JPH06290812A - Chemical battery with safety mechanism - Google Patents

Abstract

PURPOSE:To provide a chemical battery with a safety mechanism, which can suppress a battery abnormality including a case due to internal cause. CONSTITUTION:A chemical battery 10 includes a neutralizer container 21 storing a neutralizer, which suppresses a battery reaction. The neutralizer container 21 is provided with an opening means 31 emitting the neutralizer in response to gas or heat of reaction in case of a battery malfunction. A means provided with a pressure sensitive member to be operated in response to a gas pressure, a means formed of a thermoplastic member, or a means provided with a driving member made of a shape memory alloy is available for the opening means 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical battery having a safety mechanism for suppressing abnormal reaction.

[0002]

2. Description of the Related Art In a chemical battery, when a foreign substance is mixed in from the outside or a phenomenon such as a short circuit occurs, a chemical reaction may progress abnormally, causing a remarkable rise in temperature or generation of a voluminous reaction gas. Ensuring safety is an important issue. For example, in a lithium metal battery, which is highly expected as a battery with high energy density, a large amount of gas is generated and the temperature rises due to an abnormal reaction due to the inclusion of water and the deposition of dendrites. It has become an important issue.

Therefore, a normal sealed battery is provided with a gas discharge mechanism to prevent sudden ejection or explosion of gas. In addition, various proposals have been made to suppress the progress of abnormal reactions. For example, in order to prevent the abnormal reaction of the battery from progressing, a method has been proposed in which when the internal temperature rises abnormally, the collector rod inside the battery is separated from the sealing lid that is the positive electrode terminal to interrupt the internal current passage. (See JP-A-57-67289). In addition, in a lithium metal battery, a method has been proposed in which generation of hydrogen gas due to mixing of water is absorbed by a hydrogen storage alloy to prevent gas ejection (see Japanese Patent Laid-Open No. 60-258870).

[0004]

However, the above-described conventional battery safety mechanism has the following problems. First of all, although the method of simply releasing the gas has the effect of preventing the danger such as explosion, it does not suppress the battery reaction, so the generation of the gas itself does not stop, and the fundamental safety is ensured. Absent.

Similarly, the method of providing a hydrogen storage alloy inside the lithium metal battery also has the effect of suppressing the ejection of hydrogen gas, but does not stop the battery reaction. Also, it cannot absorb gases other than hydrogen gas, such as carbon dioxide,
It is incomplete as a safety measure.

Further, although the above-mentioned method of separating the collector rod from the sealing lid when the temperature rises abnormally can cut off the current and suppress the reaction against the temperature rise due to an external short-circuit, the internal short-circuit of the battery There is a problem that it is not effective against. That is, in the case of an internal short circuit, a current path different from the current path between the collector rod and the sealing lid is formed, such as a short circuit between the electrode plates, so that the current is not interrupted even if the collecting rod is separated from the sealing lid. . In view of such conventional problems, the present invention aims to provide a chemical battery with a safety mechanism capable of reliably suppressing an abnormal reaction of the battery including an internal cause such as an internal short circuit.

[0007]

The present invention has a built-in neutralizing agent container containing a neutralizing agent that suppresses a battery reaction, and the neutralizing agent container responds to gas or reaction heat generated during abnormal battery reaction. The chemical cell is characterized by having opening means for releasing the neutralizing agent.

What is most noticeable in the present invention is that the neutralizing agent container is built in the battery, and the neutralizing agent container releases the neutralizing agent in response to gas or reaction heat generated when the battery reaction is abnormal. It has the opening means to do. The neutralizer contained in the neutralizer container suppresses the chemical reaction of the battery.
Examples include gas, liquid, powder, granules, and mixtures thereof.

Further, the opening means is operated in response to the gas generated by the abnormal reaction of the battery and the heat of reaction. There are various opening means such as one that physically responds to the gas pressure of the generated gas, one that operates by causing a chemical reaction with the generated gas, and one that physically or chemically operates by the heat of reaction.

For example, some opening means have a pressure sensitive member that responds to the gas pressure of the reaction gas of the cell reaction. The pressure sensitive member includes a piston, a diaphragm, a bellows, etc. that operate according to gas pressure. By actuating such a pressure sensitive member, the neutralizing agent can be released from the neutralizing agent container.

Some opening means are formed of a thermoplastic member. That is, at least a part of the neutralizer container can be formed of a thermoplastic member, and the neutralizer can be released by softening or melting the thermoplastic member by the reaction heat generated by the abnormal reaction of the battery.

Some opening means have a driving member made of a shape memory alloy. That is, the drive member made of the shape memory alloy can be expanded or contracted or deformed according to the reaction heat generated by the abnormal reaction of the battery to open the neutralizer container.

[0013]

In the chemical battery of the present invention, when an abnormal reaction occurs in the battery, the opening means is actuated in response to the generated gas or reaction heat generated by the abnormal reaction to release the neutralizing agent. You can As a result, the activity of the battery can be inactivated and the abnormal reaction can be suppressed or stopped. As a result, gas generation and heat generation are suppressed,
The safety of the battery can be ensured.

The suppression of the reaction by the neutralizing agent is effective both when the cause of the abnormal reaction is outside and inside. That is, regardless of whether the cause of the abnormality is an external cause such as a short circuit outside the battery or an internal cause such as an internal short circuit, the battery reaction can be effectively suppressed. As described above, according to the present invention, it is possible to provide a chemical battery with a safety mechanism capable of reliably suppressing an abnormal reaction of the battery including an internal cause such as an internal short circuit.

[0015]

【Example】

Example 1 FIG. 1 shows a lithium metal battery according to an example of the present invention.
Will be explained. In this example, as shown in FIG. 1, a neutralizing agent container 21 containing a neutralizing agent that suppresses a battery reaction is built in. The neutralizing agent container 21 is a gas or reaction heat generated when an abnormal battery reaction occurs. Opening means 3 for releasing the neutralizing agent in response to
1 is a lithium metal battery 10. The opening means 31 has a piston 35 as a pressure sensitive member that responds to the internal gas pressure of the battery.

Each of these will be described in detail below. As shown in FIG. 1, the lithium metal battery 10 of this example has a battery container 40 which also serves as a negative electrode, in which a battery reaction part 15 is housed, and a positive electrode terminal 16 is provided on the upper part of the battery container 40. An insulating member 421 is provided between the positive electrode terminal 16 and the battery case 40 to insulate the two parts 16 and 40.

A box 4 is provided at the center of the battery reaction section 15.
A neutralizer container 21 housed in No. 1 is provided. The neutralizing agent container 21 stores the neutralizing agent with a slight internal pressure applied. The neutralizing agent is carbon dioxide. Box 41
Has an upper chamber 411 for accommodating a neutralizer container and a lower chamber 412 for accommodating a piercing pin 36 described later. A pin hole 4111 is formed in the center of the bottom of the upper chamber 411. The neutralizer container 21 may also be used as the mandrel of the battery reaction unit 15.

A cylindrical convex portion 161 is formed at the center of the positive electrode terminal 16, and the piston 35 is accommodated inside the convex portion 161 via a coil spring 352. In addition, the gas discharge port 1 located above the piston 35 in the normal state is provided on the side of the convex portion 161.
62 is provided, and the discharge port 162 is sealed by, for example, a sealing paper 163 as a means for indicating that the battery is an abnormal battery that has released gas while maintaining airtightness under normal conditions. As other abnormality display means, a sheet material that changes color due to internal gas, a pressure sensitive sheet, or the like can be considered.

A rod 351 bent in a hook shape is attached to the bottom of the piston 35.
A piercing pin 36 is attached to the lower end of 1. The piercing pin 36 is housed in the lower chamber 412 of the box 41. The rod 351 bypasses the side portion of the box 41 from the piston 35, reaches the lower chamber 412, and is connected to the boring pin 36. In FIG. 1, reference numeral 151 is a lead wire that connects the battery reaction unit 15 and the positive electrode terminal 16.

Next, the function and effect of this example will be described. If the battery reaction is abnormally accelerated due to a short circuit of the battery load, the gas pressure inside the battery rises. Then, the piston 35 rises against the biasing force of the coil spring 352.

The rod 3 is interlocked with the piston 35.
51 rises, and the piercing pin 36 rises in the pin chamber. When the piercing pin 36 further rises, the pin hole 4 in the upper chamber 411
Insert 111 and break through the bottom of the neutralizer container 21. As a result, carbon dioxide, which is a neutralizer, is ejected from the neutralizer container 21. As a result, the metal Li, which is the active material of the lithium metal battery 10, becomes lithium carbonate (Li ₂ CO ₃ ),
It is inactivated and the reaction stops.

When the piston 35 rises above the lower end of the discharge port 162, the sealing paper 1 that seals the discharge port 162.
The pressure of the internal gas is applied to 63. Then, when the pressure of the gas exceeds a predetermined value, the sealing paper 163 is broken and the gas is released to the outside, so that the risk of explosion or the like can be avoided.

When the gas is released and the pressure of the gas drops, the urging force of the spring 352 causes the piston 3 to move.
Reference numeral 5 again lowers than the discharge port 162, and prevents outside air from entering the inside of the battery and reacting oxygen and water with the active substance. Further, by visually observing the damage to the sealing paper 163, the defective battery can be known. As described above, according to this example, by releasing the neutralizing agent, it is possible to stop the abnormal reaction of the battery and release the gas to avoid the explosion of the battery.

Whether the cause of the abnormal battery reaction is outside the battery such as a load short circuit or inside the battery such as an electrode short circuit, the reaction can be suppressed. As described above, according to the present invention, it is possible to provide a chemical battery with a safety mechanism capable of reliably suppressing an abnormal reaction of the battery including an internal cause such as an internal short circuit. The battery having the structure of this example can be used not only for small batteries used in small electronic devices and the like, but also for large-capacity secondary batteries for electric vehicles, power storage, and the like.

Embodiment 2 In this embodiment, as shown in FIG. 2, in Embodiment 1, a flexible operation cord 353 is attached to the piston 35 of the opening means 32, and the tip of the operation cord 353 is attached. , Neutralizer container 22
It is another embodiment in which a plug 354 inserted into a plug opening 221 provided at the bottom of the is attached.

An operation string 353 is attached to the bottom of the piston 35. The operation string 353 is inserted through the guide tube 355 and reaches below the neutralizer container 22, and a plug 354 is attached to the tip thereof. And the plug 354
Is detachably attached to a plug opening 221 provided at the bottom of the neutralizer container 22.

When the gas pressure inside the battery rises, the piston 3
5, the operating cord 353 is pulled to pull out the plug 354 from the plug opening 221 to release the neutralizing agent. Others are similar to those of the first embodiment, and similar effects can be obtained.

Example 3 This example is another example having opening means formed by a thermoplastic member. As shown in FIG. 3, this example has a safety valve 43 integrally formed with the positive electrode terminal 17, and the neutralizer container 23 is made of a thermoplastic material.

As shown in FIG. 3, the positive electrode terminal 17 is provided with a discharge port 171 that is open to the outside air, and
A safety valve 43 for shutting off outside air is provided. The neutralizer container 23 containing the neutralizer is made of a thermoplastic material. The thermoplastic member is a member that softens and melts when the internal temperature of the battery rises above a predetermined temperature.

The predetermined temperature is set to a temperature slightly higher than the internal temperature during normal operation of the battery. For example, in the case of a lithium metal battery, the melting point is 100 to 15
Resins such as polyethylene and polypropylene between 0 ° C are used. Since the melting point of lithium is about 180 ° C,
By using the material having the above melting point, it is possible to stop the battery reaction before the lithium is melted and to prevent the lithium from being melted and the internal short circuit being expanded.

In this example, when the internal temperature rises due to an abnormal reaction of the battery, the neutralizing agent container 23 is melted and the neutralizing agent is released to stop the reaction of the battery. Further, when the gas pressure inside the battery rises above a predetermined value, the safety valve 43 breaks and gas is discharged from the discharge port 171 to prevent danger.

The once broken safety valve 43 has no self-restoring force, so that the outside air cannot be shut off again. However, the valve member as shown in FIG. 1 may be used to shut off the valve again. Further, by sealing the discharge port 171 with a sealing paper as shown in FIG. 1, it is possible to have a role of maintaining airtightness and an abnormality display. Others are the same as those in the first or second embodiment. The neutralizer container 23 may be formed of a thermoplastic member only partially.

Embodiment 4 As shown in FIG. 4, this embodiment is another embodiment of Embodiment 3 in which the opening means 30 is constituted by a needle-shaped member 33 made of a shape memory alloy which expands and contracts according to temperature. . At the bottom of the lithium metal battery 10 of this example, a neutralizer container 21 containing a neutralizer is arranged.

On the upper portion of the neutralizer container 21, there is attached a spiral needle-like member 33 made of a shape memory alloy and extending downward when the temperature exceeds a predetermined temperature. When the internal temperature exceeds a predetermined value due to an abnormal reaction of the battery, the needle-shaped member 33 extends and the needle 331 at the tip pierces the neutralizer container 21.

As a result, the neutralizing agent is released and the reaction of the battery is stopped. Others are the same as in the third embodiment. The needle-shaped member 33 may be formed of bimetal instead of using the shape memory alloy.

The bimetal bends as the temperature rises.
Then, the needle-like member 33 is formed so that the diameter of the spiral is reduced by the curvature. Since the total length of the needle-shaped member 33 is substantially constant, the needle-shaped member 33 extends axially when the diameter of the spiral is reduced. As a result, the needle 331 at the tip moves down and the neutralizer container 21 can be pierced.

Example 5 In this example, as shown in FIG.
It is another embodiment in which the neutralizer container 24 and the opening means 32 are provided inside the container. As shown in FIG. 5, the assembled battery 11 of this example has four unit cells 14 housed in a case 44,
Positive and negative terminals 441 and 442 are provided.

The four unit cells 14 are connected in series in the case 44, and both terminals are connected to the terminals 441 and 442. The neutralizer container 24 and the opening means 32 are provided between each unit cell 14 and the inner wall 443 of the case 44.

Inside the opening means 32, as shown in FIG. 6, a flanged pin 322 is attached which is urged toward the outside of the case 44 by a spring 321. Then, a ball 32 is provided outside the flanged pin 322.
A cylindrical member 324 accommodating 3 is arranged. In the normal state, the opening 325 of the tubular member 324 is closed by the flange 3221 of the flanged pin 322, and the ball 323 is closed.
Is inside the tubular member 324, as indicated by the broken line.

When an abnormality such as gas ejection occurs in the unit cell 14 and a shock is applied to the case 44, the ball 323 is
As shown by the solid line in the figure, the urging force of the spring 321 is overcome to push out the flanged pin 322, and the pin tip 3222 is pierced through the neutralizer container 24.

As a result, the neutralizing agent is ejected from the neutralizing agent container 24, and the neutralizing agent can stop the reaction of the battery and suppress the expansion of the abnormal reaction of the battery. The opening means 3 of this example
Since 2 also operates by an external impact, the safety mechanism can be operated even against the external impact.

That is, it is possible to prevent the battery cell chemical reaction from running away due to breakage of the unit cell 14 and ejection of the filler due to external impact. If the ball 323 is a temperature-sensitive member that expands due to temperature, it expands due to an abnormal temperature rise and presses the flange 3221 to activate the opening means 32.

Example 6 In this example, as shown in FIG. 7 and FIG.
1 to the case 4 of the assembled battery 12
5 is another embodiment in which the neutralizing agent is placed inside the No. 5 and the foaming protrusion 251 contains the neutralizing agent. The assembled battery 12 of this example
The four unit cells 14 are housed in a case 45, and positive and negative terminals 451 and 452 are provided.

Inside the case 45, the neutralizer container 25 having the foam-like protrusions 251 is arranged. Bubble-like protrusion 2
The inside of 51 is filled with a neutralizing agent. As shown in FIG. 8, the bubble-like protrusion 251 is formed of a thin film 252 which is easily broken by a strong impact.
Melts at high temperatures of 100-150 ° C.

The foam-like projections 251 melt when the internal temperature rises due to an abnormal reaction of the battery and release the neutralizing agent to stop the battery reaction. In addition, the neutralizer container 25 normally serves as a cushioning material as a cushioning member, but the foam-like protrusions 2 do not come into contact with the impactor during strong impact or explosion.
The thin film 252 of 51 is broken to release the neutralizing agent to suppress the battery reaction and ensure safety.

As described above, the assembled battery of the present example stops the battery reaction even against external impact to ensure safety, and also functions as a cushion during normal operation. Others are the same as in the fifth embodiment.

[Brief description of drawings]

FIG. 1 is a sectional view of a battery of Example 1.

FIG. 2 is a sectional view of a battery of Example 2.

FIG. 3 is a sectional view of a battery of Example 3.

FIG. 4 is a sectional view of a battery of Example 4.

FIG. 5 is a perspective view of a battery of Example 5.

FIG. 6 is an enlarged view of the vicinity of the opening means of the battery of Example 5.

FIG. 7 is a cross-sectional view of the battery of Example 6.

FIG. 8 is an enlarged view of a neutralizer container of Example 6.

9 is a sectional view taken along the line AA of FIG.

[Explanation of symbols]

 10. ． ． Lithium metal battery, 21-25. ． ． Neutralizer container, 31, 32. ． ． Opening means, 40. ． ． Battery container,

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masanori Tabayashi, 1-1, Showa-cho, Kariya, Aichi Prefecture, Nihon Denso Co., Ltd. (72) Inventor, Tomoyasu Takeuchi 1-1, Showa-cho, Kariya, Aichi Within the corporation

Claims (4)

[Claims] 1. A neutralizing agent container containing a neutralizing agent that suppresses a battery reaction is built in, and the neutralizing agent container reacts with gas or reaction heat generated at the time of abnormal battery reaction to provide the neutralizing agent. Chemical cell characterized by having opening means for discharging. 2. The chemical battery according to claim 1, wherein the opening means has a pressure sensitive member that responds to the internal gas pressure of the battery. 3. The chemical battery according to claim 1, wherein the opening means is formed of a thermoplastic member. 4. The chemical battery according to claim 1, wherein the opening means has a driving member made of a shape memory alloy.