JP2016021338A - Positive electrode lead and alkali secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a positive electrode lead of an alkali secondary battery, by which the function of a protective material protecting a PTC thermistor is marred scarcely.SOLUTION: A positive electrode lead 50 of the present invention comprises: a PTC thermistor 533 shaped in a flat plate form and having an electrode on each side; a metal plate 531 having a flat plate form larger than that of the PTC thermistor 533, and glued to the PTC thermistor 533 on one side thereof; a metal plate 532 having a flat plate form larger than that of the PTC thermistor 533 and glued to the PTC thermistor 533 on the other side; a protective material 534 filled in a space between the metal plates 531 and 532 and covering the periphery of the PTC thermistor 533; and a sealing material connection part 51 composed of an elongated belt-shaped metal plate having an end welded to the backside of a part of the metal plate 531 to which the PTC thermistor 533 is glued.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a positive electrode lead of an alkaline secondary battery.

  A general alkaline secondary battery such as a nickel metal hydride secondary battery may generate heat and become hot when short-circuited due to an external short circuit or the like due to its low internal resistance and high internal energy. For this reason, a general alkaline secondary battery has a PTC (positive temperature) connected to the positive electrode lead that electrically connects the positive electrode and the positive electrode terminal of the electrode group inside for the purpose of ensuring safety when an external short circuit occurs. coefficient) a thermistor is incorporated (see, for example, Patent Document 1). This PTC thermistor is made of a resin containing conductive particles, and normally exhibits a low electrical resistance value and good electrical conductivity. When the temperature rises and reaches a predetermined value, the electrical resistance value increases rapidly. This is an electronic component having the characteristics of

  In the alkaline secondary battery having such a configuration, the PTC thermistor incorporated in the positive electrode lead causes an excessive current to flow and the temperature to rise when an external short circuit occurs in the alkaline secondary battery for some reason. When the temperature of the PTC thermistor reaches a predetermined value, the electrical resistance value of the PTC thermistor increases, and the current from the electrode group to the positive terminal is suppressed at the PTC thermistor portion of the positive lead. As a result, excessive current in the alkaline secondary battery is suppressed, so that heat generation of the alkaline secondary battery is suppressed when an external short circuit occurs.

  A positive electrode lead incorporating a conventional PTC thermistor has, for example, two metal strips arranged in series, the tips of the strips partially overlapping each other, and the strips of the strips facing each other. It is configured by soldering a PTC thermistor between the tip portions. The portion where the PTC thermistor is soldered is covered and protected by a protective material made of, for example, an epoxy resin having alkali resistance. This is to prevent deterioration of the PTC thermistor due to high-pressure oxygen generated inside the alkaline secondary battery, and deterioration of the soldered portion due to the alkaline atmosphere inside the alkaline secondary battery (see, for example, Patent Document 2). ).

Japanese Patent Laid-Open No. 06-243856 JP 2014-35991 A

  The positive electrode lead of the alkaline secondary battery described above is a portion of a metal strip in a limited narrow space between the positive electrode terminal and the electrode group inside the alkaline secondary battery in the manufacturing process of the alkaline secondary battery. It is necessary to install while bending. At that time, if the metal strip is bent at the portion where the protective material for covering the solder joint portion of the PTC thermistor is provided, the protective material is broken, and the solder joint portion of the PTC thermistor is exposed. As a result, the protective function of the PTC thermistor by the protective material may be impaired. Even if the metal strip is bent outside the portion provided with the protective material, the protective material may be broken by the bending stress in some cases.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a positive electrode lead of an alkaline secondary battery in which the protection function of the PTC thermistor by the protective material is less likely to be impaired.

<First Aspect of the Present Invention>
A first aspect of the present invention is a PTC thermistor having a flat plate shape and electrodes on both sides, a flat plate shape larger than the PTC thermistor, and a first metal plate bonded to one surface of the PTC thermistor, A flat plate shape larger than the PTC thermistor, filled in a space between the second metal plate bonded to the other surface of the PTC thermistor and the first metal plate and the second metal plate, and surrounding the PTC thermistor And a first lead half made of a strip-shaped metal plate having an end welded to the back side of the portion of the first metal plate to which the PTC thermistor is bonded. Lead.

  In the PTC thermistor, a first metal plate and a second metal plate that are larger than the PTC thermistor are bonded to both surfaces, and a space between the two metal plates is filled with a protective material to cover the periphery. As a result, the PTC thermistor is completely covered and sealed with the first metal plate, the second metal plate and the protective material, so that the high temperature oxygen generated inside the alkaline secondary battery, deterioration due to the alkaline atmosphere, etc. Protected. The electrodes of the PTC thermistor can be electrically connected to the positive electrode and the sealing body of the electrode group of the alkaline secondary battery through the first metal plate and the second metal plate.

  The first lead half is a member for electrically connecting one surface of the PTC thermistor to the positive electrode or the sealing body of the electrode group of the alkaline secondary battery through the first metal plate. This first lead half is extended by welding its end to the back side of the portion where the PTC thermistor of the first metal plate is bonded. Therefore, when the positive electrode lead is installed inside the alkaline secondary battery while bending the first lead half, the force acting on the first lead half acts on the portion where the PTC thermistor of the first metal plate is bonded. However, it hardly acts on the portion filled with the protective material. Accordingly, when the positive electrode lead is installed inside the alkaline secondary battery while the first lead half is bent, the possibility that the protective material is broken can be reduced.

  Thereby, according to the 1st aspect of this invention, the effect that the positive electrode lead of an alkaline secondary battery with little possibility that the protection function of the PTC thermistor by a protective material will be impaired is obtained.

<Second Aspect of the Present Invention>
According to a second aspect of the present invention, in the first aspect of the present invention described above, an end is welded to the back side of the portion of the second metal plate to which the PTC thermistor is bonded, and the first lead half And a second lead half made of a strip-shaped metal plate extending in a direction opposite to the extending direction.

  The second lead half is a member for electrically connecting the other surface of the PTC thermistor to the positive electrode or the sealing body of the electrode group of the alkaline secondary battery through the second metal plate. The second lead half is extended by welding its end to the back side of the portion where the PTC thermistor of the second metal plate is bonded. Therefore, when the positive lead is installed inside the alkaline secondary battery while the second lead half is bent, the force acting on the second lead half acts on the portion where the PTC thermistor of the second metal plate is bonded. However, it hardly acts on the portion filled with the protective material. Thereby, when the positive electrode lead is installed inside the alkaline secondary battery while the second lead half is bent, the possibility that the protective material is broken can be reduced.

<Third Aspect of the Present Invention>
According to a third aspect of the present invention, in the second aspect of the present invention described above, a portion where the end of the first lead half of the first metal plate is welded to the first metal plate. This is a positive electrode lead in which the end of the two-lead half is welded to a position where it does not overlap with each other in plan view.
According to the third aspect of the present invention, the volume occupied by the positive electrode lead in the alkaline secondary battery can be further reduced. As a result, the internal space of the alkaline secondary battery can be used more effectively. For example, the capacity of the alkaline secondary battery can be increased.

<Fourth aspect of the present invention>
According to a fourth aspect of the present invention, in the first aspect of the present invention described above, the second metal plate is formed integrally with the second metal plate and is opposite to the extending direction of the first lead half. It is a positive electrode lead including a strip-shaped second lead half extending in the direction.
Thus, by forming the second lead half integrally with the second metal plate, that is, by forming the second metal plate and the second lead half with one metal plate, the inside of the alkaline secondary battery The volume occupied by the positive electrode lead can be further reduced. As a result, the internal space of the alkaline secondary battery can be used more effectively. For example, the capacity of the alkaline secondary battery can be increased.

<Fifth aspect of the present invention>
According to a fifth aspect of the present invention, an outer can having an upper end opened, a positive electrode and a negative electrode are laminated via a separator, an electrode group accommodated together with an alkaline electrolyte in the outer can, and an opening of the outer can A sealing plate having a cover plate that is fixed in an insulated state and seals the opening and a positive electrode terminal that is electrically connected to the cover plate, and is installed between the electrode group and the sealing member; It is an alkaline secondary battery provided with the positive electrode lead in any one of the 1st-4th aspect of this invention which electrically connects the positive electrode of the said electrode group, and the said sealing body.
According to the fifth aspect of the present invention, in the alkaline secondary battery, the operational effects of any of the first to fourth aspects of the present invention described above can be obtained.

  ADVANTAGE OF THE INVENTION According to this invention, the positive electrode lead of an alkaline secondary battery with little possibility that the protection function of the PTC thermistor by a protective material will be impaired can be provided.

The perspective view which fractured | ruptured and illustrated the nickel-hydrogen secondary battery partially. Sectional drawing which illustrated the upper cross section of the nickel-hydrogen secondary battery. 1 is a plan view illustrating a first embodiment of a positive electrode lead according to the present invention. FIG. 4 is a cross-sectional view of the AA cross section of FIG. 3, which is a first embodiment of the positive electrode lead according to the present invention. The perspective view which illustrated the manufacturing method of 1st Example of the positive electrode lead which concerns on this invention. The perspective view which illustrated the manufacturing method of 1st Example of the positive electrode lead which concerns on this invention. The perspective view which illustrated the manufacturing method of 1st Example of the positive electrode lead which concerns on this invention. The perspective view which illustrated the manufacturing method of 1st Example of the positive electrode lead which concerns on this invention. The top view which illustrated the 2nd example of the positive electrode lead concerning the present invention. FIG. 10 is a cross-sectional view of the positive electrode lead according to the second embodiment of the present invention, taken along the line BB in FIG. 9. The top view which illustrated the 3rd example of the positive electrode lead concerning the present invention. 11 is a third embodiment of the positive electrode lead according to the present invention, and is a cross-sectional view taken along the line CC of FIG. The top view which illustrated the 4th example of the positive electrode lead concerning the present invention. FIG. 14 is a fourth embodiment of the positive electrode lead according to the present invention, and is a cross-sectional view taken along the line DD in FIG. 13.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In addition, this invention is not specifically limited to the Example demonstrated below, It cannot be overemphasized that a various deformation | transformation is possible within the range of the invention described in the claim.

<Configuration of NiMH secondary battery 1>
A configuration of the nickel metal hydride secondary battery 1 as the “alkali secondary battery” will be described with reference to FIGS. 1 and 2.
FIG. 1 is a perspective view illustrating a nickel-hydrogen secondary battery 1 partially cut away. FIG. 2 is a cross-sectional view illustrating an upper cross section of the nickel metal hydride secondary battery 1.

  The nickel metal hydride secondary battery 1 includes an outer can 10, an electrode group 20, a sealing body 30, and a positive electrode lead 50.

  The outer can 10 is made of a conductive material, has a bottomed cylindrical shape with an open upper end, and the bottom wall 11 functions as a negative electrode terminal.

  The electrode group 20 is accommodated in the outer can 10 together with the alkaline electrolyte, and includes a strip-shaped positive electrode 21, a negative electrode 22, and a separator 23, respectively. The electrode group 20 is configured by being wound in a spiral shape with the positive electrode 21 and the negative electrode 22 being overlapped with each other via a separator 23. The outermost periphery of the electrode group 20 is formed by a part (outermost periphery) of the negative electrode 22 and is in contact with the inner peripheral wall of the outer can 10. Thereby, the outer can 10 is electrically connected to the negative electrode 22 of the electrode group 20. A circular insulating member 42 is disposed between the electrode group 20 and the lid 31 to prevent an internal short circuit. A circular insulating member 43 is similarly disposed between the electrode group 20 and the bottom wall 11 of the outer can 10 in order to prevent internal short circuits.

  The sealing body 30 is a structure that is fixed in an insulated state to the opening edge of the outer can 10 and seals the outer can 10. The sealing body 30 includes a lid body 31, a valve body 32, and a positive electrode terminal 33. The lid 31 is a disk-shaped member having conductivity, and is a member that seals the opening of the outer can 10. A central through hole 311 is formed at the center of the lid 31, and a valve body 32 that closes the central through hole 311 is disposed on the outer surface of the lid 31. The valve body 32 is a member formed of an elastic material such as rubber. The positive electrode terminal 33 is a member formed of a flanged cylindrical conductive material, and is provided with a gas vent hole (not shown). The positive electrode terminal 33 is fixed to the upper surface of the lid body 31 so as to cover the valve body 32, and is electrically connected to the lid body 31.

  In the opening of the outer can 10, a lid body 31 and a ring-shaped insulating packing 41 surrounding the lid body 31 are arranged. The insulating packing 41 is fixed to the opening edge 12 of the outer can 10 by caulking the opening edge 12 of the outer can 10. That is, the lid 31 and the insulating packing 41 cooperate with each other to airtightly close the opening of the outer can 10. At normal times, the central through hole 311 of the lid 31 is airtightly closed by the valve body 32. When gas is generated in the outer can 10 and the internal pressure increases, the valve body 32 is compressed by the internal pressure and the central through hole 311 is opened. Thereby, the gas generated in the outer can 10 is released from the outer can 10 to the outside through the central through hole 311 and the gas vent hole of the positive electrode terminal 33. That is, the central through hole 311, the valve body 32, and the positive terminal 33 of the lid body 31 constitute a safety valve that operates when gas is generated in the outer can 10 and the internal pressure increases.

  The positive electrode lead 50 is a structure that is installed between the electrode group 20 and the sealing body 30 and electrically connects the positive electrode 21 of the electrode group 20 and the positive electrode terminal 33 of the sealing body 30. The positive electrode lead 50 includes a sealing body connection part 51, an electrode group connection part 52, and a PTC thermistor module 53.

  The sealing body connection part 51 and the electrode group connection part 52 are band-shaped members made of a conductive material. The sealing body connecting portion 51 is electrically connected to the lid body 31 of the sealing body 30. The electrode group connection portion 52 is electrically connected to the positive electrode 21 of the electrode group 20 through a slit 421 provided in the insulating member 42. The PTC thermistor module 53 is electrically connected between the sealing body connecting portion 51 and the electrode group connecting portion 52.

<First Example of Positive Electrode Lead 50>
A first embodiment of the positive electrode lead 50 according to the present invention will be described with reference to FIGS.
FIG. 3 is a plan view illustrating the first embodiment of the positive electrode lead 50. FIG. 4 is a cross-sectional view illustrating the first embodiment of the positive electrode lead 50, and illustrates the AA cross section of FIG. 3.

  The positive electrode lead 50 includes a sealing body connection part 51, an electrode group connection part 52, and a PTC thermistor module 53. The PTC thermistor module 53 includes two metal plates 531 and 532, a PTC thermistor 533, and a protective material 534.

  The PTC thermistor 533 is made of, for example, an insulating polymer in which conductive particles are dispersed. In such a PTC thermistor 533, since the conductive particles are normally in contact with each other, the electrical resistance value is low, and good conductivity is exhibited. On the other hand, when an external short circuit occurs in the nickel metal hydride secondary battery 1, the PTC thermistor 533 generates heat by flowing a large current, and this heat causes the entire insulating polymer to expand, thereby reducing the contact of conductive particles. The electric resistance value increases rapidly. By utilizing such characteristics of the PTC thermistor 533, it is possible to suppress overcurrent when an external short circuit occurs. Then, the PTC thermistor 533 returns to the original low electrical resistance value because the insulating polymer contracts when the heat generation is eliminated and the PTC thermistor 533 is cooled.

  The operating temperature of the PTC thermistor 533 must be such that the surface temperature of the nickel metal hydride secondary battery 1 does not exceed 70 ° C. (when evaluated at 25 ° C.), which is the maximum temperature of toy parts that can be contacted as defined by domestic toy standards. In consideration of suppressing the malfunction, it is preferable to set the temperature in the range of 80 ° C to 100 ° C. Since there is a temperature difference between the inside and the outside surface of the nickel metal hydride secondary battery 1, the outside surface temperature of the battery should be kept below 70 ° C. even if the operating temperature of the PTC thermistor 533 is set to 80 ° C. to 100 ° C. Because you can. More specifically, even if the PTC thermistor 533 of the nickel hydride secondary battery 1 generates heat and the temperature rises to 80 ° C. to 100 ° C., the surface temperature of the nickel hydride secondary battery 1 is about 50 ° C. to 55 ° C. It will be about.

  The metal plate 531 has a flat plate shape larger than the PTC thermistor 533, and is bonded to one surface of the PTC thermistor 533 by, for example, soldering. The metal plate 532 has a flat plate shape larger than the PTC thermistor 533 and is bonded to the other surface of the PTC thermistor 533 by, for example, soldering.

  The protective material 534 is filled in a space between the metal plate 531 and the metal plate 532 and covers the periphery of the PTC thermistor 533. The protective material 534 is used to prevent deterioration of the PTC thermistor 533 due to high-pressure oxygen generated inside the nickel metal hydride secondary battery 1, and deterioration of the soldered portion due to the alkaline atmosphere inside the nickel metal hydride secondary battery 1. For example, it is made of an epoxy resin having alkali resistance.

  As described above, the PTC thermistor 533 has two metal plates 531 and 532 larger than the PTC thermistor 533 bonded to each other, and the space between the two metal plates 531 and 532 is filled with the protective material 534 so that the periphery is surrounded. Covered. As a result, the PTC thermistor 533 is completely covered and sealed with the two metal plates 531 and 532 and the protective material 534, so that the PTC thermistor 533 is caused by high-pressure oxygen or alkali atmosphere generated inside the nickel-hydrogen secondary battery 1. Protected from deterioration. The electrodes of the PTC thermistor 533 can be electrically connected to the positive electrode 21 of the electrode group 20 of the nickel metal hydride secondary battery 1 and the positive electrode terminal 33 of the sealing body 30 through the two metal plates 531 and 532. .

  The sealing body connecting portion 51 is a member for electrically connecting one surface of the PTC thermistor 533 through the metal plate 531 to the positive terminal 33 of the sealing body 30 of the nickel metal hydride secondary battery 1. The sealing body connecting portion 51 as the “first lead half” is extended by welding the end to the back side of the portion where the PTC thermistor 533 of the metal plate 531 as the “first metal plate” is bonded. It is a strip-shaped metal plate. More specifically, in the sealing body connecting portion 51, the welded portion 511 at the end of the sealing body connecting portion 51 is welded to the back side of the portion where the PTC thermistor 533 of the metal plate 531 is bonded.

  When the positive electrode lead 50 having such a configuration is installed inside the nickel metal hydride secondary battery 1 while bending the sealing body connecting portion 51, the force acting on the sealing body connecting portion 51 is the PTC thermistor 533 of the metal plate 531. Will act on the bonded part, and will hardly act on the part filled with the protective material 534. Thereby, when the positive electrode lead 50 is installed inside the nickel metal hydride secondary battery 1 while the sealing body connecting portion 51 is bent, the possibility that the protective material 534 is broken can be reduced.

  The electrode group connection portion 52 is a member for electrically connecting the other surface of the PTC thermistor 533 to the positive electrode 21 of the electrode group 20 of the nickel hydride secondary battery 1 through the metal plate 532. The electrode group connection portion 52 as the “second lead half” is welded to the back side of the portion where the PTC thermistor 533 of the metal plate 532 as the “second metal plate” is bonded, and the sealing body connection portion 51 is a strip-shaped metal plate extending in a direction opposite to the extending direction of 51. More specifically, in the electrode group connection portion 52, the welded portion 521 at the end of the electrode group connection portion 52 is welded to the back side of the portion where the PTC thermistor 533 of the metal plate 532 is bonded.

  When the positive electrode lead 50 having such a configuration is installed inside the nickel metal hydride secondary battery 1 while bending the electrode group connection portion 52, the force acting on the electrode group connection portion 52 is caused by the PTC thermistor 533 of the metal plate 532. Will act on the bonded part, and will hardly act on the part filled with the protective material 534. Thereby, when the positive electrode lead 50 is installed inside the nickel metal hydride secondary battery 1 while the electrode group connection portion 52 is bent, the possibility that the protective material 534 is cracked can be reduced.

  As described above, according to the present invention, it is possible to provide the positive electrode lead 50 of the alkaline secondary battery in which the protection function of the PTC thermistor 533 by the protective material 534 is less likely to be impaired.

Next, an example of a method for manufacturing the positive electrode lead 50 according to the present invention will be described with reference to FIGS.
5 to 8 are perspective views illustrating a method of manufacturing the positive electrode lead 50 according to the first embodiment.

  First, the PTC thermistor module 53 is manufactured. More specifically, first, metal plates 531 and 532 are soldered to both surfaces of the PTC thermistor 533, respectively (FIGS. 5 and 6). Subsequently, the space between the metal plate 531 and the metal plate 532 is filled with a protective material 534 to cover the periphery of the PTC thermistor 533 (FIG. 7).

Subsequently, the sealing body connecting part 51 and the electrode group connecting part 52 are welded and attached to the PTC thermistor module 53 (FIG. 8). The welding may be any welding method such as resistance welding or laser welding. More specifically, the welded portion 511 at the end of the sealing body connecting portion 51 is welded to the back side of the portion where the PTC thermistor 533 of the metal plate 531 is bonded. Further, the welded portion 521 at the end of the electrode group connecting portion 52 is welded to the back side of the portion of the metal plate 532 where the PTC thermistor 533 is bonded.
The sealing body connecting portion 51 or the electrode group connecting portion 52 may be subjected to a bending process or the like as necessary before welding to the PTC thermistor module 53.

<Second Example of Positive Electrode Lead 50>
A second embodiment of the positive electrode lead 50 according to the present invention will be described with reference to FIGS.
FIG. 9 is a plan view illustrating a second embodiment of the positive electrode lead 50. FIG. 10 is a cross-sectional view illustrating a second embodiment of the positive electrode lead 50, and illustrates a cross section taken along the line BB of FIG.

The second embodiment of the positive electrode lead 50 includes a sealing body connecting portion 51, an electrode group connecting portion 52, and a PTC thermistor module 53, as in the first embodiment. The PTC thermistor module 53 includes two metal plates 531 and 532, a PTC thermistor 533, and a protective material 534.
The same constituent elements as those in the first embodiment are designated by the same reference numerals, and detailed description thereof is omitted.

  The electrode group connection portion 52 as the “first lead half” is extended by welding the end to the back side of the portion where the PTC thermistor 533 of the metal plate 532 as the “first metal plate” is bonded. It is a strip-shaped metal plate. More specifically, in the electrode group connection portion 52, the welded portion 521 at the end of the electrode group connection portion 52 is welded to the back side of the portion where the PTC thermistor 533 of the metal plate 532 is bonded.

  In the second embodiment of the positive electrode lead 50, the force acting on the electrode group connection portion 52 when the electrode group connection portion 52 is installed inside the nickel hydride secondary battery 1 while bending the electrode group connection portion 52 is the PTC thermistor 533 of the metal plate 532. Will act on the bonded part, and will hardly act on the part filled with the protective material 534. Thereby, when the positive electrode lead 50 is installed inside the nickel metal hydride secondary battery 1 while the electrode group connection portion 52 is bent, the possibility that the protective material 534 is cracked can be reduced.

  On the other hand, the sealing body connecting portion 51 as the “second lead half” is integrally formed with the metal plate 531 as the “second metal plate” and extends in the direction opposite to the extending direction of the electrode group connecting portion 52. Has been.

  In this way, by forming the sealing body connecting portion 51 integrally with the metal plate 531, that is, by forming the metal plate 531 and the sealing body connecting portion 51 with a single metal plate, the inside of the nickel metal hydride secondary battery 1. In this case, the volume occupied by the positive electrode lead 50 can be further reduced. As a result, the internal space of the nickel metal hydride secondary battery 1 can be used more effectively. For example, the capacity of the nickel metal hydride secondary battery 1 can be increased.

<Third Example of Positive Electrode Lead 50>
A third embodiment of the positive electrode lead 50 according to the present invention will be described with reference to FIGS.
FIG. 11 is a plan view illustrating a third embodiment of the positive electrode lead 50. FIG. 12 is a cross-sectional view illustrating a third embodiment of the positive electrode lead 50, and illustrates the CC cross section of FIG.

The third embodiment of the positive electrode lead 50 includes a sealing body connecting portion 51, an electrode group connecting portion 52, and a PTC thermistor module 53, as in the first embodiment. The PTC thermistor module 53 includes two metal plates 531 and 532, a PTC thermistor 533, and a protective material 534.
The same constituent elements as those in the first embodiment are designated by the same reference numerals, and detailed description thereof is omitted.

  The sealing body connecting portion 51 as the “first lead half” is extended by welding the end to the back side of the portion where the PTC thermistor 533 of the metal plate 531 as the “first metal plate” is bonded. It is a strip-shaped metal plate. More specifically, in the sealing body connecting portion 51, the welded portion 511 at the end of the sealing body connecting portion 51 is welded to the back side of the portion where the PTC thermistor 533 of the metal plate 531 is bonded.

  In the third embodiment of the positive electrode lead 50, the force acting on the sealing body connecting portion 51 when the sealing body connecting portion 51 is installed inside the nickel hydride secondary battery 1 while being bent is the PTC thermistor 533 of the metal plate 531. Will act on the bonded part, and will hardly act on the part filled with the protective material 534. Thereby, when the positive electrode lead 50 is installed inside the nickel metal hydride secondary battery 1 while the sealing body connecting portion 51 is bent, the possibility that the protective material 534 is broken can be reduced.

  On the other hand, the electrode group connection portion 52 as the “second lead half” is integrally formed with the metal plate 532 as the “second metal plate” and extends in the direction opposite to the extending direction of the sealing body connection portion 51. Has been.

  Thus, by forming the electrode group connection part 52 integrally with the metal plate 532, that is, by forming the metal plate 532 and the electrode group connection part 52 with a single metal plate, the inside of the nickel metal hydride secondary battery 1 is provided. In this case, the volume occupied by the positive electrode lead 50 can be further reduced. As a result, the internal space of the nickel metal hydride secondary battery 1 can be used more effectively. For example, the capacity of the nickel metal hydride secondary battery 1 can be increased.

<Fourth Example of Positive Electrode Lead 50>
A fourth embodiment of the positive electrode lead 50 according to the present invention will be described with reference to FIGS.
FIG. 13 is a plan view illustrating a fourth embodiment of the positive electrode lead 50. FIG. 14 is a cross-sectional view illustrating a fourth embodiment of the positive electrode lead 50, and illustrates a DD cross section of FIG. 13.

The fourth embodiment of the positive electrode lead 50 includes a sealing body connecting portion 51, an electrode group connecting portion 52, and a PTC thermistor module 53, as in the first embodiment. The PTC thermistor module 53 includes two metal plates 531 and 532, a PTC thermistor 533, and a protective material 534.
The same constituent elements as those in the first embodiment are designated by the same reference numerals, and detailed description thereof is omitted.

  The sealing body connecting portion 51 as the “first lead half” is provided on the back side of the portion where the PTC thermistor 533 of the metal plate 531 as the “first metal plate” is bonded. The welding part 511 is welded. The electrode group connection portion 52 as the “second lead half” is an end portion of the electrode group connection portion 52 on the back side of the portion where the PTC thermistor 533 of the metal plate 532 as the “second metal plate” is bonded. The welded portion 521 is welded.

  In the fourth embodiment of the positive electrode lead 50, the welded portion 511 at the end of the sealing body connecting portion 51 and the welded portion 521 at the end of the electrode group connecting portion 52 do not overlap each other in plan view. With such a configuration, the fourth embodiment of the positive electrode lead 50 can further reduce the volume occupied by the positive electrode lead 50 inside the nickel metal hydride secondary battery 1. As a result, the internal space of the nickel metal hydride secondary battery 1 can be used more effectively. For example, the capacity of the nickel metal hydride secondary battery 1 can be increased.

DESCRIPTION OF SYMBOLS 1 Nickel metal hydride secondary battery 50 Positive electrode lead 51 Sealing body connection part 52 Electrode group connection part 53 PTC thermistor module 511, 521 Welding part 531, 532 Metal plate 533 PTC thermistor 534 Protective material

Claims (5)

A PTC thermistor having a flat plate shape and electrodes on both sides;
A first metal plate having a flat plate shape larger than the PTC thermistor and bonded to one surface of the PTC thermistor;
A second metal plate having a flat plate shape larger than the PTC thermistor and bonded to the other surface of the PTC thermistor;
A protective material that fills the space between the first metal plate and the second metal plate and covers the periphery of the PTC thermistor;
A positive electrode lead comprising: a first lead half made of a strip-shaped metal plate having an end welded to a back side of a portion of the first metal plate to which the PTC thermistor is bonded.   2. The positive electrode lead according to claim 1, wherein an end portion is welded to a back side of a portion of the second metal plate to which the PTC thermistor is bonded, and extends in a direction opposite to an extending direction of the first lead half. A positive electrode lead further comprising a second lead half made of a strip-shaped metal plate.   3. The positive electrode lead according to claim 2, wherein a portion where the end of the first lead half of the first metal plate is welded to an end of the second lead half of the second metal plate is welded. The positive electrode lead is located in a position that does not overlap with each other in plan view.   2. The positive electrode lead according to claim 1, wherein the second metal plate is formed integrally with the second metal plate and extends in a direction opposite to the extending direction of the first lead half. Positive lead, including lead half. An outer can with an open top;
A positive electrode and a negative electrode are laminated via a separator, and an electrode group accommodated together with an alkaline electrolyte in the outer can;
A sealing body that is fixed in an insulated state to the opening edge of the outer can, and has a lid plate that seals the opening and a positive electrode terminal that is electrically connected to the lid plate;
The positive electrode lead according to any one of claims 1 to 4, which is installed between the electrode group and the sealing body and electrically connects the positive electrode of the electrode group and the sealing body. Secondary battery.

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