JP2009087835A - Storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a storage battery in which, by improving an upper current collector welded to the tip portion of a current collection part of one of electrode plates protruded to the upper side of the electrode group, current collection on the outer periphery side of the electrode group in which the current flow distance from a tab terminal is far is improved and which has a small internal resistant and is suitable for large current discharge. <P>SOLUTION: In the storage battery, the upper current collector 21 has a plurality of cut-out portions 25 of nearly rectangular shape radially at equal intervals from near the central part 24 of the flat plate to the outer periphery part 23, and has cut-out portions 31 of nearly triangular shape at the flat part between the cut-out portions 25 of nearly rectangular shape from the outer periphery part 23 to the inside. Each of rib-shape projections 26, 32 facing downward installed by molding integrally at the fringe part of the nearly rectangular and triangular cut-out portions 25, 31 crosses the tip portion of the current collection part 30 of the electrode plate and one part is welded by entering into the tip portion of the current collection portion 30. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a storage battery including a group of electrode plates wound in a spiral, and more particularly to a storage battery used as a driving power source for a vehicle.

  Alkaline storage batteries represented by nickel-cadmium storage batteries and nickel-hydrogen storage batteries are widely used in various applications such as mobile phones and laptop computers because they are reliable and easy to maintain. In recent years, there has been a demand for the development of an alkaline storage battery suitable for large current discharge as a power source for power tools, power-assisted bicycles and electric vehicles.

  The alkaline storage battery is composed of a strip-shaped positive electrode plate, a negative electrode plate, and a separator. The tip of the current collector of the positive electrode protrudes upward, and the tip of the current collector of the negative electrode protrudes downward. An electrode plate group, an upper current collector welded to a tip portion of a current collector part of a positive electrode plate protruding upward of the electrode plate group, and a current collector part of a negative electrode plate protruding downward of the electrode plate group A bottomed current collector welded to the front end portion, a metal bottomed case containing an electrolytic solution therein, and an opening of the metal bottomed case are sealed by a sealing plate.

  Since such an alkaline storage battery may be used for an application that requires a large current discharge, it is necessary to reduce its internal resistance.

  For this reason, in an alkaline storage battery that requires a large current discharge, in order to reduce the internal resistance, the current collection of the positive electrode plate that protrudes upward from the electrode plate group that is spirally wound around the positive electrode plate and the negative electrode plate via a separator. The current collecting property from the electrode plate group is enhanced by welding an upper current collector made of a rectangular or substantially circular flat plate to the portion at a plurality of locations. Thus, in the electrode group wound in a spiral shape, the diameter of the electrode group is different on the winding start side (inner periphery side) and the winding end side (outer periphery side), so the interval between the welding points is the inner periphery. There is a problem that the current is small on the side and large on the outer peripheral side, resulting in a non-uniform current collecting form.

Therefore, as a method of reducing the uneven current collecting form between the inner peripheral side and the outer peripheral side of the electrode plate group, Patent Document 1 discloses that three approximately extending from the vicinity of the center of the upper current collector to the outer peripheral edge. A rectangular notch, and one substantially rectangular notch from the center to the outer peripheral edge of the upper current collector, and a rib shape provided downward on the edges of these notches A method is described in which a protruding piece is welded to a current collecting portion of a positive electrode plate protruding upward from an electrode plate group (see Patent Document 1).
JP 2001-60456 A

  However, the above-mentioned conventional method can collect current from a large number of points that are relatively evenly distributed in the longitudinal direction of the belt-like positive electrode plate. However, current collection from the outer peripheral side of the electrode plate group is insufficient. there were.

  A tab terminal for electrically connecting the sealing plate and the upper current collector is welded near the center of the upper current collector. It was necessary to increase the current collection on the outer peripheral side of the far electrode plate group so that the interval between the welding points on the outer peripheral side was smaller than the interval between the welding points on the inner peripheral side of the electrode plate group that is close to the tab terminal.

  The present invention relates to a storage battery including a group of electrode plates wound in a spiral shape, and improves an upper current collector welded to a tip portion of a current collector part of one electrode plate protruding upward of the electrode plate group. Providing a storage battery suitable for large current discharge with low internal resistance by increasing current collection on the outer peripheral side of the electrode plate group that is electrically connected to the tab terminal electrically connected near the center of the upper current collector With the goal.

  In order to solve the above problems, the storage battery of the present invention comprises a strip-like positive electrode plate, a negative electrode plate, and a separator, the tip of the current collector of one electrode plate projects upward, and the current collector of the other electrode plate A rectangular plate welded to a tip portion of a current collector portion of each electrode plate protruding from above and below each of the electrode plate groups, the electrode plate group having a tip portion protruding downward and wound in a spiral shape An upper current collector and a lower current collector made of a substantially circular flat plate, a bottomed case in which an electrolytic solution is housed, a sealing plate that seals an opening of the bottomed case, the sealing plate and the upper part A storage battery having a tab terminal for electrically connecting a current collector, wherein the upper current collector has a plurality of substantially rectangular cutouts extending from near the center of the flat plate to the outer peripheral edge. Provided radially at equal intervals between each other, the substantially rectangular cut-out portion A downward rib-like projection piece provided with a substantially triangular cutout portion inwardly from the outer peripheral edge portion of the flat portion and integrally molded at the edge portion of the substantially rectangular shape and the substantially triangular cutout portion. Each of these crosses with the front-end | tip part of the current collection part of an electrode plate, The one part bites into the front-end | tip part of a current collection part, and is welded.

  With this configuration, it is possible to increase current collection on the outer peripheral side of the electrode plate group and reduce the internal resistance of the storage battery.

  The present invention solves the above-mentioned conventional problems, and is welded near the center of the upper current collector, and a tab terminal for electrically connecting the upper current collector and the sealing plate and a pole having a long energization distance. A storage battery suitable for large current discharge with low internal resistance is provided by increasing current collection on the outer peripheral side of the plate group.

  In the present invention, it is composed of a strip-like positive electrode plate, a negative electrode plate and a separator, and the tip portion of the current collector of one electrode plate protrudes upward, and the tip portion of the current collector of the other electrode plate protrudes downward. An upper electrode group consisting of a spirally wound electrode plate group and a rectangular or substantially circular flat plate welded to the tip of the current collector of each electrode plate protruding from above and below each electrode plate group A bottomed case that houses an electric current body and a lower current collector, and an electrolyte, a sealing plate that seals an opening of the bottomed case, and an electrical connection between the sealing plate and the upper current collector The upper current collector has a plurality of substantially rectangular cutouts extending from near the center of the flat plate to the outer peripheral edge at equal intervals in a radial manner. Provided on the flat part between the substantially rectangular cutouts from the outer peripheral edge Each of the downward rib-like projection pieces formed integrally with the edges of the substantially rectangular and substantially triangular cutouts is provided on the current collecting portion of the electrode plate. Crossing with the tip portion, a part of the tip portion bites into the tip portion of the current collector and is welded.

  According to this configuration, the interval between the welding points on the outer peripheral side of the electrode plate group can be made smaller than the interval between the welding points on the inner peripheral side of the upper current collector and the electrode plate group. It is possible to provide a storage battery suitable for large current discharge with a small internal resistance by increasing the current collection on the outer peripheral side of the electrode plate group having a long energization distance with the tab terminal that electrically connects the electric body.

  Next, problems when the conventional current collector is used will be described in detail with reference to the drawings.

FIG. 1A is a plan view showing an example of a conventional upper current collector, FIG. 1B is a perspective view thereof, and FIG. 1C is a diagram in which an electrode plate group and a tab terminal are connected to the upper current collector. It is a perspective view which shows a state. Electrode group 9
Current collector 10 and upper current collector 1 electrically connected to tab terminal 2, three substantially rectangular cutouts 5 extending from center 4 to outer peripheral edge 3, and A rib-like projection piece provided by punching out one substantially rectangular cutout 7 from the central portion 4 to the outer peripheral edge 3 in the shape of a hole, and provided downward at the edges of the cutouts 5 and 7. 6 and 8 are welded to the current collector 10 of the positive electrode plate protruding above the electrode plate group 9. However, in such a conventional upper current collector 1, although current can be collected on the outer peripheral side of the electrode plate group 9, 1/4 to 1/3 in the vicinity of the outer peripheral side with respect to the electrode plate length is the interval between the welding points. Therefore, it contributes little to the characteristics of the storage battery and does not reach a complete solution.

  2 (a) is a plan view showing another example of a conventional upper current collector, FIG. 2 (b) is a perspective view thereof, and FIG. 2 (c) is an electrode plate group and a tab terminal on the upper current collector. It is a perspective view which shows the state connected. As shown in FIGS. 2 (a) to 2 (c), the current collector 10 of the electrode plate group 9 and the upper current collector 1 electrically connected to the tab terminal 2 are connected from the central part 4 to the outer peripheral edge part. Four substantially rectangular cutout portions 5 extending over 3 are provided at equal intervals, and a flat portion between the four cutout portions 5 has a cutout having the same shape inward from the outer peripheral edge portion 3. Four portions 11 are provided, and rib-like projection pieces 6 and 12 provided downward on the edges of the cutout portions 5 and 11 are welded to the current collector portion 10 of the positive electrode plate protruding above the electrode plate group 9. is doing. The notch size of the notch 11 is about 1/3 of the radius of the electrode plate group 9. By providing a large number of substantially rectangular cutouts 5 and 11 in this way, the interval between the welding points near the outer peripheral side with respect to the electrode plate length is reduced, but the cutout area of the upper current collector 1 is large. Due to this and the notch shape, the electrical conductivity of the upper current collector 1 itself decreases, and as a result, the electrical conductivity from the electrode plate group 9 decreases.

  From the above, when using a plate group for large current discharge that requires a uniform current collecting configuration on the inner and outer peripheral sides of the electrode plate group, the conductivity of the upper current collector itself is reduced. However, it is necessary to reduce the interval between the welding points on the outer peripheral side of the electrode plate group.

  As a result of repeated studies to solve the above problem, as shown in FIGS. 3A to 3C, the upper current collector 21 of the present invention has an outer peripheral edge portion 23 from near the central portion 24 of the flat plate. Four substantially rectangular cutout portions 25 are provided radially at equal intervals between each other, and a flat portion between the substantially rectangular cutout portions 25 has a substantially triangular shape inward from the outer peripheral edge portion 23. In this shape, a total of four notches 31 are provided. The cut-out dimension of the substantially triangular notch 31 is about ３ of the radius of the electrode plate group 29. Each of the downward rib-like protrusions 26 and 32 formed integrally with the edges of the substantially rectangular notch 25 and the substantially triangular notch 31 is the tip of the current collector 30 of the electrode plate. Crossing the part, the part bites into the tip part of the current collector and welds. The cutting dimension of the substantially triangular notch 31 provided in the upper current collector 21 is set to about 1/3 of the radius of the electrode plate group 29, thereby reducing the energization path of the upper current collector 21 itself. In addition, the interval between the welding points on the outer peripheral side from the inner peripheral side in the length direction of the electrode plate of the electrode plate group 29 can be reduced.

  Since the diameter of the electrode plate group 29 is small on the inner peripheral side of the electrode plate group 29, four substantially rectangular cutout portions 25 extending from the vicinity of the central portion 24 of the upper current collector 21 to the outer peripheral edge portion 23 are provided. The welding points with the electrode plates can be appropriately provided only by providing them radially at equal intervals.

  The substantially triangular notch 31 provided in the upper current collector 21 is mainly welded to the outer peripheral electrode plate of the electrode plate group 29, and the interval between the outer peripheral welding points is set to the inner peripheral welding point interval. The purpose is to: Accordingly, if there is only one substantially triangular notch 31, welding points on the outer peripheral side can be formed only at one place per circumference, and the effect is small in the electrode plate group 29 having a large diameter. If two substantially triangular cutout portions 31 are provided, a welding point can be formed at least one half of the electrode plate group 29 on the outer periphery side of the electrode plate group 29. The interval between the welding points on the outer peripheral side of the outer periphery can be substantially the same as the interval between the welding points on the inner peripheral side or can be made smaller.

  From the above, it is preferable to provide two or more substantially triangular cutout portions 31, and more preferably, the condition that the substantially triangular cutout portion 31 is provided between all of the substantially rectangular cutout portions 25 is the most. preferable. That is, when four substantially rectangular cutout portions 25 are provided, a substantially triangular cutout portion 31 is provided between all of them, so that a substantially rectangular cutout portion 25 and a substantially triangular cutout portion are provided. The condition that the number of 31 is 4 each is most preferable.

  In addition, although the thing which consists of metal foil, a metal porous body, etc. is used for the current collection part 30 of the electrode group 29 in this invention, the short circuit at the time of welding with this current collection part 30 and the upper current collector 21 is used. In order to prevent this, it is preferable that the positive electrode plate and the negative electrode plate are wound in a state shifted in the width direction from 0.5 mm to 5 mm, particularly from 1 mm to 3 mm.

  In addition, examples of the storage battery to which the upper current collector 21 of the present invention is applied include a cylindrical storage battery using an electrode plate group 29 in which a positive electrode plate and a negative electrode plate are wound via a separator. Among the storage batteries, it is particularly effective for a cylindrical storage battery used for an application that requires a large current discharge of 10 A or more.

Example 1
A positive electrode plate made of a paste-type nickel electrode (substrate as a current collector: foamed nickel) having a length of 850 mm and a thickness of 0.30 mm, and a paste-type hydrogen storage alloy electrode having a length of 900 mm and a thickness of 0.20 mm (current collector) The electrode plate of the wound body is wound around a negative electrode plate made of a perforated iron-nickel plated steel plate through a 0.16 mm thick separator so that it can be accommodated in a maximum amount in a battery can with an inner size of 31 mm. Group 29 was made. As shown in FIG. 3, the current collector 30 of the positive electrode plate 29 has a substantially circular upper current collector 21 made of a metal plate having a diameter of 29 mm. Four substantially rectangular cutouts 25 having a length of 8 mm and a width of 3 mm are provided radially at equal intervals between the two, and an edge of the substantially rectangular cutout 25 has a length of 8 mm. Then, a rib-like projection piece 26 having a width of 0.5 mm was integrally formed downward. Further, a substantially triangular notch 31 is provided in an inward direction from the outer peripheral edge 23 in the flat portion between the four substantially rectangular notches 25, and the edge of the substantially triangular notch 31 is provided. Further, a rib-like projection piece 26 having a length of 5 mm and a width of 0.5 mm was integrally formed downward and provided. The substantially triangular cutout 31 has a side length of 5 mm and is provided in total. One end of the tab terminal 22 was connected to the central portion 24 of the upper current collector 21 by resistance welding.

  The upper current collector 21 and the electrode plate group 29 are electrically connected to each other by a rib-like projection piece 26 formed integrally with the edge of the substantially rectangular notch 25 of the upper current collector 21, and Each of the rib-like protrusions 32 formed integrally with the edge of the substantially triangular notch 31 intersects with the tip of the current collector of the electrode plate, and a part thereof is the tip of the current collector. It was welded to bite into. A lower current collector was connected to the lower side of the electrode plate group 29 in the same manner as the upper current collector 21.

  Next, the electrode plate group 29 connecting the upper current collector 21 and the lower current collector is inserted into a metal bottomed case, and an insulating ring is inserted into the upper surface of the upper current collector 21 from the opening of the bottomed case. did. Then, the upper part of the bottomed case is grooved to hold the electrode plate group 29, and the inner bottom surface of the bottomed case and the lower current collector are welded, and a predetermined amount of alkaline electrolyte is applied to the upper current collector 21. It poured into the bottomed case using the central hole. One end of a tab terminal 22 is welded to the central portion 24 of the upper current collector 21, and a sealing plate constituting an external terminal of the storage battery is welded to the other end of the tab terminal 22. This sealing plate was placed in the groove portion of the bottomed case and caulked to form a cylindrical alkaline storage battery. The cylindrical alkaline storage battery configured as described above was designated as battery A of Example 1.

(Example 2)
A cylindrical alkaline storage battery configured in the same manner as in Example 1 except that two substantially triangular cutout portions 31 were provided at positions facing the upper current collector 21 was designated as battery B of Example 2.

(Comparative Example 1)
Instead of the upper current collector 21 of the first embodiment, as shown in FIG. 1, a metal plate having a diameter of 29 mm has a rib-like projection piece 6 having a length of 8 mm and a width of 0.5 mm, and the center from the outer peripheral edge 3. Three notches 5 having a length of 8 mm toward the portion 4 and a width of 3 mm are provided, and the rib-like protruding pieces 8 having a length of 10 mm and a width of 0.5 mm are provided. The length 10 mm from the central portion 4 toward the outer peripheral edge 3. A cylindrical alkaline storage battery configured in the same manner as in Example 1 was used except that the upper current collector 1 provided with one notch 7 having a width of 3 mm was used as Comparative Example 1.

(Evaluation)
When the cylindrical alkaline storage batteries of Example 1 and Comparative Example 1 were configured, the welding points and their distribution between the upper current collector and the current collector of the electrode plate group were measured. This measurement was performed by peeling the welded upper current collector from the current collector, unwinding the electrode plate group, and measuring the length from the inner peripheral end of the electrode plate group to each welding point. .

  FIG. 4 (a) shows the state of welding between the upper current collector and the current collector in Example 1, and FIG. 4 (b) shows the state of welding between the upper current collector and the current collector in Comparative Example 1. The distribution of welding points from the end of the electrode plate on the winding start side (inner peripheral side) to the end of the winding end side (outer peripheral side) is shown.

  As is clear from the results shown in FIGS. 4A and 4B, it can be confirmed that the distance between the welding points in Comparative Example 1 increases from the vicinity of the center of the electrode plate to the outer peripheral side as compared with Example 1. It was.

  In Example 1, the welding is sufficiently performed on the outer peripheral side of the electrode plate. In addition, compared with Comparative Example 1, Example 1 is more on the outer peripheral side than the interval of the welding points near the center in the length direction of the electrode plate. It was found that the intervals between the welding points were small and uniformly dispersed.

  Next, the internal resistance was compared as follows using the battery A of Example 1 and the battery C of Comparative Example 1.

  The battery A of Example 1 and the battery C of Comparative Example 1 were used and discharged at room temperature (25 ° C.) at a current value of 2 A until the battery voltage became 0.9 V, and then 30 at a current value of 6.5 A. Charged for a minute. Next, after resting for 1 hour, the battery was discharged for 20 seconds at a current value of 20 A, and the battery voltage after 10 seconds was measured. Subsequently, after discharging the discharged capacity, similarly, the battery was discharged at a current value of 40A, 60A, 80A, and 100A for 20 seconds, and the battery voltage after 10 seconds was measured. The battery voltage after 10 seconds thus obtained is taken as the vertical axis, and each current value is taken as the horizontal axis, and the slope of the straight line in the I (current) -V (voltage) characteristic is obtained. The result is shown in FIG. .

  As is clear from FIG. 5, the battery C of Comparative Example 1 was found to have a larger linear slope (internal resistance) than the battery A of Example 1.

  Average values obtained by measuring 50 internal resistances of the batteries A, B, and C were 2.00 mΩ, 2.05 mΩ, and 2.15 mΩ, respectively, and compared with the battery C of Comparative Example 1, the inside of the battery A of Example 1 It was found that the resistance was 0.15 mΩ small, and the internal resistance of Battery B was 0.10 mΩ. This is because the welding area between the upper current collector and the current collector of the electrode plate group has increased, and the welding distance has been sufficiently reduced even on the outer peripheral side of the electrode plate. It is thought that. This is considered to enable large current discharge.

In this example, the upper current collector made of a substantially circular flat plate was used. However, the same effect was obtained even when the upper current collector made of a rectangular flat plate was used.

  The storage battery according to the present invention is useful as a power source for power-assisted bicycles, electric vehicles and the like as well as electric tools that require large current discharge.

(A) Plan view showing an example of a conventional upper current collector, (b) Perspective view showing an example of a conventional upper current collector, (c) Electrode plate group and tab on the upper current collector showing a conventional example The perspective view which shows the state which connected the terminal (A) The top view which shows the other example of the conventional upper collector, (b) The perspective view which shows the other example of the conventional upper collector, (c) The upper collector which shows the other example of the former The perspective view which shows the state which connected the electrode group and the tab terminal to (A) A plan view showing the upper current collector of the present invention, (b) a perspective view showing the upper current collector of the present invention, (c) an electrode plate group and a tab terminal connected to the upper current collector of the present invention. Perspective view showing the state (A) The figure which showed the state of welding with the upper electrical power collector of Example 1, and the electrode plate by distribution of the welding point from the edge part by the side of the winding start side of the electrode plate to the edge part by the side of winding, (b) ) The welding state between the upper current collector and the electrode plate of Comparative Example 1 is shown by the distribution of welding points from the end of the electrode plate on the winding start side to the end of the winding end side. Diagram showing I (current) -V (voltage) characteristics

Explanation of symbols

21 Upper current collector 22 Tab terminal
23 Outer peripheral edge portion 24 Central portion 25 Notch portion 26 Rib-shaped projection piece 29 Electrode plate group 30 Current collecting portion 31 Notch portion 32 Rib-shaped projection piece

Claims (1)

It consists of a strip-shaped positive electrode plate, negative electrode plate, and separator, and the tip part of the current collector part of one electrode plate protrudes upward, and the tip part of the current collector part of the other electrode plate protrudes downward and winds in a spiral shape A group of electrode plates,
An upper current collector and a lower current collector made of a rectangular or substantially circular flat plate welded to a tip portion of a current collecting portion of each electrode plate protruding from above and below each electrode plate group; A bottomed case that houses the inside,
A sealing plate for sealing the opening of the bottomed case;
A storage battery comprising a tab terminal for electrically connecting the sealing plate and the upper current collector,
The upper current collector is provided with a plurality of substantially rectangular cutouts extending from the vicinity of the center of the flat plate to the outer peripheral edge at equal intervals between each other,
Provide a substantially triangular notch inward from the outer peripheral edge to the flat part between the substantially rectangular notch,
Each of the downward rib-like projection pieces formed integrally with the edges of the substantially rectangular and substantially triangular cutout portions intersects with the tip portion of the current collecting portion of the electrode plate, and a part of them is collected. A storage battery characterized by being welded by biting into a tip portion of an electric part.

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