JP2010080246A - Separator for alkaline battery, method for manufacturing the same, and alkaline battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separator for an alkaline battery capable of sufficiently securing shock-resistant characteristics without deteriorating battery performance. <P>SOLUTION: The separator 13 for the alkaline battery is formed in a cylindrical shape with a bottom having an opening 36 at a negative electrode terminal side by winding two turns or more of one sheet of a separator material 31, and is arranged between a positive electrode mixture and a gelatinous negative electrode mixture. The separators 31 are not fixed on both electrodes contact section 35 brought into contact with the positive electrode mixture and the gelatinous negative electrode mixture. Meanwhile, the most inner end 33 of the separator material 31 located at a separator inner side and a section 34 of at least the second turn from the separator inner side are fixed on the opening 36 at a negative electrode terminal side which does not belong to both electrodes contact section 35. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an alkaline battery separator disposed between a positive electrode active material and a negative electrode active material, a method for producing the same, and an alkaline battery configured using the alkaline battery separator.

  Generally, an alkaline battery includes a bottomed cylindrical positive electrode can, a ring-shaped positive electrode mixture housed in the positive electrode can, a gel-like negative electrode mixture disposed in the center of the positive electrode can, and a positive electrode mixture. And a gelled negative electrode mixture, and a current collector attached to the opening of the positive electrode can.

  The cylindrical separator used for the conventional alkaline battery is produced by the following method.

  First, as a first method, like the separator 50 shown in FIG. 4, the separator material 51 is wound in a cylindrical shape, and the outermost end 52 of the separator material 51 and the portion 53 of the second circumference from the outside are covered over the entire length. It is produced by bonding with an adhesive 54. Further, as a second method, like the separator 55 shown in FIG. 5, the separator material 51 is wound in a cylindrical shape, and the bottom 57 is formed by heat welding or bottom paper without the body portion 56 being bonded. It is made with. Further, as a third method, like the separator 59 shown in FIG. 6, the long and narrow separator materials 60 and 61 are stacked and solidified with an adhesive to form a cylindrical shape, and the entire surface is adhered with an adhesive. The Moreover, as a 4th method, like the separator 62 shown in FIG. 7, two or more separator material 63,64 is piled up in a cross shape, and it is produced in a cylinder shape.

In the alkaline battery, when the gelled negative electrode mixture contained in the separator leaks to the positive electrode side, an internal short circuit occurs. As a countermeasure, an alkaline battery has been proposed in which an opening of a separator is bonded to a sealing gasket of a current collector to prevent an internal short circuit (see Patent Documents 1 and 2).
Japanese Patent Application Laid-Open No. 07-134777 Japanese Patent Laid-Open No. 10-172525

  However, when the outermost end 52 of the separator 50 is bonded as shown in FIG. 4 or only the bottom 57 of the separator 55 is formed as shown in FIG. 5, the inner sides of the separators 50 and 55 are not fixed. In the step of immersing the electrolytic solution in the separators 50 and 55, the separators 50 and 55 are bent inward, and a gap is formed between the gelled negative electrode mixture and the positive electrode mixture. In this case, since the positive electrode and the negative electrode in the portion where the gap is formed become a portion that does not react during heavy load discharge, the discharge performance of the battery is degraded. Moreover, since the inner side is not fixed also in the separator 62 of FIG. 7, the separator 62 may bend inward and the discharge performance may deteriorate. Furthermore, as in the case of the separator 59 in FIG. 6, when the adhesive is applied to the entire surface, the adhesive becomes a resistance, so that the discharge performance is deteriorated. Further, the flexibility of the separator 59 is lost due to the adhesive. For this reason, the separator 59 is torn by impact or the like, and the gelled negative electrode mixture leaks out to the positive electrode material mixture side, so that an internal short circuit easily occurs.

  This invention is made | formed in view of said subject, The objective is to provide the separator for alkaline batteries with favorable heavy load pulse discharge. Another object is to provide a production method suitable for producing the alkaline battery separator. Furthermore, another object is to provide an alkaline battery excellent in discharge performance.

  In order to solve the above-described problem, in the invention according to claim 1, the separator material is formed into a bottomed cylindrical shape having a negative electrode terminal side opening by winding one separator material two or more times, and the positive electrode active material and the negative electrode active material are formed. A separator for an alkaline battery disposed between materials, wherein the separator material is not fixed to each other at a bipolar contact portion in contact with the positive electrode active material and the negative electrode active material, and the separator is located inside the separator. The gist of the separator for alkaline batteries is characterized in that the innermost end of the material and at least the second round portion from the inside of the separator are fixed in the opening on the negative electrode terminal side that does not belong to the bipolar contact portion. .

  According to the first aspect of the present invention, the internal resistance is lowered as compared with the case where the separator materials are fixed to each other by an adhesive or heat fusion at the bipolar contact portions in contact with the positive electrode active material and the negative electrode active material. be able to. In addition, since the innermost end of the separator material located on the inner side of the separator and the second round portion from the inner side of the separator are fixed at the opening on the negative electrode terminal side, the separator can be used even when the electrolyte is immersed in the separator. Therefore, each active material can be efficiently reacted at the bipolar contact portion in contact with the positive electrode active material and the negative electrode active material. Moreover, by fixing a separator partially in a negative electrode terminal side opening part, the fall of a softness | flexibility can be suppressed and impact resistance can be ensured.

  The gist of the invention described in claim 2 is that, in claim 1, the innermost end of the separator material and the second round portion from the inside of the separator are fixed by thermal fusion.

  According to invention of Claim 2, a separator material can be reliably fixed by heat sealing | fusion.

  The gist of the invention described in claim 3 is that, in claim 1, the innermost end of the separator material and the portion of the second circumference from the inside of the separator are bonded and fixed by an adhesive.

  According to invention of Claim 3, a separator material can be reliably fixed with an adhesive agent.

  According to a fourth aspect of the invention, in any one of the first to third aspects, the outermost end of the separator material located on the outer side of the separator and the second round part from the outer side of the separator are not fixed. Is the gist.

  According to the invention described in claim 4, since the outermost end of the separator material and the second round part from the outside of the separator are not fixed, it is possible to suppress a decrease in flexibility, and to improve the impact resistance of the separator. It can be secured sufficiently.

  The invention according to claim 5 is a method for producing the separator for an alkaline battery according to claim 4, wherein a rectangular separator material including a thermoplastic binder fiber is used, and one corner portion in the separator material is used. A water applying step for adding water, a winding step for winding the separator material two or more times so that the corner with water is on the inner end side, and a cylindrical shape, An alkaline battery comprising: a partial fixing step of partially fixing the innermost end of the separator material and the second round portion from the inside of the separator by heating the separator material at a separator opening. The gist of the manufacturing method of the separator for the printer.

  According to the invention of claim 5, in the water application step, after water is applied to one corner of the separator material, the winding step is performed, and the separator is arranged such that the corner is on the inner end side. The material is wound two or more times into a cylindrical shape. At this time, in the portion where water adheres in the separator material, the thermoplastic binder fiber swells with moisture and becomes soft. Thereafter, when the cylindrical separator is heated, the softened binder fiber functions as a thermoplastic adhesive and the binder fiber re-solidifies, so that the second round from the innermost end of the separator material and the inner side of the separator. Is partially fixed at the separator opening. If it does in this way, the separator for alkaline batteries of Claim 4 can be manufactured reliably.

  The gist of an invention described in claim 6 is an alkaline battery comprising the alkaline battery separator according to any one of claims 1 to 4.

  According to the invention of claim 6, an alkaline battery excellent in impact resistance and discharge performance can be obtained.

  As described above in detail, according to the first to fourth aspects of the present invention, it is possible to provide an alkaline battery separator that can sufficiently ensure impact resistance without deteriorating battery performance. In addition, according to the invention described in claim 5, it is possible to reliably manufacture an alkaline battery separator that can sufficiently ensure impact resistance without deteriorating battery performance. Furthermore, according to the invention of claim 6, an alkaline battery excellent in impact resistance and discharge performance can be provided.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of an alkaline battery in the present embodiment.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a schematic configuration of an alkaline battery 10 in the present embodiment. In addition, the alkaline battery 10 of the present embodiment is an LR6 type (AA) battery.

  As shown in FIG. 1, the alkaline battery 10 includes a bottomed cylindrical positive electrode can 11, a ring-shaped positive electrode mixture 12 (positive electrode active material) fitted along the inner surface of the positive electrode can 11, and A bottomed cylindrical separator 13 inserted inside the positive electrode mixture 12, a gelled negative electrode mixture 14 (negative electrode active material) disposed in a hollow portion of the separator 13 which is the center of the positive electrode can 11, and a positive electrode And a current collector 16 attached to the opening 15 of the can 11.

  The positive electrode can 11 is a press-processed product made of a nickel-plated steel plate, and is press-formed into a bottomed cylindrical shape having an opening 15, a body portion 17, and a bottom portion 18. A positive terminal 19 projects from the center of the bottom 18 of the positive electrode can 11.

  The positive electrode mixture 12 is produced by regulating the positive electrode mixture powder in which electrolytic manganese dioxide, graphite, potassium hydroxide, and a binder are mixed, and then press-molding the powder into a cylindrical shape.

  The gelled negative electrode mixture 14 is produced by mixing and dissolving water, zinc oxide and an aqueous potassium hydroxide solution, and mixing a gelling agent such as polyacrylic acid and zinc powder.

  The current collector 16 includes a negative electrode terminal plate 21, a negative electrode current collector 22, and a sealing gasket 23. Near the opening 15 of the positive electrode can 11, a bead portion 24 for mounting the current collector 16 is formed. The positive electrode can 11 is sealed by curling and drawing the opening 15 of the positive electrode can 11 with the current collector 16 placed on the bead portion 24.

  The current collector 16 has a negative electrode current collector 22 formed in the shape of a rod using brass and resistance-welded to the negative electrode terminal plate 21 at the proximal end thereof, and a sealing gasket 23 is fitted to the neck of the negative electrode current collector 22. It is formed by wearing. The tip side of the negative electrode current collector 22 is inserted into the gelled negative electrode mixture 14.

  The negative electrode terminal plate 21 is produced by press-molding a nickel-plated steel plate in the same manner as the positive electrode can 11 and seals the opening 15 of the positive electrode can 11 through a sealing gasket 23. The sealing gasket 23 is manufactured by injection molding using a resin material such as polyolefin resin or polyamide resin.

  A boss portion 26 is provided at the center of the sealing gasket 23, and the negative electrode current collector 22 is passed through the boss portion 26. Further, a thin portion 27 (safety valve) having a thin plate thickness is formed in the vicinity of the boss portion 26 in the sealing gasket 23. When the internal pressure is increased due to the generation of gas, the thin portion 27 of the sealing gasket 23 is broken by the pressure increase, and the gas is discharged to the outside.

  As shown in FIG. 2, the separator 13 is formed into a cylindrical shape by, for example, winding a separator material 31 such as a vinylon / rayon nonwoven fabric containing vinylon binder fibers (thermoplastic binder fibers) twice. The innermost end 33 of the material 31 and the portion 34 of the second round from the inside are fixed by heat sealing. More specifically, in the separator 13, the separator materials 31 are not fixed to each other in the bipolar contact portion 35 in contact with the positive electrode mixture 12 and the gelled negative electrode mixture 14, but the negative electrode terminal side does not belong to the bipolar contact portion 35. In the opening 36, the innermost end 33 of the separator material 31 and the portion 34 of the second circumference from the inside are partially fixed by heat fusion. Further, in the separator 13 of the present embodiment, the outermost end 37 of the separator material 31 located on the outer side and the portion 34 of the second round from the outer side are not fixed. By configuring the separator 13 in this manner, the fixing portion by heat fusion can be minimized. For this reason, the liquid retention rate of the electrolytic solution in the separator 13 is increased and flexibility is ensured.

  In addition, in the alkaline battery 10, at the time of manufacture, the separator 13 is inserted into the hollow portion of the positive electrode mixture 12 that is press-fitted into the positive electrode can 11, and then an electrolytic solution is injected into the positive electrode mixture 12 and the separator 13. The electrolyte is soaked.

  Separator 13 of the present embodiment is manufactured by the following method.

  First, in the preparation step, a separator base paper of vinylon / rayon nonwoven fabric containing thermoplastic vinylon binder fibers is cut into a rectangular shape to prepare one separator material 31 (see FIG. 3A).

  And in a water adhesion process, the water 40 is made to adhere to one corner | angular part 39 in the rectangular separator material 31 (refer FIG.3 (b)). Since the vinylon binder fiber is a fiber having hydrophilicity (water absorption), the portion to which the water 40 is adhered swells and becomes soft. In addition, as a method of attaching the water 40 to a predetermined portion, for example, there is a method of discharging the water 40 from its tip using a dropper-like instrument, but the invention is not particularly limited to this and any method can be adopted. it can. However, in this case, it is necessary to use an instrument that prevents the water 40 from adhering to other parts. Thereafter, in the winding step, the separator material 31 is wound around the outer periphery of a rod-shaped jig (not shown) so that the corner 39 with water 40 is located on the inner end side to form a cylindrical shape (see FIG. 3 (c)). Further, in the partial fixing step, the separator material 31 wound in a cylindrical shape is brought into contact with the portion to which the water 40 is attached and the separator material 31 on the outer peripheral side, and the contact portion is heated by a heating device such as a heater (illustrated). (Omitted) is used to heat. Thereby, the softened binder fiber is re-solidified to fix the innermost end 33 of the separator material 31 and the portion 34 of the second round from the inside of the separator in a spot shape (see FIG. 3D).

  After the separator material 31 is fixed in a cylindrical shape, one cylindrical end portion 41 (the lower end portion that is not fixed in FIG. 3D) is bent in the cylinder axis direction and overlapped by the bending. The bottomed cylindrical separator 13 having the bottom 38 is manufactured by heat sealing (see FIG. 2).

  The inventors of the present invention produced an alkaline battery 10 using the separator 13 produced by the above method, and conducted a discharge test and an impact test of the alkaline battery 10. The test results are shown in Table 1 as Example 1. In addition, the discharge test is a test assuming a digital camera. A discharge of 1500 mW for 2 seconds and a discharge of 650 mW for 28 seconds is one cycle. After discharging 10 cycles (5 minutes) in 1 hour, the discharge is performed for 55 minutes. The test was conducted in a rest mode. The final voltage (EPV) to end this discharge test is 1.05V. Moreover, as an impact test, after dropping freely from a height of 1 m onto a flat floor, the voltage of the battery was measured to confirm the occurrence rate of internal short circuit.

In addition, each test was done also about the alkaline battery produced using the separator of a prior art example, and the result is shown here. Specifically, the case where the separator 50 of FIG. 4 (a separator in which the outermost end 52 and the portion 53 of the second circumference from the outside are bonded) is used is the conventional example 1, and the separator 55 of FIG. The case of using the separator (bonded) is shown as Conventional Example 2, and the case of using the separator 59 (separator with the entire surface bonded) of FIG. Furthermore, not only the innermost end and the second round portion from the inside, but also the outermost end and the second round portion from the outside were bonded (all the openings were bonded), and the separator was used. The test results are shown as Example 2.

  As shown in Table 1, the number of cycles until the final voltage EPV or less in the discharge test is 99 cycles for Conventional Example 1, 97 cycles for Conventional Example 2, and 92 cycles for Conventional Example 3. there were. On the other hand, in the case of Example 1, the number of cycles is 118 cycles, and in the case of Example 2, it is 117 cycles. In Examples 1 and 2, sufficient discharge performance is obtained as compared with Conventional Examples 1 to 3. It was confirmed that

  Moreover, about the impact test, it carried out about each alkaline battery of the prior art example 3, Example 1, and Example 2. FIG. In the case of Conventional Example 3, an internal short circuit occurred with a probability of 8 out of 10. On the other hand, in the case of Example 1, an internal short circuit did not occur in all ten batteries. Furthermore, in the case of Example 2, an internal short circuit occurred with a probability of 5 out of 10, but the probability of occurrence could be reduced as compared with the case of Conventional Example 3.

  Therefore, according to the present embodiment, the following effects can be obtained.

  (1) Since the separator 13 of this Embodiment is not fixing the separator materials 31 in the bipolar contact part 35 which is in contact with the positive mix 12 and the gelled negative mix 14, the bipolar contact part 35 is used as an adhesive. The internal resistance can be lowered as compared with the case of fixing with, for example. Further, in the separator 13, the innermost end 33 of the separator material 31 positioned on the inner side and the portion 34 of the second round from the inner side are fixed in the negative electrode terminal side opening 36. In this way, even when the electrolyte solution is immersed in the separator 13, the separator 13 does not bend inward, so that the respective electrode contact portions 35 of the positive electrode mixture 12 and the gelled negative electrode mixture 14 are in contact with each other. The active materials of the agents 12 and 14 can be reacted efficiently. Moreover, by fixing the separator 13 partially in the negative electrode terminal side opening part 36, the fall of a softness | flexibility can be suppressed and impact resistance can be ensured. Therefore, the alkaline battery 10 excellent in impact resistance and discharge performance can be manufactured by using the separator 13 according to the present embodiment.

  (2) In the separator 13 of the present embodiment, the separator material 31 is fixed in a cylindrical shape by thermal fusion, so that the internal resistance can be lowered as compared with the case of fixing with an adhesive.

  (3) In the separator 13 of the present embodiment, the innermost end 33 of the separator material 31 and the second-round portion 34 from the inside are fixed, and the outermost end 37 of the separator material 31 and the second-round portion from the outside 34 is not fixed (in the case of Example 1), compared with the case where the outermost end 37 and the portion 34 of the second round from the outside are fixed (in the case of Example 2), the impact resistance is improved. It can be raised enough.

  In addition, you may change embodiment of this invention as follows.

  -Although separator 13 of the above-mentioned embodiment was fixed in the shape of a cylinder by heat welding, you may adhere and fix using an adhesive. Moreover, although the bottom part 38 of the separator 13 was formed by heat sealing | fusion, it is not limited to this. For example, the bottom of the separator may be formed by disposing a bottom paper (separator material) so as to close the opening of the separator. If it does in this way, a bottom part can be formed, without fixing separator materials. Therefore, compared with the case where the bottom is formed by heat fusion, the electrolytic solution can be absorbed with certainty, and the liquid retention rate of the separator can be increased.

  In the separator 13 of the above-described embodiment, the separator material 31 is formed by wrapping twice (the overlapping portion is triple), but the separator material 31 may be formed by wrapping three or more times. In this case, a separator having excellent impact resistance can be realized by fixing the innermost end 33 of the separator material 31 and the second portion 34 from the inside of the separator.

  In the above embodiment, at the time of manufacturing the alkaline battery separator 13, the water application step is performed before the winding step, and the predetermined portion of the separator material 31 is sufficiently swollen and softened, and then the fixing step is performed. However, for example, the water application step may be performed after the winding step. However, in the case of the latter method in which the water application step is performed after the winding step, it is necessary to devise a method for preventing the water 40 from adhering to an unintended location. .

  In the above embodiment, when the alkaline battery separator 13 is manufactured, the bottom portion 38 is formed by performing heat fusion after the partial fixing step, but the bottom portion is formed by performing heat fusion simultaneously with the partial fixing step. 38 may be formed.

  In the above embodiment, the invention is embodied in the AA alkaline battery 10, but may be embodied in an AA alkaline battery.

  Next, in addition to the technical ideas described in the claims, the technical ideas grasped by the above-described embodiments are listed below.

(1) The separator for alkaline batteries according to any one of claims 1 to 4, wherein the separator members are not fixed to each other at the bottom of the separator.
(2) A method for producing an alkaline battery separator according to claim 4,
Using a rectangular separator material containing vinylon binder fibers, a water applying step for spotting water to one corner of the separator material, and the separator so that the corner with water is on the inner end side From the innermost end of the separator material and the inner side of the separator by heating the separator material in a cylindrical shape by winding the material around the rod-shaped jig two or more times to form a cylindrical shape And a step of partially fixing the second round portion at the opening of the separator.

BRIEF DESCRIPTION OF THE DRAWINGS Sectional drawing which shows the alkaline battery of one Embodiment which actualized this invention. (A) is a perspective view of a separator, (b) is a top view of a separator. (A)-(d) is explanatory drawing which shows the manufacturing method of a separator. (A) is a perspective view of the conventional separator, (b) is a top view of the conventional separator. The perspective view which shows the conventional separator. The perspective view which shows the conventional separator. The perspective view which shows the conventional separator.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Alkaline battery 12 ... Positive electrode mixture as a positive electrode active material 13 ... Separator 14 ... Gel-like negative electrode mixture as a negative electrode active material 31 ... Separator material 33 ... Innermost end 34 ... Second-round part 35 ... Bipolar contact part 36 ... Negative electrode terminal side opening 37 ... Outermost end 39 ... Corner 40 ... Water

Claims (6)

A separator for an alkaline battery that is formed into a bottomed cylindrical shape having an opening on the negative electrode terminal side by winding one separator material two or more times, and is disposed between a positive electrode active material and a negative electrode active material,
While the separator materials are not fixed to each other in contact with the positive electrode active material and the negative electrode active material, the innermost end of the separator material located inside the separator and at least a second turn from the inside of the separator A separator for an alkaline battery, wherein the portion is fixed in the opening on the negative electrode terminal side that does not belong to the bipolar contact portion.   2. The separator for an alkaline battery according to claim 1, wherein an innermost end of the separator material and a portion of the second round from the inner side of the separator are fixed by heat fusion.   2. The separator for an alkaline battery according to claim 1, wherein the innermost end of the separator material and the second round portion from the inside of the separator are bonded and fixed with an adhesive.   The separator for an alkaline battery according to any one of claims 1 to 3, wherein an outermost end of the separator material located outside the separator and a portion of the second circumference from the outside of the separator are not fixed. . A method for producing the alkaline battery separator according to claim 4,
Using a rectangular separator material containing a thermoplastic binder fiber, a water application step of adding water to one corner of the separator material;
A winding step in which the separator material is wound two or more times so that the corner with water is on the inner end side to form a cylinder;
A partial fixing step of partially fixing the innermost end of the separator material and the second round portion from the inside of the separator by heating the separator material in a state of being wound in a cylindrical shape. The manufacturing method of the separator for alkaline batteries characterized by including.   An alkaline battery comprising the alkaline battery separator according to any one of claims 1 to 4.

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