JP2001283895A - Manufacturing method of electrochemical cell and electrochemical cell electrode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrode plate that does not generate winding slippage at winding and is not impaired in current collection at welding with the current collector in an electrochemical cell having a whirlpool shape electrode body of which electrode plate of the positive and negative electrodes is wound in a whirlpool shape and the electrode plates which are welded to the current collector. SOLUTION: At least one of the electrode plates has a core body which is provided with many punched holes nearly uniform on the total surface and active material is filled in the core body except for the one side of edge portion area along the long length direction, and the edge portion is installed with a conductive metal member of ribbon shape which is to be welded on the current collector.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrochemical cell such as an alkaline primary battery and an alkaline storage battery, and more specifically, to a cylindrical or rectangular electrochemical cell having a spiral electrode body and an electrode plate. It relates to a manufacturing method.

[0002]

2. Description of the Related Art A paste type (non-sintered type) electrode plate is formed by filling a conductive perforated core with an active material paste.
It is suitable for manufacturing spiral electrode bodies for cylindrical alkaline storage batteries such as nickel-cadmium storage batteries and nickel-hydride storage batteries because it has fewer steps and higher productivity than sintered type. Have been.

FIG. 1 shows a schematic configuration of such an alkaline storage battery. In FIG. 1, a spiral electrode body (1) has a positive electrode plate (10).
And a negative electrode plate (20) with a separator (30) interposed therebetween, which is formed by spirally winding the spirally wound electrode body (1).
The edge (10a) in the longitudinal direction (winding direction) of the positive electrode plate is
(12), the edge (20a) in the longitudinal direction (winding direction) of the negative electrode plate (20) is spot-welded to the negative electrode current collector plate (22), and then the cylindrical negative electrode terminal is closed. It is housed in the outer can (3), which also serves as the outer can. The negative electrode current collector (22) is spot-welded on the bottom surface of the outer can (3). The positive electrode current collector plate (12) is integrally formed with a current collecting lead piece (14) in advance, and the positive electrode current collector plate (12)
Of the current collecting lead piece (14) is welded to the bottom surface of the sealing body (4) also serving as a positive electrode terminal. Alkaline electrolyte is injected into the outer can (3), and after the gasket (6) is placed on the sealing body (4), the upper opening of the outer can (3) is swaged inward to allow the alkaline storage battery to enter. It is made.

[0004]

In this cylindrical alkaline storage battery, there is one in which a core of an electrode plate is manufactured by using a so-called punched metal having a large number of punched holes. This electrode plate is formed as follows. Have been made. As the core substrate, a punch substrate having a large number of punch holes formed substantially equally and including a core for a plurality of cells is prepared, and the entire surface thereof is filled with an active material to prepare an electrode substrate. Of the active material filled in, peel off the active material filled at a position that will be one edge along the longitudinal direction of the core of each cell (a part welded to the current collector plate during battery assembly), After exposing a part of the core substrate, the electrode substrate is appropriately cut to obtain an electrode plate for each cell. In this specification,
The “core substrate” means a substrate in which a large number of punch holes are formed substantially uniformly on the entire surface, the size includes a plurality of cells of the core, and is not filled with the active material. "Means a state in which the electrode material is cut to the size of the electrode plate and is not filled with the active material. Further, the "electrode substrate" means a state in which the core substrate is filled with an active material,
“Electrode plate” means a plate cut into a predetermined electrode plate size and filled with an active material.

By the way, when the electrode plate for each cell is cut from the electrode substrate, the electrode plate is cut through a punch hole, so that the end face of the core of the obtained electrode plate becomes jagged. FIG.
A single cell core (41) is shown, where (40) is a punch hole. FIG. 5 shows an electrode plate (20) in which a portion other than one edge along the longitudinal direction of the core (41) is filled with the active material (42). However, when a spiral electrode body is manufactured using the electrode plate shown in FIG. 5 and is welded to the current collector, the number of welding locations is small because the punched holes cannot contact the current collector. Therefore, there is a problem that the current collecting property is poor.

Therefore, as shown in FIG. 6, only the longitudinal edge portion of the core body (41) to be welded to the current collector plate is defined as a portion without a punch hole (non-porous portion) (46). There is an electrode plate to be used. However, the core made of punched metal has a thickness of about 0,0.
Since it is as thin as about 05 mm to 0.1 mm and does not have sufficient rigidity, there is a considerable difference in strength between the part with a punched hole (40) (perforated part) and the part without a punched hole (non-perforated part). There is. The filling of the core substrate with the active material is performed through the steps of coating the active material, drying and rolling, but with such a difference in strength,
During rolling, distortion occurs between a perforated portion and a non-perforated portion due to a difference in extensibility. For this reason, when the obtained electrode plate is spirally wound, a winding shift due to distortion occurs. When the winding displacement occurs, the active material surfaces of the positive and negative electrode plates do not completely face each other, so that the effective reaction area decreases,
There is a problem that battery capacity and operating voltage are reduced.

In order to prevent this winding deviation, as shown in FIG. 7, both edges of the core body in the longitudinal direction are connected to a non-porous portion (4).
6) (46). Since one edge is welded to the current collector plate, it is unavoidable not to fill the active material, but if the other edge is not coated with the active material, the battery capacity is reduced. However, even if the active material is applied to the non-porous portion, the coating strength there is smaller than that of the perforated portion. is there. Since the falling off of the active material causes an internal short circuit, it is not preferable to apply the active material to the non-porous portion.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is possible to manufacture a spiral electrode body without causing a winding deviation and to weld to a current collector plate without impairing the current collecting performance. An object of the present invention is to provide an alkaline storage battery using an electrode plate that can be used, and a method for manufacturing an electrode plate for the alkaline storage battery.

[0009]

In order to achieve the above object, according to the present invention, there is provided a spiral electrode body in which positive and negative electrode plates are spirally wound with a separator interposed therebetween. In the alkaline storage battery welded to the electric plate, at least one of the electrode plates has a core body having a large number of punch holes formed substantially uniformly on the entire surface, and one edge along the longitudinal direction of the core body. A portion other than the portion is filled with an active material, and a ribbon-shaped conductive metal member to be welded to the current collector is attached to the edge.

The electrode plate of the present invention has a size including a plurality of cores of a single cell, and prepares a core substrate having a large number of punch holes formed substantially uniformly on the entire surface thereof. A step of preparing an electrode substrate filled with the active material by coating the active material on the entire surface of the substrate, drying and rolling, and the length of the core of each cell among the active materials filled in the electrode substrate. Peel the active material filled at the position that will be one edge along the direction,
A step of exposing a part of the core substrate, a step of welding a ribbon-shaped conductive metal member to an exposed surface of the core substrate, and a step of cutting the electrode substrate to obtain an electrode plate for each cell. You.

The method of manufacturing the electrode plate includes, in addition to the order of the above-described steps, production of an electrode substrate → separation of an active material →
The order may be as follows: cutting of the electrode substrate → welding of the conductive metal member, or the order of producing the electrode substrate → cutting of the electrode substrate → peeling of the active material → welding of the conductive metal member. In the case where an electrode plate is manufactured using a core cut in advance for a single cell from a core substrate, filling of an active material → peeling of an active material → welding of a conductive metal member is performed in the following order. .

[0012]

In the electrode plate for a spiral-wound alkaline storage battery according to the present invention, the longitudinal edge of the core to be welded to the current collector is straight, and sufficient welding is performed when welding with the current collector. Since a portion can be secured, there is no possibility that the current collecting property may be reduced due to poor welding. Because there is no non-porous part in the core,
Compared to the conventional case where the edge portion is a non-porous portion, distortion generated in the electrode plate when rolling is performed is reduced. Therefore, it is possible to reduce the winding deviation caused when the electrode plate is spirally wound. Further, since the edge portion is a perforated portion, the active material has a high coating strength, and the active material does not easily fall off during winding or charge / discharge cycle. A battery provided with such an electrode plate is less likely to cause current collector welding failure than a conventional electrode plate, and has an electrode body formed by winding the electrode plate of the present invention and a counter electrode through a separator. In this case, since the winding displacement is small, the decrease in the facing area is extremely small. In addition, since the active material is less likely to fall off from the electrode plate, a highly reliable spiral alkaline storage battery having a higher capacity, a higher operating voltage, and higher voltage than a battery using a conventional electrode plate can be obtained. The manufacturing of the electrode plate is also a simplified process, so that automation is easy and the productivity is excellent.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of an alkaline storage battery to which the electrode plate of the present invention is applied is as shown in FIG. 1 and its schematic configuration has already been described. This will be described with an example. In the following invention examples, examples are shown in which the electrode plate according to the present invention is applied to a negative electrode plate. Further, a hydrogen storage alloy is used for the negative electrode.

[0014] will be described with reference to FIG. 3 a production method of the inventive example invention embodiment of the electrode plate (negative electrode). A hole with a hole diameter of 1.8 mm has a distance between circle centers of 4 mm in the horizontal direction (parallel to the winding direction of the electrode plate) and a distance of 2.8 mm in the vertical direction (perpendicular to the winding direction of the electrode plate). In a belt-like thin steel plate (thickness 0.06 mm,
(Width 192 mm) was prepared as a core substrate (28) (FIG. 3).
(a)). Note that the number of columns is not limited to this. The thin plate provided for this core substrate is
Usually, a metal plate mainly composed of iron or nickel is used.However, the present invention is not limited to this. Various metal thin plates conventionally used as an electrode substrate, such as a copper plate and a silver plate, are used. be able to.

Next, 20 parts by weight of a 5% by weight aqueous solution of polyethylene oxide (PEO) as a binder is added to 100 parts by weight of the hydrogen storage alloy powder, and these are mixed to prepare an active material paste. The material paste is applied to the entire core substrate, dried and rolled, so that the active material (4
An electrode substrate (29) filled with 2) is produced (see FIG. 3B).

Of the active material (42) filled in the electrode substrate (29), the active material filled at a position corresponding to one edge along the longitudinal direction of the core body (41) of each cell is peeled off, A part of the core substrate (28) is exposed (see FIG. 3 (c)). The peeling of the active material (42)
For example, ultrasonic vibration can be applied to the electrode substrate (29).

A ribbon-shaped conductive metal member (24) is welded to the exposed surface of the core substrate (28) (see FIG. 3D). Examples of the ribbon-shaped conductive metal member include nickel and iron plated with nickel. In the figure, the punch holes (40) of the core substrate (28) are indicated by broken lines.

The electrode substrate (29) is cut along an XX line passing through the central portion in the width direction of the welded conductive metal member (24) and a YY line having a predetermined electrode plate length (FIG. 3). (See (d)), thickness 0.
A negative electrode plate having a size of 40 mm, a length of 560 mm, a width of 48.0 mm, and an active material application area of 560 mm × 47.0 mm was prepared. FIG. 2 shows the obtained negative electrode plate (electrode plate) (20) for one cell. In FIG.
The portion of the hole (40) of the core body below the conductive metal member (24) is indicated by a broken line. The width of the ribbon-shaped conductive metal member (24) is preferably 1.0 mm or more in the case of the electrode plate size of the present embodiment.

COMPARATIVE EXAMPLE 1 A negative electrode plate having the same structure as that of the above-described invention was prepared except that one edge in the longitudinal direction of the core was made non-porous and no ribbon-shaped conductive member was attached. This negative electrode plate is the same as that shown in FIG.

Comparative Example 2 In this negative electrode plate, both edges in the longitudinal direction of the core were made non-porous, and the edge on the side to be welded to the current collector plate was provided with Comparative Example 1
Similarly to the above, the ribbon-shaped conductive member is not attached, and the edge on the side not welded to the current collector is filled with an active material.
Other than these edges, the structure is the same as that of the above-described invention, and this is referred to as Comparative Example 2. This negative electrode plate is the same as that shown in FIG. 7 (however, the active material is not shown in the non-porous portion in FIG. 7).

COMPARATIVE EXAMPLE 3 A negative electrode plate having the same structure as that of the above-described present invention example was prepared except that a ribbon-shaped conductive metal member was not attached to one edge of the core in the longitudinal direction. This negative electrode plate is the same as that shown in FIG.

With respect to each of the negative electrodes of the invention examples and Comparative Examples 1 to 3, a negative electrode plate and a nickel positive electrode plate having the same active material coating surface width were used. The upper end of the material-filled portion was placed so as to face the same height, and was wound with a separator interposed therebetween to produce a spiral electrode body of nickel / metal hydride.

With respect to the produced spiral electrode body, the amount of winding deviation (mm) between the positive and negative electrode plates was measured. Further, it was also observed whether or not the active material dropped during winding. Table 1 shows the measurement results of the amount of winding deviation.

[0024]

[Table 1]

Referring to Table 1, Comparative Example 1 has the largest amount of winding deviation. This is because, in Comparative Example 1, since only one edge portion is a non-porous portion, the difference in extensibility at both edges is large, and distortion due to rolling between the non-porous portion side and the perforated portion side is reduced. It is considered that this occurred greatly. Further, Comparative Example 2 has a larger winding displacement amount than Comparative Example 1. In Comparative Example 2, both edges were made non-porous, but also in this case, when the electrode plate was rolled after application of the active material, distortion due to the difference in extensibility at both edges was small. It is considered that winding deviation occurred during winding. There was almost no difference in the amount of winding deviation between the invention example and Comparative Example 3, and the amount of winding deviation was small in both cases. This is considered to be because the invention example and the comparative example 3 have perforated portions at both edges in the longitudinal direction.

Observation of whether or not the active material fell off during the winding showed that the active material fell off in Comparative Example 2 in which the non-porous portion at one edge was filled with the active material. From this, the strength of both ends of the core body is secured by making both edges along the longitudinal direction of the core body non-porous, and the reaction area is secured by applying active material to one of them. It has been found that the method to be used may cause a decrease in battery performance due to the loss of the active material.

Next, a test battery was manufactured using the above-mentioned spiral electrode body of nickel / metal hydride. After welding the lower end of the electrode body (the edge in the longitudinal direction of the core body) to the negative electrode current collector, it was inserted into an outer can, and the other end of the negative electrode current collector was welded to the bottom of the can. Next, a 7.5 N aqueous solution of potassium hydroxide was injected as an electrolytic solution, and the cells were sealed to produce three test nickel / metal hydride storage batteries having a nominal capacity of 7000 mAH.

With respect to the test batteries of the invention examples and Comparative Examples 1 to 3, after performing initial conditioning by charging and discharging, the batteries were charged to 160% of the nominal capacity at a current of 1400 mA, and charged at a relatively large current of 70 A to 1%. The battery discharge capacity and operating voltage when discharged to 0.0 V were measured. Table 2 shows the measurement results.

[0029]

[Table 2]

Referring to the results in Table 2, the working voltage is the poorest in Comparative Example 1. This is because the amount of winding deviation of Comparative Example 1 was the largest, and irregularities were generated at the portion where the negative electrode plate of the spiral electrode body and the negative electrode current collector plate were to be welded. Probably because of the rise. Comparative Example 2 also had a considerable amount of winding deviation,
Operating voltage is low. In Comparative Example 3, although the amount of winding deviation was small, it is considered that the number of welding points was reduced due to the presence of punch holes at the edges of the negative electrode plate to be welded, resulting in an increase in internal resistance. On the other hand, the operating voltage of the invention example was large because the spiral displacement of the spiral electrode body of the invention example was small and the edge of the negative electrode plate to be welded was straight, so that the number of welding points was sufficient. Probably because it was able to secure.

Next, with respect to the discharge capacity, the invention example shows a larger result than the comparative examples 1 to 3. This is presumably because the working voltage of the invention example was higher than that of the comparative examples 1 to 3, and the time required to reach the entire voltage became longer. Further, in Comparative Examples 1 and 2, it is considered that the effective reaction area was reduced due to a large amount of winding displacement, and the substantial electrode plate capacity was also reduced.

From the results shown in Tables 1 and 2, it can be seen that the smaller the amount of winding deviation, the more the discharge capacity and operating voltage are improved.

The electrode plate of the present invention can be applied to a positive electrode plate.
Also in this case, similarly to the case of the negative electrode plate, an active material, a binder, a conductive agent and water are mixed and kneaded to prepare a positive electrode mixture having an appropriate viscosity, and applied to a punching metal, After drying and rolling, the filling of the active material can be performed.

Although the above embodiments have been described with reference to an alkaline storage battery, the present invention is not limited to this, and includes various types of cylindrical or prismatic electrochemical batteries having a spiral electrode body, including an alkaline primary battery. Of course, it can be applied to

[Brief description of the drawings]

FIG. 1 is a perspective view showing a schematic configuration of an alkaline storage battery having a spiral electrode body, with the inside of the battery cut away.

FIG. 2 is a view showing an electrode plate of the present invention.

FIG. 3 is a diagram illustrating an example of a process for manufacturing an electrode plate according to the present invention.

FIG. 4 is a view showing a core of a punching metal.

FIG. 5 is a view showing another example of a conventional electrode plate.

FIG. 6 is a view showing another example of a conventional electrode plate.

FIG. 7 is a view showing another example of a conventional electrode plate.

[Description of Signs] (1) Spiral electrode body (10) Positive electrode plate (electrode plate) (20) Negative electrode plate (electrode plate) (22) Negative current collector plate (24) Ribbon-shaped conductive metal member (28) Core Body substrate (29) Electrode substrate (30) Separator (40) Punch hole (41) Core (42) Active material (46) Non-porous part

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01M 6/02 H01M 6/02 Z // H01M 10/28 10/28 A (72) Inventor Takaaki Ikemachi Osaka 2-5-5 Keihanhondori, Moriguchi-shi, F-term (reference) in Sanyo Electric Co., Ltd. CC12 5H050 AA19 BA04 BA11 CA03 CB16 FA05 GA02 GA03 GA07 GA08 GA12 GA22

Claims (5)

[Claims] 1. An electrochemical cell comprising a spirally wound electrode body in which positive and negative electrode plates are spirally wound with a separator interposed therebetween, and wherein the electrode plate is welded to a current collecting plate. The plate has a core body in which a number of punch holes are formed substantially evenly on the entire surface, and a portion other than one edge along the longitudinal direction of the core is filled with an active material. An electrochemical cell, wherein a ribbon-shaped conductive metal member to be welded is attached to a current collector plate. 2. A method for producing an electrode plate for an electrochemical battery, wherein an active material is filled in a portion other than one edge along a longitudinal direction of a conductive core having a large number of punched holes, Prepare a core substrate having a size that includes a plurality of cores of a single cell, and having a number of punch holes formed substantially uniformly on the entire surface,
A step of applying an active material to the entire surface of the core substrate, drying and rolling to produce an electrode substrate filled with the active material; Exfoliating the filled active material at a position to be one edge along the longitudinal direction of the core body to expose a part of the core substrate; and a ribbon-shaped conductive metal member on the exposed surface of the core substrate. Welding an electrode substrate, and cutting an electrode substrate to obtain an electrode plate for each cell,
A method for producing an electrode plate for an electrochemical cell, characterized by being formed by: 3. A method for producing an electrode plate for an electrochemical cell, wherein an active material is filled in a portion other than one edge along a longitudinal direction of a conductive core having a large number of punched holes, Prepare a core substrate having a size that includes a plurality of cores of a single cell, and having a number of punch holes formed substantially uniformly on the entire surface,
A step of applying an active material to the entire surface of the core substrate, drying and rolling to produce an electrode substrate filled with the active material; A step of exfoliating the active material filled at a position to be one edge along the longitudinal direction of the core body and exposing a part of the core body substrate; A method for manufacturing an electrode plate for an electrochemical cell, comprising: a step of obtaining an electrode plate for each exposed cell; and a step of welding a ribbon-shaped conductive metal member to an exposed surface of a core. 4. A method for producing an electrode plate for an electrochemical cell, wherein an active material is filled in a portion other than one edge along a longitudinal direction of a conductive core having a large number of punched holes, Prepare a core substrate having a size that includes a plurality of cores of a single cell, and having a number of punch holes formed substantially uniformly on the entire surface,
A step of applying an active material to the entire surface of the core substrate, drying and rolling to prepare an electrode substrate filled with the active material; and cutting the electrode substrate to form an electrode plate for each cell. And exfoliating the active material filled in the electrode plate at a position to be one edge along the longitudinal direction of the core of each cell, exposing a part of the core. And a step of welding a ribbon-shaped conductive metal member to an exposed surface of the core body. A method for manufacturing an electrode plate for an electrochemical cell, comprising: 5. A method for producing an electrode plate for an electrochemical cell, wherein an active material is filled in a portion other than one edge along a longitudinal direction of a conductive core having a large number of punched holes, A step of applying the active material to a core body having a large number of punch holes formed substantially uniformly on the entire surface, drying and rolling, thereby filling the entire surface of the core body with the active material; Exfoliating the active material, which is filled at a position corresponding to one edge along the longitudinal direction of the core body, to expose a part of the core body, and forming a ribbon-shaped conductive material on the exposed surface of the core body. A method of manufacturing an electrode plate for an electrochemical cell, wherein the method is performed by welding a metal member.