the thin portion is kept to some extent by making the shape into an arc shape. I was able to.

[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 in the battery of the present invention, a thin portion and its vicinity. 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, and FIG. 2 (b) is an X of FIG. 2 (a). It is a sectional view taken along the line X-. FIG. 3 is a partially enlarged sectional view showing a state when pressure is applied to the bottom of the battery container shown in FIG. 1 from the inside of the battery container. FIG. 4 is a sectional view of a thionyl chloride-lithium battery showing an embodiment of the present invention. FIG. 5 schematically illustrates the planar shape of the grooves other than the cross-shaped groove of the battery container used in 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 view of each. It is a figure. 6 to 7 are enlarged cross-sectional views showing a groove, a thin portion and its vicinity formed in a battery container of a battery having a configuration different from that of the present invention, and FIG. 6 shows a case where the groove has an inverted trapezoidal cross-section. FIG. 7 shows a case where the groove is V-shaped in cross section and has a rounded tip as used in alkaline batteries. DESCRIPTION OF SYMBOLS 1 ... Battery container, 2 ... Bottom part, 3 ... Groove, 4 ... Thin part, 11 ... Negative electrode, 12 ... Separator, 13 ... Positive electrode, 15 ... Battery lid, 16 ... Glass layer, 18 ... Electrolyte solution

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Yokoyama, 1-88, Tora, Ibaraki-shi, Osaka Prefecture Hitachi Maxell Co., Ltd. (72) Osamu Watanabe, 1-88, Tora, Ibaraki-shi, Osaka Hitachi Maxel Co., Ltd.

Claims (1)

[Scope of utility model registration request] 1. A battery container (1) is prepared by using an oxyhalide-based liquid such as thionyl chloride, sulfuryl chloride or phosphoryl chloride as a positive electrode active material and an alkali metal such as lithium, sodium or potassium as a negative electrode (11). In a non-aqueous liquid active material battery sealed by a hermetic seal, a W-shaped cross section is formed on the bottom (2) of the battery container (1).
Forming a groove (3) having a central portion lower than both ends and an arc-shaped tip portion, and forming the groove (3) at the bottom (2) of the battery container (1) for explosion-proof thin wall A non-aqueous liquid active material battery, characterized in that a portion (4) is provided and the thin-walled portion (4) has an arc-shaped cross section.