JPH03263755A - Organic electrolyte battery - Google Patents

Abstract

PURPOSE:To prevent the burst or firing of a battery under the dangerous high- pressure state when gas is generated in the battery and improve safety by providing an elastic body between a valve body and a cap with a gas vent hole. CONSTITUTION:A valve body 4 made of a metal plate is stuck to a valve hole 3a provided at the center section of a sealing plate lower case 3 from the inside face of the sealing plate lower case 3 with heat fusion resin 6 made of fluororesin for sealing, then a cap 5 arranged with an elastic body 7 made of columnar styrene butadiene rubber is covered on a protruded section 5b with a gas vent hole 5a, the opening edge 3b of the sealing plate lower case 3 is folded inward and caulked and fixed for sealing. When the internal pressure of a battery rises due to the occurrence of gas, the metal valve body 4 is pushed up to open the valve hole 3a, thus no dangerous burst or explosion occurs. The valve body 4 again seals the valve hole section 3a via the pressure of the elastic body 7 after the internal pressure of the battery is lowered to the stable pressure, and thus the infiltration of the moisture in the atmosphere or the leak of an electrolyte does not occur.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an organic electrolyte battery that uses light metals such as lithium, sodium, and magnesium as a negative electrode active material. This relates to explosion-proof and safety structures against increases in battery internal pressure and battery temperature.

[Conventional technology]

In recent years, organic electrolyte batteries that use light metals such as lithium, sodium, and magnesium as negative electrode active materials have
Due to its advantages of high energy density, low self-discharge, and excellent long-term reliability, it is used as a power source for memory hack-ups, cameras, etc., and demand for it is increasing. More recently, batteries have been used as a power source for portable information devices such as laptop computers and word processors, AV devices such as camera-integrated VTRs, portable CD players, and LCD televisions, and mobile communication devices such as mobile phones and car phones. However, with the development of a wide variety of devices that require large current output, there is a demand for secondary batteries with higher energy density. For this reason, research and development efforts are being actively conducted to develop the organic electrolyte battery having a high energy density into a secondary battery, and some of these batteries have begun to be put into practical use.

However, this kind of lit! In order for an IT battery to be used stably over a long period of time, it is necessary to prevent electrolyte leakage and reactions with battery active materials, electrolytes, etc. due to the intrusion of atmospheric moisture, oxygen, etc. into the battery. In order to prevent poor battery performance caused by Nasarekoi z).

On the other hand, when the organic electrolyte used in this type of battery is exposed to high temperatures, or when excessive voltage or current is applied, it volatilizes or decomposes, producing gas. Further, some of the gas, the organic electrolyte, and the eaves metal used as the negative electrode active material are flammable and easily ignite materials.

For this reason, this type of battery is exposed to high temperatures.

If the temperature is extremely high due to an external short circuit, a short circuit due to deterioration of electrodes or separators, a change in shape, etc., or a forced overcurrent discharge t8 by the external 1ifi, or an excessive amount of T (, If charging is done, etc.
The gas generated inside the battery is trapped inside the battery, and the inside of the battery acts and ruminates, causing the battery case to expand and deform, causing the battery to become clogged. If the L7 ruptures, it may ignite, creating a safety problem.

In order to solve problems like 0), conventionally, when the internal pressure of the battery drops due to gas generation, the pressure inside the battery rises to 118°C, which is high enough to cause a dangerous rupture. (1) and (2) below in which the thin part or part of the thin plate part installed in the battery or sealing plate is destroyed and the gas is allowed to escape. method has not been implemented
(1) As shown in FIG. 2, the annular or -f'r-shaped thin part +13 provided at the bottom of the battery case 11 (7) is destroyed when the internal pressure is collapsed.

(2) As shown in Fig. 3, a thin plate 24 of metal, synthetic resin, synthetic resin, etc.
However, it is destroyed when the inner H8 is raised by a destruction protrusion 25b provided on the cap 25 that defines the gas vent hole 25a.

[Problem to be solved by the invention]

However, in the above method f+,), the thin wall portion 1.1 formed in the battery case 11 made of iron or sand
a (7) The thickness is Q, (-3 for each piece less than 15 mm, τ is the machining accuracy - L. The actual situation is that it is difficult to produce !). If the pressure is higher than 1), the thin wall part of the casing will be destroyed by force 3', and there is a problem that the rupture will be difficult to achieve and sufficient safety cannot be obtained.

In addition, in the method (2) above, when the internal pressure of the battery increases by 1 -
1. To operate explosion-proof at low pressure (preferably about 20 kg/- or less) without causing dangerous explosion. Kei; j The thickness of the thin plate placed inside the D plate depends on the material, but the metal 0
), it needs to be several tens of fi or less, and in the case of synthetic resin or base rubber, it needs to be about 0.3 fi or less. At this thickness, if synthetic resin or rubber sole is used, moisture in the atmosphere will easily pass through, and if lifts are made of metal, such a thin plate cannot be sealed inside the machine. Even if you fix it with a kasome,
There was a problem in that the airtightness of the cannes was insufficient and the battery performance deteriorated due to moisture intrusion.

Furthermore, a more serious problem is that methods (1) and (2) of E.
), the explosion-proof function is activated due to the destruction of a part of the battery case or sealing plate, etc., and when the battery is in use or stored, the internal pressure of the battery rises, the explosion-proof function is affected, and the battery loses its function. 1- There is a thing ζ″ that cannot be used. That is,
The hole in the destroyed part of the hole Eiura L 7) Water intrudes into the water, reacts with the negative electrode and makes the electrode passivated, and at the same time, the electrolyte leaks out, etc. Unfortunately, JT's normal battery response stopped 1+1 and the battery lost its function.) Also, leakage 1. The electrolyte can contaminate equipment in which batteries are assembled and stored.
Avoid getting it wet and causing equipment failures such as poor contact and corrosion damage.

There was a drawback that there was.

Stage F for Solving Problem 1] In order to solve the above-mentioned problems, the present invention provides a valve hole on the bottom of the case under the sealing plate, and seals this valve hole part with a seal.
The valve body made of a metal plate is resistant to organic electrolytes from the inside of the J plate.
It is adhered and sealed with a heat-sealing resin made of Sono resin with excellent moisture permeability, and an elastic body is interposed between the valve body and the knob having a gas vent hole. The elastic body pressurizes the valve body.

As the elastic body for pressurizing the valve body made of a metal plate, for example, a ball, cylinder, rectangular parallelepiped, etc. made of synthetic rubber such as silicone rubber, styrene-butadiene rubber, chloroprene rubber, or butyl rubber, or a metal coil spring, plate spring, etc. are suitable.

In addition, the metal valve body is bonded to the valve hole part of the lower case of the sealing plate, and the heat-sealable resin used to seal the valve hole has resistance to reaction with organic electrolytes, dissolution, etc. A fluororesin is used that has excellent adhesive properties and moisture permeation resistance. Examples of such fluorine resins include ethylene-4-fluorinated ethylene copolymer resin (hereinafter abbreviated as ETFE) and 47-fluorinated ethylene-6-fluorinated propylene copolymer resin (FEP).
.

Examples include vinylidene fluoride resin (PVDF), chlorinated ethylene trifluoride resin (PCTFE), and 47-ethylene-perfluoroalkoxyethylene copolymer resin (PFA).

Furthermore, the structure of the sealing slope case in which the valve hole is provided is not limited to the flat bottom shape as shown in FIG. A structure in which it is provided on a flat portion or a curved surface is possible, and these are also included in the present invention.

[Effect]

The above configuration provides sufficient airtightness against the intrusion of atmospheric moisture through the valve hole, and at the same time, the organic electrolyte has excellent resistance to the metal valve body! ii) Since it is sealed with a decomposing fluororesin adhesive layer, there is an elastic body that pressurizes the valve body! The electrolyte does not cause deterioration such as corrosion or dissolution, and stable leakage resistance is maintained over a long period of time.

Furthermore, according to the configuration of the present invention, when the internal pressure of the battery increases due to gas generation and exceeds a certain pressure, the metal valve body is pushed up and the valve hole opens, allowing the gas inside the battery to escape to the outside, resulting in dangerous rupture or explosion. does not occur, and after the battery internal pressure has decreased to a stable pressure, the valve body seals the valve hole again due to the pressure of the elastic body pressurizing the metal valve body, preventing moisture intrusion into the atmosphere and electrolyte leakage. Therefore, as in the case where a part of a conventional battery case or sealing plate is destroyed and a permanent hole is created, a sudden explosion occurs in a short period of time due to the activation of the explosion protection function only once. (within 1 day) There is no loss of battery function, and in the case of the present invention, the battery can be used repeatedly even after the explosion-proof function is activated. However, when the explosion-proof function is activated for the first time, part of the fluororesin that seals the metal valve body to the valve hole peels off, so the airtightness against moisture intrusion from the atmosphere is reduced to some extent compared to before. Durability decreases at high temperatures, etc., but it can be used for a long time in normal usage environments.

[Example-1] Hereinafter, the present invention will be explained in more detail with reference to Examples.

FIG. 1 is a cross-sectional view of a cylindrical lithium battery showing an example of the present invention. In FIG. This is a battery power generation element that is spirally wound with a separator in between. The positive electrode is 3
Electrolytic manganese dioxide heat-treated at 80°C is used as an active material,
A carbon conductive agent, a polymeric resin binder, and water were added to this, mixed and kneaded, applied to SUS expanded metal in the form of a sheet, dried, rolled, and dried by heating under reduced pressure. The electrolyte is a 1=1 mixed solvent of propylene carbonate and 1,2-dimethoxyethane with LiCj! An organic electrolyte in which 1 mol/1 O was dissolved was used.

Reference numeral 1 denotes a battery case made of Ni-plated iron or SUS, which also serves as a negative electrode terminal. The thickness of this plate was approximately 0.3 mm. After filling the battery case 1 with the power generation element B, the SUS current collector glue 12, which had been previously crimped onto the negative electrode lithium, was welded to the bottom of the battery case 1 with a groove.

A is a sealing plate according to the present invention, in which a valve hole 3a provided in the center of a lower case 3 of the sealing plate is inserted from the inner surface of the lower case of the sealing plate using a fluororesin having excellent organic electrolyte resistance, metal adhesion, and i3 moisture resistance. After adhering and sealing the valve body 4 made of a metal plate with a heat-fusible resin 6 made of
The convex portion 5b is covered with a cap 5 having a cylindrical elastic body 7 made of styrene-butadiene rubber, and the opening edge 3b of the sealing plate case is bent inward and caulked to seal and fix. The cap 5 is made of iron with a thickness of 0.3 mm and is plated with Nj.
, 3u of 5US430 board was used. The valve body 4 of the valve hole portion 3a-2 of the sealing plate F case was bonded and sealed in the following manner. That is, after a heat-fusible resin film made of the fluororesin is heat-adhered to the valve body 4 in advance, the fluororesin side of the valve body is sealed by sealing the valve hole portion 3aL of the lower case of the l-1 plate. It was placed on the board and bonded by heating and fusing.

Subono F-welding i7.4 positive electrode current collector leads 8 are attached to the bottom surface of the case 3 of the sealed IJ board A made using this keyaki. Ta.

Reference numeral 9 denotes a gasket mainly made of polypropylene 1.1 pyrene, which is interposed between the sealing EJ plate and the battery case 1 to maintain electrical insulation between the first electrode and the negative electrode, and at the same time prevent the opening of the battery case 1. [11 By bending the edges inward, the battery contents are sealed and sealed.10
A and 10b are insulating rings mainly made of polypropylene to prevent internal short circuits.

In the above case, the valve hole diameter of the sealing plate is 2, the metal valve body 4 is a disk with an outer diameter of 4n, and the valve body 4 is made of styrene-butadiene-YJ2 with a diameter of 14 m as an elastic body. height 2.7
Using a bottom-shaped one, the diameter is 14 mm and the total height is 50 mm.
cylindrical shape of wM', 1-fI'7r, make a battery,,'
fj. 1. The valve hole 3a is bonded and sealed with the metal valve body 4 using adhesive bamboo resin (5, thickness 80 m (N)) as described above.
Batteries A, B, C, and I) of the present invention using TFE, FEP, PVDF, and PC'rFE, and for comparison, batteries A, B, C, and I) of the present invention using TFE, FEP, PVDF, and PC'rFE, and for comparison, batteries of 14' l. Vinyl acetate resin and ethylene 1. - 100 each of batteries E and D using copolymer resin were made and stored in an atmosphere at a temperature of 60°C and a relative humidity of 90%, and the number of battery leakages and internal resistance was measured. We investigated the changes.

The results are shown in Table 1 and Figure 4.

Table 1: Number of leaks (units) From the results in Table 1 and Figure 4, it is clear that the rate of leaks and deterioration due to moisture permeation from the external environment of the battery using a rising sealing plate is extremely low in the present invention. I understand.

[Example 2] A dummy battery cell with the same configuration as in Example 1 was constructed using the same sealing plate as in Example 1, except that the battery case was not filled with battery power generating elements (electrodes, 7/7 L/L, electrolyte, etc.). was created. Drill a hole with three diameters in the bottom of the battery case 1 of this dummy cell, seal it with a jig to prevent air leakage, and send pressurized air into the dummy cell through this hole to increase the pressure and seal it with the valve body. As a result of investigating the pressure and shape change of the multi-cell when part of the adhesive with the plate Tris peeled off and activated the explosion protection, it was found that the explosion protection activation pressure was a low pressure of 11 to 20 kg/cffl in both cases.6. At this time, there were no detectable changes in other parts of these dummy cells.

However, in the above embodiment, only a cylindrical sound range rubber was used as the elastic body that pressurizes the metal valve body, but the function of this elastic body is limited to a predetermined range of about 20 kg/cd or less. It is necessary to maintain the adhesion between the metal valve body and the sealed under-desk case until pressure is reached to maintain airtightness and liquidtightness.The shape and J method are selected and the elastic stress is adjusted depending on the embodiment. In particular, metal wings, plate wings, etc., resins of arbitrary shapes such as cylindrical, spherical, rectangular parallelepiped, etc., sound range rubber, etc. are also included in the present invention. Also, battery shape 73
．． 1g seal 1'' plate shape and 2 are cylindrical shapes only, but cylindrical shapes (Z1), square shapes (square prism shapes), polygonal shapes such as 21-sided shapes, elliptical shapes, etc., etc. are shown. It goes without saying that the shape of the shape has similar effects and is included in the present invention.

Also, I! The electrolyte is also not limited to the examples,
For example, 1., icj!On, 1.+BF4 is added to a single or mixed solvent of a 1-ton organic solvent such as ethylene carbon, butylene carbonate, 7-butyrolactone, tetrahydrofuran, dioxolane, etc. .LtP
Fai, 1CF3so, and other ion dissociative salts dissolved therein can be used.

〔Effect of the invention〕

As described in detail above, according to the present invention, battery rupture and ignition are prevented under dangerous high pressure conditions when gas is introduced into the battery, thereby improving safety, reducing deterioration over time, and providing explosion-proof function. We can provide a battery that can be used repeatedly without losing battery function even after activation, and that does not leak electrolyte due to explosion-proof operation.
It is more effective not only for primary batteries but also for secondary batteries that are used by repeatedly charging and discharging.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an example of a battery implemented in the present invention, Figs. 2 and 3 are cross-sectional views of a battery using a conventional explosion-proof structure, and Fig. 4 shows a temperature of 60°C and a relative humidity of 90°C. FIG. 3 is a comparison diagram of changes in internal resistance when stored in an atmosphere of 10%. 5... Cap 5a... Gas vent hole 6... Adhesive 7... Elastic body 8... Positive electrode current collector lead 9... Gasket 10a... Insulating ring a 10b... Insulating ring b A. ... Sealing plate B ... Power generation element

Claims (1)

[Claims] A valve hole is provided on the bottom of the case under the sealing plate that contains at least a negative electrode, a positive electrode, and an organic electrolyte and also serves as one electrode lead terminal, and a valve body made of a metal plate is inserted into the valve hole from the inside of the sealing plate using fluororesin. The valve hole is sealed by adhering with a heat-fusible resin, and further, an elastic body is interposed between the valve body and a cap having a gas vent hole, and the valve body is pressurized by this elastic body. An organic electrolyte battery characterized by the following features: