JP3681597B2 - Batteries having a pressure sensitive current interruption mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a battery having a pressure-sensitive current interruption mechanism for a battery, and more particularly, to a battery having a pressure-sensitive current interruption mechanism suitable for a Li polymer secondary battery.
[0002]
[Prior art]
In a device that is required to be small and thin, such as a cellular phone / camera-integrated video tape recorder, the same requirements are also applied to the battery. Li (lithium) polymer secondary batteries have been taken up as potential candidates for battery options.
[0003]
Even if it is small, safety measures are necessary. That is, even if charging of such a Li polymer secondary battery is completed, or if charging is performed with a current larger than a specified current, a chemical change occurs in the Li polymer secondary battery, Gas is generated and the battery internal pressure rises. And there existed a possibility that the exterior body of a Li polymer secondary battery might expand, and a crack and a rupture might arise.
[0004]
Therefore, a pressure-sensitive current interrupting mechanism that interrupts the electric circuit between the power generator and the external terminal when the battery internal pressure rises to a predetermined value or more has been proposed.
[0005]
For example, there is a pressure-sensitive current interruption mechanism described in JP-A-2-112151. In this conventional example, an explosion-proof valve that bulges outward due to an increase in the internal pressure of the battery is provided in the metal can of the battery, and the explosion-proof valve bulges outward due to the internal pressure so that the current is cut off from the internal electrode. Is done.
[0006]
Further, there is a mechanism described in JP-A-11-154504. This other conventional example is for a rectangular battery, in which a diaphragm, a shut-off mechanism using the same, a safety valve, and the like are incorporated on the battery plate surface (wide surface) near the inside of the external electrode.
[0007]
[Problems to be solved by the invention]
By the way, the Li polymer secondary battery used in recent years has a plate shape and is provided with an exterior by film lamination, and the thickness of the battery body is only about 1 to 4 mm. Therefore, in the Li polymer secondary battery, in the configuration in which the diaphragm and various mechanisms are formed in the end face direction of the metal can of the battery as in the prior art, there is no space for incorporating the size of the diaphragm, and there is no fixing method. In addition, there were problems such as difficulty in incorporation.
[0008]
However, simply installing a diaphragm or a shut-off mechanism using it on the plate surface (wide surface) of the battery would increase the overall thickness of the battery due to the provision of the shut-off mechanism, etc. Alternatively, the thinness of other thin batteries cannot be utilized.
[0009]
An object of the present invention is to form a current interrupting mechanism separately from the battery outer body, detect expansion of the outer body, and incorporate a power generator in most of the current interrupting mechanism interrupting part and the like. It is an object of the present invention to provide a battery having a pressure-sensitive current interrupting mechanism that can be made compact by making use of the space of the exterior body seal part and effectively utilizing the space of the exterior body seal part.
[0010]
[Means for Solving the Problems]
The object is to provide a plate-shaped power generation body, an exterior body that incorporates the power generation body, is airtight, and can be deformed by internal pressure, and a plurality of extractions that serve as an electrical path from the power generation body to the exterior of the exterior body. A terminal, an exterior body seal portion that is positioned in the direction of the end face of the power generation body, is thinner than a portion in which the power generation body is incorporated, and forms a part of the exterior body; end upper surface or lower surface of the power generating body, and the other end positioned in the vicinity of the outer body seal section, is displaced outwardly by detecting the rise and also such will displacements in the internal pressure of the top portion or the bottom surface portion of the outer body The operation member and the exterior body seal portion are in the upper surface or lower surface direction, one end is electrically connected to at least one of the takeout terminals, the other end is electrically connected to an external electrode, and the exterior body is When the pressure expands by more than a predetermined amount due to an increase in internal pressure A blocking unit for blocking the electrical connection between the takeout lead terminal and the external electrode by the actuating member, it is achieved by first means having.
[0011]
The above object is that, in the first means, the blocking part is held by the holding member fixed to the exterior body seal part, is held by the holding member, has brittleness, and one end is at least one of the extraction terminals. And an element having a conductive path electrically connected and the other end electrically connected to the external electrode, and the other end of the operating member is located on the exterior body seal portion side of the element, When one end of the actuating member is displaced by the internal pressure, the other end of the actuating member is also displaced accordingly, and when it is displaced by a predetermined amount or more, the second means for blocking the element by the other end of the actuating member is achieved.
[0012]
In the first means, the object further includes an outer case having a rigidity higher than that of the exterior body, and the outer case further includes a displacement restricting portion for suppressing displacement of the other end of the operating member due to expansion due to an increase in internal pressure. This is achieved by the third means.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is a perspective view of a battery having a pressure-sensitive current interrupting mechanism according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a concept of the battery having a pressure-sensitive current interrupting mechanism according to an embodiment of the present invention. 3 (a) and 3 (b) are a left side view and a front view showing a state before the operation of the pressure sensitive current interruption mechanism, and FIGS. 4 (a) and 4 (b) are states after the operation of the pressure sensitive current interruption mechanism. It is the left view and front view which show.
[0015]
In these drawings, reference numeral 1 denotes a plate-like power generation body made up of power generation elements, and this power generation body 1 is built in an exterior body 2. The exterior body 2 has airtightness and can be deformed by an internal pressure.
[0016]
Reference numeral 3 denotes a plurality of extraction terminals serving as electric paths from the power generation body 1 to the exterior of the exterior body 2, and the extraction terminals 3 and 3 are connected to external electrodes.
[0017]
4 is an exterior body seal portion which is a top seal portion of a thin laminate film. This exterior body seal portion 4 is located in the end face direction of the power generation body 1 and is thinner than the thickness of the portion in which the power generation body 1 is incorporated. Is part of.
[0018]
In the space portion on the upper surface of the exterior body seal portion 4, a cutoff portion 5 of a pressure-sensitive current cutoff mechanism is disposed. The blocking portion 5 is held by the holding member 6 fixed to the exterior body seal portion 4, is held by the holding member 6, has brittleness, one end is electrically connected to at least one of the takeout terminals, and the other end is And an element 7 having a conductive path electrically connected to the external electrode.
[0019]
That is, as shown in FIGS. 1 and 3A, the holding member 6 includes a bottom plate portion 6a, a pair of side plate portions 6b at both ends thereof, and a protruding portion 6c extending inward from each side plate portion 6b. It consists of and. As shown in FIG. 3A, a lead plate 8 constituting an electric circuit is disposed below each projection 6c so as to penetrate each side plate 6b, and the upper surface of the lead plate 8 and the lower surface of the projection 6c. Both ends of the element 7 are sandwiched between and electrically connected to each other. The other end of the operating member 9 is disposed on the lower surface of the element 7.
[0020]
As shown in FIGS. 1 and 3 (b), the actuating member 9 has a long shape, and one end side thereof is bonded and fixed to the outside of the exterior body 2. Further, the other end of the actuating member 9 is bent and positioned on the lower center surface of the element 7 as described above. On the other end of the actuating member 9, a protruding portion 9 a protruding upward is formed so as to hit the center lower surface of the element 7. Thereby, since the force due to the displacement of the operating member 9 is concentrated from the protrusion 9a and the force acts on the element 7, even if the battery is thin, it can operate stably and cut off the current.
[0021]
When the upper surface portion of the exterior body 2 is displaced outward as the internal pressure of the power generator 1 is increased, the operating member 9 is also displaced upward, and one end of the operating member 9 is also displaced upward. And if it displaces more than predetermined amount, the projection part 9a of the other end of the action | operation member 9 will push up the center lower surface of the element 7 from the downward direction, and will divide the element 7 in the center. Thereby, the electric circuit for interruption | blocking (not shown) of the element 7 is disconnected, and the electric conduction between the lead plates 8 and 8 is cut off, so that further charging of the power generator 1 is stopped.
[0022]
Next, the operation of the pressure-sensitive current interruption mechanism will be described based on FIGS. 3 (a) and 3 (b) and FIGS. 4 (a) and 4 (b).
[0023]
When charging progresses and overcharges, or when charging is performed with a current larger than the specified current, gas is generated and filled due to the chemical change of the power generation element, and the internal pressure in the battery starts to rise due to the gas. Due to the increase in internal pressure, the upper surface of the exterior body 2 expands outward and is displaced. Accordingly, one end of the operating member 9 bonded to the upper surface portion of the exterior body 2 is also displaced upward, and the other end of the operating member 9 is also displaced upward to push up the central lower surface of the element 7. At this time, both ends of the element 7 are received by the lower surfaces of the protrusions 6 c and 6 c of the holding member 6. And if it displaces more than predetermined amount, the projection part 9a of the other end of the action | operation member 9 will divide the element 7 in the center. Thereby, the electric circuit for interruption | blocking (not shown) of the element 7 is disconnected, and the electric conduction between the lead plates 8 and 8 is cut off, so that further charging of the power generator 1 is stopped.
[0024]
As described above, when the exterior body 2 expands due to an increase in internal pressure and is displaced upward, the actuating member 9 is also displaced upward, and when displaced by a predetermined amount or more, the element 7 is projected by the protrusion 9a at the other end of the actuating member 9. Is provided in the exterior body seal portion 4 so that the space can be incorporated into the exterior body seal portion 4 to make it compact and the plate-shaped (or button-shaped) battery can be made compact. Take advantage of thinness.
[0025]
It should be noted that at least one end of the actuating member 9 is positioned on the upper surface or the lower surface of the power generator 1 and the other end is positioned in the vicinity of the exterior body seal portion 4 so as to be displaced outward as the internal pressure increases.
[0026]
The blocking portion 6 is in the direction of the upper surface or the lower surface of the exterior body seal portion 4, one end of which is electrically connected to at least one of the takeout terminals 3, and the other end is electrically connected to the external electrode. When the body 2 expands by a predetermined amount or more due to an increase in internal pressure, the electrical connection between the extraction terminal 3 and the external electrode may be cut off by the displacement of the operation member 9.
[0027]
Next, another embodiment of the present invention will be described with reference to FIG.
[0028]
5 (a) and 5 (b) are explanatory views showing states before and after operation of a battery having a pressure-sensitive current interrupting mechanism according to another embodiment of the present invention. The same parts as those in the embodiment shown in FIG. 1 or parts that can be regarded as the same parts are denoted by the same reference numerals, and detailed description thereof is omitted.
[0029]
The other embodiment is different from the embodiment shown in FIGS. 1 to 4 in that it further includes an outer case 10 having higher rigidity than the exterior body.
[0030]
As shown in FIGS. 5A and 5B, the outer case 10 is formed so as to enclose the exterior body 2 and the exterior body seal portion 4, and operates from the upper surface (or side surface) of the outer case 10. A displacement restricting portion 11 is provided at a position facing one end of the member 9.
[0031]
The actuating member 9 is set to have a longer right end than the actuating member of the embodiment shown in FIG. In addition, there is a gap above the upper surface of the exterior body 2, the exterior body 2 expands, and the other end side of the operating member 9 can be displaced upward.
[0032]
Next, the operation will be described.
[0033]
As described above, when the exterior body 2 expands due to an increase in internal pressure, one end side of the operating member 9 on the upper surface of the exterior body 2 is also displaced upward. At this time, in another embodiment, as shown in FIG. 5A, the displacement restricting portion 11 can suppress the upward displacement of one end of the operating member 9. For this reason, the actuating member 9 has one end whose displacement is suppressed by the displacement restricting portion 11 as a fulcrum and the other end on the blocking portion 5 side as an action point, and a power point (expanded by an increase in internal pressure) between the fulcrum and the action point. 5), the amount of displacement at the force point, that is, the amount of expansion of the exterior body 2 is set as shown in FIG. 5 (b). The other end of the actuating member 9 can be displaced by being enlarged, and even when the amount of expansion of the exterior body 2 is minute, it can be detected.
[0034]
In each of the above embodiments, the outer package 2 is wrapped with a thin film laminate outer seal on a plate-shaped battery, and its mouth is sealed by heat welding or the like, which is the heat welded portion (top seal portion). Although the pressure sensitive current cutoff mechanism such as the cutoff portion 6 is incorporated in the exterior body seal portion 4, the present invention is not limited to a plate-shaped battery, and for example, even if it is a button battery, an exterior body seal portion is provided. Applicable.
[0035]
【The invention's effect】
According to the present invention, one end of the operating member is positioned on the upper surface or the lower surface of the power generator, and the operating member is displaced outward by detecting the displacement of the internal pressure of the upper surface portion or the lower surface portion of the exterior body. It is possible to detect the displacement due to the expansion of the substrate more efficiently, and to effectively cut off the electrical connection between the extraction terminal and the external electrode.
[0036]
According to the present invention, the blocking portion is held by the holding member fixed to the exterior body seal portion, held by the holding member, has brittleness, one end is electrically connected to at least one of the takeout terminals, and the other An element having a conductive path whose end is electrically connected to an external electrode, and the other end of the operating member is located on the exterior body seal portion side of the element, and when one end of the operating member is displaced by internal pressure, Accordingly, the other end of the actuating member is also displaced, and when the element is displaced by a predetermined amount or more, the element is shut off by the other end of the actuating member.
[0037]
According to the present invention, the outer case further includes an outer case that is more rigid than the outer case, and the outer case further includes a displacement restricting portion that suppresses displacement of one end of the operating member due to expansion due to an increase in internal pressure. Even small displacements can be detected and can be made thinner.
[Brief description of the drawings]
FIG. 1 is a perspective view of a battery having a pressure-sensitive current interrupting mechanism according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram showing a concept of a battery having a pressure-sensitive current interrupting mechanism according to an embodiment of the present invention.
FIGS. 3A and 3B are a left side view and a front view showing a state before the operation of the pressure-sensitive current interrupting mechanism.
FIGS. 4A and 4B are a left side view and a front view showing a state after the operation of the pressure-sensitive current interruption mechanism, respectively.
FIGS. 5A and 5B are explanatory views showing states before and after operation of a battery having a pressure-sensitive current interrupting mechanism according to another embodiment of the present invention. FIGS.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Electric power generation body 2 Exterior body 3 Extraction terminal 4 Exterior body seal part 5 Blocking part 6 Holding member 7 Element 8 Lead plate 9 Actuating member 9a Protrusion part 10 Outer case 11 Displacement regulation part

Claims (3)

A plate-shaped power generator,
An exterior body containing the power generation body, airtight, and deformable by internal pressure;
A plurality of extraction terminals serving as electric paths from the power generation body to the exterior of the exterior body;
An exterior body seal portion that is located in the direction of the end face of the power generation body and is thinner than the thickness of the part in which the power generation body is incorporated, and forms a part of the exterior body;
In the outside of the outer body, at least one end upper surface or lower surface of the power generating body, and the other end positioned in the vicinity of the outer body seal section, together to an increase in the internal pressure of the upper surface portion or the lower surface portion of said outer body an actuating member which is displaced outwardly by detecting the name cormorants displacement,
One end is electrically connected to at least one of the take-out terminals and the other end is electrically connected to an external electrode in the direction of the upper surface or the lower surface of the exterior body seal portion. A battery having a pressure-sensitive current interrupting mechanism, comprising: a shut-off part that shuts off an electrical connection between the take-out terminal and the external electrode when the operation member is expanded by a predetermined amount or more. In Claim 1, The said interruption | blocking part is
A holding member fixed to the exterior body seal part;
An element having a conductive path that is held by the holding member, has brittleness, has one end electrically connected to at least one of the extraction terminals, and the other end electrically connected to an external electrode. ,
The other end of the operating member is located on the exterior body seal part side of the element, and when one end of the operating member is displaced by internal pressure, the other end of the operating member is also displaced accordingly, and when displaced by a predetermined amount or more, A battery having a pressure-sensitive current interrupting mechanism, wherein the element is interrupted by the other end of the operating member. The outer case according to claim 1, further comprising a rigid outer case than the exterior body,
The battery having a pressure-sensitive current interrupting mechanism, wherein the outer case further includes a displacement restricting portion that suppresses displacement of the other end of the operating member accompanying expansion due to an increase in internal pressure.

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