JP2003086171A - Secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a secondary battery in which a plurality of leads are drawn out of the positive and negative electrodes of a rolled electrode body contained in a battery can to enable electric power generated by the rolled electrode body to be taken out of a pair of electrode terminal parts via the leads, the secondary battery having a current-path interrupting mechanism which does not limit current values during charge and discharge. SOLUTION: In the secondary battery, the plurality of leads 3 are connected to the electrode terminal parts via a connection device 5. The connection device 5 has the current-path interrupting mechanism which forms a current path between the plurality of leads 3 and the electrode terminal parts, and which interrupts the current path when pressure exceeding a certain value is applied to its input parts. A shaft member 6 which expands axially as temperature rises is disposed at the center of the rolled electrode body 2, with the ends of the shaft member 6 opposed to the input of the current-path interrupting mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery in which an electrode body serving as a power generating element is housed in a battery can and electric power generated by the electrode body can be extracted to the outside.
The present invention relates to a secondary battery including a current path cutoff mechanism that cuts off a current path when a temperature rise exceeding a predetermined value occurs.

[0002]

2. Description of the Related Art Heretofore, a secondary battery has been proposed in which a temperature fuse (heat sensitive element) is provided inside a sealed battery can to shut off a current path when a temperature rise exceeding a predetermined value occurs. JP-A-6-203827). In the secondary battery,
One end of the thermal fuse is connected to the positive electrode of the electrode body via the lead, and the other end of the thermal fuse is connected to the positive electrode terminal via the lead. Therefore, if the temperature of the battery exceeds a predetermined value for some reason, the thermal fuse is blown, thereby interrupting the current path between the lead and the positive electrode terminal, and forcibly stopping the subsequent charging / discharging.

[0003]

However, in the current path breaking mechanism using the thermal fuse, since the thermal fuse itself forms an energizing path, the capacity of the thermal fuse causes the secondary battery to charge and discharge. There was a problem that the current value was limited.

Therefore, an object of the present invention is to provide a secondary battery having a current path cutoff mechanism in which the current value during charging / discharging is not limited.

[0005]

In the secondary battery according to the present invention, one or a plurality of leads are respectively drawn from the positive electrode and the negative electrode of the winding electrode body housed inside the battery can. The electric power generated by the winding electrode body can be taken out from the pair of electrode terminal portions to the outside through the lead. One or a plurality of leads drawn from at least one of the positive electrode and the negative electrode is connected to an electrode terminal portion via a connecting device, and the connecting device is
The current path is formed between the one or more leads and the electrode terminal section, and the input section is provided with a current path cutoff mechanism that cuts off the current path when a pressing force exceeding a certain value is received. At the winding center of the winding electrode body, a shaft member that extends in the axial direction as the temperature rises is provided, and an end portion of the shaft member protrudes from the winding electrode body to input the current path cutoff mechanism. Is facing.

In the secondary battery of the present invention, the current path formed in the connecting device is closed at normal charge / discharge temperature, and charge / discharge is performed through the current path.
When the temperature inside the battery can rises for some reason, the shaft member extends in the axial direction as the temperature rises. Here, since the end portion of the shaft member faces the input portion of the current path breaking mechanism, the input portion of the current path breaking mechanism exceeds a certain value from the end portion of the shaft member due to the extension of the shaft member. Receive pressing force. This activates the current path breaking mechanism. As a result, the current path between one or a plurality of leads and the electrode terminal portion is cut off, and the charge / discharge is forcibly stopped. Since the shaft member is arranged at the winding center of the winding electrode body, the shaft member senses the temperature of the central portion of the winding electrode body where the temperature rise in the battery can is the largest.

In a specific configuration, the shaft member includes a solid or hollow shaft body, and expands in the axial direction by thermal expansion of the shaft body. In this specific configuration, when the temperature inside the battery can rises for some reason, the shaft body of the shaft member expands in the axial direction due to thermal expansion, and the end portion of the shaft member is displaced toward the current path interruption mechanism side. As a result, the current path cutoff mechanism receives a pressing force exceeding a certain value from the end of the shaft member with respect to the input section, and cuts off the current path.

In another specific configuration, the shaft member is
The spring body includes a plurality of shaft bodies and a spring body interposed between the shaft bodies. The spring body is formed of a shape memory alloy and expands when a temperature higher than a normal charge / discharge temperature is reached. In the specific configuration, when the temperature inside the battery can reaches a temperature higher than the normal charge / discharge temperature for some reason, the spring body is extended, whereby the distance between the plurality of shaft bodies is increased. The size of the shaft member is increased, and the end of the shaft member is displaced toward the current path interruption mechanism. As a result, the current path cutoff mechanism is
A pressing force exceeding a certain value is applied to the input portion from the end portion of the shaft member to interrupt the current path.

In yet another specific configuration, the shaft member is expandable and contractable in the axial direction and has a sealed space inside,
The closed space is filled with a gas that expands as the temperature rises. In the specific configuration, when the temperature inside the battery can rises for some reason, the gas filled in the sealed space of the shaft member expands, whereby the shaft member expands in the axial direction and the shaft member The end is displaced toward the current path cutoff mechanism. As a result, the current path cutoff mechanism receives a pressing force exceeding a certain value from the end of the shaft member with respect to the input section, and cuts off the current path.

In yet another specific configuration, the shaft member is expandable and contractable in the axial direction and has a sealed space inside,
The closed space is filled with a liquid or solid that is vaporized as the temperature rises. In this specific configuration, when the temperature inside the battery can rises for some reason, the liquid or solid enclosed in the sealed space of the shaft member vaporizes, and the internal pressure of the sealed space rises, which causes the shaft member to rise. Extends in the axial direction, and the end of the shaft member is displaced toward the current path interruption mechanism side. As a result, the current path cutoff mechanism receives a pressing force exceeding a certain value from the end of the shaft member with respect to the input section, and cuts off the current path.

In still another specific configuration, when the shaft member reaches a temperature higher than a normal charge / discharge temperature, it is possible to press the input portion of the current path interrupting mechanism to interrupt the current path. Extend to a certain length. In the specific configuration, when the temperature inside the battery can reaches a temperature higher than the normal charge / discharge temperature for some reason,
The shaft member extends. As a result, the current path cutoff mechanism receives a pressing force exceeding a certain value from the end of the shaft member with respect to the input section, and cuts off the current path.

[0012]

According to the secondary battery of the present invention, the current path is formed separately from the structure of the current path cutoff mechanism.
The cross-sectional area of the current path can be increased regardless of the configuration of the current path cutoff mechanism. Therefore, the current value during charging / discharging is not restricted.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments in which the present invention is applied to a lithium secondary battery will be specifically described below with reference to the drawings. [First Embodiment] As shown in FIG. 1, a lithium secondary battery of this embodiment is a cylindrical battery can in which lids (11) and (11) are welded and fixed to both ends of a cylinder (12). Winding electrode body inside (1)
It is configured to accommodate (2). The positive electrode terminal (40) is attached to one lid body (11), and the winding electrode body (2) is attached.
A plurality of leads (3) extending from the positive electrode are connected to the positive electrode terminal (40) through a connecting device (5). The other lid (1
A negative electrode terminal (47) is attached to 1), and a plurality of leads (3) extending from the negative electrode of the winding electrode body (2) are connected to the negative electrode terminal (47) via a coupling device (5). ing. This makes it possible to take out the electric power generated by the winding electrode body (2) from the pair of electrode terminals (40) and (47) to the outside. Further, each lid (11) has two gas discharge valves (15) which are broken when the internal pressure of the battery can (1) exceeds a predetermined pressure.
(15) is installed. Note that, in FIG. 1, for convenience, only a state in which the tips of some of the leads (3) are connected to the coupling devices (5) and (5) is shown, and the tips of the other leads (3) are shown. Is not shown in the state of being connected to the connecting devices (5) and (5).

The winding electrode body (2) is, as shown in FIG.
A strip-shaped separator (22) is interposed between the strip-shaped positive electrode (21) and the strip-shaped negative electrode (23) to form a solid shaft member made of fluororesin.
(6) is wound in a spiral shape. Positive (21)
Is formed by applying a positive electrode active material (24) made of a lithium composite oxide on both sides of a strip-shaped core made of aluminum foil, and the negative electrode (23) is made of a carbon material on both sides of the strip-shaped core made of copper foil. The negative electrode active material (25) containing it is applied and constituted.
In addition, the positive electrode (21) has a non-coated portion on which the positive electrode active material (24) is not applied, and a plurality of leads are provided on the non-coated portion.
The base end of (3) is welded. Similarly, for the negative electrode (23),
A non-coated portion not coated with the negative electrode active material (25) is formed, and the base end portions of the leads (3) are welded to the non-coated portion.

The positive electrode terminal is composed of a screw member attached through the lid body (11) of the battery can (1) as shown in FIG.
A flange portion (45) is formed at the base end portion of the positive electrode terminal (40).
An insulating member (43) made of resin is attached to the through hole of the lid body (11) to maintain the electrical insulation and sealing property between the lid body (11) and the positive electrode terminal (40). A washer (42) is fitted to the positive electrode terminal (40) from the outside of the battery can (1), and a nut (41) is attached.
Are screwed together, tighten the nut (41), and
By sealing the insulating member (43) by the collar portion (45) of the (40) and the washer (42), the sealing performance is improved. Negative terminal
(47) is the same as the positive electrode terminal (40), the other lid (1
It is attached to 1).

Since the connecting devices (5) and (5) have the same structure as the connecting devices (5) and (5) on the positive electrode side and the negative electrode side, respectively, the connecting device (5) on the positive electrode side will be described. The coupling device (5) on the positive electrode side includes a pair of claw members (51) (51) screwed to the end surface (44) of the positive electrode terminal (40) and the pair of claw members (51) (51). A disk-shaped current collecting member (50) locked by the tip portion, and the shaft member
A U-shaped pressing member that is screwed to the end surface (61) of (6) and faces the back surface of the current collecting member (50) with a slight gap.
It is composed of (7) and. The claw members (51) (51) and the pressing member (7) are made of fluororesin and are elastically deformable. The current collecting member (50) is formed by using an aluminum plate, and the current collecting member that constitutes the connection device on the negative electrode side is formed by using a copper plate. A pair of through holes (53) (53) are formed in the center of the current collecting member (50), and the tip ends of the pair of claw members (51) (51) are through holes (53) (53). Is engaged with the opening edge of the. As a result, the surface of the current collecting member (50) is in pressure contact with the end surface (44) of the positive electrode terminal (40). Further, the tips of the plurality of leads (3) are welded to the back surface of the current collecting member (50). As a result, from the tips of the plurality of leads (3), through the current collecting member (50), to the end surface of the positive electrode terminal (40).
A current path leading to (44) is formed. Incidentally, the current collecting member
The contact area between the surface of (50) and the end surface (44) of the positive electrode terminal (40) is
The current value at the time of charging / discharging is formed so that it can be energized. Here, the current collecting member (50) is pulled toward the winding electrode body by one or more of the plurality of leads (3). Further, the pair of claw members (51) (51) and the pressing member (7) constitute a current path breaking mechanism. Here, the pressing member (7) serves as an input unit to receive the pressing force for breaking the current path.

Next, a method for manufacturing the above lithium secondary battery will be described.
explain about.Fabrication of positive electrode First, lithium cobalt oxide (LiCoO_Two) Powder and carbon
Conductive agent consisting of powder and polyvinylidene fluoride (PVd
90% to 5% by weight of a binder consisting of F)
And mixed to prepare a positive electrode mixture. Then this positive
Slurry by adding N-methyl-2-pyrrolidone to the electrode mixture
And apply it to aluminum foil,
After vacuum drying for a period of time, a positive electrode (21) as shown in Fig. 2 is prepared.
To make. In addition, the non-coated part is made of multiple aluminum.
Weld the lead (3).Fabrication of negative electrode First, natural graphite powder and polyvinylidene fluoride (PV
90% by weight ratio with a binder consisting of dF)
To prepare a negative electrode mixture. Next, this negative electrode mixture
N-methyl-2-pyrrolidone was added to
Then, apply this to copper foil and vacuum dry at 150 ° C for 2 hours.
Then, a negative electrode (23) as shown in FIG. 2 is produced. Also, non
Weld multiple nickel leads (3) to the coating section.
It

[0018]Fabrication of winding electrode body The positive electrode (21) obtained by the step of producing the positive electrode,
Between the negative electrode (23) obtained by the manufacturing process of the negative electrode,
A separator (22) consisting of a polyethylene microporous thin film
These are put on top of each other and sandwiched. However, the positive electrode (21)
The negative electrode (23) and the negative electrode (23)
Position (3) in the opposite orientation. Positive superimposed
The pole (21), the separator (22), the negative electrode (23), the shaft member (6)
Winding electrode body in a spiral shape as a winding shaft
(2) is prepared. After that, both end surfaces (61) (62) of the shaft member (6)
The pressing members (7) and (7) are screwed to the.Preparation of electrolyte Volume of ethylene carbonate and diethyl carbonate
A mixed solvent is prepared by mixing at a ratio of 1: 1. this
1 mol / liter of lithium hexafluorophosphate in mixed solvent
To prepare an electrolytic solution.

[0019]Production of current collector The current collector (50) on the positive electrode side is not made of an aluminum disc.
A pair of through-holes (53) (53) at the center of the disc.
A current collecting member (50) is produced. The current collector on the negative electrode side is a copper circle.
It consists of a plate, and a pair of through holes is opened in the center of the disk.
A current collecting member is produced.Battery assembly First, as shown in FIG. 1, it is attached to one lid (11).
On the end face (44) of the positive electrode terminal (40)
Screw 1). Also, attached to the other lid (11)
Also, screw a pair of claw members to the end face of the negative electrode terminal (47).
To Next, extending from the positive electrode of the winding electrode body (2)
Connect the tip of multiple leads (3) to the positive side
It welds to the back surface of the current collecting member (50) which comprises (5). With this
Similarly, it extends from the negative electrode of the winding electrode body (2).
Connect the tips of the leads (3) to the connecting device (5) on the negative electrode side.
Is welded to the back surface of the current collecting member. After that, the cylinder (1
The winding electrode body (2) is housed inside 2) and the positive electrode terminal (40)
Tip of a pair of claw members (51) (51) screwed to the end face (44) of the
Part is pushed into the through holes (53) (53) of the positive electrode side current collecting member (50).
Only the tip of both claw members (51) (51) should open through holes (53) (53).
Engage with the rim. Similarly to this, the negative terminal (47)
Attach the tips of the pair of claw members screwed to the end faces to the negative electrode side.
Push into the through hole of the electric member (50) and engage with the opening edge of the through hole
Excuse me. Next, attach the gas discharge valves (15) and (15) to each lid (11).
Attach and weld one lid (11) to the opening edge of the cylinder (12)
Then, pour the electrolyte into the tube (12) through the other opening of the tube (12).
To enter. Finally, weld the lid (11) to the opening edge of the cylinder (12).
The lithium secondary battery of this example is completed.

In the lithium secondary battery according to the present invention, as shown in FIG. 1, the surface of the current collecting member (50) (50) of each pole is the end face (44) of each pole terminal (40) (47). It is pressed against (48) to form a current path between the lead (3) and the electrode terminals (40) and (47). As a result, charging / discharging is possible at normal operating temperatures. When the temperature inside the battery can (1) rises for some reason, the shaft member (6) thermally expands as the temperature of the winding electrode body (2) rises. By this, the shaft member
(6) extends in the axial direction. For this reason, the U-shaped pressing member (7) attached to the positive end surface (61) of the shaft member (6) moves toward the back surface of the current collecting member (50), Both ends of the pressing member (7) are pressed against the back surface of the current collecting member (50) with a force exceeding a certain value. As a result, FIG.
As shown in FIG. 5, the U-shaped pressing member (7) is deformed at the both ends in the expanding direction, and the both ends of the pressing member (7) have a pair of claw members (51).
Push (51) to expand. As a result, the tips of the claw members (51) (51) are disengaged from the opening edges of the through holes (53) (53) of the current collecting member (50). At this time, since the current collecting member (50) is pulled toward the winding electrode body (2) by the at least one lead (3), the current collecting member (50) is fixed to the winding electrode body (2). Move towards. As a result, the surface of the current collecting member (50) and the end surface (44) of the positive electrode terminal (40) are separated from each other, and as a result, the current path between the plurality of leads (3) and the positive electrode terminal (40) is cut off. To be done. The connecting device (5) on the negative electrode side has the same configuration as the connecting device (5) on the positive electrode side. Therefore, the current path between the negative electrode terminal (47) and the plurality of negative electrode leads (3) is cut off similarly to the current path between the positive electrode terminal (40) and the plurality of positive electrode leads (3). . As a result, the subsequent charge / discharge is forcibly stopped. At the time of the temperature rise, the shaft member (6) has a winding electrode body.
Since it is arranged at the winding center of (2), the shaft member
(6) senses the center temperature of the winding electrode body (2) which becomes the highest when the temperature inside the battery can (1) rises, and activates the current path breaking mechanism. In addition, a current path cutoff mechanism composed of a pair of claw members (51) (51) and a pressing member (7), current collecting members (50) (50) and end faces of the pole terminals (40) (47) ( Since it has a different structure from the current path formed by the contact with (44) and (48), the cross-sectional area of the current path can be determined according to the magnitude of the current value during charging and discharging. Therefore, the current value during charging / discharging is not restricted by the configuration of the current path cutoff mechanism.

[Second Embodiment] As shown in FIG. 4, a lithium secondary battery of the present embodiment has a shaft member (8) made of two fluororesin shaft bodies (80) and (80) and a spring body. The spring body (81) is sandwiched between the two shaft bodies (80) and (80). The spring body (81) is made of a shape memory alloy,
When the temperature inside the battery can exceeds the upper limit of the normal charge / discharge temperature, the battery can expands in the axial direction. In the lithium secondary battery of this embodiment, a winding electrode body is manufactured by using the shaft member (8) as a winding shaft, and assembled in the same manner as the lithium secondary battery of the first embodiment.

In the lithium ion secondary battery of this embodiment, when the temperature inside the battery can exceeds the upper limit of the normal charge / discharge temperature for some reason, the spring body (81) made of a shape memory alloy expands. . Therefore, the two shaft bodies (80) (80) sandwiching the spring body (81) are separated from each other in the axial direction. Thereby, the pressing members (7) (7) installed on the end faces (83) (84) of the shaft member (8)
Is a force that the tip of the pair exceeds a certain value.
0) When pressed against the back surface of (50), the pair of tip portions are deformed in the direction in which they separate from each other. As a result, similar to the lithium secondary battery of the first embodiment, the current path is cut off and charge / discharge is forcibly stopped.

[Third Embodiment] As shown in FIG. 5, in the lithium secondary battery of the present embodiment, the shaft member (9) is a hollow cylindrical body (90) made of fluororesin, and the cylindrical body (90). It is composed of two caps (91) (91) made of fluorocarbon resin that seal both openings of the shaft member (9).
4) is filled. The lithium secondary battery of this example is
A winding electrode body was produced using the shaft member (9) as a winding shaft, and the sealed space of the shaft member (9) was filled with argon gas (94). And assemble.

In the lithium secondary battery of this embodiment,
If the temperature inside the battery can rises for any reason,
Argon gas (9) filled in the closed space of the shaft member (9)
4) expands. For this reason, the caps (91) (91) at both ends of the shaft member (9) are pushed outward. As a result, the pressing member installed on the end surface (92) (93) of the shaft member (9)
(7) The pair of tips of (7) should be in contact with the back surface of the current collecting member (50) (50) and be pressed against the back surface of the current collecting member (50) (50) with a force exceeding a certain value. Thus, the pair of tip portions are deformed in the direction in which they are separated from each other. As a result, similarly to the lithium secondary battery of the first embodiment, the current path formed by the connecting mechanism is cut off, and charge / discharge is forcibly stopped.

[Fourth Embodiment] As shown in FIG. 6, the lithium secondary battery of the present embodiment has the same structure of the shaft member as the lithium secondary battery of the third embodiment. However, diisopropyl ether (95) is enclosed in the closed space of the shaft member (9). In the lithium secondary battery of the present embodiment, a winding electrode body was produced using the shaft member (9) as a winding shaft,
After diisopropyl ether (95) is sealed in the sealed space of (9), the lithium secondary battery of the first embodiment is assembled.

In the lithium ion secondary battery of this embodiment, when the temperature inside the battery can rises for some reason, the diisopropyl ether (95) enclosed in the closed space of the shaft member (9) evaporates, As a result, the internal pressure in the closed space increases. For this reason, the caps (91) (91) at both ends of the shaft member (9) are pushed outward. As a result, the pair of tips of the pressing members (7) and (7) installed on the end faces (92) and (93) of the shaft member (9) come into contact with the back surfaces of the current collecting members (50) and (50), Power collecting member (50) (50) with a force exceeding a certain value
By being pressed against the back surface of the pair, the pair of tip portions are deformed so as to be separated from each other. As a result, similarly to the lithium secondary battery of the first embodiment, the current path formed by the connecting mechanism is cut off, and charge / discharge is forcibly stopped.

In order to confirm the interruption of the current path of the secondary battery according to the present invention, the following invention batteries 1 to 4 were manufactured and tested. Inventive battery 1 was produced in the same manner as in the first embodiment. Inventive battery 2 was manufactured using a spring body made of a shape memory alloy having a shape change temperature of 50 ° C. in the same manner as in the second embodiment. The invention battery 3 is the third battery described above.
It was manufactured in the same manner as in the example. The invention battery 4 is the fourth battery described above.
It was manufactured in the same manner as in the example.

First, in order to measure the charge / discharge characteristics of each battery, the battery was charged to 4.2 V with a charging current value of 10 A and then discharged to 2.7 V with a discharging current value of 10 A.
The charge and discharge characteristics of each battery are as follows: discharge capacity is 80Ah, average discharge voltage is 3.6V, and discharge power capacity is 288W.
It was h. [Experiment] Each battery has a charging current value of 10 A and 4.2 V
After charging up to, the discharge current value was set to 10 A and the charging / discharging cycle of discharging to 2.7 V was repeated. However, the charging current value was increased by 5 A for each cycle. Table 1 shows the charging current value when the current path is interrupted during charging.

[0029]

[Table 1]

The current path of each battery was interrupted during charging with the charging current value shown in Table 1.

The configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims. For example, as the configuration of the coupling device,
Not limited to the configuration of the above embodiment, various configurations capable of receiving a pressing force of a certain value or more and interrupting the current path can be adopted. Further, the material of the shaft member (6) shown in FIG. 1 is not limited to fluororesin, and various materials having a required coefficient of thermal expansion can be adopted. Where the shaft member
When a metal is used as the material of (6), in order to prevent a short circuit between both electrodes, the surface is covered with a fluororesin, or the shaft member is divided into two and an insulator is interposed between them. The structure can be adopted.

Further, the gas filled in the closed space of the shaft member (9) shown in FIG. 5 is not limited to argon gas, but various gases having a required coefficient of thermal expansion can be adopted. Furthermore, the gas generating substance sealed in the closed space of the shaft member (9) shown in FIG. 6 is not limited to diisopropyl ether, and any substance that is vaporized by a temperature rise, either liquid or solid, can be adopted. Also, the substance to be enclosed is 1
There is no limitation on the type, and it is also possible to enclose a plurality of substances and generate a gas by a chemical reaction accompanying a temperature rise.

Further, in each of the examples, the winding electrode body was manufactured by using the shaft member as the winding shaft, but the winding electrode body was manufactured by using the conventional winding shaft, and the winding shaft was wound. It is also possible to employ a step of inserting the shaft member according to the present invention into the space formed in the central portion of the winding electrode body after the shaft member is extracted from the electrode body.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a lithium secondary battery according to the present invention.

FIG. 2 is a partially exploded perspective view of a winding electrode body used in the secondary battery.

FIG. 3 is a cross-sectional view showing a state in which a current path of the secondary battery is cut off.

FIG. 4 is a cross-sectional view of another lithium secondary battery according to the present invention.

FIG. 5 is a cross-sectional view of still another lithium secondary battery according to the present invention.

FIG. 6 is a cross-sectional view of still another lithium secondary battery according to the present invention.

[Explanation of symbols]

(1) Battery can (2) Winding electrode body (3) Lead (40) Positive terminal (47) Negative electrode terminal (5) Connection device (50) Current collector (51) Claw member (6) Shaft member (7) Pressing member (8) Shaft member (81) Spring body (9) Shaft member (90) Cylindrical body (91) Cap (94) Argon gas (95) Diisopropyl ether

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideo Hagino             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Toshiyuki Noma             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. (72) Inventor Ikuro Ikuro             2-5-3 Keihan Hondori, Moriguchi City, Osaka Prefecture             Within Yo Denki Co., Ltd. F term (reference) 5H022 AA09 CC08 CC12 CC16 KK01                 5H028 AA05 CC05 CC12                 5H029 AJ12 AK03 AL07 DJ05

Claims (6)

[Claims] 1. One or a plurality of leads are drawn from a positive electrode and a negative electrode of a winding electrode body housed inside a battery can, respectively, and electric power generated by the winding electrode body is
In a secondary battery that can be taken out from the pair of electrode terminal portions via the lead, of the positive electrode and the negative electrode,
One or a plurality of leads drawn out from at least one of the electrodes is connected to an electrode terminal portion via a connecting device, and the connecting device is provided between the one or a plurality of leads and the electrode terminal portion. In addition to forming a current path, the input section is provided with a current path cutoff mechanism that cuts off the current path when it receives a pressing force exceeding a certain value. A secondary battery in which a shaft member extending in a direction is provided, and an end portion of the shaft member projects from the winding electrode body and faces the input portion of the current path cutoff mechanism. 2. The secondary battery according to claim 1, wherein the shaft member includes a solid or hollow shaft body, and expands in the axial direction by thermal expansion of the shaft body. 3. The shaft member comprises a plurality of shaft bodies and a spring body interposed between the shaft bodies, the spring body being formed of a shape memory alloy and having a temperature higher than a normal charge / discharge temperature. The secondary battery according to claim 1, which expands when reaching a temperature. 4. The shaft member is capable of expanding and contracting in the axial direction and has a hermetically sealed space therein, and the hermetically sealed space is filled with a gas that expands as the temperature rises. Secondary battery. 5. The shaft member is capable of expanding and contracting in the axial direction and has a hermetically sealed space therein, and the hermetically sealed space is filled with a liquid or a solid that vaporizes with a rise in temperature. The secondary battery according to. 6. The shaft member extends to a length capable of pressing the input portion of the current path cutoff mechanism to cut off the current path when it reaches a temperature higher than a normal charge / discharge temperature. Item 6. The secondary battery according to any one of items 1 to 5.