JP2008027668A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a current interruption mechanism that has high safety even though having a simple configuration, and to provide a battery using the same. <P>SOLUTION: The battery is manufactured by using the current interruption mechanism that is composed of an insulating sealing gasket which has a disk provided with a hole, and an insulating sealer erected at the outer peripheral edge of the disk, and in which the disk is provided between a pressure-sensitive valve and a power-generating element; and the pressure-sensitive valve that is composed so as to be deformed in an internal-pressure direction when the battery internal pressure rises. The pressure-sensitive valve and an electrode terminal provided in the power-generating element are electrically connected with each other via the hole of the disk. The electrode terminal is arranged while having a flexure in a space between the power-generating element and the disk of the insulating sealing gasket. At least either of the flexure and the terminal end of the electrode terminal is arranged outside the hole of the disk. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a battery that cuts off current in the battery when the internal pressure of the battery increases.

  In recent years, with the remarkable development of portable electronic technology, electronic devices such as mobile phones, notebook personal computers, and PDAs (Personal Digital Assistants) have been recognized as fundamental technologies that support an advanced information society. It was. Furthermore, research and development related to the enhancement of the functionality of these devices is being pursued energetically, and the power consumption of electronic devices is steadily increasing in proportion thereto. On the other hand, these electronic devices are required to be driven for a long time, and it has been desired to increase the energy density of the secondary battery, which is a driving power source.

  From the viewpoint of the occupied volume and weight of the battery built in the electronic device, the higher the energy density of the battery, the better. Therefore, in order to meet this demand, batteries using lithium (Li) as an electrode reactant, for example, lithium / manganese dioxide batteries, lithium / iron sulfide batteries, and lithium ion batteries have been proposed. These batteries have a winding structure in which a positive electrode and a negative electrode are stacked via a separator and wound in a spiral shape, thereby exhibiting high storage characteristics, low temperature characteristics, load characteristics, and the like.

  On the other hand, the temperature in the battery rises when a large current flows due to overcharging or misuse. Since these batteries use a non-aqueous solvent as an electrolytic solution, there is a risk of thermal runaway when the temperature in the battery rises. In addition, gas may be generated and the battery internal pressure may increase.

  Therefore, in order to deal with such a problem, as in Patent Document 1 below, when the temperature in the battery rises or when a large current flows, a current interruption mechanism that physically interrupts the circuit in the battery is provided. Provided batteries have been proposed.

Japanese Patent No. 2701375

  Further, as in Patent Document 2 below, there is a battery using a thermal resistance element (Positive Temperature Coefficient; PTC element) that limits the current by increasing the resistance value when the temperature rises, as well as the current interruption mechanism.

JP 2004-031165 A

  In Patent Document 1 and Patent Document 2, as a current interruption mechanism, a pressure-sensitive valve 3 that deforms in the direction of the internal pressure when the battery internal pressure rises as shown in FIG. 1, and the pressure-sensitive valve 3 is provided on the opposite side to the side that causes deformation. In addition, a shut-off disk 7 having a hole 7a at the approximate center and an insulating disk holder 6 provided between the pressure-sensitive valve 3 and the shut-off disk 7 are provided, and an electrode terminal 15 passes through the hole 7a of the shut-off disk 7. It has a configuration connected to the pressure sensitive valve 3.

  The pressure sensitive valve 3 is formed with a protruding portion 3a toward the shut-off disk 7 side, and this protruding portion 3a is located at a portion where the hole portions 6a and 7a of the disc holder 6 and the shut-off disc 7 are overlapped. Is configured to do. Further, the disc holder 6 and the shut-off disc 7 may be provided with gas venting holes 6b and 7b in addition to the holes 6a and 7a provided at substantially the center.

  The battery having the current interruption mechanism as described above is provided with the pressure-sensitive valve 3 on the inner surface of the battery lid 2, and the protrusion 3 a of the pressure-sensitive valve 3 and the electrode terminal 15 led out from the wound electrode body 10 are connected to the disk holder 6 and A ring-shaped insulating sealing gasket in which the battery can 1 containing the wound electrode body 10 and the battery lid 2 are provided inside the open end of the battery can 1 after being connected through the holes 6 a and 7 a of the blocking disk 7. It is produced by caulking through 5.

  2A and 2B show operations before and after current interruption of such a current interruption mechanism of the battery. As shown in FIG. 2B, when the battery internal pressure rises, the current cutoff mechanism configured as shown in FIG. 2A is deformed in the internal pressure direction, and the contact portion with the electrode terminal 15 connected to the pressure sensitive valve 3 is Peeling or breaking of the electrode terminal 15 interrupts the current, and further heat generation and increase in internal pressure are suppressed.

  However, such a current interrupting mechanism uses a large number of parts and has a complicated structure. In addition, since many parts for current interrupting are fitted together, each part must have high dimensional accuracy. Therefore, there is a problem that the manufacturing cost is high, and it is not used in a primary battery.

  Therefore, in view of the above problems, an object of the present invention is to provide a battery having a simple configuration and high safety.

  In order to solve the above-described problems, the present invention includes a power generation element, a battery can, and a current interrupting mechanism. The current interrupting mechanism is a pressure-sensitive valve that is deformed by an increase in the internal pressure of the battery can, and a disk part having a hole. And an insulating sealing portion erected on the outer peripheral edge of the disk portion, and the disk portion includes an insulating sealing gasket provided between the pressure-sensitive valve and the power generation element, and is provided on the pressure-sensitive valve and the power generation element. The electrode terminal is electrically connected through a hole in the disk portion, and the electrode terminal has a bent portion in a space between the power generating element and the disk portion of the insulating sealing gasket, and the bent portion and the terminal end of the electrode terminal. The battery is characterized in that at least one of the batteries is disposed outside the hole of the disk portion.

  In the battery described above, it is preferable that the diameter of the hole in the disk portion is 3 mm or more and 75% or less with respect to the distance between the bent portion and the terminal end of the electrode terminal.

  Further, the tip end folded portion may be provided by folding the tip end portion of the electrode terminal. Also in such a case, it is preferable that the diameter of the hole of the disk portion is 3 mm or more and 75% or less with respect to the distance between the bent portion of the electrode terminal and the tip folded portion.

  In this invention, the electrode terminal is caught by the insulating sealing gasket due to the deformation of the pressure sensitive valve, and the pressure sensitive valve and the electrode terminal are separated, whereby the current can be cut off.

  Further, by adopting a configuration in which the electrode terminal is caught by the insulating sealing gasket, the current interrupting mechanism can be configured with a small number of parts.

  According to the present invention, it is possible to obtain a highly safe battery with a simple configuration.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 3 shows a lithium iron sulfide primary battery 20 which is an example of a nonaqueous electrolyte primary battery according to an embodiment of the present invention. The lithium iron sulfide primary battery 20 shown in FIG. 3 is a so-called cylindrical type, and has a wound electrode body 30 that is a power generation element inside a substantially hollow cylindrical battery can 21. The wound electrode body 30 is formed by winding a strip-shaped positive electrode 31 having a positive electrode active material and a strip-shaped negative electrode 32 having a negative electrode active material through a separator 33 having ion permeability.

  The battery can 21 is made of, for example, iron plated with nickel, and has one end closed and the other end open. Inside the battery can 21, a pair of insulating plates 27 and 28 are arranged perpendicular to the peripheral surface so as to sandwich the wound electrode body 30.

  At the open end of the battery can 21, there is provided a battery lid 22, a heat sensitive resistance element 24 provided inside the battery lid 22, and a current interruption mechanism 26 comprising a pressure sensitive valve 23 and an insulating sealing gasket 25. ing. The current interruption mechanism 26 is configured by attaching the pressure sensitive valve 23 and the heat sensitive resistance element 24 by caulking through an insulating sealing gasket 25, and the inside of the lithium iron sulfide primary battery 20 is sealed.

  The battery lid 22 is configured to have a protrusion 22a that protrudes toward the outside of the battery at a substantially central portion. When the lithium iron sulfide primary battery 20 is used, the protrusion 22a is in contact with the + terminal of the electronic device. The battery lid 22 is made of, for example, the same material as the battery can 21.

  When the temperature rises, the heat sensitive resistance element 24 limits the current by increasing the resistance value and prevents abnormal heat generation due to a large current, and is made of, for example, a barium titanate semiconductor ceramic.

  Hereinafter, the current interrupt mechanism 26 and the positive terminal 35 connected to the current interrupt mechanism 26 will be described in detail with reference to FIGS. 4 and 5. 4 is a cross-sectional view showing the configuration of the open end of the battery can 21, and FIG. 5 is a perspective view of a half of each component provided at the open end of the battery can 21.

  The current interruption mechanism 26 includes a pressure-sensitive valve 23 and an insulating sealing gasket 25 to which a positive electrode terminal 35 led out from the wound electrode body 30 is connected.

  The pressure sensitive valve 23 is made of a conductive metal material or the like, and is electrically connected to the battery lid 22 via, for example, a heat sensitive resistance element 24. The pressure-sensitive valve 23 has a disk shape having a protruding portion 23a whose substantially central portion protrudes toward the wound electrode body 30. The outer surface of the protruding portion 23a is a contact surface to which the positive electrode terminal 35 is connected. It is said that. The protrusion 23 a is configured to be inverted when the internal pressure of the battery becomes a certain level or more due to an internal short circuit or external heating, pressurization, or the like, and can be deformed in the direction of the battery lid 2.

  The insulating sealing gasket 25 is composed of an insulating member in which a side wall portion 25a as an insulating sealing portion is erected on the outer peripheral edge portion of a disk portion 25b made of a ring-shaped member having a hole portion 25c. Has been. Asphalt is applied to at least the surface of the side wall 25a.

  The side wall 25a of the insulating sealing gasket 25 is provided along the inside of the open end of the battery can 21. When the lithium iron sulfide primary battery 20 is produced by crimping the battery lid 22, Insulates the battery lid 22 and seals the lithium iron sulfide primary battery 20 to prevent inflow of moisture and gas from the outside, leakage of the non-aqueous electrolyte in the lithium iron sulfide primary battery 20 and the like. The disk portion 25b is disposed between the pressure-sensitive valve 23 and the wound electrode body 30, and the pressure-sensitive valve 23 and the positive electrode terminal 35 are connected to each other by, for example, resistance welding through the hole portion 25c. When the pressure sensitive valve 23 is deformed at the time of rising, the positive electrode terminal 35 is configured to be caught by the disk portion 25b. In the disk portion 25b, a gas vent hole may be formed around the hole portion 25c.

  As shown in FIGS. 4 and 5, an insulating sealing gasket 25, a pressure-sensitive valve 23, a heat-sensitive resistance element 24, and a battery lid 22 are provided in order from the bottom surface portion toward the open end of the battery can 2. It has been. Further, the protruding portion 23a of the pressure sensitive valve 23 is disposed in the hole portion 25c of the insulating sealing gasket 25, and the protruding portion 23a and the positive electrode terminal 35 are connected through the hole portion 25c.

  The positive electrode terminal 35 is preferably made of a material having a certain degree of rigidity. For example, aluminum (Al) is selected. This is to prevent the positive electrode terminal 35 from being drawn into the hole 25c when the pressure sensitive valve 23 is deformed in the direction of the battery lid 22.

  The positive electrode terminal 35 is disposed so as to approach the battery can 2 after being led out from the spirally wound electrode body 30 through the insulator 28, and a folded portion 35b that is a bent portion that is folded back toward the battery central portion again. The folded portion 35 b and the terminal end 35 a of the electrode terminal 35 are provided so as to be located outside the hole portion 25 c of the insulating sealing gasket 25. As a result, when the pressure sensitive valve 23 is deformed, the folded portion 35b and the terminal end 35a are caught by the disc portion 25b.

  As shown in FIG. 4, the positive electrode terminal 35 is bent at the portion where the positive electrode terminal 35 is connected to the pressure sensitive valve 23 so as to approach the protruding portion 23 a of the pressure sensitive valve 23. Is not limited to such a configuration, and the folded portion 35b to the terminal end 35a may be provided in a substantially straight line.

  When the rigidity of the positive electrode terminal 35 is sufficiently high, either the folded portion 35 b or the terminal end 35 a may be provided so as to be located outside the hole portion 25 c of the insulating sealing gasket 25. This is because the connection portion is released without the positive electrode terminal 35 following the deformation of the pressure sensitive valve 23 only by one of them being caught by the disk portion 25b when the pressure sensitive valve 23 is deformed.

  Here, it is preferable that the diameter of the hole part 25c shown with the referential mark L of FIG. 4 shall be 3 mm or more. When the diameter of the hole portion 25c is less than 3 mm, it is difficult to weld or process the pressure sensitive valve 23 and the positive electrode terminal 35, and connection strength may not be obtained.

  In addition, the diameter L of the hole 25c is preferably 75% or less of the folded length of the positive electrode terminal 35 indicated by the reference symbol 1 in FIG. Here, the folded length is a distance from the folded portion 35b to the terminal end 35a. When the diameter L of the hole portion 25c exceeds 75% of the folding length l of the positive electrode terminal 35, the positive electrode terminal 35 is easily drawn into the hole portion 25c when the battery internal pressure rises, and the connection can be released. There is a risk of disappearing. By setting the diameter of the hole 25c to 75% or less of the folded length of the positive electrode terminal 35, the connection between the pressure sensitive valve 23 and the positive electrode terminal 35 can be reliably released, and the current can be interrupted. .

  Further, as shown in FIG. 6, by providing a tip folded portion 35 c obtained by further folding the tip portion of the positive electrode terminal 35 and connecting it to the pressure sensitive valve 23, it is possible to further prevent the positive terminal 35 from being drawn into the hole portion 25 c. In this case, the length from the front end folding portion 35c to the end 35a is not particularly limited, and a high effect can be obtained by folding back about several mm.

  In the case of the configuration as shown in FIG. 6 as well, as in the case of the configuration as shown in FIG. 4, the diameter of the hole 25 c is preferably 3 mm or more, and 75% or less of the folded length of the positive electrode terminal 35. It is preferable that Note that the folding length of the positive electrode terminal 35 in the case where the tip folding portion 35c is provided as shown in FIG. 6 is the distance from the folding portion 35b to the tip folding portion 35c.

  Moreover, you may comprise so that the width | variety of the positive electrode terminal 35 may become substantially equal or wider than the diameter of the hole 25c. It is also possible to combine the configuration of the positive electrode terminal 35 as described above, and this can more reliably interrupt the current.

  The current interrupt mechanism 26 having the above-described configuration interrupts the current by the following operation.

  In the lithium iron sulfide primary battery 20 provided with such a current interruption mechanism 26, the pressure sensitive valve 23 is deformed in the direction of the battery lid 2 when the battery internal pressure rises, and the connection with the electrode terminal 35 is released, so that the current flows. Blocked. As shown in FIG. 7A, the positive electrode terminal 35 connected to the pressure sensitive valve 23 through the hole 25c is deformed by reversing the pressure sensitive valve 23 in the direction of the battery lid 22 as shown in FIG. .

  At this time, each of the folded portion 35b and the terminal end 35a is caught by the disk portion 25b of the insulating sealing gasket 25, and the connection portion with the positive electrode terminal 35 is peeled without following the deformation of the pressure sensitive valve 23. Thereby, the electric current inside the battery is cut off, and further heat generation and internal pressure increase are suppressed.

  Hereinafter, the wound electrode body 30 will be described.

[Wound electrode body]
A positive electrode terminal 35 made of aluminum or the like is connected to the positive electrode 31 of the spirally wound electrode body 30, and a negative electrode terminal 36 made of nickel or the like is connected to the negative electrode 32. The positive terminal 35 is electrically connected to the battery lid 22 by being welded to the pressure sensitive valve 23. The negative electrode terminal 36 is welded and electrically connected to the battery can 21.

  In addition, the separator 33 between the positive electrode 31 and the negative electrode 32 is impregnated with, for example, a non-aqueous electrolyte as a non-aqueous electrolyte. The separator 33 has a function of preventing physical contact between the positive electrode 31 and the negative electrode 32 by being disposed between the positive electrode 31 and the negative electrode 32. In addition, the separator 33 holds the non-aqueous electrolyte by absorbing the non-aqueous electrolyte and allows lithium ions to pass through during discharge.

[Positive electrode]
The positive electrode 31 includes a positive electrode current collector having a belt-like shape and a positive electrode mixture layer formed on both surfaces of the positive electrode current collector. The positive electrode current collector is a metal foil such as an aluminum (Al) foil, a nickel (Ni) foil, a stainless steel (SUS) foil, or the like.

The positive electrode mixture layer includes, for example, iron disulfide (FeS ₂ ) that is a positive electrode active material, a conductive agent, and a binder. Iron disulfide, which is a positive electrode active material, is obtained by pulverizing pyrite (Pyrite) that exists mainly in nature. Chemical synthesis, for example, ferrous chloride (FeCl ₂ ) is converted to hydrogen sulfide (H ₂ S). Iron disulfide obtained by firing inside can also be used.

  As the binder, for example, polyvinylidene fluoride, polytetrafluoroethylene or the like is used. Further, as the conductive agent, a material that can be mixed with an appropriate amount of the positive electrode active material to impart conductivity, for example, carbon powder such as graphite and carbon black can be used.

[Negative electrode]
The negative electrode 32 is made of a metal foil having a strip shape. Examples of the metal foil material that is also the negative electrode active material include lithium metal or lithium alloy obtained by adding an alloy element such as aluminum to lithium.

[Electrolyte]
The electrolytic solution is a solution in which an electrolyte salt is dissolved in a non-aqueous solvent, and generally used materials can be used.

  Examples of the non-aqueous solvent include propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, γ-butyrolactone, tetrahydrofuran, 2-dimethoxyethane, 1,3-dioxolane, 4-methyl-1,3-dioxolane. , Diethyl ether, sulfolane, methyl sulfolane, acetonitrile or propionitrile, anisole, acetic acid ester, tangled acid ester or propionic acid ester, etc. are preferred, and any one of these or a mixture of two or more may be used. it can.

As the electrolyte salt, one that dissolves in the non-aqueous solvent is used, and a combination of a cation and an anion is used. Alkali metal or alkaline earth metal is used as the cation, and Cl ⁻ , Br ⁻ , I ⁻ , SCN ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ or the like is used as the anion. It is done. Specifically, for example, LiCl, LiClO ₄ , LiAsF ₆ , LiPF ₆ , LiBF ₄ , LiB (C ₆ H ₅ ) ₄ , LiBr, CH ₃ SO ₃ Li, CF ₃ SO ₃ Li, N (CnF _{2n + 1} SO ₂ ) ₂ Li and the like, and any one of these or a mixture of two or more thereof is used. Among them, it is preferable to mainly use LiPF ₆ . The electrolyte salt concentration is not a problem as long as it can be dissolved in the non-aqueous solvent, but the lithium ion concentration is 0.4 mol / kg or more and 2.0 mol / kg or less with respect to the non-aqueous solvent. A range is preferable.

[Separator]
The separator 33 is composed of, for example, a porous film made of a polyolefin-based material such as polypropylene (PP) or polyethylene (PE), or a porous film made of an inorganic material such as a ceramic nonwoven fabric. The porous film may be laminated. Among these, polyethylene and polypropylene porous films are the most effective.

  The thickness of the separator 33 is preferably 5 μm or more and 50 μm or less, and more preferably 7 μm or more and 30 μm or less. If the separator 33 is too thick, the amount of the active material filled is reduced, the battery capacity is reduced, and the ionic conductivity is reduced to deteriorate the current characteristics. On the other hand, if the film is too thin, the mechanical strength of the film decreases.

  The lithium iron sulfide primary battery 20 having the above-described configuration can be manufactured as follows, for example.

[Production of positive electrode]
The above-mentioned positive electrode active material, binder, and conductive agent are uniformly mixed to form a positive electrode mixture, and this positive electrode mixture is dispersed in a solvent such as N-methyl-2-pyrrolidone, and a ball mill, a sand mill is used as necessary. Then, the slurry is made into a slurry using a biaxial kneader or the like. Next, this slurry is uniformly applied to both surfaces of the positive electrode current collector 31b by a doctor blade method or the like. Furthermore, after drying at room temperature or high temperature to drive off the solvent, the positive electrode active material layer 31a is formed by compression molding with a roll press or the like. At this time, the positive electrode active material layer 31a may be formed by attaching a positive electrode mixture formed in a sheet shape to the positive electrode current collector 31b.

  The solvent is not particularly limited as long as it is inert to the electrode material and can dissolve the binder, and any of inorganic solvents and organic solvents can be used.

  The coating apparatus is not particularly limited, and slide coating, extrusion type die coating, reverse roll, gravure, knife coater, kiss coater, micro gravure, rod coater, blade coater and the like can be used. Also, the drying method is not particularly limited, but standing drying, blower dryer, hot air dryer, infrared heater, far infrared heater, and the like can be used.

  A positive electrode terminal 35 is welded to one end of the positive electrode 31 by resistance welding or ultrasonic welding. The positive electrode terminal 35 is preferably welded to a positive electrode current collector exposed portion provided at an end portion of the positive electrode 31.

[Production of negative electrode]
A negative electrode terminal 36 is welded to one end of the negative electrode 32 made of lithium metal or a lithium alloy by resistance welding, ultrasonic welding, pressure bonding, or the like, similarly to the positive electrode 31. The negative electrode terminal 36 is preferably made of a material that does not form an alloy with lithium, such as copper (Cu), iron (Fe), nickel (Ni), or stainless steel (SUS), and copper (Cu) is particularly preferable. . Since lithium and copper have low contact resistance, the internal resistance of the battery can be reduced and the voltage and load characteristics can be improved.

[Production of lithium iron sulfide primary battery]
Next, the positive electrode 31 having the strip shape obtained as described above, the negative electrode 32, and the separator 33 are laminated in the order of, for example, the positive electrode 31, the separator 33, the negative electrode 32, and the separator 33, and a large number in the longitudinal direction. A wound electrode body 30 is produced by winding.

  Next, the wound electrode body 30 is housed in a battery can 21 in which an insulating plate 27 is inserted in advance at the bottom and nickel plating is applied in advance on the inside. Thereafter, the end of the negative electrode terminal 36 is welded to the battery can 21 in order to collect the current of the negative electrode 32. As a result, the battery can 21 is electrically connected to the negative electrode 32 and becomes an external negative electrode.

  Next, the insulating plate 28 is disposed on the upper surface of the wound electrode body 30. Thereafter, in order to collect the current of the positive electrode 31, the end of the positive electrode terminal 35 is connected to the protruding portion 23 a of the pressure-sensitive valve 23 provided on one surface of the battery lid 22 via the heat sensitive resistance element 24. The positive terminal 35 is connected to the protrusion 23 a through the hole 25 c of the insulating sealing gasket 25. As a result, the battery lid 22 is electrically connected to the positive electrode 31 and becomes an external positive electrode.

  Further, after injecting the nonaqueous electrolyte into the battery can 21, the insulating sealing gasket 25 and the pressure sensitive valve 23 are arranged so as to be positioned between the wound electrode body 30 and the pressure sensitive valve 23, and this insulating sealing is provided. The battery cover 22 is caulked through the gasket 25.

  Thus, a cylindrical lithium iron sulfide primary battery with the battery lid 22 fixed is manufactured. Since the lithium iron sulfide primary battery 20 manufactured in this way uses the current interrupt mechanism 26 having a simple configuration, the manufacturing cost is reduced and the safety is high. In addition, the manufacturing process can be simplified because the current interrupt mechanism 26 has few parts. Furthermore, even when the current interrupting component of the present invention that does not require the dimensional accuracy as in the conventional case is used, the current can be interrupted.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples.

  In this example, a lithium iron sulfide primary battery was manufactured by changing the configuration of the current interruption mechanism, and the current interruption state was confirmed.

<Sample 1>
[Production of positive electrode]
Using iron disulfide as the positive electrode active material, graphite as the conductive agent, and polyvinylidene fluoride as the binder, mixing 95% by weight of iron disulfide, 2% by weight of graphite, and 3% by weight of polyvinylidene fluoride, It was sufficiently dispersed in N-methyl-2-pyrrolidone as a solvent to obtain a positive electrode mixture slurry.

  Next, the positive electrode mixture slurry was applied to both surfaces of a positive electrode current collector made of a strip-shaped aluminum foil having a thickness of 20 μm, dried at 120 ° C. for 2 hours to volatilize N-methyl-2-pyrrolidone, A belt-like positive electrode was produced by compression molding at a constant pressure. Furthermore, the positive electrode terminal which consists of aluminum foil was welded to this positive electrode.

[Production of wound electrode body]
Subsequently, after laminating the belt-like positive electrode produced as described above and the negative electrode made of 150 μm thick metal lithium welded to the negative electrode terminal made of nickel foil in this order, the positive electrode, the separator, the negative electrode, and the separator. A number of turns were wound to produce a wound electrode body.

[Production of lithium iron sulfide primary battery]
The wound electrode body obtained as described above was accommodated in a nickel-plated iron battery can. At this time, an insulating plate was disposed on the lower surface of the wound electrode body. Next, a nickel negative electrode terminal was welded to the battery can. Subsequently, after an insulating plate is also provided on the upper surface of the wound electrode body, a pressure sensitive valve is provided on the battery lid via a heat sensitive element, and further, asphalt is coated on the surface, as shown in FIG. The insulating sealing gasket having a shape having a portion was disposed so that the convex portion of the pressure-sensitive valve was positioned in the hole portion of the insulating sealing gasket, and the positive electrode terminal and the convex portion were welded through the hole portion.

  Next, lithium iodide (LiI) was added to a mixed solvent of 1,3-dioxirane (DOL) and 1,2-dimethoxyethane (DME) in a volume ratio of 2: 1 to obtain a molar concentration of lithium iodide. A non-aqueous electrolyte adjusted to 1.0 mol / l was poured into the battery can.

  Finally, the battery lid was caulked to fix the pressure sensitive valve, the heat sensitive resistance element, and the battery lid to maintain the airtightness in the battery. The insulating sealing gasket used at this time was configured such that the diameter of the hole was 75% of the folded length of the positive electrode terminal. As described above, a cylindrical lithium iron sulfide primary battery was produced.

<Sample 2>
After the pressure sensitive valve is provided on the battery lid via the heat sensitive resistance element, the disc holder and the shut-off disc are arranged as shown in FIG. 1, and the positive terminal and the convex of the pressure-sensitive valve are inserted through the respective holes of the disc holder and the shut-off disc. The part was welded. Further, after injecting a non-aqueous electrolyte, a cylindrical lithium was formed in the same manner as in Sample 1 except that the battery lid was caulked through an insulating sealing gasket whose hole diameter was 75% of the folded length of the positive electrode terminal. An iron sulfide primary battery was produced.

<Sample 3>
A cylindrical lithium iron sulfide primary battery was fabricated in the same manner as Sample 1, except that the diameter of the hole of the insulating sealing gasket was 80% of the folded length of the positive electrode terminal.

[Evaluation of current interruption mechanism]
With respect to the lithium iron sulfide primary batteries of Samples 1 to 3 produced as described above, the cutoff pressure was evaluated. In each sample, 100 lithium iron sulfide primary batteries were produced.

(A) Measurement of cutoff pressure The internal pressure of the battery was controlled by hydraulic pressure, and the cutoff pressure at which the current was interrupted was measured. A hole was made in the lithium iron sulfide primary battery of each sample, oil was injected into the lithium iron sulfide primary battery by a manual hydraulic pressure generator, the battery internal pressure was gradually increased, and the pressure at which current interruption occurred was measured. 100 lithium iron sulfide primary batteries were prepared for each sample, and the pressure at which current interruption occurred in all batteries was defined as the cutoff pressure. Further, the increase in the internal pressure is up to 40 kgf at which the pressure-sensitive valve is cleaved, and it is assumed that the lithium iron sulfide primary battery in which the pressure-sensitive valve has been cleaved by applying a pressure of 40 kgf has not been blocked.

  Table 1 below shows the evaluation results of Samples 1 to 3.

  As can be seen from the above results, the lithium iron sulfide primary battery of Sample 1 using the current interruption mechanism according to the present invention can interrupt current under substantially the same conditions as Sample 2 using the conventional current interruption mechanism. I understand that.

  Further, when the hole diameter of the insulating sealing gasket is configured to be 80% of the folded length of the positive electrode terminal as in Sample 3, the blocking probability is remarkably lowered. This is because the positive terminal is drawn into the hole and no interruption occurs.

  From the above results, it is preferable to use an insulating sealing gasket having a side wall configured such that the diameter of the hole is 80% of the folded length of the positive electrode terminal, as in Sample 1.

  When the diameter of the hole portion of the insulating sealing gasket was less than 3 mm, it was difficult to connect the pressure sensitive valve to the positive electrode terminal, and it was difficult to produce a battery. For this reason, it is preferable that the diameter of the hole part of an insulating sealing gasket shall be 3 mm or more.

  The embodiment of the present invention has been specifically described above, but the present invention is not limited to the above-described embodiment, and various modifications based on the technical idea of the present invention are possible.

  For example, the insulating sealing gasket having the function of the blocking disk is not limited to the shape shown in the above-described embodiment.

  The numerical values and materials given in the above-described embodiment are merely examples, and different numerical values and materials may be used as necessary. The current interrupting mechanism of the present invention can be applied not only to a primary battery having a cylindrical structure other than a lithium iron sulfide primary battery but also to a cylindrical secondary battery.

It is sectional drawing which shows an example of the nonaqueous electrolyte primary battery which has the conventional electric current interruption mechanism. It is sectional drawing which shows an example of the mode of operation | movement of the conventional electric current interruption mechanism. It is sectional drawing of the lithium iron sulfide primary battery which shows an example of embodiment of this invention. It is sectional drawing which shows an example of a structure of the electric current interruption mechanism of this invention. It is a perspective view of the half part which shows an example of a structure of the electric current interruption mechanism of this invention. It is sectional drawing which shows an example of a structure of the electric current interruption mechanism of this invention. It is sectional drawing which shows an example of operation | movement of the electric current interruption mechanism of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,21 ... Battery can 2,22 ... Battery lid 3,23 ... Pressure sensitive valve 3a, 23a ... Protrusion 4,24 ... Heat-resistive element 5,25 ... Insulation sealing Gasket 6 ... Disc holder 6a, 7a ... Hole 7 ... Blocking disc 8, 9, 27, 28 ... Insulating plate 10, 30 ... Winding electrode body 11, 31 ... Positive electrode 11a, 31a ... Positive electrode active material layer 11b, 31b ... Positive electrode current collector 12, 32 ... Negative electrode 13, 33 ... Separator 14, 34 ... Center pin 15, 16 ... Electrode terminal DESCRIPTION OF SYMBOLS 20 ... Lithium iron sulfide primary battery 25a ... Side wall part 25b ... Disk part 25c ... Hole part 26 ... Current interruption mechanism 35 ... Positive electrode terminal 36 ... Negative electrode terminal

Claims (5)

A power generation element, a battery can, and a current interruption mechanism;
The current interruption mechanism is
A pressure-sensitive valve that is deformed by an increase in the internal pressure of the battery can;
A disk part having a hole part, and an insulating sealing part erected on the outer peripheral edge of the disk part, wherein the disk part is provided between the pressure-sensitive valve and the power generation element; With
The pressure sensitive valve and the electrode terminal provided in the power generation element are electrically connected through the hole of the disk portion,
The electrode terminal has a bent portion in a space between the power generation element and the disk portion of the insulating sealing gasket,
A battery, wherein at least one of the bent portion and the terminal end of the electrode terminal is disposed outside the hole of the disk portion.   2. The battery according to claim 1, wherein when the internal pressure of the battery is increased, the pressure sensitive valve is deformed, and an electric connection between the pressure sensitive valve and the electrode terminal is released to interrupt current. The diameter of the hole of the disk part is 3 mm or more,
2. The battery according to claim 1, wherein the battery is 75% or less with respect to a distance between the bent portion and an end of the electrode terminal.   The battery according to claim 1, wherein the electrode terminal further includes a tip folding portion at a tip portion of the electrode terminal. The diameter of the hole of the disk part is 3 mm or more,
5. The battery according to claim 4, wherein the battery is 75% or less with respect to a distance between the bent portion and the tip folded portion.

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