JP5433248B2 - Cylindrical battery - Google Patents

Description

  The present invention relates to a cylindrical battery in which a power generation element is accommodated in a bottomed cylindrical battery can, and more specifically to an explosion-proof safety mechanism for the cylindrical battery.

  A typical example of a cylindrical battery that is an object of the present invention is a manganese dioxide-lithium lithium battery (CR type battery) using manganese dioxide as a positive electrode active material and metal lithium as a negative electrode active material. FIG. 5 shows the structure of a conventional CR battery. (A) is a top view when the said battery 1 is seen from upper direction, (B) is dd arrow sectional drawing in (A). Moreover, (C) is an enlarged view of the DD arrow cross section in (A). The CR type battery 1b shown in the figure is a bobbin type, and is formed into a hollow cylindrical shape with a bottomed cylindrical positive electrode can 11 having an opening at the top, and a positive electrode active material such as manganese dioxide together with a conductive aid such as graphite. The positive electrode mixture 21, the cylindrical negative electrode lithium 22, the cylindrical cup-shaped separator 23, and the sealing body 30 that also serves as a negative electrode terminal to hermetically seal the opening of the battery can 11.

  The positive electrode can 11 is made of metal and serves as a battery case and a positive electrode current collector. On the lower bottom surface, a positive electrode terminal portion 12 that is convex outward is formed by pressing. In addition, a beading portion 10 is formed around the opening by drawing. In the positive electrode can 11, a positive electrode mixture 21, a separator 23, and a negative electrode lithium 22 are sequentially loaded to form a hollow cylindrical electrode body.

  The negative electrode lithium 22 is a rolled metal lithium plate, and one end of the negative electrode lead 33 is attached to a part of the negative electrode lithium 22 in advance. The negative electrode lead 33 is formed of a strip-shaped metal thin plate and also serves as a negative electrode current collector. The other end is spot welded to the inside (battery inside) of a disc-shaped sealing plate 32 made of a metal thin plate such as stainless steel constituting the sealing body 30. The sealing body 30 includes the sealing plate 32 and a negative electrode terminal plate 31 made of a metal such as stainless steel. The negative electrode terminal plate 31 has a dish shape having a flange around it, and is laminated with the sealing plate 32 in a state where the bottom surface is faced up and the dish is turned down to constitute the sealing body 30.

  The positive electrode can 11 is filled with a non-aqueous electrolyte (not shown), and the sealing body 30 is mounted together with the gasket 34 inside the opening of the positive electrode can 11 with the beading portion 10 as a seat, and the positive electrode can 11. The opening is caulked inward (curled) and is fitted into the battery can 11.

  By the way, in the battery 1 having the above-described structure, a substantially V-shaped notch 40 is defined substantially at the center of the bottom surface 44 of the plate-shaped negative electrode terminal plate 31, and a tongue piece formed by the notch 40 is a base end thereof. 49 is bent inward of the battery can 11. Thereby, the tongue piece becomes a cutting blade 41 having a sharp tip 47. The tip 47 is close to the sealing plate 32. Further, by forming the cutting blade 41 on the bottom surface 44 of the negative electrode terminal plate 31, an acute-angled triangular hole (exhaust port) 42 that communicates the inside and the outside opens.

  A small hole (a vent hole) 43 that communicates the inside and outside of the negative electrode terminal plate 31 is formed on a wall surface (peripheral surface) 45 with the periphery 46 of the bottom surface 44 of the dish-shaped negative electrode terminal plate 31 as an edge. The sealing plate 32 and the cutting edge 41 operate as an explosion-proof safety mechanism when gas is generated inside the battery 1 due to overdischarge or forced charging due to misuse of the battery 1 and the internal pressure rises. The exhaust port 42 serves as a passage (exhaust passage) for connecting the inside and outside of the battery can 11 and releasing the gas to the outside. The vent hole 43 serves as an auxiliary exhaust passage.

  The operation of the explosion-proof safety mechanism in the conventional bobbin type battery 1 will be specifically described. First, the sealing plate 32 swells upward as the internal pressure rises, and the tip 47 of the cutting blade 41 pierces the sealing plate 32 and the sealing plate 32 Make a hole in. Thereby, a path (exhaust path) from this hole to the exhaust port 42 is formed, and the gas inside the battery 1 escapes to the outside. A part of the gas is exhausted outside through an exhaust path from the hole to the vent hole 43. In this way, the battery 1 can be prevented from bursting.

  In the conventional cylindrical battery, when the internal pressure in the battery can explosively rises at an unexpected speed, when the cutting blade sticks into the sealing plate, the sealing plate is torn, and the torn sealing plate is brought into the exhaust port. In some cases, the air bubble expands so as to be greatly bent, and the expanded portion blocks the exhaust port. FIG. 6 shows the operation state of the explosion-proof safety mechanism when such an explosive internal pressure rises. In this figure, the expanded sectional view of the sealing body 30 is shown. First, when gas is generated in the battery can and the internal pressure rises, the sealing plate 32 expands upward and comes into contact with the tip 47 of the cutting blade 41, and a hole 35 is opened in the sealing plate 32 (A). If the generation of gas is explosive, the sealing plate 32 is divided from the hole 35 with the cutting edge 41 as a boundary. Then, without being exhausted to the outside through the exhaust port 42, the divided sealing plate 32 is bent toward the exhaust port 42 at a stretch using the peripheral portion of the disk fitted to the battery can 11 as a fulcrum. Stick to the back side 48 of the bottom surface 44. As a result, the largest exhaust passage is blocked (B). When such an explosive internal pressure rises, solids such as positive electrode mixture and separator fragments are also ejected. Therefore, even if the exhaust port 42 is not completely blocked by the sealing plate 32, it remains in the exhaust port 42. This solid matter concentrates in a slight gap, and the exhaust port 42 is completely blocked. Of course, the vent hole 43 having a small diameter is also blocked.

  In such a state, as indicated by an arrow 50, the gas generated in the battery is located above the sealing plate 32 from a hole (or a cut surface) 35 formed in the sealing plate 32 by the cutting blade 41. After that, only the space (halftone dot portion) 36 between the terminal plate 31 and the sealing plate 32 having no exhaust passage is used as a buffer region, and further increase in internal pressure cannot be suppressed. . As a result, there is a possibility of a very dangerous situation where the battery bursts or ignites.

  Therefore, even if the gas explosively occurs in the battery and the pressure in the battery can rises at an unexpected abnormal speed, the present invention reliably releases the internal pressure to the outside of the battery, It aims at providing the cylindrical battery provided with the advanced safety mechanism which prevents ignition.

In order to achieve the above object, the present invention is characterized in that a power generation element is housed in a bottomed cylindrical metal battery can that opens upward, and a sealing member is fitted to the opening of the battery can via a gasket. A cylindrical battery in which the battery can is sealed,
The sealing body is composed of a metal dish-shaped terminal plate with the upper surface as a bottom surface, and a sealing plate made of a disk-shaped metal thin plate disposed below the terminal plate,
The dish-like terminal plate includes a cutting blade formed by bending a tongue piece formed by a substantially V-shaped first notch on a bottom surface so as to be erected substantially vertically inward of the battery can, Equipped with a substantially triangular opening of the trace that formed the cutting blade as an exhaust port,
In addition to the first notch on the bottom surface of the dish-shaped terminal plate, at least one other notch is formed,
The tongue formed by the other cutout is bent so as to stand substantially vertically inward of the battery can to form a protrusion,
The tip of the cutting blade is close to the upper surface of the sealing plate, and is configured to penetrate the sealing plate when the sealing plate expands upward as the internal pressure increases in the battery can.
The tip of the protrusion is close to the top surface of the sealing plate, and when the sealing plate expands upward as the internal pressure in the battery can rises, it contacts the sealing plate and resists the expansion. However, the cylindrical battery is configured so as not to break the sealing plate .

  It is more preferable that the tip of the projection is flattened so as to be parallel to the surface of the sealing plate, or the tip of the cutting blade is positioned below the tip of the projection.

  According to the cylindrical battery of the present invention, even if the internal pressure rises at an unexpected abnormal speed, the internal pressure can be surely released to the outside of the battery, and the battery can be prevented from bursting or firing. Can be secured. In addition, the extremely high safety can be achieved only by changing the structure of the terminal board. When manufacturing the battery, no separate parts or processes are required, and the increase in manufacturing cost can be suppressed to a very low level.

It is a structural diagram of the cylindrical battery in the Example of this invention. It is the figure which showed the structure of the sealing body in the said Example, and the operation principle of an explosion-proof safety mechanism. It is a block diagram of the sealing body in the other Example 1 of this invention. It is a block diagram of the sealing body in the other Example 2 of this invention. It is a structural diagram of a conventional cylindrical battery. It is a figure which shows the state which the explosion-proof safety mechanism in the conventional cylindrical battery operate | moved incompletely.

  The basic structure of the cylindrical battery in the embodiment of the present invention is substantially the same as that of the conventional bobbin battery 1 shown in FIG. 5, and a power generation element (21-21) is placed in a cylindrical metal battery can 11 that opens upward. 23) is housed, and the battery can 11 is sealed by fitting the sealing body 30 into the opening. However, the battery of the present embodiment is provided with an extremely reliable explosion-proof safety mechanism that can reliably exhaust the generated gas in the battery can 11 against the explosive increase in internal pressure that has been a problem in the conventional battery. Yes.

=== Embodiment of the Invention ===
FIG. 1 shows the structure of a cylindrical battery in an example of the present invention. (A) is a top view from above, (B) is a side sectional view, and shows a cross section taken along the line AA in (A). The battery 1a according to this embodiment has the same basic configuration as that of the conventional battery 1, but has a substantially V-shaped notch for forming the cutting edge 41 on the bottom surface 44 of the plate-like negative electrode terminal plate 31a. In addition to the (cutting blade notch) 40, a U-shaped notch (projection notch) 50 is defined.

  The protrusion notch 50 is defined such that the U-shaped open end (base end) 54 and the V-shaped open end (base end) 49 of the cutting blade notch 40 are parallel to each other. A tongue piece formed by the projection cutout 50 is bent inward of the battery 1 a at the base end 54, and a substantially rectangular projection 51 is formed in parallel with the cutting blade 41. It should be noted that the tip (53, 47) of each of the protrusion 51 and the cutting blade 41 may be located below, but in this embodiment, when the sealing plate 32 expands upward when the internal pressure increases, the cutting blade is first cut. The tip 47 of the cutting blade 41 is positioned below the tip 53 of the protrusion 51 so that the exhaust path can be secured by contacting the tip 47 of the pin 41.

=== Operation of explosion-proof safety mechanism ===
2A to 2C show the operation of the explosion-proof safety mechanism in the cylindrical battery 1a of this embodiment. In this figure, the sectional side view of the sealing body 30a is shown. When gas is explosively generated inside the battery 1a, the sealing plate 32 expands upward in an instant, and the tip 47 of the cutting blade 41 comes into contact with the sealing plate 32 (A). Open. Then, the sealing plate 32 breaks into two parts with the cutting edge 41 as a boundary (B). At this time, since the gas tends to escape outward from the openings (42, 42b) of the negative electrode terminal plate 31a, a part of the broken sealing plate 32 is bent toward the openings (42, 42b). However, in this embodiment, since there is the protrusion 51, the sealing plate 32 comes into contact with the tip 53 of the protrusion 51, and upward bending is suppressed at this contact portion. As a result, the front end side 37 of the sealing plate 32 that is broken with the front end 53 of the protrusion 51 as a fulcrum rises upward and bends along the protrusion 51 (C). As a result, the exhaust port 42 is not blocked, the exhaust path 60a is reliably secured, and the battery 1a can be prevented from being ruptured or ignited.

=== Explosion-proof performance test ===
Here, the performance of the explosion-proof safety mechanism was compared between the conventional cylindrical battery and the cylindrical battery of the present invention. In the comparison, the cylindrical battery (invention product) 1a in the example shown in FIG. 1 and the conventional cylindrical battery (conventional product) 1 shown in FIG. 5 were prepared as samples. The sample was a CR8 type with a diameter of 17.0 mm and a height of 45.0 mm, and the inventive product 1a and the conventional product 1 all had the same structure except for the presence or absence of the protrusion 51 on the negative electrode terminal plate (31a, 31). And about the said invention product 1a and the conventional product 1, a hole was made in the lower end of the battery can 11, and air was supplied from the hole, and the internal pressure in a battery (1a, 1) was raised.

  In the test, the amount of air inflow per second by air supply was changed, and the internal pressure increase state at various speeds was reproduced. 100 samples were prepared for each of the inventive product 1a and the conventional product 1 for each internal pressure increase rate. Moreover, the test result was determined by whether or not the battery burst by the end of the air supply after 1 second.

Table 1 shows the test results.

  In the test, 0.1 Mpa / sec, which is the lowest rate of increase in internal pressure, is faster than the rate of increase in internal pressure associated with possible misuse. In the conventional product 1, there was no rupture at the internal pressure increase rate of 0.1 Mpa / sec and 0.5 Mpa / sec, but at 0.8 Mpa / sec, two samples out of 100 ruptured. In addition, at 2.0 Mpa / sec, which is an internal pressure increase rate that is almost impossible, 85% of the conventional product 1 burst. On the other hand, the invention product 1a did not rupture even after elapse of time after the end of the air supply, and none of the 100 samples that had ruptured even at an internal pressure increase rate of 2.0 Mpa / sec. That is, the cylindrical battery 1a in the embodiment of the present invention does not rupture even at a rate 1.5 times the internal pressure increase rate, which was ruptured in the conventional cylindrical battery, and has extremely high safety. I was able to confirm.

=== About the number, position, and shape of protrusions ===
The protrusion 51 is not limited to the above-described embodiment, and can prevent the upward bending of the sealing plate 32 that is broken when the internal pressure rises explosively and can secure the exhaust path 60a from the exhaust port 42. The number, size, position, and shape may be set in any way. 3 and 4 show another embodiment of the present invention. In these drawings, (A) is a plan view when the sealing body 30b (30c) is viewed from above, and (B) is a cross-sectional view taken along line bb (c-c) in (A). is there.

  The sealing body 30b shown in FIG. 3 is the same as the above embodiment in that the cutting edge 41 and the protrusion 51 are formed on the negative electrode terminal plate 31b, but the base end 49 of the cutting edge notch 40 is the same. Both notches (40, 50) are formed side by side so that a perpendicular line extending from the side to the vertex of the V-shape is parallel to the base end 54 of the projection notch 50. Thereby, the cutting blade 41 and the protrusion 51 are formed so that both surfaces are orthogonal to each other. In the outside 30c shown in FIG. 4, the projection 50 shown in FIG. 3 is formed on the opposite side of the negative terminal plate 31c with the cutting blade 41 in between, and two projections are formed in total. That is, a substantially U-shaped cross-section wall surface is formed by the surface of the cutting blade 41 and the surfaces of the two protrusions 51.

  The cylindrical battery (1, 1a) shown as the conventional example or the example is different from a general dry battery in that the lead terminal is attached to the bottom surface 44 of the negative electrode terminal plate (31, 31a to 31c) by spot welding or the like. Often used in the installed state. In the cylindrical battery 1a of the present invention, in addition to the exhaust port 42 that is the trace of the cutting blade 41, a hole 42b for forming the protrusion 41b opens in the negative terminal plate 31a, and the number of the 42b is increased. If the opening area is increased or the opening area is increased, there is no place to attach the lead terminal.

  Further, if the number of the protrusions 51 is too large or the opening area of the trace hole 52 where the protrusions 51 are formed is too large, the strength of the negative electrode terminal plates (31a to 31c) decreases. Further, the cutting blade 41 and the protrusion 51 are large at their base ends (49, 54) in order to make a hole 35 in the sealing plate 32 when the internal pressure increases or to prevent the sealing plate 32 from expanding upward. Power is added. Therefore, if a plurality of notches (40, 50) for forming the cutting blade 41 and the protrusion 51 are very close to each other, the large force cannot be resisted, and the cutting blade 41 and the protrusion 51 are distorted or the negative electrode terminal. There is a possibility of tearing off the plates (31a to 31c).

  Further, the shape of the protrusion 51 may be any shape as long as it can resist the sealing plate 32 that expands upward. In the above embodiment, the resistance 53 against the expansion of the sealing plate 32 is dispersed and the tip 53 of the projection 51 is flat so as to be parallel to the surface of the sealing plate 32 so that the sealing plate 32 is not broken by the projection 51. Further, the protrusion 51 has a structure in which the tongue formed by the simple U-shaped protrusion notch 50 is simply bent inward of the battery can 11, thereby reducing the increase in manufacturing cost as much as possible. I am letting.

  In any case, when the protrusions 51 are formed, the number and size thereof may be set in consideration of the mounting location and strength of the lead terminals. In the experiment, each of the terminal boards (31a to 31c) shown as examples of the present invention and other examples has excellent explosion-proof safety performance, can be attached with lead terminals, and has a practically strong strength. There was no problem.

DESCRIPTION OF SYMBOLS 1, 1a Tubular battery 11 Battery can 21 Positive electrode mixture 22 Negative electrode lithium 23 Separator 30, 30a-30c Sealing body 31, 31a-31c Terminal board 32 Sealing plate 34 Gasket 35 Hole of sealing body, or cut 40 Notch for cutting blade 41 Cutting blade 50 Protrusion notch 51 Protrusion 42 Exhaust port 43 Vent hole 44 Bottom surface of terminal plate 45 Peripheral surface of terminal plate 60a Exhaust path

Claims (3)

A cylinder in which a power generation element is housed in a bottomed cylindrical metal battery can that opens upward, and a sealing body is fitted into the opening of the battery can via a gasket so that the battery can is sealed. Battery
The sealing body is composed of a metal dish-shaped terminal plate with the upper surface as a bottom surface, and a sealing plate made of a disk-shaped metal thin plate disposed below the terminal plate,
The dish-like terminal plate includes a cutting blade formed by bending a tongue piece formed by a substantially V-shaped first notch on a bottom surface so as to be erected substantially vertically inward of the battery can, Equipped with a substantially triangular opening of the trace that formed the cutting blade as an exhaust port,
In addition to the first notch on the bottom surface of the dish-shaped terminal plate, at least one other notch is formed,
The tongue formed by the other cutout is bent so as to stand substantially vertically inward of the battery can to form a protrusion,
The tip of the cutting blade is close to the upper surface of the sealing plate, and is configured to penetrate the sealing plate when the sealing plate expands upward as the internal pressure increases in the battery can.
The tip of the protrusion is close to the top surface of the sealing plate, and when the sealing plate expands upward as the internal pressure in the battery can rises, it contacts the sealing plate and resists the expansion. is configured so as not to break the sealing plate while,
The cylindrical battery characterized by the above-mentioned.   The cylindrical battery according to claim 1, wherein a tip of the protrusion is flat so as to be parallel to a surface of the sealing plate.   The cylindrical battery according to claim 1 or 2, wherein a tip of the cutting blade is positioned below a tip of the protrusion.

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