JP2008153111A - Safety structure of resin battery can - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a safety structure of a resin battery can which can avoid contamination and breakage of installations due to a big volume of gas erupting at a moment and strongly from a battery can and in which a working groove can swell at a moment. <P>SOLUTION: The safety structure of a resin battery can is composed of a resin can which is molded integrally and has a housing space with an open mouth inside and into which an electrode plate and an electrolyte are inserted from the open mouth, and the housing space can be airtight with the open mouth sealed by a battery lid. At least one working groove 30 is formed in advance on an inside wall surface of the housing space of the battery can 20, and a groove mouth of the working groove faces inside the battery can and between a bottom portion of the working groove and a wall surface of an external portion of the battery can, there is formed a thinnest working portion of the wall surface of the whole battery can, and when a gas pressure inside the battery can becomes extraordinarily high, the working portion swells greatly outside alongside in a radius direction of the battery can and a crack develops and a pressurized gas is discharged out. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a safety structure of a resin battery can, and more particularly, to a safety structure of a resin battery can that can safely discharge internal pressure gas.

Lithium-ion secondary batteries can be made into high-capacity power sources (for example, lithium iron phosphate secondary batteries) due to significant progress in technology. For example, high-capacity secondary batteries such as electric bicycles and wheelchairs The lithium ion secondary battery using such a high-capacity non-aqueous electrolyte has a larger power storage capacity and power supply capacity than the conventional one, and its battery can It is common to use an aluminum battery can, and after putting the electrode plate and non-aqueous electrolyte into the battery can, cover the lid of the battery can to ensure long-term stability inside the battery And sealed by laser welding.

When the internal current exceeds the normal value due to overcharging or the battery is short-circuited due to misuse, the non-aqueous electrolyte inside the battery can is severely decomposed. When a large amount of gas is generated and the pressure of the gas inside the sealed battery can exceeds the pressure value that the battery can withstand, the battery can explode rapidly and a large amount of gas As a result, the equipment for this battery is damaged or contaminated with the electrolyte.

Therefore, the conventional lithium ion secondary battery using non-aqueous electrolyte generally has a vent hole in the aluminum lid of the battery can in advance, and the vent hole is formed by a thinner aluminum safety diaphragm. Seal, and if the gas pressure exceeds a predetermined value, the aluminum safety diaphragm is destroyed by the gas pressure and the gas inside is released.

In particular, the safety diaphragm is provided on the end face of the lid, and the distance from the middle stage of the electrode plate is long, and the hole diameter of the vent hole is small due to the restriction of the area of the lid. It takes a lot of time to destroy, so when the gas pressure inside the battery can becomes abnormally high, the aluminum safety diaphragm often does not break even if the middle stage of the battery can swell and explode. It was.

FIG. 1 shows a safety structure of an aluminum battery can proposed in US Pat. No. 6,964,690, mainly having a plurality of cutting grooves 11 on the outer surface of the longitudinal side surface of the aluminum battery can 10. The inner surface corresponding to the battery can 10 at the bottom of the shaving groove 11 is formed with a portion that can be easily ruptured by making the wall thickness thinner, so that the gas pressure inside the battery can exceeds a predetermined value. In this case, the aluminum safety diaphragm is destroyed by the gas pressure, and the internal gas is released.

The design that forms a part that is easy to rupture by opening a groove on the outside of the metal battery can is a groove that easily breaks when the gas pressure inside the battery can becomes abnormally high. The size of the rupture hole in the battery can becomes extremely large because a large amount of gas impacts a rupture site with a small area in a very short time, and thus the gas and non-aqueous electrolyte are Since the battery plate is strongly ejected from the rupture site and the electrode plate inside the battery is exposed to the outside in a large area, the equipment using the battery may be destroyed.
U.S. Patent No. 6964690

The main object of the present invention is to previously open a plurality of working grooves on the inner surface of a battery can integrally formed of resin, the groove of the working groove facing the inside of the battery can, and the gas inside the battery can If the pressure becomes abnormally high, the working groove will swell instantaneously, and the swelled working part will not burst immediately, but will crack when the wall thickness gradually becomes zero. In addition, since the pressure gas inside the battery can is released from the crack, a safety structure for the resin battery can that can prevent a large amount of gas from being ejected from the battery can and contaminating and destroying the equipment is provided. There is.

Another object of the present invention is to provide a safety structure for a resin battery can in which a working groove can swell instantaneously.

The invention of the present application made to achieve the above-mentioned object is integrally molded with a resin, a housing space having an opening is formed inside, an electrode plate and an electrolytic solution are inserted from the opening, In the safety structure of the resin battery can in which the opening is closed by a battery lid and the housing space is in a sealed state, at least one working groove is formed in advance on a wall surface inside the housing space of the battery can, The slot of the working groove faces the inside of the battery can, and the thinnest working portion of the entire wall of the battery can is formed between the bottom of the working groove and the outer wall surface of the battery can. When the gas pressure inside the battery becomes abnormally high, the working part is greatly expanded outward along the radial direction of the battery can to generate a crack, and the gas having pressure is released from the crack. Plastic battery can safety structure It is the gist that there.

In the invention of the present application, the working groove is a safety structure for a resin battery can according to claim 1, wherein the working groove has a V-shaped cross section and the groove opening faces the inside of the battery can. It is a summary.

The gist of the present invention is the resin battery can safety structure according to claim 1, wherein the working groove is formed along a longitudinal direction of the inner wall surface of the battery can.

The gist of the invention of the present application is the resin battery can safety structure according to claim 1, wherein the working groove is formed along a lateral direction of the inner wall surface of the battery can.

According to the safety structure of the resin battery can of the present invention, it is possible to avoid that a large amount of gas is strongly ejected from the battery can to contaminate and destroy the equipment, and the working groove can be instantly expanded. Have.

Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

First, reference will be made to FIGS. In the safety structure of the resin battery can of the present invention, at least one working groove is formed in advance inside the battery can.

The battery can 20 is a round battery can integrally formed of a resin, and an accommodation space 21 having an opening is formed therein, and includes a battery core 40, a packing 60, a non-aqueous electrolyte 50, and the like. A battery member is inserted from the opening, a coupling edge 22 is protruded from an edge of the opening, the opening is closed by a battery lid 23, and the battery lid 23 and the coupling edge 22 are tightened with a screw 24. Then, the storage space 21 of the battery can 20 is in a sealed state.

In particular, at least one working groove 30 is formed in advance on the inner wall surface of the housing space of the battery can 20 of the present invention, and the groove 31 of the working groove 30 faces the inside of the battery can 20. Between the bottom of the working groove 30 and the outer wall surface of the battery can 20, the thinnest working portion 32 of the wall surface of the battery can 20 was formed.

When the battery becomes abnormal (for example, overcharge, electrode piece short circuit, overload, etc.) and the non-aqueous electrolyte decomposes violently into high-pressure gas, the operating site 32 is greatly increased outward along the radial direction of the battery can. It swells and gradually thins to generate a crack, and high-pressure gas is released from the crack.

That is, in the battery can made of resin, the working groove is formed in advance on the inner wall surface, and when the gas pressure inside the battery can exceeds the set value, the working portion of the working groove first swells and gradually increases. Thus, the battery can be prevented from exploding at an instant, and the pressure gas can be released in a safe state.

Next, the operation process of the safety structure of the resin battery can of the present invention will be described in detail. As shown in FIGS. 2 to 4, the present invention is a battery can 20 integrally formed of resin, and a plurality of working grooves 30 are formed in advance on the inner wall surface of the battery can 20. The thinnest working portion 32 of the wall surface of the entire battery can 20 is formed between the bottom of the battery can 20 and the outer wall surface of the battery can 20, and the number of working grooves 30 depends on the actual dimensions of the battery can 20. For example, in the case of a round battery can 20 having a diameter of 20 centimeters, four working grooves 30 are provided along the axial direction of the inner wall surface of the round battery can 20 and each action is provided. The grooves 30 are arranged at equal intervals.

Further, as shown in FIGS. 4 to 6, when the battery becomes abnormal and the nonaqueous electrolyte is violently decomposed into the high-pressure gas 70, the battery can 20 swells outward by the high-pressure gas 70. In some cases, the abnormal portion may be only one side surface of the battery can 20, and in this case, the pressure value received on the inner wall surface of the battery can 20 is the maximum, and the working groove 30 closest to the maximum pressure point is a gas. Due to the pressure, the working part 32 swells instantaneously, and the battery can 20 is a resin product, and the wall surface is flexible, so that the working part 32 swelled instantaneously does not burst immediately, and the working part 32 When the wall thickness gradually becomes zero, a fine crack 33 is generated for the first time, and the high-pressure gas 70 inside the battery is released from the crack 33.

In particular, since the battery can of the present invention is a resin product, the test result of the battery drop collision test was superior to the conventional aluminum battery can.

Further, as shown in FIG. 4, the working groove 30 of the present invention has a V-shaped cross section and the groove opening 31 faces the inside of the battery can 20, so that an abnormal gas pressure is generated inside the battery can 20. When adding to the wall surface, the direction of the groove opening 31 of the working groove 30 faces the direction of the gas pressure, the stress is concentrated, and the thinnest operating portion 32 swells outward along the radial direction of the battery, Finally, it can be seen that the cracks 33 are formed gradually, so that the direction of the groove 31 is extremely important.

In addition, the position where the working groove 30 is opened is a position where the gas 40 inside the battery can 20 is to be released, and the working groove 30 is disposed at an appropriate position through the structural design of the present invention. The position where the gas 40 is discharged can be predicted, and the facility using the battery can be prevented from being contaminated or damaged by being shocked, while the opening direction of the working groove 30 is as shown in FIG. In addition, it may be established along the vertical direction of the inner wall surface of the battery can 20, and as shown in FIG. 8, the vertical action groove 30 and the lateral action groove 30 a are simultaneously formed on the inner wall surface of the battery can 20. Both may be established and both can safely release gas pressure.

The safety structure of the resin battery can of the present invention may be applied to a round battery can or a cubic battery can. FIG. 9 is a schematic view showing a state in which the working groove 30 and the working part 32 of the present invention are formed on the inner wall surface of the cubic battery can 20a. FIG. 10 shows the working part 32 of the battery can 20a in FIG. It is the schematic which shows the state from which gas is discharge | released after bursting by.

As is apparent from the above description, the present invention mainly includes at least one working groove formed in advance on the inner wall surface of the battery can, and the resin battery can has flexibility, so that the inside of the battery can When the gas pressure increases abnormally, the working part at the bottom of the working groove swells instantly outward along the radial direction of the battery can, and the thickness gradually decreases and cracks occur. The gas having pressure is released from the crack, that is, the battery can of the present invention releases the gas after buffering the impact force of the gas whose pressure has increased abnormally due to the flexibility of the resin. It is possible to safely release the gas that has risen.

It is a perspective view of the safety structure of the aluminum battery can proposed in the conventional US Pat. No. 6,964,690. It is a disassembled perspective view of the round resin battery can and battery core of this invention. It is the longitudinal cross-sectional schematic of the combined state of the safety structure of the round resin battery can of this invention. In the combined state of the safety structure of the round resin battery can of the present invention, FIG. FIG. 5 is a schematic cross-sectional view in the vertical direction in a state where the operation site of FIG. FIG. 5 is a schematic longitudinal cross-sectional view of a state in which gas is released after the working part of FIG. 4 has expanded and burst. It is a perspective view of the state which formed the operation groove of the lengthwise direction and the width direction in the round resin battery can of the present invention. FIG. 8 is a schematic longitudinal cross-sectional view of a state in which gas is released after the working part swells and bursts in the assembled state of the battery can of FIG. 7. It is a disassembled perspective view of the cube-shaped resin battery can and battery core of this invention. FIG. 10 is a schematic cross-sectional view in the longitudinal direction in a state where gas is released after the working part swells and bursts in the assembled state of the battery can of FIG. 9.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Aluminum battery can 11 Cutting groove 20, 20a Battery can 21 Storage space 22 Joining edge
23 Battery lid 24 Screws 30 and 30a Working groove 31 Groove opening 32 Working part 33 Crack 40 Battery core 50 Non-aqueous electrolyte 60 Packing 70 Gas

Claims (4)

It is integrally molded with resin and has a housing space with an opening inside. The electrode plate and electrolyte are inserted through the opening, and the opening is closed by a battery lid to seal the housing space. In the safety structure of the resin battery can
At least one working groove is pre-formed on the inner wall surface of the battery can housing space, the groove opening of the working groove faces the inside of the battery can, the bottom of the working groove, and the outside of the battery can If the gas pressure inside the battery can becomes abnormally high, the working part is along the radial direction of the battery can. A safety structure for a resin battery can characterized in that a gas having a pressure is released from the crack by causing the crack to bulge greatly outward. 2. The resin battery can safety structure according to claim 1, wherein the working groove has a V-shaped cross section and a groove opening faces the inside of the battery can. 3. The safety structure for a resin battery can according to claim 1, wherein the working groove is formed along a longitudinal direction of an inner wall surface of the battery can. The safety structure for a resin battery can according to claim 1, wherein the working groove is formed along a lateral direction of the inner wall surface of the battery can.