JPH0615400Y2 - Explosion-proof battery - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an explosion-proof battery having a sealing body provided with an explosion-proof device.

[Conventional technology]

For example, in a cylindrical lithium battery that uses an organic electrolyte, when gas is generated inside the battery due to the occurrence of an internal short circuit, and the pressure inside the battery is about to rise abnormally,
The flexible thin plate bends upward and contacts the cutting edge to destroy it, thereby discharging the gas inside the battery to the outside of the battery and preventing the battery from exploding, so-called explosion. Is being prepared (for example, Japanese Utility Model Publication No. 59-15398).

The inventors of the present invention also conducted extensive research on an explosion-proof battery having such an explosion-proof device provided in the sealing body, and have developed a battery as shown in FIG. 5 so far.

In the battery shown in FIG. 5, the peripheral edge of the flexible thin plate 40 that closes the gas vent hole 11 of the sealing plate 10 and the annular packing 30 are sandwiched between the brim-shaped peripheral edge 22 of the terminal plate 20 and the sealing plate 10. However, if the pressure inside the battery rises due to an internal short circuit,
As shown in the figure, the flexible thin plate 40 bends upward and the terminal plate 20
The gas inside the battery is discharged to the outside of the battery from the gas exhaust hole 23 of the terminal plate 20 through the gas vent hole 11 of the sealing plate 10 to prevent the battery from rupturing by contacting and breaking the cutting edge 24 provided on the To do.

[Problems to be solved by the device]

However, in both the battery shown in FIG. 5 and the battery disclosed in Japanese Utility Model Publication No. 59-15398, the cutting blade 24 has a triangular shape with a sharp tip. Although it is suitable for breaking the flexible thin plate 40, since the tip is sharp and pointed, the hole formed in the flexible thin plate 40 becomes small as shown in FIG. Therefore, the pressure inside the battery rises faster than the discharge of gas through the hole, which may lead to battery rupture.

As described above, the present invention has a problem that the conventional explosion-proof battery has a small hole in the flexible thin plate 40 because the tip of the cutting edge 24 is sharp and sharp, and therefore the gas emission efficiency of the explosion-proof device is poor. It is an object of the present invention to provide an explosion-proof battery having excellent gas discharge efficiency and capable of reliably operating an explosion-proof device.

[Means for Solving the Problems]

Means for achieving the above object will be described with reference to FIGS. 1 and 3 corresponding to the first embodiment of the present invention.
In the present invention, the shape of the cutting edge 24 provided on the terminal board 20 is
The trapezoid has a width of 0.3 to 0.9 mm, and the cutting edge 24 is inclined with respect to the flexible thin plate 40.

[Action]

When the shape of the tip portion 24a of the cutting blade 24 has a width,
The flexible thin plate 40 is less likely to break, and the operating pressure of the explosion-proof device is higher, but the pressure inside the battery is higher and the flexible thin plate 40 is
When the 40 is destroyed, as shown in Fig. 2, the flexible thin plate 40 is greatly destroyed, so that the gas accumulated inside the battery is discharged in a short time, and the explosion-proof device operates reliably. As a result, the pressure increase inside the battery does not occur faster than the discharge of gas, which has been found in conventional batteries.

Moreover, when the cutting blade 24 is inclined with respect to the flexible thin plate 40 (see FIG. 3 (b)), the flexible thin plate 40 will be broken up and down, and a large breakage will occur. The accumulated gas is discharged in a short time, and the explosion-proof device operates reliably.

[Detailed Description of Means for Solving the Problems]

In the present invention, the width of the tip portion 24a of the cutting blade 24 is 0.3 to 0.9 m.
Although it is specified as m, this is because if the width of the tip portion 24a of the cutting blade 24 is too narrow, the holes formed in the flexible thin plate 40 become small as described above, and the gas discharge efficiency deteriorates. 24 tips
If the width of 24a becomes too wide, the area when the flexible thin plate 40 is destroyed becomes large, and the operating pressure of the explosion proof device becomes too high, and the explosion proof device will not operate within the range where safety can be secured. Is based. That is, when the width of the tip 24a of the cutting edge 24 is narrower than 0.3 mm, the flexible thin plate 40 is easy to tear because the tip 24a of the cutting edge 24 is sharp as in the conventional case,
Therefore, the operating pressure of the explosion-proof device is low, but since the flexible thin plate 40 has only small holes, the gas discharge efficiency is poor, and the pressure rise inside the battery is faster than the gas discharge, and the battery bursts. I have something to say. On the other hand, when the width of the tip portion 24a of the cutting edge 24 exceeds 0.9 mm, the flexible thin plate 40 is less likely to break as described above, and the operating pressure of the explosion-proof device becomes too high, so that the safety can be secured. Explosion-proof device stops working inside. The terminal plate 20 is made of a metal plate such as a rolled steel plate (SPC plate) with a nickel plating on the surface or a stainless steel plate (SUS304 plate, SUS430 plate, etc.) in terms of material, and its thickness is the size of a battery. Although it is slightly different depending on the material of the pod, it is usually about 0.2 to 0.4 mm. Then, the cutting blade 24 is formed by partially making a cut in the upper plate portion of the main body portion 21 of the terminal plate 20 and bending it from the tip end side to the inside (lower side in the drawing). The width of the tip portion 24a of the cutting edge 24 of 0.3 to 0.9 mm is approximately 1 to 3 times the plate thickness of the terminal plate 20.

Further, in the present invention, the cutting edge 24 is inclined with respect to the flexible thin plate 40, which is also for the purpose of greatly breaking the flexible thin plate 40 and improving the gas discharge efficiency. That is, when the cutting blade 24 is bent inward at a right angle as in the conventional case (note that the conventional cutting blade is shown in FIG. 7; see FIG. 7B in particular), the flexible thin plate 40 is broken. However, the degree of destruction is small and the gas discharge efficiency is poor. In contrast,
As shown in FIG. 3 (b), when the cutting blade 24 is inclined with respect to the flexible thin plate 40, the flexible thin plate 40 is less likely to break,
When broken, the flexible thin plate 40 is largely broken up and down, and the gas discharge efficiency is improved. However, if the cutting blade 24 is inclined too much with respect to the flexible thin plate 40, the flexible thin plate 40 is less likely to be broken and the explosion-proof device does not operate within a range where safety can be secured. Blade Angle (This cutting edge angle means the angle θ formed by the main body portion 21 of the terminal board 20 and the cutting blade 24 in the state shown in FIG. 3 (b). That is, shown in FIG. 3 (b). In this state, the depression angle when the tip of the cutting blade 24 is seen from the body 21 side of the terminal board 20) is 50 to 70 °
It is preferably within the range. That is, when the cutting edge angle (θ) is smaller than 50 °, the cutting edge 24 is set to the flexible thin plate 40.
If the flexible thin plate 40 is less likely to be broken, the explosion-proof device does not operate within the range where safety can be secured, and the cutting edge angle (θ) becomes larger than 70 °. The breakage of the flexible thin plate 40 is reduced, and the gas discharge efficiency is deteriorated.

〔Example〕

FIG. 1 is an enlarged cross-sectional view showing a first embodiment of the explosion-proof battery of the present invention, and FIG. 2 is an enlarged cross-sectional view of essential parts of the battery explosion-proof device shown in FIG. 1 in an operating state. FIG. 3 is an enlarged view of the cutting edge of the battery shown in FIG. 1 and its periphery, and FIG. 3 (a) is a sectional view taken along the same cutting plane as in FIG.
FIG. 3 (b) is a sectional view taken along line AA of FIG. 3 (a).

In the figure, 1 is a sealing body provided with an explosion-proof device, and this sealing body 1 includes a sealing plate 10 having a gas vent hole 11 and a main body portion.
A low-cap-shaped terminal plate 20 having a gas exhaust hole 23 and a cutting blade 24 in the main body portion 21 and a ring-shaped packing 30 arranged on the peripheral portion of the sealing plate 10. When,
The peripheral portion is arranged on the annular packing 30 and is composed of the flexible thin plate 40 sandwiched between the flange-shaped peripheral portion 22 of the terminal plate 20 and the sealing plate 10 together with the annular packing 30.

The sealing plate 10 has a shallow container shape, but its opening edge is bent inward when the sealing body 1 is assembled,
By crimping the bent edge 12, the brim-shaped peripheral portion 22 of the terminal plate 20 is pressed to make the sealing body 1 airtight and liquid-tight.
The terminal plate 20 is composed of a main body portion 21 and a flange-shaped peripheral portion 22, the main body portion 21 is provided with a cutting edge 24 and a gas exhaust hole 23, and the flange-shaped peripheral portion 22 is bent obliquely upward. The tip is bent so that it is almost horizontal. The main body portion 21 of the terminal plate 20 is composed of an upper plate portion and a peripheral wall portion, and the cutting blade 24 partially cuts into the upper plate portion of the main body portion 21 of the terminal plate 20 so that the portion is on the tip side. From inside (lower side in the drawing)
The gas exhaust hole 23 is a hole formed in the upper plate portion of the main body portion 21 by the formation of the cutting edge 24. Annular packing 30
The inner diameter of the terminal is larger than the outer diameter of the main body portion 21 of the terminal plate 20, and the outer peripheral side of the main body portion 21 of the terminal plate 20 is sealed in the radial direction. The peripheral edge portion of the flexible thin plate 40 together with the annular packing 30 is a flange-shaped peripheral edge portion 22 of the terminal plate 20 and a sealing plate.
The flexible thin plate (40) is held between the central part of the flexible thin plate (40) and normally closes the gas vent hole (11) of the sealing plate (10).
The annular packing 30 includes the sealing plate 10 and the flexible thin plate 40.
It is optionally used to enhance the tightness between and.

The cutting edge 24 has a trapezoidal shape as shown in detail in FIG. 3 (a), and the width of the tip portion 24a is 0.3 to 0.9 mm. Further, the cutting edge 24 is inclined with respect to the flexible thin plate 40 as shown in FIG. 3 (b), and the cutting edge angle, that is, the angle θ between the cutting edge 24 and the main body portion 21 of the terminal board 20. Is preferably 50 to 70 °. That is, when the cutting edge angle is less than 50 °, the cutting edge 24 is moved to the flexible thin plate 40.
Since it is inclined too much with respect to the flexible thin plate 40, it is difficult to break the flexible thin plate 40, and the explosion-proof device may not operate within a range where safety can be secured. On the other hand, when the cutting edge angle is larger than 70 °, the breakage of the flexible thin plate 40 becomes small as in the conventional case, the gas discharge efficiency deteriorates, the internal pressure rises faster than the gas discharge, and the battery ruptures. There is a risk.

Then, the sealing body 1 is mounted via an insulating packing 4 in the opening of the battery case 2 in which the power generating element 3 has been filled in advance, so that an explosion-proof battery is manufactured. That is, the battery case 2 is preliminarily loaded with the power generation element 3, that is, the positive electrode active material, the negative electrode active material, the electrolytic solution, the separator, etc., in a state suitable for causing a battery reaction when necessary, and the battery case 2 A constriction for supporting the lower peripheral edge of the sealing body 1 is formed near the opening end, and the sealing body 1 is inserted into the opening of the battery case 2 together with the insulating packing 4, and then the opening edge of the battery case 2 is turned inward. Tighten and seal the opening of the battery case 2. As a result, the battery is kept in a sealed state under normal conditions. The power generation element 3 may have a publicly known configuration, and a representative example thereof is an organic electrolyte-based power generation element, for example, a negative electrode plate in which lithium is used as a negative electrode active material and the plate-like material is pressure-bonded to a current collector. And a positive electrode plate in which a positive electrode mixture having manganese dioxide as a positive electrode active material is held by a current collector is spirally wound with a separator interposed, and an organic electrolyte solution. .

When an internal short circuit or the like occurs in this battery and gas is generated inside the battery to increase the pressure inside the battery, the flexible thin plate
40 bends upward and contacts the cutting edge 24, the flexible thin plate 40 is destroyed by the cutting edge 24 as shown in FIG. 2, the explosion-proof device operates, and the gas inside the battery is the gas of the sealing plate 10. The gas is exhausted from the gas exhaust hole 23 of the terminal board 20 to the outside of the battery through the ventilation hole 11. At this time, the flexible thin plate 40 is provided with the cutting blade 24 as shown in FIG.
The gas inside the battery is discharged to the outside of the battery in a short time, and the pressure rise inside the battery does not become faster than the discharge of the gas, and the explosion-proof device operates reliably.

The following Table 1 shows that the sealing body 1 is assembled by changing the width of the tip portion 24a of the cutting blade 24 and the cutting blade angle (θ), and the sealing body 1 is attached to the opening of the battery case 2 via the insulating packing 4. It shows the relationship between the gas discharge time of the installed explosion-proof battery during operation of the explosion-proof device and the operating pressure of the explosion-proof device.

The battery sealing plate used to check the gas discharge time and the operating pressure of the explosion-proof device shown in Table 1 above.
Is a stainless steel plate (SUS430 plate) having a thickness of 0.3 mm and formed in a shallow container shape, and the annular packing 30 is formed of polypropylene. Flexible thin plate 40 is thick
It consists of a 0.015 mm titanium plate, and the terminal plate 20 is a rolled steel plate (SPC plate) with a thickness of 0.3 mm whose surface is nickel plated.
The cutting blade 24 is formed into a shape as shown in the figure, and the cutting blade 24 is formed by making a notch of a predetermined shape in the upper plate portion of the main body portion 21 of the terminal board 20 and bending it inward from the tip end side. It was done.

The battery uses manganese dioxide as a positive electrode active material, lithium as a negative electrode active material, and an electrolyte solution having a capacity ratio of propylene carbonate and 1,2-dimethoxyethane of 1: 2.
This is a cylindrical manganese dioxide-lithium battery with a diameter of 15 mm and a total height of 40 mm that uses an organic electrolyte solution containing 1.0 mol / mol of lithium perchlorate as a mixed solvent of manganese dioxide. The positive electrode mixture prepared by mixing with a resin binder is held on a current collector to form a positive electrode plate,
Lithium is a plate-shaped one that is pressed onto the current collector to form a negative electrode plate,
The positive electrode plate and the negative electrode plate are inserted into the battery case 2 in a spirally wound state with a separator interposed therebetween. The operating condition of the explosion-proof device is that the battery is internally short-circuited and the gas discharge time and the operating pressure during the operation of the explosion-proof device are examined.

Sample Nos. 1 to 3 in the above Table 1 correspond to the embodiments of the present invention, but in those Samples No. 1 to 3, as shown in Table 1, the gas discharge time during operation of the explosion-proof device is shown. there were 7 seconds, 5 seconds, 4 seconds and short and respective actuating pressures ^{5kg / cm 2, 6kg / cm} 2, a 7 kg / cm ² explosion-proof equipment at low pressures in the range that can ensure the safety of explosion-proof equipment Could be activated. On the other hand, a sample equivalent to the conventional product
In NO.5, the operating pressure of the explosion-proof device was as low as 4 kg / cm ² , but the gas discharge time during operation of the explosion-proof device was as long as 15 seconds, so the pressure rise inside the battery was faster than the gas discharge, There was a possibility of the battery exploding. Further, in sample No. 5 in which the width of the tip of the cutting blade was 1.2 mm, the operating pressure of the explosion-proof device was high, the explosion-proof device did not operate, and the battery burst.

FIG. 4 is an enlarged sectional view of an essential part showing a second embodiment of the explosion-proof battery of the present invention. In the battery of the second embodiment shown in FIG. 4, the sealing plate 10 and the body portion 21 of the terminal plate 20 are An annular heat-deformable member is provided in a portion of the space 60 formed by the upper side of the flexible thin plate 40.
50 are arranged. The annular heat-deformable member 50 is formed of, for example, a thermoplastic resin such as polyethylene and is flexible with respect to a temporary increase in internal pressure caused by a temperature change within a normal operating temperature range (generally 60 ° C or less). The diameter of the flexible portion of the thin plate 40 is regulated so that the explosion-proof device does not operate unless a large increase in internal pressure occurs.On the other hand, thermal deformation occurs in response to a continuous increase in internal pressure accompanied by temperature rise such as internal short circuit. Therefore, the diameter of the flexible portion of the flexible thin plate 40 is increased to allow the explosion-proof device to operate with a pressure low enough to ensure safety.

The battery of the second embodiment shown in FIG. 4 has the same structure as that of the battery of the first embodiment shown in FIG. 1 except that the annular thermal deformation member 50 is arranged as described above. Even in the battery of the second embodiment, when the flexible thin plate 40 breaks, the flexible thin plate 40 largely breaks, and the gas discharge efficiency is good, and the battery is more discharged than the gas discharge seen in the conventional battery. The explosion-proof device operates reliably without the internal pressure rising faster.

[Effect of device]

As described above, in the present invention, the cutting edge 24 is attached to the tip portion thereof.
24a has a trapezoidal shape with a width of 0.3 to 0.9 mm and a cutting edge 24
By inclining the flexible thin plate 40 with respect to the flexible thin plate 40, the breakage of the flexible thin plate 40 is increased, and the gas discharge efficiency is increased,
I was able to operate the explosion-proof device reliably.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view showing a first embodiment of the explosion-proof battery of the present invention, and FIG. 2 is an enlarged cross-sectional view of essential parts of the battery explosion-proof device shown in FIG. 1 in an operating state. FIG. 3 is an enlarged view of the cutting edge used in the battery shown in FIG. 1 and its periphery, and FIG. 3 (a) is a cross-sectional view of the same section view as FIG. FIG. 3 (b) is a sectional view taken along the line AA of FIG. 3 (a). FIG. 4 is an enlarged cross-sectional view of an essential part showing a second embodiment of the explosion-proof battery of the present invention. FIG. 5 is an enlarged cross-sectional view of an essential part showing an example of an explosion-proof battery having a configuration different from that of the present invention, and FIG. 6 is an enlarged cross-sectional view of the essential part in an operating state of the battery explosion-proof device shown in FIG. . FIG. 7 is an enlarged view showing the cutting edge used in the battery shown in FIG. 5 and its periphery. FIG. 7 (a) is a sectional view taken along the same cutting plane as in FIG. FIG. 7 (b) is a sectional view taken along line BB in FIG. 7 (a). 1 ... Sealing body, 2 ... Battery case, 3 ... Power generation element, 4
...... Insulating packing, 10 ...... Seal plate, 11 ...... Gas vent, 12 ...... Bend edge, 20 ...... Terminal plate, 21 ...... Main body part, 23
...... Brim edge, 23 …… Gas exhaust hole, 24 …… Cut blade, 24a
...... Tip part, 30 …… Annular packing, 40 …… Flexible thin plate

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Yoshiki Yoshitomo 1-88 Irakura, Ibaraki, Osaka Prefecture 1-88, Hitachi Maxell Co., Ltd. Within Hitachi Maxell, Ltd.

Claims (1)

[Scope of utility model registration request] 1. An explosion-proof battery in which a sealing body 1 equipped with an explosion-proof device is attached to an opening of a battery case 2 containing a power-generating element 3 through an insulating packing 4, the sealing body 1 being a gas. A gas exhaust hole 23 and a cutting edge 24 are formed in the main body portion 21 and are composed of a sealing plate 10 having a ventilation hole 11 formed therein, a main body portion 21 and a flange-shaped peripheral portion 22.
And a flexible thin plate 40 which is sandwiched between the flange-shaped peripheral portion 22 of the terminal plate 20 and the sealing plate 10 either alone or together with the annular packing 30 at the peripheral portion. When the gas inside the battery is generated and the pressure inside the battery rises, the flexible thin plate 40 bends upward and comes into contact with the cutting edge 24 to destroy the gas inside the battery of the sealing plate 10. In what is discharged to the outside of the battery from the gas exhaust hole 23 of the terminal plate 20 through the gas vent hole 11, the tip 24a of the cutting blade 24,
An explosion-proof battery characterized in that it has a trapezoidal shape having a width of 0.3 to 0.9 mm and the cutting edge 24 is inclined with respect to the flexible thin plate 40.