JP5979441B2 - Electrode plate, stacked electrode group, battery, and cylindrical battery - Google Patents

Description

  The present invention relates to an electrode plate, a stacked electrode group formed using the electrode plate, a battery, and a cylindrical battery.

  As a conventional cylindrical battery, as shown in Patent Document 1, a cylindrical electrode is formed by winding a belt-like positive electrode plate and a negative electrode plate in a spiral shape through a belt-like separator around a cylindrical battery case. Some have housed groups.

  However, when the belt-like positive electrode plate, negative electrode plate, and separator are wound in a spiral shape, the positive electrode plate and the negative electrode plate are unwound in the winding process. If it does so, problems, such as not being able to obtain a desired battery capacity in a cylindrical battery and causing an internal short circuit, will arise.

Japanese Patent Laid-Open No. 11-185767

  Therefore, the inventor of the present application considers accommodating a stacked electrode group in a cylindrical battery in order to solve various problems associated with winding misalignment and winding misalignment.

  However, when the stacked electrode group is composed of a plurality of electrode plates, a plurality of current collecting terminals led out from each positive electrode plate are connected so as to overlap a common current collecting plate, There is a possibility that the current collection efficiency may vary. Moreover, the operation | work which welds the current collection terminal of each positive electrode plate to a current collection plate becomes complicated.

  In order to solve these disadvantages, it is conceivable to form an electrode group using a single thick electrode plate. However, the thick electrode plate is difficult to compress at a conventional press pressure, and the packing density of the active material is reduced. Also, when the press thickness is increased in order to increase the packing density, the current collector is broken or the density of the current collector inside the electrode plate is decreased, and the internal resistance is increased. There's a problem.

  Therefore, the present invention has been made to solve the above problems, and in the stacked electrode group, it is possible to reduce the number of current collecting terminals and improve the filling rate of the active material as the whole electrode. On the other hand, reducing the internal resistance of the electrode plate is the main desired problem.

  That is, the electrode plate according to the present invention is an electrode plate configured by holding an active material on a current collector, and is a substantially flat plate formed on both sides of the active material non-holding portion and the active material non-holding portion. A first electrode plate element in which the active material non-holding portion is bent so that the active material holding portions on both sides face each other, and the active material non-holding portion and the active material A second electrode plate element having a holding portion, wherein the active material holding portion of the second electrode plate element is in contact with and overlapped with the active material holding portion of the first electrode plate element, and the first electrode plate element The active material non-holding portion of the second electrode plate element and the active material non-holding portion of the second electrode plate element are welded.

  If this is the case, the electrode plate is composed of a first electrode plate element and a second electrode plate element, and the first electrode plate element is composed of two active material holding portions and an active material non-holding portion. By providing a current collecting terminal in the active material non-holding part, it can be used as a common current collecting terminal for the two active material holding parts, the number of current collecting terminals can be reduced, and welding work is simplified. can do. Here, since the active material holding part of the second electrode plate element is in contact with the active material holding part of the first electrode plate element, the current collecting terminal of the first electrode plate element is used for collecting the current of the second electrode plate element. Can be performed. Further, by dividing the electrode plate into the first electrode plate element and the second electrode plate element, the thickness of the current collector in each electrode plate element can be reduced, and the filling ratio of the active material to each current collector Can be improved. Furthermore, the current collector can be prevented from being broken in the press after being filled with the active material, and the density of the current collector inside the electrode plate can be prevented from being lowered, thereby reducing the internal resistance of the electrode plate. In addition, since the second electrode plate element is welded to the active material non-holding portion of the first electrode plate element, the internal resistance of the electrode plate can be further reduced.

  The second electrode plate element has an active material non-holding portion and a substantially flat active material holding portion formed on both sides of the active material non-holding portion, and the active material holding portions on both sides face each other. As described above, the active material non-holding portion is bent, and the active material holding portion of the second electrode plate element is overlapped in contact with the active material holding portion of the first electrode plate element. Preferably, the active material non-holding portion of the second electrode plate element is welded to the active material non-holding portion of the first electrode plate element. If this is the case, the first electrode plate element and the second electrode plate element excluding the current collecting terminal can be made to have substantially the same shape, and can be folded together after being overlapped, thereby improving workability. Can do. Here, before the first electrode plate element and the second electrode plate element are bent, the active material non-holding portion of the first electrode plate element and the active material non-holding portion of the second electrode plate element are welded, so that The electrode plate can be easily bent. Further, since the second electrode plate element is composed of one electrode plate element, the number of parts can be reduced. Furthermore, if the first electrode plate element and the second electrode plate element before the current collecting terminal are welded are formed in substantially the same shape, the number of parts can be further reduced.

  It is desirable that the current collector is a three-dimensional metal porous body such as a foamed nickel porous body. By using a three-dimensional porous metal body, the manufacturing process can be made simpler than other current collector base materials, and good current collection characteristics can be obtained even when an active material with low conductivity is used. It is excellent in that the capacity of the electrode can be increased.

  In addition, the electrode plate according to the present invention includes two active material holders and a conductive member that connects the two active material holders, and the conductive member so that the active material holders face each other. A first electrode plate element bent and a second electrode plate element having an active material non-holding portion and an active material holding portion, and the second electrode plate in an active material holding body of the first electrode plate element. The active material holding portion of the element is overlapped in contact, and the conductive member of the first electrode plate element and the active material non-holding portion of the second electrode plate element are welded.

  In such an electrode plate, the electrode plate is composed of a first electrode plate element and a second electrode plate element, and the first electrode plate element is composed of two active material holders and a conductive member. By using a conductive member as a current collecting terminal element, it can be used as a common current collecting terminal for two active material holders, the number of current collecting terminals can be reduced, and welding work can be simplified. Can do. Here, since the active material holding part of the second electrode plate element is in contact with the active material holding body of the first electrode plate element, the current collecting terminal of the first electrode plate element is used for collecting current of the second electrode plate element. Can be performed. Further, by dividing the electrode plate into the first electrode plate element and the second electrode plate element, the thickness of the current collector in each electrode plate element can be reduced, and the filling ratio of the active material to each current collector Can be improved. Furthermore, the current collector can be prevented from being broken in the press after being filled with the active material, and the density of the current collector inside the electrode plate can be prevented from being lowered, thereby reducing the internal resistance of the electrode plate. In addition, since the second plate element is welded to the conductive member of the first plate element, the internal resistance of the electrode plate can be further reduced.

  As a configuration of an electrode group in which the electrode plate of the present invention can be suitably used, an electrode having a laminated structure formed by sandwiching electrode plates having different polarities through a separator between the active material holding portions on both sides. Is a group. The electrode plate of the present invention has a structure in which an active material holding body is formed on both sides of a linear active material non-holding portion or a current collecting terminal, and is bent at the active material non-holding portion or current collecting terminal. Opposing active material holding portions have the same polarity. Since it is such a structure, a laminated electrode group can be comprised only by inserting | pinching the electrode plate from which polarity differs between the active material holding parts which oppose. As electrode plates with different polarities, it is considered to use a three-dimensional base material such as a pocket electrode, foamed nickel, etc., and an electrode obtained by applying an active material to a two-dimensional base material such as a perforated steel plate. It is done. At this time, a laminated electrode group is constituted by one negative electrode plate and one positive electrode plate.

  As a specific configuration of the laminated electrode group, a first electrode plate made of the electrode plate of the present invention and two surfaces of the first electrode plate sandwiched between the first electrode plate and the first electrode plate are unfolded. And a second electrode plate having a polarity different from that of the first electrode plate, the separator being folded, and an electrode structure formed by bending the first electrode plate wrapped in the separator. It is characterized by having.

  It is desirable to configure a laminated battery group constituted by using the electrode plate of the present invention as a cylindrical battery housed in a cylindrical battery case. In the conventional spirally wound electrode group, the positive electrode plate and the negative electrode plate are unwound in the winding process, and a desired battery capacity cannot be obtained in the cylindrical battery. This causes problems such as However, by accommodating the stacked electrode group in the cylindrical battery case as in the present invention, various problems associated with the winding deviation and winding deviation of the electrode group can be solved. Moreover, since it is a cylindrical battery case, it can be strengthened in strength against an increase in internal pressure. In addition, since a substantially rectangular parallelepiped electrode group is arranged with respect to the cylindrical battery case, the use amount of the base material and the separator is reduced, so that the space in the battery case can be increased and the internal pressure of the battery is increased. In addition, the amount of electrolyte in the cylindrical battery can be increased.

  According to the present invention configured as described above, the number of current collecting terminals can be reduced by sharing the current collecting terminals by the two active material holding portions. Further, since the electrode plate is divided into the first electrode plate element and the second electrode plate element, the internal resistance of the electrode plate can be reduced while improving the filling property of the active material as the whole electrode.

The longitudinal cross-sectional view of the cylindrical battery in this embodiment. The cross-sectional view of the cylindrical battery in the same embodiment. The top view, front view, and perspective view which show the positive electrode plate of the embodiment. The top view which shows the expansion | deployment state of the positive electrode plate of the embodiment. The figure which shows the manufacturing process of the positive electrode plate of the embodiment. The top view, front view, and perspective view which show the negative electrode plate of the embodiment. The top view which shows the expansion | deployment state of the negative electrode plate of the embodiment. The figure which shows the manufacturing process of the negative electrode plate of the embodiment. The longitudinal cross-sectional view of the electrode group of the embodiment. The figure which shows the separator accommodation process of the electrode group of the embodiment. The figure which shows the negative electrode plate bending process and positive electrode plate bending process of the electrode group of the embodiment. The top view, front view, and perspective view which show the positive electrode plate which concerns on deformation | transformation embodiment. The top view, front view, and perspective view which show the positive electrode plate which concerns on deformation | transformation embodiment. The figure which shows the manufacturing process of the positive electrode plate which concerns on deformation | transformation embodiment.

  An embodiment of a cylindrical battery according to the present invention will be described below with reference to the drawings.

  The cylindrical battery 100 according to the present embodiment is an alkaline storage battery such as a nickel / cadmium storage battery or a nickel / hydrogen storage battery. Specifically, as shown in FIGS. 1 and 2, a metal battery case 2 having a bottomed cylindrical shape, and a positive electrode plate 31, a negative electrode plate 32, and a separator 33 are arranged in the battery case 2. The electrode group 3 has a substantially rectangular parallelepiped shape.

  The battery case 2 has a bottomed cylindrical shape with nickel plating, and the upper opening is sealed with a sealing body 5 via an insulator 4 as shown in FIG. Further, a current collecting terminal 311 provided so as to protrude from the upper end portion of the positive electrode plate 31 is connected to the back surface of the sealing body 5 by, for example, welding directly or via a current collecting plate (not shown). It becomes the positive terminal. In the present embodiment, as will be described later, the current collecting terminal 321 of the negative electrode plate 32 positioned on the outermost side of the electrode group 3 is welded to the bottom surface 2B of the battery case 2.

  The electrode group 3 has a substantially rectangular parallelepiped shape in which a positive electrode plate 31 and a negative electrode plate 32 are laminated via a separator 33 made of, for example, a nonwoven fabric made of polyolefin (see FIG. 2). The separator 33 is impregnated with an electrolytic solution such as potassium hydroxide.

  The positive electrode plate 31 is filled with a positive electrode current collector made of foamed nickel and a mixture of a nickel hydroxide active material and a cobalt compound of a conductive material (hereinafter simply referred to as a positive electrode active material) in the hollow of the positive electrode current collector. It is a thing. The nickel hydroxide active material is, for example, nickel hydroxide in the case of a nickel / cadmium storage battery, and nickel hydroxide to which calcium hydroxide is added in the case of a nickel / hydrogen storage battery.

  Specifically, as shown in FIGS. 3 and 4, the positive electrode plate 31 includes one first electrode plate element 31 </ b> P having a current collecting terminal 311 and one second electrode plate element 31 </ b> Q having no current collecting terminal 311. It consists of.

  As shown in FIGS. 3 and 4, the first electrode plate element 31 </ b> P is formed on both sides of the linear active material non-holding portion 31 </ b> A that does not hold the positive electrode active material and the active material non-holding portion 31 </ b> A. An active material holding part 31B for holding the positive electrode active material. The active material non-holding part 31A is formed symmetrically so as to include the center line H1 of the positive electrode current collector, and the active material holding part 31B is symmetrical with respect to the active material non-holding part 31A (see FIG. 4).

  As shown in FIG. 3, in the first electrode plate element 31 </ b> P, the positive electrode current collector is bent in a substantially U shape at the active material non-holding portion 31 </ b> A so that the active material holding portions 31 </ b> B on both sides face each other. Specifically, the active material non-holding part 31A and the active material holding part 31B are bent so that the inner side of the active material non-holding part 31A and the active material holding part 31B are at right angles to each other with a folding line slightly inside the boundary. ing.

  Further, in the first electrode plate element 31P, a current collecting terminal 311 made of, for example, a nickel steel plate is provided in an active material non-holding portion 31A that is a bent portion formed between two active material holding portions 31B. The current collecting terminal 311 extends outward in one of the width directions orthogonal to the opposing direction of the two active material holding portions 31B. In FIG. 3, the current collecting terminal 311 extends to one outer side (front side in FIG. 3) along the same direction as the linear direction of the active material non-holding portion 31A. The current collecting terminal 311 may be inclined from the linear direction. The current collecting terminal 311 is provided over substantially the entire active material non-holding portion 31A in order to improve the current collecting efficiency from the positive electrode current collector. Thus, since the current collecting terminal 311 is provided so as to extend outward in one of the width directions orthogonal to the opposing direction of the two active material holding portions 31B, the unfolded positive electrode plate 31 is folded in two. When the separator 33 is accommodated so as to be sandwiched by the separator 33, the bent portion of the separator 33 is positioned on the side 31n facing the side 31m where the current collector terminal 311 extends outward, so that the current collector terminal 311 is accommodated by the separator 33. Does not get in the way.

  Further, as shown in FIGS. 3 and 4, the second electrode plate element 31Q is formed on both sides of the linear active material non-holding portion 31C that does not hold the positive electrode active material and the active material non-holding portion 31C. And an active material holding part 31D for holding the positive electrode active material. The active material non-holding part 31C is formed symmetrically so as to include the center line H3 of the positive electrode current collector, and the active material holding part 31D is symmetrical with respect to the active material non-holding part 31C (see FIG. 4). Further, the developed shape of the second electrode plate element 31Q of the present embodiment is substantially the same shape as the first electrode plate element 31P before the current collecting terminal 311 is welded.

  As shown in FIG. 3, in the second electrode plate element 31Q, the positive electrode current collector is bent in a substantially U shape in the active material non-holding portion 31C so that the active material holding portions 31D on both sides face each other. Specifically, the active material non-holding part 31C and the active material holding part 31D are bent so that the inner side of the active material non-holding part 31C and the active material holding part 31D are at right angles to each other with a fold line as a folding line. ing.

  In the first electrode plate element 31P and the second electrode plate element 31Q having the above-described configuration, the active material non-holding portions 31A and 31C of the elements 31P and 31Q are located on the same side and overlap, and the active elements on both sides of the elements 31P and 31Q are overlapped. The positive electrode plate 31 is formed in a state where the substance holding portions 31B and 31D are in contact with each other and overlapped (see FIG. 3). Further, in the first electrode plate element 31P and the second electrode plate element 31Q that are superposed in this manner, the active material non-holding portions 31A and 31C of the elements 31P and 31Q are welded to each other. That is, the positive electrode plate 31 of the present embodiment is not only in contact with the first electrode plate element 31P and the second electrode plate element 31Q, but also by welding the active material non-holding portions 31A and 31C to each other. The current collecting terminal 311 is configured to collect the second electrode plate element 31Q.

  Next, a method for manufacturing the positive electrode plate 31 (the first electrode plate element 31P and the second electrode plate element 31Q) configured as described above will be briefly described.

  First, as shown in FIG. 5, with respect to a base material (collector base material) X made of nickel foam having a long shape, a linear active material non-holding portion is formed at the center along the longitudinal direction. A portion (non-holding region X1) is pressed (pressing step). Next, the positive electrode active material is filled so that the portion other than the non-holding region X1 becomes the active material holding region (holding region X2) (active material filling step). After this active material filling step, the entire current collector substrate is pressed (electrode plate pressing step). And it cut | disconnects in the direction orthogonal to the non-holding area | region X1 so that it may become the same shape as the expansion | deployment state of the 1st electrode plate element 31P (except the terminal 311) and the 2nd electrode plate element 31Q (cutting process). Thereby, the 1st electrode plate element 31P before the current collection terminal 311 is welded and the 2nd electrode plate element 31Q of an unfolded state are formed. Further, the current collecting terminal 311 is welded to the active material non-holding portion 31A of the positive electrode current collector that becomes the first electrode plate element 31P (terminal welding process). Thereby, the unfolded first electrode plate element 31P is formed. The first electrode plate element 31P and the second electrode plate element 31Q configured as described above are overlapped so that their outer peripheral portions substantially coincide with each other, and the active material non-holding portion 31A and the first electrode plate element 31P of the first electrode plate element 31P are overlapped. The positive electrode plate 31 in the unfolded state is formed by welding the active material non-holding portion 31C of the bipolar plate element 31Q (see FIG. 10).

  In the above method, the active material non-holding portions 31A and 31C are formed without filling the positive electrode active material of the base material X, and the active material holding portions 31B and 31D are arranged on both sides of the active material non-holding portions 31A and 31C. Since they are formed, the elongation rates of the active material holding portions 31B and 31D and the active material non-holding portions 31A and 31C are different and may break at the boundary portions. For this reason, it is possible to use the following method. That is, the positive electrode active material is filled in the entire base material X (current collector base material) made of foamed nickel (active material filling step). After this active material filling step, the entire current collector base X is pressed (electrode plate pressing step). Next, the positive electrode active material is removed by ultrasonic removal or the like in order to form a non-holding region X1 that becomes the linear active material non-holding portion 31A at the center of the base material X filled with the positive electrode active material (active material). Substance removal step). And the non-holding area | region X1 in the base material X in which the non-holding area | region X1 was formed is pressed (press process). Thereafter, the base material X on which the non-holding region X1 is pressed is cut in a direction orthogonal to the non-holding region X1 (cutting step). Thereby, the unfolded second electrode plate element 31Q is formed. Further, the current collecting terminal 311 is welded to the active material non-holding portion 31A of the positive electrode current collector that becomes the first electrode plate element 31P (terminal welding process). Thereby, the unfolded first electrode plate element 31P is formed.

  Moreover, you may implement a cutting process between an electrode plate press process and an active material removal process. That is, the positive electrode active material is filled in the entire base material X (current collector base material) made of foamed nickel (active material filling step). After this active material filling step, the entire current collector base X is pressed (electrode plate pressing step). Next, the pressed base material X is cut into a developed shape of the first electrode plate element 31P (excluding the terminal 311) and the second electrode plate element 31Q (cutting step). Then, the positive electrode active material is removed by ultrasonic removal or the like in order to form a non-holding region X1 that becomes the linear active material non-holding portion 31A at the center of the cut base material X (active material removal step). And the non-holding area | region X1 in the base material X in which the non-holding area | region X1 was formed is pressed (press process). Thereby, the unfolded second electrode plate element 31Q is formed. Further, the current collecting terminal 311 is welded to the active material non-holding portion 31A of the positive electrode current collector that becomes the first electrode plate element 31P (terminal welding process).

The negative electrode plate 32 is made of, for example, a negative electrode current collector made of a flat perforated steel sheet plated with nickel, and a negative electrode active material coated on the negative electrode current collector. The negative electrode active material is, for example, a mixture of cadmium oxide powder and metal cadmium powder in the case of a nickel-cadmium storage battery, and mainly in the case of a nickel-hydrogen storage battery, for example, AB type ₅ (rare earth) or is a powder of hydrogen absorbing alloy of AB ₂ type (Laves phase).

  Specifically, as shown in FIGS. 6 and 7, the negative electrode plate 32 sandwiches a linear active material non-holding portion (uncoated portion) 32A that does not hold the negative electrode active material and the active material non-holding portion 32A. And an active material holding part (coating part) 32B for holding the negative electrode active material. The active material non-holding part 32A is formed symmetrically so as to include the center line H3 of the negative electrode current collector, and the active material holding part 32B is symmetrical with respect to the active material non-holding part 32A (see FIG. 7).

  As shown in FIG. 6, in the negative electrode plate 32, the negative electrode current collector is bent in a substantially U shape in the active material non-holding portion 32 </ b> A so that the active material holding portions 32 </ b> B on both sides face each other. Specifically, the active material non-holding part 32A and the active material holding part 32B are bent so that the active material non-holding part 32A and the active material holding part 32B are at right angles to each other with a fold line slightly inside the boundary between the active material non-holding part 32A and the active material holding part 32B. ing.

  Furthermore, the negative electrode plate 32 is formed with a current collecting terminal 321 welded to the bottom surface 2B of the battery case 2 by bending a part of the active material non-holding portion 32A outward. Specifically, the current collection terminal 321 is formed by making a cut 32C in a part of the active material non-holding portion 32A so as to have a desired current collection terminal shape and bending the inside of the cut 32C outward. .

  Next, a method for manufacturing the negative electrode plate 32 configured as described above will be briefly described.

  First, as shown in FIG. 8, with respect to a base material (current collector base material) Y having a long shape made of a perforated steel plate, a linear uncoated region Y1 is formed at the center along the longitudinal direction. The negative electrode active material is applied to both sides to form the coating regions Y2 and Y3 (coating process). Then, a substantially U-shaped cut 32C is punched and formed in the uncoated region Y1 using a punching die (punching step). Then, it cut | disconnects so that it may become the same shape as the expansion | deployment state of the negative electrode plate 32 (cutting process). Thereby, the negative electrode plate 32 in a developed state is formed. The cut 32C may be formed after the negative electrode plate 32 is cut.

  In the stacked electrode group 3 of the present embodiment, the positive electrode plate 31 having a substantially U shape in which two active material holding portions 31B (31D) are arranged to face each other, and the two active material holding portions 32B are opposed to each other. It is configured to be laminated so as to mesh with the arranged negative electrode plate 32 having a substantially U shape. Specifically, as shown in FIG. 9, one active material holding part 31 </ b> B (31 </ b> D) of the positive electrode plate 31 is sandwiched between two active material holding parts 32 </ b> B of the negative electrode plate 32 and one of the negative electrode plates 32. Two active material holding portions 32B are stacked so as to be sandwiched between two active material holding portions 31B (31D) of the positive electrode plate 31. In the present embodiment, the bent portion of the positive electrode plate 31 (active material non-holding portion 31A (31C)) and the bent portion of the negative electrode plate 32 (active material non-holding portion 32A) are stacked so as to face each other. Therefore, in the electrode group 3 of the present embodiment, the outer surfaces 32a and 32b of the negative electrode plate 32 are the outermost surfaces. In FIG. 1, FIG. 2, FIG. 9, etc., for ease of understanding, the electrode plates 31 and 32 and the separator 33 are illustrated with an interval, but they are laminated in contact with each other. The

  More specifically, the stacked electrode group 3 of the present embodiment is composed of two negative electrode plates 32 and one positive electrode plate 31, and each of the two adjacent negative electrode plates 32 holds one active material. The portions 32B (active material holding portions 32B adjacent to each other in the two negative electrode plates 32) are stacked so as to be sandwiched between two active material holding portions 31B (31D) of one positive electrode plate 31.

  Next, a manufacturing method of the multilayer electrode group 3 configured as described above will be described.

First, as shown in FIGS. 10 and 11, a developed positive electrode plate 31, a developed negative electrode plate 32, and a developed separator 33 are prepared. Then, as shown in FIG. 10, the unfolded positive electrode plate 31 is placed on one half surface with respect to the fold line 33 a of the separator 33. In this state, the positive electrode plate in the developed state is welded with the active material non-holding portion 31A of the first electrode plate element 31P and the active material non-holding portion 31C of the second electrode plate element 31Q.
At this time, the side (lower side 31 n) facing the side (upper side 31 m) where the current collecting terminal 311 extends outward is placed along the fold line 33 a of the separator 33. Then, the separator 33 is folded in half along the folding line 33a (separator housing step). As a result, the bent portion of the separator 33 is positioned on the lower side 31 n of the positive electrode plate 31, and the positive electrode plate 31 in the developed state is accommodated in the separator 33 except for a portion extending to the outside of the current collecting terminal 311. It becomes a state. Then, the upper side and the left and right side sides of the separator 33 that accommodates the positive electrode plate 31 excluding the positive electrode terminal portion are welded and fixed by ultrasonic welding or the like. Note that a notch 33 b is formed in the current collecting terminal portion of the positive electrode plate 31 in the separator 33. Thereby, when the current collecting terminal 311 is bent, the separator 33 is prevented from being turned over due to the deformation of the current collecting terminal 311. In addition, the positive electrode plate 32 can also be packaged by using an envelope separator 33 in which three sides of the separator 33 are closed in advance.

  Next, as shown in FIG. 11, one of two active material holding portions 31 </ b> B (31 </ b> D) provided on the left and right of the developed positive electrode plate 31 accommodated in the separator 33 and one of the developed negative electrode plate 32. The active material holding part 32B is overlaid. Then, the unfolded negative electrode plate 32 is bent into a substantially U shape, whereby each of the two active material holding portions 31B (31D) of the positive electrode plate 31 is sandwiched between the negative electrode plates 32 (negative electrode plate bending step). At this time, the current collecting terminal 321 is bent outward from the active material non-holding portion 32 </ b> A of the negative electrode plate 32. Thereafter, the positive electrode plate 31 sandwiched between the negative electrode plates 32 is bent into a substantially U-shape (positive electrode plate bending step). Thereby, the stacked electrode group 3 is formed. The laminated electrode group 3 formed in this way is wound with a binding tape (not shown) so as not to be separated.

  And the cylindrical battery 100 of this embodiment has the spacer 6 for fixing the electrode group 3, as shown in FIG.1 and FIG.2. The spacer 6 is a pair of spacers 61 and 62 that are provided between the inner peripheral surface 2 A of the battery case 2 and the outer surface of the electrode group 3 and fix the electrode group 3 to the battery case 2. The pair of spacers 61 and 62 are disposed in a space between the inner peripheral surface 2A of the battery case 2 and the outer surface of the electrode group 3 so as to sandwich the electrode group 3 from the stacking direction L. . Note that the stacking direction L coincides with the facing direction of the active material holding portions 31B and 32B of the electrode plates 31 and 32, respectively.

  The pair of spacers 61 and 62 are made of resin such as acrylic resin, polypropylene resin, nylon resin, or metal such as stainless steel, and have the same shape.

  Each of the spacers 61 and 62 presses substantially the entire outermost surface of the electrode group 3 in the stacking direction L (specifically, the outer surfaces 32a and 32b of the negative electrode plate 32). Further, the spacers 61 and 62 are in contact with the inner peripheral surface of the battery case 2 in the vertical direction. Thereby, the whole electrode group 3 will be pressed uniformly by a pair of spacers 61 and 62, and charging / discharging efficiency will improve. The specific shape of each spacer includes a rectangular flat plate electrode contact portion 6A having a contact surface on one surface 6a that contacts substantially the entire outer surfaces 32a and 32b of the negative electrode plate 32, and other electrode contact portions 6A. Two case contact portions 6B extending from the direction 6b and contacting the inner peripheral surface 2A of the battery case 2 are provided.

  The two case contact portions 6B are formed in parallel with each other along the central axis direction C on the other surface 6b of the electrode contact portion 6A. Specifically, the battery case 2 is formed symmetrically so as to sandwich the central axis of the battery case 2 in a state of being accommodated in the battery case 2. Furthermore, the contact portion (tip surface of the free end side portion) of the case contact portion 6B with the inner peripheral surface 2A of the battery case 2 has a curved surface that is substantially the same as the curved surface of the inner peripheral surface 2A of the battery case 2. Thus, the case contact portion 6B and the battery case 2 are configured to be in surface contact (see FIG. 2). Moreover, the recessed part formed between 6 A of electrode contact parts and case contact part 6B becomes a welding space, The current collection terminal 321 of the negative electrode plate 32 can be welded to the bottom face 2B of the battery case 2 by the said welding space.

  When the electrode group 3 is pressed by the spacers 61 and 62 in this way, the active material holding part 31B of the first electrode plate element 31P of the positive electrode plate 31 and the active material holding part 31D of the second electrode plate element 31Q are pressed against each other. In contact with each other, the conductivity of the first electrode plate element 31P and the second electrode plate element 31Q is improved. Since the first electrode plate element 31P and the second electrode plate element 31Q are in press contact as described above, the current collecting terminal 311 of the first electrode plate element 31P efficiently collects the current from the second electrode plate element 31Q. Can be done.

  Next, a method for manufacturing the cylindrical battery 100 configured as described above will be briefly described.

  The stacked electrode group 3 described above is sandwiched between the pair of spacers 61 and 62 from the stacking direction L. The structure thus formed is placed in the battery case 2. In addition, the collector terminal 321 of the negative electrode plate 32 is positioned between the two case contact portions 6B of the pair of spacers 61 and 62 while the lower surface of the case contact portion 6B of the spacers 61 and 62 is the current collector. A part of the terminal 321 is pressed against the bottom surface 2 </ b> B of the battery case 2. In addition, after accommodating the electrode group 3 in the battery case 2, the pair of spacers 61 and 62 may be accommodated so as to sandwich the electrode group 3. Then, with the electrode group 3 fixed to the battery case 2, a welding rod is inserted into the space formed between the case contact portion 6B of the spacers 61 and 62 and the inner peripheral surface 2A of the battery case 2, and the negative electrode plate 32 current collecting terminals 321 are connected to the bottom surface 2B of the battery case 2 by welding. Thereafter, an electrolytic solution is injected into the battery case 2. And after pouring, while the current collection terminal 311 of the positive electrode plate 31 is connected to the back surface of the sealing body 5 directly or through a current collection board (not shown), the said sealing body 5 is connected to the battery case 2 via the insulator 4. It is fixed to the upper opening of the door by caulking or the like.

<Effect of this embodiment>
According to the cylindrical battery 100 according to the present embodiment configured as described above, the positive electrode plate 31 (first electrode plate element 31P) has a substantially U-shape including two active material holding portions 31B and an active material non-holding portion 31A. Since the current collecting terminal 311 is provided in the active material non-holding portion 31A, the two active material holding portions 31B are collected by the common current collecting terminal 311 to suppress the variation in the current collecting efficiency. Electric efficiency can be improved. Here, since the active material holding portion 31D of the second electrode plate element 31Q is in contact with the active material holding portion 31B of the first electrode plate element 31P, the current collection of the second electrode plate element 31Q is performed by the first electrode plate. This can be done by the current collecting terminal 311 of the element 31P. Moreover, it can be set as the common current collection terminal 311 with respect to the two active material holding | maintenance parts 31B, the number of current collection terminals 311 to weld can be reduced, and welding work can be simplified. Furthermore, by dividing the positive electrode plate 31 into the first electrode plate element 31P and the second electrode plate element 31Q, the thickness of the positive electrode current collector in each electrode plate element 31P, 31Q can be reduced, and each positive electrode current collector The filling rate of the positive electrode active material into the body can be improved. In addition, it is possible to reduce the internal resistance of the positive electrode plate 31 by preventing the positive electrode current collector from being broken in the press after being filled with the active material, and preventing the decrease in the density of the positive electrode current collector inside the positive electrode plate 31. it can. In addition, since the active material non-holding portion 31C of the second electrode plate element 31Q is welded to the active material non-holding portion 31A of the first electrode plate element 31P, the internal resistance of the positive electrode plate 31 can be further reduced. it can.

  In the present embodiment, the active material holding portion 31D of the second electrode plate element 31Q is brought into contact with and superposed on the active material holding portions 31B on both sides of the first electrode plate element 31P. The current collecting efficiency of the second electrode plate element 31Q can be improved by the current collecting terminal 311 of 31P. Here, since the first electrode plate element 31P and the second electrode plate element 31Q excluding the current collecting terminal 311 have the same shape, the workability can be improved by bending them into a U shape after overlapping them. Can be made. Furthermore, since the active material non-holding portion 31A of the first electrode plate element 31P and the active material non-holding portion 31C of the second electrode plate element 31Q are welded, the positive electrode plate 31 can be easily bent. The second electrode plate element 31Q is not only composed of one electrode plate element, but the first electrode plate element 31P and the second electrode plate element 31Q before the current collector terminal 311 is welded are the same. Since the shape is adopted, the number of parts can be further reduced.

  Next, the positive electrode plate of the present invention (invention example) in which the active material non-retaining parts are welded together, the positive electrode plate (comparative example A, comparative example B) in which the active material non-retaining parts are not welded together, and the conventional positive electrode plate ( A method for producing a cylindrical battery using Comparative Example C) and the results of these evaluation tests are shown below. The evaluation test is a measurement of the nickel hydroxide utilization factor (IEC) of the positive electrode plate and the internal resistance of the battery.

Various materials used for the cylindrical battery are as follows.
The positive electrode active material is a nickel hydroxide surface containing 3% by mass of zinc and 0.6% by mass of cobalt in a solid solution state and coated with 7% by mass of cobalt hydroxide using an 18M sodium hydroxide solution. What performed the air oxidation process at 110 degreeC for 1 hour was used. An aqueous solution in which a thickener (carboxymethylcellulose) was dissolved was added to this positive electrode active material to prepare a paste. The paste was filled in foamed nickel having a substrate surface density of 320 g / m ² , dried, and then pressed to a predetermined thickness to obtain positive electrode plates of invention examples, comparative examples A, and comparative examples B. . The positive electrode plate of Comparative Example C was produced in the same manner as the inventive example except that the paste was filled in foamed nickel having a substrate surface density of 500 g / m ² .
As the negative electrode active material, a hydrogen storage alloy having a composition of MmNi _3.8 Co _0.8 Mn _0.3 Al _0.3 pulverized to an average particle diameter of 50 μm was used. An aqueous solution in which a thickener (methylcellulose) is dissolved is added to 100 parts by mass of the alloy powder, and further 1 part by mass of a binder (styrene butadiene rubber) is added to form a paste. It was applied to. This was dried and then pressed to a predetermined thickness to obtain a negative electrode plate. The average particle size is a particle size having a cumulative degree of 50% in a volume standard particle size distribution.
For the separator, a polyolefin resin subjected to a sulfonation treatment was used. As the electrolytic solution, an electrolytic solution having a composition of 4M KOH + 3M NaOH + 0.8M LiOH was used.

  The invention example is the positive electrode plate of the above embodiment. Further, Comparative Example A is a positive electrode plate configured without welding the first electrode plate element and the second electrode plate element of the embodiment. The comparative example B is a positive electrode plate in which a plate-like second electrode plate element 31Q consisting only of the active material holding part 31D is brought into contact with the active material holding parts 31B on both sides of the first electrode plate element 31P, that is, the embodiment described above. The second electrode plate element 31Q is a positive electrode plate without the active material non-holding portion 31C. In each of these invention examples and comparative examples A and B, the current collector thickness at the time of filling the active material in each electrode plate element is 1.6 mm, and the electrode plate element thickness after pressing is 0.75 mm. On the other hand, Comparative Example C is a single positive electrode plate. In Comparative Example C, the current collector thickness at the time of filling the active material is 3 mm, and the positive electrode plate thickness after pressing is 1.5 mm.

  Each assembled battery was initialized and completed under the following conditions. A constant current charge was performed at 20 ° C. under a condition of 100 mA for 12 hours, and then a constant current discharge was performed until the voltage became 1 V at 200 mA. This was repeated for 2 cycles. Thereafter, it was stored at 40 ° C. for 48 hours. A constant current charge was performed at 20 ° C. under a condition of 100 mA for 12 hours, and then a constant current discharge was performed until the voltage became 1 V at 200 mA. This was repeated for 2 cycles to complete the initialization.

The measurement of the nickel hydroxide utilization rate (IEC) of the positive electrode plate was performed as follows. The above battery was charged at a constant current under the conditions of 20 ° C. and 0.1 ItA for 16 hours, and the cycle charge and discharge for performing constant current discharge at 20 ° C. and 0.2 ItA until reaching 1.0 V was repeated 3 cycles. The “discharge capacity” of the battery in each cycle at this time was measured. The “theoretical capacity” in this test is the theoretical capacity of the positive electrode plate, and is a value calculated using the nickel hydroxide filling amount and the theoretical capacity. The utilization rate is a value calculated by the following formula.
Utilization rate (%) = discharge capacity / theoretical capacity x 100
Moreover, the measurement of the internal resistance of a positive electrode plate is the value which measured the resistance of the terminal of a battery and a battery case can bottom at 20 degreeC using the Hioki3560ACm (ohm) high tester.

  As can be seen from Table 1 above, the invention example constituted by the first electrode plate element and the second electrode plate element, and the comparative examples A and B are more water than the comparative example C constituted by one current collector. The utilization factor of nickel oxide is improved, and the discharge capacity can be increased. Further, the invention example and the comparative examples A and B can reduce the internal resistance as compared with the comparative example C. Furthermore, the invention example configured by welding the first electrode plate element and the second electrode plate element is compared with Comparative Examples A and B configured without welding the first electrode plate element and the second electrode plate element, The internal resistance can be further reduced.

<Other modified embodiments>
The present invention is not limited to the above embodiment.

  For example, the second electrode plate element 31Q of the embodiment has the active material non-holding portion 31C and the active material holding portions 31D formed on both sides thereof, like the first electrode plate element 31P. As shown in FIG. 12, a substantially flat active material holding part 31D that is in contact with and superposed on the active material holding parts 31B on both sides of the first electrode plate element 31P, and an active material non-active material of the first electrode plate element 31P. It may have a welded portion 31E welded to the holding portion 31A. The welded portion 31E has a substantially linear shape that does not hold the active material, and is formed on one side of the active material holding portion 31D. In this case, the second electrode plate element 31Q may be provided only in one of the active material holding portions 31B on both sides of the first electrode plate element 31P.

  In the above embodiment, the second electrode plate element 31Q is provided so as to be overlapped with the inside of the first electrode plate element 31P, but may be provided so as to be overlapped with the outside of the first electrode plate element 31P. The two second electrode plate elements 31Q may be provided so as to overlap both the inside and the outside of the first electrode plate element 31P.

  Further, in the above-described embodiment, the first electrode plate element in the expanded state and the second electrode plate element in the expanded state are bent after being welded, but the first electrode plate element in the bent state and the second electrode in the bent state are bent. The plate elements may be welded.

  In addition, the positive electrode plate 31 of the above embodiment is composed of one first electrode plate element 31P and one second electrode plate element 31Q, but has a plurality of first electrode plate elements 31P. Or a plurality of second electrode plate elements 31Q.

  In addition, in the first electrode plate element 31P of the above-described embodiment, the active material non-holding portion 31A and the active material holding portion 31B are configured by one positive electrode current collector, but are not limited thereto. Specifically, as shown in FIG. 13, the first electrode plate element 31P includes two active material holders 31s and 31t in which a positive electrode current collector holds a positive electrode active material, and the two active material holders 31s. , 31t may be provided with a current collecting terminal 31u which is a conductive member. The active material holders 31 s and 31 t have the same shape and are configured by filling a positive electrode active material into nickel foam having a substantially rectangular shape. And the active material removal part 31x for welding the current collection terminal 31u is formed in the part. The current collecting terminal 31u has a substantially T shape in plan view, and the left and right end portions of the T-shaped horizontal portion 31u1 are welded to the active material removing portions 31x of the active material holding bodies 31s and 31t, respectively. In this unfolded state, the T-shaped vertical portion 31u2 of the current collecting terminal 31u is an extending portion that extends outward in the width direction from the active material holding bodies 31s and 31t. The positive electrode plate 31 is bent in a substantially U shape at the T-shaped horizontal portion 31u1 of the current collecting terminal 31u so that the two active material holding bodies 31s and 31t face each other, and the U-shaped vertical portion 31u2 It extends toward one outer side in the width direction orthogonal to the opposing direction of the two active material holding plates 31s and 31t.

  Next, a method for manufacturing the first electrode plate element 31P configured as described above will be briefly described. As shown in FIG. 14, the entire base material Z (current collector base material) made of nickel foam having a long shape is filled with an active material (active material filling step). After this active material filling step, the entire current collector substrate is pressed (electrode plate pressing step). Next, the base material Z filled with the active material is cut into the size of the active material holders 31s and 31t (cutting step). Then, the positive electrode active material is removed by ultrasonic removal or the like in order to form a substantially rectangular active material removing portion 31x at the short-side central portion of the cut active material holding bodies 31s and 31t (active material removing step). Thereafter, each end of the T-shaped horizontal portion 31u1 of the T-shaped terminal 31u is welded to the two active material removing portions 31x (terminal welding process). Note that the T-shaped terminal is not limited to a single one, and two current collecting terminals having a strip shape may be welded in a T-shape. Moreover, you may comprise so that two active material holding bodies 31s and 31t may be connected with connection members other than a current collection terminal, and a current collection terminal may be welded to the said connection member. Furthermore, you may comprise a 2nd electrode plate element by connecting the two active material holding bodies 31s and 31t with the connection member which is electroconductive members other than a current collection terminal.

  In addition, as the shape of the positive electrode plate and the negative electrode plate, the configuration of bending in a substantially U shape has been described as one aspect of bending in a substantially U shape. You may comprise so that it may be bent in a U shape.

  The laminated electrode group 3 of the above embodiment is configured by laminating one positive electrode plate 31 and two negative electrode plates 32. However, a plurality of positive electrode plates 31 and a plurality of negative electrode plates 32 are laminated. It may be configured as follows.

  In addition, the positive electrode plate and the negative electrode plate of the embodiment may be reversed. That is, you may comprise so that the current collection terminal 311 of a positive electrode plate may be welded to the inner surface of a battery case. The negative electrode plate may be composed of a first electrode plate element and a second electrode plate element.

  The present invention can be applied to secondary batteries such as lithium ion secondary batteries in addition to alkaline storage batteries, or may be applied to primary batteries. Further, the present invention is not limited to a cylindrical battery, and may be applied to a battery having another shape of a rectangular battery.

  In addition, it goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 100 ... Cylindrical battery 2 ... Battery case 3 ... Laminated electrode group 31 ... Positive electrode plate 31P ... 1st electrode plate element 31A ... Active material non-retaining part 31B ... Active Material holding part 311 ... Current collecting terminal 31Q ... Second electrode plate element 31C ... Active material non-holding part 31D ... Active material holding part 32 ... Negative electrode plate 321 ... Current collecting terminal 32A ... Active material non-holding part 32B ... Active material holding part 33 ... Separator 31s ... Active material holder 31t ... Active material holder 31u ... Current collecting terminal

Claims (7)

An electrode plate configured by holding an active material on a current collector,
An active material non-holding portion and a substantially flat active material holding portion formed on both sides of the active material non-holding portion, and the active material holding portions on both sides face each other. A first electrode plate element in which the non-holding portion is bent;
A second electrode plate element having an active material non-holding portion and an active material holding portion;
The active material holding part of the second electrode plate element is in contact with and superposed on the active material holding part of the first electrode element, and the active material non-holding part of the first electrode element and the second electrode element An electrode plate welded to the active material non-holding portion. The second electrode plate element has an active material non-holding portion and a substantially flat active material holding portion formed on both sides of the active material non-holding portion, and the active material holding portions on both sides face each other. The active material non-holding portion is bent,
The active material holding portion of the second electrode plate element is in contact with the active material holding portion of the first electrode plate element,
The electrode plate according to claim 1, wherein the active material non-holding portion of the second electrode plate element is welded to the active material non-holding portion of the first electrode plate element.   The electrode plate according to claim 1, wherein the current collector is a three-dimensional porous metal body. A first electrode plate element having two active material holders and a conductive member connecting the two active material holders, wherein the conductive member is bent so that the active material holders face each other When,
A second electrode plate element having an active material non-holding portion and an active material holding portion;
The active material holding part of the second electrode plate element is brought into contact with and superposed on the active material holding member of the first electrode plate element, and the conductive material of the first electrode plate element and the active material of the second electrode plate element An electrode plate welded to the non-holding part.   A stacked electrode group configured using the electrode plate according to claim 1.   A battery comprising the electrode plate according to claim 1.   A cylindrical battery comprising: a battery case having a cylindrical structure, the electrode group having a laminated structure configured using the electrode plate according to any one of claims 1 to 4.