JP5159076B2 - Cylindrical storage battery and manufacturing method thereof - Google Patents

Description

  The present invention relates to a cylindrical storage battery such as a nickel-hydrogen storage battery, a nickel-cadmium storage battery, or a lithium secondary battery. In particular, the positive electrode plate and the negative electrode plate are stacked via a separator, and the electrode group is wound in a spiral shape. An electrode body in which a positive electrode current collector is welded to one end and a negative electrode current collector is welded to the other end is a metal first outer can that also serves as a positive electrode terminal and a second outer can that also serves as a negative electrode terminal The present invention relates to a cylindrical storage battery that is housed in between, the openings of the first outer can and the second outer can are sealed through an insulator, and the electrode body is sealed in these cans.

  In recent years, cylindrical storage batteries such as nickel-hydrogen storage batteries, nickel-cadmium storage batteries, and lithium secondary batteries have been used for personal computers (PCs), personal digital assistants (PDAs), mobile phones, electric vehicles (EV), hybrid vehicles ( HEV), electric bikes, assist bicycles, electric tools, etc. have become widespread. Among these, especially in high output applications such as electric vehicles (EV), hybrid vehicles (HEV), electric motorcycles, assist bicycles or electric tools, high reliability such as battery performance and long-term durability, and more High quality is required and various developments are being made.

  In this type of cylindrical storage battery, a positive electrode plate and a negative electrode plate are usually laminated via a separator and wound into a spiral shape to form an electrode group, and then a conductive edge (negative electrode core body) of the negative electrode plate of this electrode group. ) To the negative electrode current collector, and the conductive edge (positive electrode core) of the positive electrode plate is welded to the positive electrode current collector to form an electrode body. Next, the obtained electrode body is inserted into a metal outer can that also serves as a negative electrode terminal, the negative electrode current collector is welded to the bottom of the metal outer can, and the current collecting lead portion extending from the positive electrode current collector is connected to the positive electrode. Generally, after welding to the bottom of the sealing body that also serves as a terminal, an electrolytic solution is injected, and the sealing body is attached to the opening of the outer can via an insulating gasket and sealed.

  By the way, in the cylindrical storage battery used for the high output application as described above, charging and discharging are performed with a large current of several tens of amperes to several hundreds of amperes. As a result of the voltage drop, the operating voltage is lowered, resulting in a problem that high voltage and high energy density cannot be obtained. For this reason, in order to achieve high output characteristics and high energy density, it is desired to reduce the resistance at the current collecting lead portion. Therefore, a cylindrical storage battery that can achieve a high output characteristic and a high energy density by adopting a connection structure that can omit the current collecting lead portion is proposed in Patent Document 1 (Japanese Patent Laid-Open No. 2001-160388). It was.

  In the cylindrical storage battery 40 proposed in Patent Document 1 as described above, as shown in FIG. 8, a positive electrode plate 41 and a negative electrode plate 42 are stacked via a separator 43 and wound in a spiral shape to form an electrode. Then, the conductive edge (positive electrode core) 41a of the positive electrode plate 41 of this electrode group is welded to the positive electrode current collector 44, and the conductive edge (negative electrode core) 42a of the negative electrode plate 42 is welded to the negative electrode current collector. An electrode body is formed by welding to the body 45. Next, the obtained electrode body is inserted into a metal outer can 46 also serving as a negative electrode terminal, and the negative electrode current collector 45 is welded to the bottom of the metal outer can 46. On the other hand, a protrusion 47a is provided on the lower surface of the sealing body 47 that seals the opening of the metal outer can 46 and also serves as a positive electrode terminal, and the protrusion 47a and the positive electrode current collector 44 are welded and fixedly connected. Yes.

  Thereafter, an electrolytic solution is injected, and a sealing body 47 is attached to the opening of the outer can via an insulating gasket 48 so as to be sealed. A gas vent hole 47b is provided at the center of the sealing body 47, and a positive electrode cap 49 is disposed so as to cover the gas vent hole 47b. A valve plate 49a, a spring 49b, The valve body which consists of is provided. As described above, when the projecting portion 47a is provided on the lower surface of the sealing body 47, the sealing body 47 and the positive electrode current collector 44 can be reliably welded even if the current collecting lead portion is omitted. Since the resistance can be reduced to zero, the output characteristics of the battery can be improved and the battery voltage can be prevented from decreasing during high rate discharge.

  However, in the cylindrical storage battery 40 proposed in Patent Document 1 as described above, a groove is formed on the outer periphery of the outer can 46 to form an annular groove 46a, and the outer periphery of the sealing body 47 is insulated. The gasket 48 is fitted. Thereafter, the insulating gasket 48 is disposed in the annular groove 46a, and a pressure is applied to the sealing body 47 using a press machine. The sealing body 47 is moved to the outer can 46 until the lower end of the insulating gasket 48 is positioned at the annular groove 46a. After being pushed in, the opening edge of the outer can 46 is caulked inward to seal it. Therefore, a space portion is formed between the positive electrode current collector 44 and the sealing body 47, and a downward projecting portion 47a of the sealing body 47 corresponding to the distance of the space portion (this lower projecting portion 47a serves as a current collecting lead). (Which can be said to be equivalent) is required to be high (the length of the current collecting lead is long), which causes a problem that the battery resistance increases.

  Therefore, the present applicant does not use the sealing body 47 in which the downward projecting portion 47a is formed, but a cylindrical storage battery in which the entire surface of the positive electrode current collector is in direct contact with the sealing body (in this case, the first casing). Proposed in Japanese Patent Application No. 2006-52324. The cylindrical storage battery 50 proposed in Japanese Patent Application No. 2006-52324 includes a container including a conductive first casing 51 and a second casing 52, as shown in FIG. Then, the positive electrode plate 53 and the negative electrode plate 54 are spirally wound through the separator 55 in the container, and the positive electrode current collector 53 (positive electrode core) 53a of the positive electrode plate 51 of the electrode group is connected to the positive electrode current collector 56. An electrode body that is welded and in which a negative electrode current collector 57 is welded to a conductive edge (negative electrode core) 54a of the negative electrode plate 54 is accommodated.

  Here, the second casing 52 accommodates most of the electrode bodies, and the first casing 51 accommodates the remaining electrode bodies. The upper end wall of the container to which the positive electrode current collector 56 is welded is the bottom wall of the first casing 51, and the first casing 51 functions as a positive electrode terminal. The lower end wall of the container to which the negative electrode current collector 57 is welded is the bottom wall of the second casing 52, and the second casing 52 has a function as a negative electrode terminal. In order to connect the opening ends of the first casing 51 and the second casing 52, outward flanges 51b and 52b are respectively connected to the casings 51 and 52 at the opening ends of the first and second casings 51 and 52, respectively. It is integrally formed.

Then, the outer peripheral edge of the outward flange 52b of the second casing 52 becomes a caulking portion, and this caulking portion is bent so as to cover the outer peripheral portion of the outward flange 51b of the first casing 51, and the outward direction of the first casing 51 The outer peripheral part of the flange 51b is restrained. As a result, the first casing 51 and the second casing 52 are coupled, and the inside of the battery is hermetically sealed. However, the outward flange 51 b of the first casing 51 is substantially covered with an annular insulating gasket 59 in order to ensure electrical insulation and airtightness between the first casing 51 and the second casing 52. In addition, a gas vent hole is formed in the center of the bottom wall of the first casing 51, and a positive electrode cap 58 is disposed so as to cover the gas vent hole, and a valve plate 58a and a spring 58b are provided in the positive electrode cap 58. A valve body is provided.
JP 2001-160388 A

  However, in the cylindrical storage battery 50 proposed in the above-mentioned Japanese Patent Application No. 2006-52324, the positive electrode current collector welded to the upper end of the spiral electrode group is directly welded to the inner bottom surface of the first casing 51. . For this reason, if the height of the spiral electrode group varies, there arises a problem that the whole battery height varies and a uniform product cannot be stably produced. On the other hand, if the pressing force (compression force) of the annular insulating gasket 59 serving as the sealing portion is adjusted in order to prevent the variation in the total battery height, this causes the compression variation of the insulating gasket 59 to occur. For this reason, when the pressing force (compression force) of the insulating gasket 59 is weak, there arises a problem that the electrolyte solution leaks at the sealing portion.

  Accordingly, the present invention has been made to solve the above-described problems, and even if the spiral electrode group has a height variation, a uniform product can be stably produced so that the overall battery height does not vary. An object of the present invention is to provide a highly reliable and high-quality cylindrical storage battery that can be produced and does not cause electrolyte leakage in the sealing portion.

The cylindrical storage battery of the present invention has a positive electrode current collector welded to one end of an electrode group in which a positive electrode plate and a negative electrode plate are laminated via a separator and wound in a spiral shape, and a negative electrode current collector is connected to the other end. The electrode body to which the electric body is welded is accommodated between a metal first outer can that also serves as a positive electrode terminal and a metal second outer can that also serves as a negative electrode terminal, and the first outer can and the second outer can The opening is sealed through an insulator, and the electrode body is sealed in these cans. And in order to solve the said subject, a positive electrode collector is directly electrically connected to the bottom part of the metal 1st exterior can which also serves as a positive electrode terminal, and a negative electrode current collector is a metal 2nd exterior can also serving as a negative electrode terminal. The first and second outer cans are electrically connected directly to the bottom, and each of the first outer can and the second outer can is a bottomed cylindrical portion, an opening edge of the cylindrical portion, and a portion in the vicinity thereof. And a flange portion extending in the radial direction , and a concave portion is formed toward the inside of the battery in at least one bottom portion of the bottomed cylindrical portion.

As described above, when the concave portion is formed toward the inside of the battery in at least one bottom portion of the bottomed cylindrical portion, the pressing force to the concave portion is adjusted even if the spiral electrode group has a height variation. As a result, the overall height of the battery can be made uniform. As a result, there is no variation in the overall height of the battery, and there is no leakage at the sealing portion, so that a highly reliable and high quality cylindrical storage battery can be provided. In this case, the recess together is formed in the center portion of the bottom portion of the cylindrical portion of the bottomed, the bottom surface of the recess is desirably are made flat.

In order to manufacture the cylindrical storage battery as described above, a second metal made also serving as a negative electrode terminal having a bottomed cylindrical portion and a flange portion extending outward from the edge of the opening of the cylindrical portion. A negative electrode current collector of an electrode body is welded to the bottom surface of the outer can, and a bottomed cylindrical portion, an opening edge of the cylindrical portion, and a vicinity thereof , a flange portion extending from the cylindrical portion in an outer diameter direction A welding step of welding the positive electrode current collector of the electrode body to the bottom surface of the metal first outer can also serving as the positive electrode terminal, and between the flange portion of the first outer can and the flange portion of the second outer can After the insulating gaskets are arranged and overlapped so that both flange portions face each other, a predetermined distance is formed between the bottom surface of the cylindrical portion of the first outer can and the bottom surface of the cylindrical portion of the second outer can. The pressurizing process that pressurizes each other and caulking part of both flanges that are overlapped to face each other It is sufficient to include a sealing step of sealing.
Thus, if a concave portion is formed toward the inside of the battery in at least one bottom portion of the bottomed cylindrical portion, the concave portion is deformed (bulged out) from the inside of the can to the outside due to the pressurizing force in the pressurizing step. ) And variation in the overall battery height is suppressed.

  According to the present invention, it is possible to suppress variation in low resistance and variation in the overall height of the battery and compression variation of the insulating member in the sealing portion. Therefore, a highly reliable cylindrical battery in which the overall height of the battery is uniform and no electrolyte leakage occurs. Can be provided.

  Below, although one embodiment at the time of applying the present invention to a nickel-hydrogen storage battery is described based on Drawing 1-Drawing 7, the present invention is not limited to this, and the range which does not change the gist And can be implemented with appropriate changes. FIG. 1 is a view showing a nickel-hydrogen storage battery according to an embodiment of the present invention. FIG. 1 (a) shows an electrode body housed in a battery container composed of a first outer can and a second outer can. It is sectional drawing which shows the completed nickel-hydrogen storage battery typically, FIG.1 (b) shows typically the electrode body by which the positive / negative electrode electrical power collector was welded to the upper and lower end part of the spiral electrode group. FIG. 1C is a top view schematically showing a negative electrode current collector welded to the lower end portion of the spiral electrode group. FIG. 2 is a view showing an outer can, FIG. 2 (a) is a half sectional view showing a first outer can (positive electrode outer can), and FIG. 2 (b) is a second outer can (negative electrode outer can). FIG.

  FIG. 3 is a view showing a welding process, and FIG. 3A is a half sectional view schematically showing a state in which the negative electrode current collector is welded to the bottom surface of the second outer can (negative electrode outer can). (B) is a half cross-sectional view schematically showing a state in which the positive electrode current collector is welded to the bottom surface of the first outer can (positive electrode outer can). FIG. 4 is a half sectional view schematically showing the sealing step. FIG. 5 is a half sectional view schematically showing a nickel-hydrogen storage battery in a temporarily sealed state. FIG. 6 is a half cross-sectional view showing a state in the vicinity of the bottom of the second outer can (negative electrode outer can) of the nickel-hydrogen storage battery after sealing, and FIG. 6 (a) is a state when the total height of the spiral electrode group is low. FIG. 6B is a half sectional view schematically showing a state in which the total height of the spiral electrode group is high. FIG. 7 is a half sectional view schematically showing a nickel-hydrogen storage battery according to a modification of the present invention.

1. Nickel-hydrogen storage battery As shown in FIG. 2A, the nickel-hydrogen storage battery 10 of the embodiment of the present invention also serves as a positive electrode terminal, and has a bottomed cylindrical portion 11a and an opening edge of the cylindrical portion. As shown in FIG. 2B, the first metal outer can 11 provided with the flange portion 11b extending outward, and also serving as the negative electrode terminal, the bottomed cylindrical portion 12a, and the cylindrical portion A battery container including a second outer can 12 having a flange portion 12b extending outward from the edge of the opening is provided. As shown in FIG. 1, a positive electrode plate 14 and a negative electrode plate 15 are stacked in this battery container via a separator 15 and wound in a spiral shape at one end of a spiral electrode group a1. The electrode body a to which the electric body 16 is welded and the negative electrode current collector 17 is welded to the other end portion and the alkaline electrolyte are accommodated.

  In this case, as shown in FIG. 1B, the positive electrode current collector 16 has a central opening 16b for inserting a welding electrode formed at the center of a substantially circular main body 16a. A large number of burring holes 16c are formed toward the end of the main body 16a, and projection projections 16d are formed around the central opening 16b. Further, a pair of slits 16e and 16e are formed which open from the middle between the center opening 16b and the end of the main body 16a toward the end edge. By providing such slits 16e, 16e, it becomes possible to reduce the invalid welding current and increase the effective welding current. The positive electrode current collector 16 is directly electrically connected by welding a projection projection 16d to the bottom surface of the first metal outer can 11 serving also as a positive electrode terminal.

  On the other hand, as shown in FIG. 1C, the negative electrode current collector 17 has a plurality of projection protrusions 17b formed at the center of a substantially circular main body portion 17a, and the main body extends from the periphery of the projection protrusions 17b. A large number of burring holes 17c are formed toward the end of the portion 17a, and a pair of slits 17d and 17d are formed that open from the middle to the edge of the center portion and end of the main body portion 17a. Yes. The negative electrode current collector 17 is configured to be directly electrically connected by welding a projection projection 17b to the bottom surface of the second metal outer can 12 also serving as a negative electrode terminal.

  Here, a recess 12c is formed at the center of the bottom of the cylindrical portion 12a of the second outer can 12, and the bottom surface of the recess 12c is a flat surface. A convex portion 12d that protrudes outward from 12c is formed. A gas vent hole 11c is formed in the center of the bottom of the cylindrical portion 11a of the first outer can 11 and a positive electrode cap 18 is attached so as to cover the gas vent hole 11c. A valve body composed of a valve plate 18a and a spring 18b is disposed therein.

2. Manufacturing Method Next, a manufacturing method of the nickel-hydrogen storage battery having the above-described configuration will be described below.
After forming a nickel sintered porous body on the surface of the positive electrode core body made of punching metal, an active material mainly composed of nickel hydroxide was filled into the nickel sintered porous body by a chemical impregnation method to form an active material filled layer. . Subsequently, after drying this, it rolled until it became predetermined thickness, and cut | disconnected so that it might become a predetermined dimension, and the nickel positive electrode plate 13 was produced. A core body exposed portion 13 a is formed at the upper end of the nickel positive electrode plate 13 so that the positive electrode core body is exposed.

  On the other hand, the surface of the negative electrode core made of punching metal was filled with a paste-like negative electrode active material made of a hydrogen storage alloy to form an active material filled layer. Next, after drying this, it was rolled to a predetermined thickness and cut to a predetermined size to produce a hydrogen storage alloy negative electrode plate 14. Note that a core body exposed portion 14 a in which the negative electrode core body is exposed is formed at the lower end portion of the hydrogen storage alloy negative electrode plate 14.

  These nickel positive electrode plate 13 and hydrogen storage alloy negative electrode plate 14 are laminated with a separator 15 made of polypropylene nonwoven fabric interposed therebetween, and then wound into a spiral shape so that the diameter becomes approximately 30 mm. Electrode group a1 was produced. The core exposed portion 13a of the nickel positive electrode plate 13 is exposed at the upper portion of the spiral electrode group a1 thus manufactured, and the core exposed portion 14a of the hydrogen storage alloy negative electrode plate 14 at the lower portion thereof. Is exposed.

  Next, the positive electrode current collector 16 described above is placed on the core body exposed portion 13a of the nickel positive electrode plate 13 exposed at the upper end surface of the spiral electrode group a1 thus obtained. A pair of welding electrodes (not shown) are mounted. The positive electrode current collector 16 is pressed by the pair of welding electrodes so that each burring hole 16c of the positive electrode current collector 16 is bitten into the core body exposed portion 13a of the positive electrode plate 13 slightly protruding from the electrode plate group a1. The positive electrode current collector 16 was welded to the core exposed portion 13a of the nickel positive electrode plate 13 by flowing a welding current between the pair of welding electrodes and resistance welding.

Further, the above-described negative electrode current collector 17 is placed on the core exposed portion 14 a of the hydrogen storage alloy negative electrode plate 14 exposed at the lower end surface of the spiral electrode group a 1, and the negative electrode current collector 17 is placed on the negative electrode current collector 17. A pair of welding electrodes (not shown) is placed. The negative electrode current collector 17 is pressed by the pair of welding electrodes so that each burring hole 17c of the negative electrode current collector 17 is bitten into the core body exposed portion 14a of the negative electrode plate 14 slightly protruding from the electrode plate group a1. The negative electrode current collector 17 was welded to the core exposed portion 14a of the hydrogen storage alloy negative electrode plate 14 by resistance welding with a welding current flowing between the pair of welding electrodes.
Thus, the positive electrode current collector 16 is welded to the upper end surface of the spiral electrode group a1, and the negative electrode current collector 17 is welded to the lower end surface of the spiral electrode group a1 (see FIG. 1B). Will be obtained.

  Next, as shown in FIG. 2 (a), an iron provided with a bottomed cylindrical portion 11a that also serves as a positive electrode terminal and a flange portion 11b that extends outward from the opening edge of the cylindrical portion 11a. A metal first outer can 11 with nickel plating was prepared. A gas vent hole 11c is formed at the center of the bottom of the cylindrical portion 11a of the first outer can 11, and a positive electrode cap 18 is attached to cover the gas vent hole 11c. A valve body including a valve plate 18 a and a spring 18 b is disposed in the positive electrode cap 18.

  On the other hand, as shown in FIG. 2 (b), an iron provided with a bottomed cylindrical portion 12a that also serves as a negative electrode terminal and a flange portion 12b that extends outward from the opening edge of the cylindrical portion 12a. A metallic second outer can 12 having a nickel plating was prepared. In this case, a recess 12c is formed at the center of the bottom of the cylindrical portion 12a of the second outer can 12, and the bottom surface of the recess 12c is a flat surface. A convex portion 12d that protrudes outward from 12c is formed. A part of the flange portion 12b has a rising portion 12e perpendicular to the flange portion 12b.

  Next, the electrode body a was housed in the cylindrical portion 12 a of the second outer can 12 so that the negative electrode current collector 17 side of the electrode body a formed as described above faces downward. Thereafter, as shown in FIG. 3A, the first welding electrode R1 is disposed on the outer bottom surface of the second outer can 12 and the second welding electrode (welding electrode rod) is passed through the central opening 16b of the positive electrode current collector 16. ) R2 was inserted in contact with the surface of the negative electrode current collector 17. Thereafter, an energization process was performed in which a predetermined welding current (in this case, a pulse current of 2 kA) was passed between the welding electrodes R1 and R2. By this energization process, the flat surface of the recess 12 c formed at the bottom of the cylindrical portion 12 a of the second outer can 12, and the projection protrusion 17 d formed on the negative electrode current collector 17 welded to the hydrogen storage alloy negative electrode plate 15, Will be resistance welded. Thereafter, 10 g of alkaline electrolyte made of 7N KOH was injected into the second outer can 12.

  Next, as shown in FIG. 3 (b), after the nylon insulating gasket 19 is disposed on the flange portion 12 b of the second exterior can 12, the first exterior can 11 is disposed on the second exterior can 12. did. Thereafter, the third welding electrode R3 was disposed on the outer bottom surface of the second outer can 12 and the fourth welding electrode R4 of the first outer can 11 was disposed. In this case, a space R4-a for protecting the positive electrode cap 18 is formed on the lower surface of the fourth welding electrode R4. Thereafter, an energization process was performed to pass a predetermined welding current (in this case, a 4 kA pulse current) between the welding electrodes R3 and R4. By this energization process, the inner bottom surface of the first outer can 12 and the projection protrusion 16 d formed on the positive electrode current collector 16 welded to the nickel positive electrode plate 14 are resistance-welded.

  Next, the negative electrode current collector 17 is welded to the flat surface of the concave portion 12c formed at the center of the bottom portion of the cylindrical portion 12a of the second outer can 12 as described above, and the inner portion of the cylindrical portion 11a of the first outer can 11 is After welding the positive electrode current collector 16 to the bottom surface, the second outer can 12 was placed in a cylindrical fixing jig 20 as shown in FIG. In this case, the flange portion 12 b of the second outer can 12 was arranged to be placed on the upper end portion of the fixing jig 20. Thereafter, the lower caulking punch 22 was inserted into the fixing jig 20 from below the fixing jig 20, and the lower caulking punch 22 was brought into contact with the outer bottom surface of the second outer can 12. Next, an upper caulking punch 23 was disposed on the upper portion of the first outer can 12. Thereafter, a pressing force is applied to each of the lower caulking punch 22 and the upper caulking punch 23 to press the bottom surface portion of the cylindrical portion 11a of the first outer can 11 to a predetermined position, and the lower surface portion of the second outer can 12 is predetermined. Pressed to position.

  Thereby, according to the height variation of the electrode group a1, the recess 12c formed at the center of the bottom of the cylindrical portion 12a of the second outer can 12 is pressed toward the outside of the second outer can 12, The second outer can 12 is deformed (bulged) outward. At this time, while pressing the upper caulking punch 23, the tapered portion 23 a formed on the outer peripheral portion of the upper caulking punch 23 is pressed against the rising portion 12 e of the flange portion 12 b of the second outer can 12. As a result, the rising portion 12e of the flange portion 12b of the second outer can 12 is bent inward, and the flange portion 11b of the first outer can 11 is inserted through the insulating gasket 19 as shown in FIG. 2 The outer can 12 is temporarily sealed by the rising portion 12e.

  In this case, when the upper caulking punch 23 comes into contact with the first outer can 11, the positive electrode terminal and the negative electrode terminal are short-circuited. For example, the cylindrical insulating member 24 is disposed on the bottom surface of the upper caulking punch 23. Thus, it is necessary to prevent contact between the upper caulking punch 23 and the first outer can 11. Then, after temporarily sealing as described above, the temporary sealing portion is pressed by a caulking punch (not shown) formed so that the contact surface is horizontal, so that the nominal capacity as shown in FIG. A 0 Ah cylindrical nickel-hydrogen storage battery was produced, and this was designated as battery A of Example 1.

  On the other hand, using the electrode body a described above, a cylindrical nickel-hydrogen storage battery having a nominal capacity of 6.0 Ah was prepared as described in Patent Document 1 (see FIG. 8), and this was used as the battery of Comparative Example 1. X. Further, similarly as described in the prior application (Japanese Patent Application No. 2006-52324: see FIG. 9), a cylindrical nickel-hydrogen storage battery having a nominal capacity of 6.0 Ah is manufactured using the electrode body a described above. This was designated as Battery Y of Comparative Example 2.

3. Battery Test (1) Battery Total Height Results Next, using the battery A of Example 1, the battery X of Comparative Example 1, and the battery Y of Comparative Example 2 manufactured as described above, each of these 100 batteries A, The total heights of X and Y were measured respectively. Thereafter, a battery having a height variation of 2% or more with respect to the total battery height (reference value) is determined as the total battery height NG (defective), and the number thereof is obtained. The result shown in Table 1 below is obtained. Obtained.

(2) Measurement of battery resistance index Next, using the battery A of Example 1, the battery X of Comparative Example 1, and the battery Y of Comparative Example 2 manufactured as described above, 6A (1 ItA ) To 50% of the battery capacity.
Then, 30A discharge → 30A charge → 60A discharge → 60A charge → 90A discharge → 90A charge → 120A discharge → 120A charge → 150A discharge → 150A charge The battery voltage (V) after 10 seconds was measured.
Thereafter, the V-I straight line was obtained with the discharge current (A) as the horizontal axis (X axis) and the battery voltage (V) after 10 seconds as the vertical axis (Y axis).
Next, the slope of the V-I straight line is obtained as the battery DC resistance, the battery DC resistance of the battery A is taken as a reference (100), and the battery DC resistance of the battery X and the battery Y is obtained as a ratio thereof. The results shown were obtained.

  As is clear from the results in Table 1 above, it can be seen that the battery X of Comparative Example 1 has a high battery resistance and a large variation in the overall battery height. In addition, it can be seen that the battery Y of Comparative Example 2 has low battery resistance but small variation in the overall battery height. On the other hand, it can be seen that the battery A of Example 1 has a low battery resistance and a small variation in the total battery height. That is, in the battery A of Example 1, it is possible to reduce the variation in the total battery height while maintaining a low battery resistance.

  FIG. 6 schematically shows a state in the vicinity of the bottom of the second outer can (negative electrode outer can) 12 of the battery A of Example 1 after completion. Here, when the total height of the spiral electrode group a1 is low, as shown in FIG. 6A, it can be seen that the amount of deformation (bulging) of the recess 12c is small. On the other hand, when the total height of the spiral electrode group is high, as shown in FIG. 6B, it can be seen that the amount of deformation (bulging) of the recess 12c becomes large. Thus, in the battery A of Example 1, the deformation of the recess 12c formed on the bottom of the cylindrical portion 12a of the second outer can (negative electrode outer can) 12 according to the height of the spiral electrode group a1 ( The amount of bulging will change. As a result, the variation in the height of the spiral electrode group a1 can be absorbed by the deformation (bulge) amount of the recess 12c, so that the compression amount of the insulating gasket 19 at the sealing portion can always be kept constant. become. As a result, in a cylindrical nickel-hydrogen storage battery for high output use, it is possible to achieve high sealing performance, high quality and high reliability.

4). In the above-described first embodiment, the example in which the concave portion is formed in the bottom portion of the cylindrical portion of the second outer can (negative electrode outer can) has been described. Such a concave portion is formed in the first outer can (positive electrode outer can). You may make it provide. Next, a cylindrical nickel-hydrogen storage battery of a modified example in which a concave portion is formed at the bottom of the cylindrical portion in the first outer can (positive electrode outer can) will be described with reference to FIG.
As shown in FIG. 7, the cylindrical nickel-hydrogen storage battery 30 of this modification forms a battery container with a first outer can (positive electrode outer can) 31 and a second outer can (negative electrode outer can) 32. In this container, an electrode body a (one end portion of a spiral electrode group a1 in which a positive electrode plate 14 and a negative electrode plate 15 are laminated via a separator 15 and wound in a spiral manner, as in the above-described embodiments) The positive electrode current collector 16 is welded to the other end, and the negative electrode current collector 17 is welded to the other end) and the alkaline electrolyte is sealed.

  The first outer can (positive electrode outer can) 31 includes a bottomed cylindrical portion 31a in which nickel plating is applied to iron, and a flange portion 31b extending outward from the opening edge of the cylindrical portion 31a. ing. In this case, a concave portion 31c is formed at the bottom of the cylindrical portion 31a, and a convex portion 32d is formed at the outer peripheral portion of the concave portion 31c. A gas vent hole 31e is formed at the center of the bottom of the cylindrical portion 31a of the first outer can 31 and a positive electrode cap 38 is attached so as to cover the gas vent hole 31e. A valve body including a valve plate 38a and a spring 38b is disposed in the positive electrode cap 38. On the other hand, the second outer can (negative electrode outer can) 32 includes a bottomed cylindrical portion 32a in which nickel is plated on iron, and a flange portion 32b extending outward from the opening edge of the cylindrical portion 32a. It has.

  When such a first outer can (positive electrode outer can) 31 is used, as shown in FIG. 4, a pressing force is applied to the lower caulking punch 22 and the upper caulking punch 23, and the bottom surface of the cylindrical portion 31 a of the first outer can 31. When the bottom portion of the second outer can 32 is pressed to a predetermined position, the bottom portion of the cylindrical portion 31a of the first outer can 31 is formed according to the height variation of the electrode group a1. The recessed portion 31 c is deformed (bulged) toward the outside of the first outer can 31. As a result, in the cylindrical nickel-hydrogen storage battery 30 of the present modification, as in the embodiment, the height variation of the spiral electrode group a1 can be absorbed by the deformation (bulge) amount of the recess 31c. The amount of compression of the insulating gasket 39 at the stop portion can be kept constant at all times, so that the sealing performance is high, and high quality and high reliability can be achieved.

  In addition, although the bottom part of the cylindrical part 32a of the 2nd exterior can (negative electrode exterior can) 32 of this modification is formed so that the whole may become a plane, the cylindrical part 12a of the Example mentioned above is also formed in this bottom part. You may make it form a recessed part similarly to a bottom face. Further, although the projection protrusions 16d and 17b are respectively provided on the positive electrode current collector 16 and the negative electrode current collector 17 in the above-described embodiment, the positive electrode current collector and the first exterior can be provided without providing these projection protrusions. The same effect can be obtained if the can (positive electrode outer can) and the negative electrode current collector can be in direct contact with the second outer can (negative electrode outer can).

  In the embodiment described above, an example in which the present invention is applied to a nickel-hydrogen storage battery has been described. However, the present invention can be applied to a sealed storage battery such as a nickel-cadmium storage battery or a lithium secondary battery in addition to a nickel-hydrogen storage battery. It is clear that the same effect can be obtained even if applied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view showing a nickel-hydrogen storage battery according to an embodiment of the present invention, and FIG. 1 (a) is a diagram showing a completed nickel-hydrogen battery housed in a battery container composed of a first outer can and a second outer can. FIG. 1 (b) is a perspective view schematically showing an electrode body in which positive and negative electrode current collectors are welded to the upper and lower ends of a spiral electrode group; FIG.1 (c) is a top view which shows typically the negative electrode electrical power collector welded to the lower end part of the spiral electrode group. FIG. 2A is a half sectional view schematically showing a first outer can (positive electrode outer can), and FIG. 2B is a second outer can (negative electrode outer can). It is a half sectional view showing typically. FIG. 3 (a) is a half sectional view schematically showing a state in which the negative electrode current collector is welded to the bottom surface of the second outer can (negative electrode outer can). FIG. 5 is a half cross-sectional view schematically showing a state in which a positive electrode current collector is welded to the bottom surface of a first outer can (positive electrode outer can). It is a half cross-sectional view schematically showing the sealing step. It is a half sectional view showing typically a nickel-hydrogen storage battery of a temporarily sealed state. FIG. 6A is a half cross-sectional view showing a state in the vicinity of the bottom of the second outer can (negative electrode outer can) of the nickel-hydrogen storage battery after sealing, and FIG. 6A schematically shows the state when the total height of the spiral electrode group is low. FIG. 6B is a half sectional view schematically showing a state where the total height of the spiral electrode group is high. It is a half sectional view showing typically the nickel hydride storage battery of the modification of the present invention. It is sectional drawing which shows typically the cylindrical nickel-hydrogen storage battery of a prior art example (comparative example 1). It is a half sectional view showing typically a cylindrical nickel-hydrogen storage battery of other conventional examples (comparative example 2).

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Nickel-hydrogen storage battery, 11 ... 1st exterior can (positive electrode exterior can), 11a ... Cylindrical part, 11b ... Flange part, 12 ... 2nd exterior can (negative electrode exterior can), 12a ... Cylindrical part, 12b ... Flange part , 12c ... concave portion, 12d ... convex portion, 13 ... nickel positive electrode plate, 13a ... core exposed portion, 14 ... hydrogen storage alloy negative electrode plate, 14a ... core exposed portion, 15 ... separator, 16 ... positive electrode current collector, 17 ... Negative electrode current collector, 18 ... Positive electrode cap, 18a ... Valve plate, 18b ... Spring, 19 ... Insulating gasket

Claims (4)

An electrode body in which a positive electrode current collector is welded to one end of an electrode group in which a positive electrode plate and a negative electrode plate are stacked via a separator and wound in a spiral shape, and a negative electrode current collector is welded to the other end Is accommodated between a metal first outer can also serving as a positive electrode terminal and a metal second outer can also serving as a negative electrode terminal, and an opening between the first outer can and the second outer can is interposed via an insulator. A cylindrical storage battery that is sealed and the electrode body is sealed in these cans,
The positive electrode current collector is directly electrically connected to the bottom surface of the first metal outer can also serving as the positive electrode terminal, and the negative electrode current collector is directly electrically connected to the bottom surface of the second metal outer can serving also as the negative electrode terminal. Connected to the
The first outer can and the second outer can each have a bottomed cylindrical portion, an opening edge of the cylindrical portion, and a portion in the vicinity thereof , and a flange portion extending in an outer diameter direction from the cylindrical portion. A cylindrical storage battery, wherein a recess is formed in the bottom of at least one of the bottomed cylindrical portions toward the inside of the battery.   2. The cylindrical storage battery according to claim 1, wherein the concave portion is formed at a central portion of the bottom portion of the bottomed cylindrical portion, and a bottom surface of the concave portion is a flat surface. An electrode body in which a positive electrode current collector is welded to one end of an electrode group in which a positive electrode plate and a negative electrode plate are stacked via a separator and wound in a spiral shape, and a negative electrode current collector is welded to the other end Is accommodated between the first metal outer can also serving as the positive electrode terminal and the second outer can serving also as the negative electrode terminal, and the opening between the first outer can and the second outer can is sealed through an insulator. A cylindrical storage battery manufacturing method for sealing the electrode body in these cans,
The bottom of the metal second outer can that also serves as a negative electrode terminal having a bottomed cylindrical portion, an opening edge of the cylindrical portion, and a portion in the vicinity thereof , and a flange portion extending from the cylindrical portion in the outer diameter direction. A negative electrode current collector of the electrode body is welded to a bottomed cylindrical portion, an opening edge of the cylindrical portion, and a portion in the vicinity thereof , and a flange portion extending in an outer diameter direction from the cylindrical portion. Welding the positive electrode current collector of the electrode body to the bottom of the first metal outer can that also serves as the positive electrode terminal;
After the insulating gasket is disposed between the flange portion of the first outer can and the flange portion of the second outer can and the two flange portions are opposed to each other, the cylindrical portion of the first outer can A pressurizing step of pressurizing each other so that a predetermined distance is formed between the bottom of the second outer can and the cylindrical portion of the second outer can,
A method of manufacturing a cylindrical storage battery, comprising: a sealing step of caulking and sealing a part of both flange portions that are overlapped so as to face each other. At least one bottom of the bottomed cylindrical portion is formed with a recess toward the inside of the battery, and the recess is deformed from the inside of the can toward the outside by the pressing force in the pressurizing step. The manufacturing method of the cylindrical storage battery of Claim 3 characterized by the above-mentioned.

Images