JP2006128010A - Sealed battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To close a relief valve of a sealing plate in a watertight structure with a very simple structure, and to prevent internal-pressure increase of a battery by smoothly exhausting gas etc. <P>SOLUTION: The sealed battery is provided with an exhaust opening 4 of the relief valve 3 in a projected electrode 2 of the sealing plate 1 and exhausts contents in the battery from the exhaust opening 4 in a state that internal pressure of a outer package can 5 increases to open the relief valve 3. In the sealed battery, the exhaust opening 4 is provided in a peripheral wall of the projected electrode 2, and the projected electrode 2 is inserted in an elastic ring 6 formed by shaping a rubber like elastic body in a circle to resiliently press an inner circumferential surface 6A on a surface of the projected electrode 2. In the sealed battery, the exhaust opening 4 is closed with the elastic ring 6. The elastic ring 6 closes the exhaust opening 4 when the relief valve 3 is closed, and assumes the state for exhausting the contents exhausted from the relief valve 3 outside from the exhaust opening 4 when the relief valve 3 is opened. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement in a sealed battery, and more particularly to a sealed battery that can effectively prevent corrosion due to moisture.

  The sealed battery is provided with a safety valve to prevent the outer can from being destroyed when the internal pressure of the battery becomes abnormally high. The safety valve opens when the internal pressure becomes higher than the set pressure, and discharges internal gas, electrolyte, and the like to lower the internal pressure. This safety valve is built in the convex electrode provided on the sealing plate. The convex electrode incorporating the safety valve is provided with an exhaust opening for exhausting a fluid such as gas that has passed through the opened safety valve.

  The battery having this structure has a harmful effect that water enters from the exhaust opening and corrodes. In particular, a lithium ion secondary battery has a high voltage and is liable to cause electrolytic corrosion of metal parts. If the metal is corroded by electrolytic corrosion, problems such as leakage of the electrolyte and the inability to use the battery occur. This problem can be solved by using the battery without moisture. However, since the battery is used in various environments, it is impossible to eliminate moisture adhesion. For example, when charging a battery while forcibly blowing and cooling it, dust and moisture may enter along with the air. Thus, it is important that batteries used in various environments do not corrode even if water adheres to them.

In order to improve the water resistance, a structure in which the end face of the battery is covered with a waterproof cap has been developed (see Patent Document 1).
Japanese Patent Laid-Open No. 49-101832

  The battery described in this publication has a watertight structure in which a waterproof cap is watertightly attached to the tip of the battery. Further, this waterproof cap has a terminal metal penetrating in a watertight manner and fixed to the center in order to connect the convex electrode to the outside. The terminal metal contacts the convex electrode of the battery for electrical connection. The battery having this structure has a drawback that the outer shape becomes large due to the waterproof cap. For this reason, it is not possible to easily attach the battery to the battery mounting portion with the waterproof cap attached, and there is a disadvantage that the outer shape becomes large when the battery is combined to form a battery pack. Moreover, since the convex ring part of the waterproof cap is inserted into the outer peripheral groove of the battery and connected to the battery in a watertight state, if the convex ring part is displaced, a waterproof structure cannot be obtained. In order to reduce this defect, if the convex ring portion is strongly inserted into the outer peripheral groove, gas or the like cannot be discharged smoothly with the safety valve opened. Further, the battery having this structure has a drawback that contact failure is likely to occur. This is because the contact failure between the terminal metal and the convex electrode cannot be completely eliminated because the battery is connected to the battery via the terminal metal. In addition, this structure has a drawback that the manufacturing cost is high because the structure of the waterproof cap is complicated.

  The present invention has been developed for the purpose of solving this drawback. An important object of the present invention is that the safety valve of the sealing plate can be closed to a watertight structure with a very simple structure, and when the safety valve opens, the gas etc. can be smoothly exhausted to prevent an increase in the internal pressure of the battery. It is an object of the present invention to provide a battery that can eliminate contact failure for making the exhaust opening of a safety valve waterproof.

The sealed battery of the present invention has the following configuration in order to achieve the above-described object.
In the sealed battery of the present invention, the exhaust electrode 4 of the safety valve 3 is provided in the convex electrode 2 of the sealing plate 1. When the internal pressure of the outer can 5 rises and the safety valve 3 opens, Discharge the contents in the battery. Further, the sealed battery is provided with an exhaust opening 4 on the peripheral wall of the convex electrode 2, and the convex electrode 2 is formed into a ring shape with a rubber-like elastic body so that the inner peripheral surface 6 </ b> A is formed on the surface of the convex electrode 2. It is inserted into an elastic ring 6 that is shaped to be elastically pressed. The sealed battery directly closes the exhaust opening 4 with the elastic ring 6 or closes the exhaust opening 4 by bringing the elastic ring 6 into close contact with the peripheral wall of the convex electrode 2 and the end face of the battery. . The elastic ring 6 closes the exhaust opening 4 when the safety valve 3 is closed, and allows the contents discharged from the safety valve 3 to be discharged from the exhaust opening 4 to the outside when the safety valve 3 is open. I am doing so.
In this specification, the contents in the battery discharged from the exhaust opening are not only fluids such as gas and electrolyte, but are also melted by various foreign matters generated in the battery due to an increase in the internal pressure of the battery, for example, heat. It is used in a broad sense including everything that is discharged with fluids such as gas and electrolyte, such as plastic, ruptured metal pieces and burrs.

  The sealed battery of the present invention can be fixed by adhering the elastic ring 6 to the end face of the battery. In the sealed battery of the present invention, the outer can 5 is covered with a heat shrinkable tube 7, and an elastic ring 6 is placed inside the heat shrinkable tube 7, and can be fixed to the end face of the battery with the heat shrinkable tube 7. . The sealed battery of the present invention can fix the elastic ring 6 to the end face of the battery by connecting the lead plate 8 to the convex electrode 2 and pressing the upper surface of the elastic ring 6 with the lead plate 8.

  In the sealed battery of the present invention, the exhaust opening 4 can be opened below the convex electrode 2. The sealed battery of the present invention can be a lithium ion secondary battery. In the sealed battery of the present invention, the elastic ring 6 can be any of synthetic rubber, natural rubber, soft synthetic resin, and synthetic resin foam having closed cells. Furthermore, in the sealed battery of the present invention, the elastic ring 6 has water repellency, or the elastic ring 6 can be subjected to water repellency treatment.

  The battery of the present invention has a very simple structure and is characterized in that the exhaust opening of the safety valve provided on the sealing plate can be closed in a watertight manner. This is because the battery of the present invention inserts the convex electrode into the elastic ring, elastically presses the inner peripheral surface of the elastic ring against the surface of the convex electrode, and closes the exhaust opening in a watertight manner with the elastic ring. is there. In particular, the battery having this structure can be very simple because the exhaust opening can be closed in a watertight manner by inserting a convex electrode in a small elastic ring.

  In addition, the battery of the present invention is characterized in that when the safety valve is opened while the exhaust opening is closed in a watertight manner, the gas in the battery is smoothly exhausted to prevent an increase in the internal pressure of the battery. This feature is because the elastic ring into which the convex electrode is inserted uses an elastic ring that opens the exhaust opening when the safety valve opens.

  Furthermore, a notable feature of the battery of the present invention is that the exhaust opening of the safety valve is not waterproof, so that contact failure of the convex electrode can be eliminated. This is because the battery of the present invention inserts the convex electrode into the elastic ring and closes the exhaust opening of the convex electrode, so that the convex electrode is used as it is as an electrode connected to the outside. That is, unlike the conventional battery, since there is no need to connect to the outside via the terminal metal, there is a feature that the contact failure between the terminal metal and the convex electrode can be eliminated.

  Further, in the battery according to claims 2 to 4 of the present invention, since the elastic ring is fixed to the surface of the sealing plate, the position of the elastic ring is not shifted and the safety valve is closed. There is a feature that the exhaust opening of the convex electrode can be reliably closed with an elastic ring to form a waterproof structure. In addition, this battery has a feature that an elastic ring can be firmly arranged on the surface of the sealing plate with a simple structure and fixed at a position where the exhaust opening of the convex electrode is closed.

  Furthermore, the battery according to claim 8 of the present invention is characterized in that since the elastic ring has water repellency, the elastic ring can repel water and waterproof the exhaust opening of the convex electrode more effectively.

  Embodiments of the present invention will be described below with reference to the drawings. However, the example shown below illustrates the sealed battery for embodying the technical idea of the present invention, and the present invention does not specify the battery as follows.

  Further, in this specification, in order to facilitate understanding of the scope of claims, numbers corresponding to the members shown in the examples are indicated in the “claims” and “means for solving problems” sections. It is added to the members. However, the members shown in the claims are not limited to the members in the embodiments.

  The sealed battery of the present invention is particularly effective in a lithium ion secondary battery. This is because the voltage of the lithium ion secondary battery is 3.6 V, which is higher than that of other batteries, so that electric corrosion due to water is likely to occur. However, the present invention does not specify a sealed battery as a lithium ion secondary battery. The battery can be any secondary battery equipped with a safety valve, such as a nickel metal hydride battery or a nickel cadmium battery.

  The battery shown in FIGS. 1 to 3 has a safety valve 3 built in the convex electrode 2 of the sealing plate 1. The safety valve 3 shown in the figure includes a thin film plate 9 that breaks and opens when the internal pressure rises to a set pressure. The thin film plate 9 is a thin film of aluminum or aluminum alloy. The thin film plate 9 is locally thin and easily broken at a set pressure. Alternatively, as shown in the drawing, the thin film plate 9 can be easily broken down. As shown in the figure, the safety valve 3 provided with the thin film plate 9 made of aluminum or an aluminum alloy inside the convex electrode 2 can be reliably broken by the set pressure to improve safety. Particularly susceptible to corrosion by water penetrating inside. For this reason, the battery including the safety valve 3 having this structure can prevent water from entering with the elastic ring 6 and can significantly improve the reliability. That is, it does not corrode with water, and when the internal pressure becomes higher than the set pressure, the valve is surely opened to prevent an abnormally high pressure.

  However, the present invention does not specify the structure of the safety valve 3 as a type that destroys the thin film plate 9. For example, as shown in FIG. 4, it can also be used for a battery incorporating a safety valve 3 in which a valve body 10 is pressed against a valve seat 12 by an elastic body 11. When the internal pressure of the battery is lower than the set pressure, the safety valve 3 is closed by the elastic body 11 pressing the valve body 10 against the valve seat 12. However, when the internal pressure of the battery becomes higher than the set pressure, the valve body 10 pushed by the elastic body 11 is opened away from the valve seat 12. Moreover, in any structure of the safety valve, if water penetrates into the convex electrode and the metal part is corroded, the battery does not operate normally as a battery. Not specified.

  The convex electrode 2 has an exhaust opening 4 in the peripheral wall. In the illustrated battery, a sealing plate 1 made of a metal plate is press-molded, and a cylindrical convex electrode 2 that closes the upper end surface is provided. The cylindrical convex electrode 2 can uniformly adhere the inner peripheral surface 6A of the elastic ring 6 described later to the outer peripheral surface of the peripheral wall. However, the battery of the present invention does not specify the convex electrode in a cylindrical shape. The convex electrode may be a polygonal cylinder such as a quadrangle. A cylindrical convex electrode 2 such as a cylinder or a square tube can be inserted so as not to come out of the elastic ring 6, and the exhaust opening 4 can be closed at the end face of the battery. Therefore, the elastic ring 6 can be fixed to the end surface of the battery without being bonded to the end surface or fixed with the heat shrinkable tube 7 or the like. However, in the sealed battery of the present invention, the convex electrode is not specified to be cylindrical, and the convex electrode can be tapered so as to become thinner toward the upper end.

  When the safety valve 3 is opened, the battery discharges the contents such as gas and electrolyte inside the battery through the exhaust opening 4 to the outside. In order to prevent water from entering the inside of the convex electrode 2 through the exhaust opening 4 with the safety valve 3 closed, the battery shown in the figure inserts the convex electrode 2 into the elastic ring 6. ing. In other words, the elastic ring 6 is disposed around the convex electrode 2.

  The elastic ring 6 has a shape in which a rubber-like elastic body is formed into a ring shape and elastically presses the inner peripheral surface 6 </ b> A against the surface of the convex electrode 2. As shown in FIGS. 1 to 3, the elastic ring 6 elastically presses the inner peripheral surface 6A against the peripheral wall of the convex electrode 2 and closes the exhaust opening 4 provided in the peripheral wall. The elastic ring 6 closes the exhaust opening 4 when the safety valve 3 is closed. However, when the safety valve 3 opens, the contents in the battery that have passed through the safety valve 3 must be discharged from the exhaust opening 4 to the outside of the battery. Therefore, the elastic pressing force with which the inner peripheral surface 6A of the elastic ring 6 closes the exhaust opening 4 is set to a pressure at which the contents can be discharged from the exhaust opening 4 when the safety valve 3 is opened.

  The pressure with which the elastic ring 6 presses the inner peripheral surface 6A against the peripheral wall surface of the convex electrode 2 is specified by the elasticity of the elastic ring 6, that is, the elastic modulus, and the ratio of the inner shape of the elastic ring 6 to the outer shape of the convex electrode 2. The The elastic ring 6 has an inner shape in an unstretched state smaller than the outer shape of the convex electrode 2 and elastically presses the inner peripheral surface 6A against the surface of the convex electrode 2, thereby closing the exhaust opening 4. . As the inner shape of the elastic ring 6 becomes closer to the outer shape of the convex electrode 2, the pressure with which the inner peripheral surface 6A presses the surface of the convex electrode 2 becomes weaker. On the contrary, as the inner shape of the elastic ring 6 is made smaller than the outer shape of the convex electrode 2, the elastic ring 6 is stretched more strongly and strongly presses the inner peripheral surface 6A against the surface of the convex electrode 2. Further, when the elastic ring 6 is made of a flexible material, the pressure with which the inner peripheral surface 6A presses the surface of the convex electrode 2 is weakened. On the contrary, when the elastic ring 6 is made of a hard material that is difficult to deform, the inner peripheral surface 6A is strongly pressed against the surface of the convex electrode 2. The pressure with which the inner peripheral surface 6A of the elastic ring 6 is pressed against the surface of the convex electrode 2 is such that when the safety valve 3 is closed, the elastic ring 6 reliably closes the exhaust opening 4 and the safety valve 3 is opened. The pressure inside the battery is set to a pressure at which the content can be discharged from the exhaust opening 4 to the outside of the battery. When the safety valve 3 is closed, no pressure acts on the exhaust opening 4. Since the elastic ring 6 only needs to close the exhaust opening 4 in this state, it is not necessary to strongly press the surface of the convex electrode 2.

  The outer shape of the elastic ring 6 shown in FIGS. 1 to 3 is substantially equal to the outer shape of the battery end face. The elastic ring 6 is fixed to the end face so as to cover the upper surface of the sealing plate 1 and the surface of the caulking ridge 13. Although not shown, the elastic ring can be fixed inside the caulking ridge. The elastic ring has an outer shape equal to the inner shape of the caulking ridge, or slightly larger than the inner shape of the caulking ridge, is elastically deformed, and is fixed to the surface of the sealing plate inside the caulking ridge.

  The elastic ring 6 is made of a rubber-like elastic body such as synthetic rubber, natural rubber, soft synthetic resin, or synthetic resin foam having closed cells. The elastic ring 6 made of these materials has a feature that can reliably prevent water from entering. Furthermore, the exhaust opening 4 of the convex electrode can be waterproofed more effectively by using a material having water repellency for the elastic ring 6 or by performing water repellency treatment on the elastic ring 6. However, the elastic ring can be made of a synthetic resin foam having open cells. This elastic ring has an advantage that the gas discharge effect can be improved when the safety valve is open. Furthermore, the elastic ring having open cells can effectively prevent the intrusion of water by making the open cells into micro-order fine bubbles or by performing water-repellent treatment on the surface or inside.

  The state in which the elastic ring 6 closes the exhaust opening 4 is as shown in FIGS. 1 to 3, in which the width of the inner peripheral surface 6A is made wider than the width of the exhaust opening 4, and the exhaust opening directly on the inner peripheral surface 6A. As shown in FIG. 5, the exhaust opening 4 is not completely closed by the inner peripheral surface 6A, but the inner peripheral surface 6A is in close contact with the surface of the convex electrode 2 and the lower surface 6B is in close contact with the battery end surface. There is a state in which the exhaust opening 4 is blocked from the outside and substantially closed. In the battery shown in FIG. 5, the lower surface 6 </ b> B of the elastic ring 6 is caulked to the protruding ridge 13, and the exhaust opening 4 is blocked from the outside. In any state, since the elastic ring 6 closes the exhaust opening 4, water does not enter the convex electrode 2 from the exhaust opening 4. Although not shown, a battery that closes the exhaust opening by bringing the lower surface of the elastic ring into close contact with the battery end surface allows the battery contents to pass between the lower surface of the elastic ring and the battery end surface while the safety valve is open. It can also be discharged. At this time, the elastic ring is deformed at the contact portion with the battery end face, or is displaced to discharge the contents in the battery to the outside.

  In the battery of FIG. 1, the outer can 5 is covered with a heat shrinkable tube 7, an elastic ring 6 is placed inside the heat shrinkable tube 7, and the elastic ring 6 is fixed to the end face of the battery with the heat shrinkable tube 7. ing. The heat shrinkable tube 7 bends its end edge so as to cover the surface side of the elastic ring 6, and securely fixes the elastic ring 6.

  In the battery shown in FIG. 2, the elastic ring 6 is bonded and fixed to the end face of the battery. The end face is fixed by bonding with an adhesive 14, or is fixed via an adhesive layer, or is fixed to the end face via a double-sided adhesive tape. The elastic ring 6 is bonded and fixed to the caulking ridge 13 or is bonded and fixed to the surface of the sealing plate 1.

  The battery of FIG. 3 presses the upper surface of the elastic ring 6 with the lead plate 8 welded and fixed to the convex electrode 2 to fix the elastic ring 6 to the end face of the battery. The elastic ring 6 fixed in this state has a thickness in an uncompressed state, that is, a height that is larger than the vertical difference between the end face of the battery and the top of the convex electrode 2. The elastic ring 6 can be fixed in a state where the lead plate 8 elastically crushes the elastic ring 6 somewhat and the lower surface 6B of the elastic ring 6 is in close contact with the battery end surface.

It is an expanded sectional view of the sealed battery concerning one Example of this invention. It is an expanded sectional view of the sealed battery concerning other examples of the present invention. It is an expanded sectional view of the sealed battery concerning other examples of the present invention. It is an expanded sectional view of the sealed battery concerning other examples of the present invention. It is an expanded sectional view of the sealed battery concerning other examples of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Sealing plate 2 ... Convex part electrode 3 ... Safety valve 4 ... Exhaust opening 5 ... Outer can 6 ... Elastic ring 6A ... Inner peripheral surface 6B ... Lower surface 7 ... Heat shrinkable tube 8 ... Lead plate 9 ... Thin film plate 10 ... Valve body 11 ... Elastic body 12 ... Valve seat 13 ... Caulking ridge 14 ... Adhesive

Claims (8)

In the state where the relief electrode (2) of the sealing plate (1) is provided with the exhaust opening (4) of the safety valve (3), the internal pressure of the outer can (5) rises and the safety valve (3) opens. A sealed battery configured to discharge the contents in the battery from the exhaust opening (4),
An exhaust opening (4) is provided on the peripheral wall of the convex electrode (2), and the convex electrode (2) is formed by molding a rubber-like elastic body into a ring shape, and the inner peripheral surface (6A) is formed on the convex electrode ( 2) Insert into the elastic ring (6) that is elastically pressed against the surface of (2) and directly close the exhaust opening (4) with the elastic ring (6), or project the elastic ring (6) The exhaust opening (4) is closed substantially in close contact with the peripheral wall of the partial electrode (2) and the end face of the battery,
The elastic ring (6) closes the exhaust opening (4) when the safety valve (3) is closed, and exhausts the contents discharged from the safety valve (3) when the safety valve (3) is open. A sealed battery configured to be discharged from the opening (4).   The sealed battery according to claim 1, wherein the elastic ring (6) is fixed to the end face of the battery by bonding.   Cover the outer can (5) with a heat-shrinkable tube (7), place an elastic ring (6) inside the heat-shrinkable tube (7), and fix it to the end face of the battery with the heat-shrinkable tube (7). The sealed battery according to claim 1.   The lead plate (8) is connected to the convex electrode (2), the upper surface of the elastic ring (6) is pressed by the lead plate (8), and the elastic ring (6) is fixed to the end face of the battery. Item 2. A sealed battery according to item 1.   The sealed battery according to claim 1, wherein the exhaust opening (4) is opened below the convex electrode (2).   The sealed battery according to claim 1, wherein the sealed battery is a lithium ion secondary battery.   The sealed battery according to claim 1, wherein the elastic ring (6) is one of synthetic rubber, natural rubber, soft synthetic resin, and synthetic resin foam having closed cells. The sealed battery according to claim 1, wherein the elastic ring (6) has water repellency or is subjected to water repellency treatment.

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