JP3081272B2 - Method for manufacturing battery with spiral electrode body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a battery provided with a spiral electrode body using an electrode base made of a three-dimensional porous metal body used for a cylindrical alkaline storage battery or the like.

[0002]

2. Description of the Related Art Conventionally, electrodes used for alkaline storage batteries and the like have been mainly produced by a sintering method in which a carbonyl nickel sintered body is impregnated with a solution of a nickel salt, a cadmium salt or the like, and converted into an active material by an alkali treatment. However, in recent years, for the purpose of cost reduction and higher energy density, a three-dimensional metal porous body such as a metal fiber sintered body, sponge-like nickel, and the active material powder are kneaded together with a paste liquid to form a paste. A non-sintering method of directly filling a paste-like active material has been studied.

One of the non-sintering methods uses a sponge-like nickel porous metal as an active material holder. In this production method, a sponge-like nickel porous body having three-dimensionally continuous pores having an average pore diameter of about 200 microns and a porosity of about 95% is filled with a powdered active material, and then rolled to obtain a finished electrode plate. . This has a simpler manufacturing process than the conventional sintering method and has a high possibility of increasing the energy density.

In a sintered electrode plate, a thin punched metal plate is used as a core body, so that a current collecting terminal can be easily attached to the metal plate by a method such as resistance welding. Extremely high.

[0005] On the other hand, non-sintered electrode plates use very high porosity substrates, making it difficult to take out the current collector terminals. Sponge-like nickel has a low metal density per area, and if a current collecting terminal is welded before filling the active material, a general resistance welding method is used because a non-uniform elongation or warpage occurs in the relevant part in the subsequent rolling process. Could not be adopted.

On the other hand, the inventors have previously disclosed in
As a countermeasure, Japanese Patent Application Laid-Open No. 186557/1988 and Japanese Patent Application Laid-Open No. 63-40253 have proposed a method of removing an active material by ultrasonic vibration and then welding a current collecting terminal.

However, in these production methods,
Regarding the strength of the terminal portion and the reliability against breakage when the electrode to which the current collecting terminal is attached is wound into a cylindrical shape, there are still insufficient ones.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems and provides a highly reliable current collecting terminal for a cylindrical alkaline storage battery using a three-dimensional porous metal such as sponge nickel as a base. It provides a retrieval method.

[0009]

According to a method of manufacturing a battery provided with a spiral electrode body according to the present invention, an active material is filled in holes of an electrode base made of a three-dimensional porous metal body, and ultrasonic waves are applied from one side of the base. After pressing the horn to remove the active material by ultrasonic vibration to form a current collecting terminal mounting portion, a current collecting terminal is attached to this mounting portion to produce an electrode, and then the surface against which the ultrasonic horn is pressed. There is characterized in configuring the spiral electrode body by winding an electrode to face the outer circumference.

Here, it is preferable that the edge portion of the tip of the ultrasonic horn is tapered or rounded so that the electrode plate compression ratio of the active material removing portion is continuously reduced from the central portion to the peripheral portion.

Preferably, an adhesive tape is attached so as to cover the entire surface of the current collecting terminal mounting portion.

[0012]

FIG. 4 is an external view in which a current collecting terminal is attached to an electrode plate. When the current collecting terminal is attached to the electrode plate and wound on the spiral electrode body, cracks or breaks occur in the current collecting portion. This is basically due to the lack of flexibility of the electrode plate, but the frequent occurrence of the phenomenon in the current collecting part is particularly due to the lack of elongation with other parts due to the fact that the relevant part is not filled with active material. This is considered to be due to the uniformity, damage to the substrate in the active material removal step, and differences in thickness.

The inventors conducted various experiments in order to clarify the significance of these factors and countermeasures. As a result, the active material was pressed by pressing an ultrasonic horn from the direction of the outer peripheral surface when winding the spiral electrode. By forming the current collector mounting part by removing and attaching the current collector to this mounting part, and forming the spiral electrode body, the welding state of the current collector is good and the strength after winding is improved. Was found.

Further, by making the edge portion of the ultrasonic horn beveled, the current collector can be welded better when forming the spiral electrode body, and the strength after winding can be improved.

Further, after welding the current collecting terminal, an adhesive tape is applied so as to cover the entire surface of the active material removing portion, so that generation of cracks or breaks in the current collecting portion can be suppressed. Strength is improved.

Hereinafter, the contents will be described in detail in embodiments.

[0017]

【Example】

[Experiment 1] Active material removal direction and thickness Since the active material is removed by pressing the ultrasonic horn from one side of the completed electrode plate and oscillating the horn while applying pressure, the active material is discharged out of the electrode plate. The horn contact portion is compressed to form a concave portion having a smaller thickness than the peripheral portion. Therefore, the side on which the concave portion is formed and the shape differ depending on the pressing direction and method of the ultrasonic horn. The following experiment was conducted on the influence of these factors.

A sponge-like nickel having an average pore diameter of 250 μm was filled with an active material mainly composed of nickel hydroxide, and rolled to produce an electrode plate having an active material density of 2.9 g / cm ³ and a thickness of 0.65 mm. The ultrasonic device has an output of 700W and a frequency of 40k
Hz and the ultrasonic horn used were each a square having a tip size of 10 × 6 mm (both manufactured by Branson Ultrasonics).

There are three types of pressing directions of the ultrasonic horn: the inner peripheral side, the outer peripheral side, and both sides at the time of winding the battery, and the shape of the current collector welded part thus completed is as shown in FIG.

The compressed thickness (hereinafter referred to as “electrode plate compression ratio”) with respect to the initial electrode plate thickness after the removal of the active material was set to 10, 15, 20, 25, 30, and 35%.

Thereafter, a current collector having a width of 3 mm was welded by ordinary resistance spot welding to obtain a completed electrode plate.

Here, the compression ratio of the electrode plate is adjusted by setting the lower stopping point position when the ultrasonic horn is pressed against the electrode plate in the active material removing step. For example, the example electrode plate (thickness 0.65 m)
In the case where the electrode plate compression ratio is set to 10% for m), it can be obtained by setting the ultrasonic horn lower stopping point at a depth of 0.065 mm from the electrode plate surface.

Further, these test electrodes were combined with a usual cadmium cathode plate via a separator and wound. Then, it was disassembled and the state of the current collector was visually observed to evaluate the strength. Table 1 shows the results.

[0024]

[Table 1]

As described above, the compression ratio of the electrode plate after the removal of the active material is increased (the thickness of the welded portion after the removal of the active material is reduced).
It can be seen that the current collector welding condition is good, but the strength after winding tends to cause a problem. However, by performing the active material removal direction from the outer peripheral side of the winding and forming the concave portion on the outer peripheral side, and controlling the electrode plate compression ratio to 15 to 25%,
The current collector is obtained in a welded state and in a state in which the strength after winding is substantially good.

The reason why the current collector welding state changes depending on the electrode plate compression ratio is that welding cannot be performed normally when the active material removal rate is low and the active material remains large (when the electrode plate compression ratio is small). ) Or the substrate is greatly damaged and the strength is reduced (when the electrode plate compression ratio is large). On the other hand, from the viewpoint of the winding strength, the value of the electrode plate compressibility should be set to a small value, but the range that can be practically employed is limited to the range described above.

[Experiment 2] Ultrasonic horn shape Based on the results of Experiment 1, the active material removal direction was taken from the outer periphery side of the winding, and the edge of the ultrasonic horn was inclined and the experiment 1 was performed.
The experiment was performed under the same conditions as described above. The shape change of the edge part of the ultrasonic horn was performed by performing round processing of R0.5 and R1.0 on the edge part. (FIG. 2) The results are shown in Table 2.

[0028]

[Table 2]

According to Experiment 2, in the case where the edge portion was not rounded, the ultrasonic horn had a relatively large damage to the base in contact with the edge portion, and the horn edge portion was inclined to collect current. It was confirmed that a favorable condition range was expanded in both the welding state and the winding strength of the body.

This is evident from the fact that the number of defects in the strength after winding at an electrode plate compression ratio of 30% is reduced by providing the edge of the ultrasonic horn with a slope.

[Experiment 3] Attaching a reinforcing adhesive tape A similar tape strength test was performed by attaching a reinforcing tape to an electrode plate whose pressing direction of the ultrasonic horn prepared in Experiment 1 was on the outer peripheral side when winding the battery. went. The reinforcing tape used was a polypropylene adhesive tape having a thickness of 50 μm, and the width was 6.0 mm, which is the same as the width of the active material removing portion, and as shown in FIG. . In the test, an electrode plate using the two types of adhesive tapes and an electrode plate not using the adhesive tape were compared.

The results are shown in Table 3.

[0033]

[Table 3]

From Table 3, it can be seen that by applying an adhesive tape so as to cover the entire surface of the active material removing portion, it is possible to improve the winding strength even when the electrode plate compression ratio increases.

[0035]

As described above, according to the method of manufacturing a battery provided with a spiral electrode body of the present invention, an active material is filled in the holes of an electrode base made of a three-dimensional porous metal body, and ultrasonic waves are applied from one side of the base. After pressing the horn to remove the active material by ultrasonic vibration to form a current collecting terminal mounting portion, a current collecting terminal is attached to this mounting portion to produce an electrode, and then the surface against which the ultrasonic horn is pressed. by but configuring the by winding the electrode spiral electrode body to face the outer circumference, in which very effective in keeping the strength of the current collector welded portion serving as the main point of the reliability of the battery Yes, its industrial value is extremely large.

In the embodiment, only the electrode plates having the same thickness have been described, but the effect can be equally applied to other types. Further, the material of the reinforcing tape, the size of the active material removing portion, and the like are not limited to those described in the embodiments.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an active material removing unit.

FIG. 2 is a cross-sectional view of a main part of an active material removing unit in which an edge portion is rounded.

FIG. 3 is a cross-sectional view of a main part of an active material removing unit in which a current collecting terminal is covered with an adhesive tape.

FIG. 4 is an external view of an electrode.

[Explanation of symbols]

 Reference Signs List 1 active material removing section 2 current collecting terminal 3 electrode plate 4 adhesive tape

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Kodama 2-18-18 Keihanhondori, Moriguchi City Sanyo Electric Co., Ltd. (56) References JP-A-1-251555 (JP, A) JP-A-4-262366 JP-A-2-186557 (JP, A) JP-A-57-67284 (JP, A) JP-A-55-9363 (JP, A) JP-A-63-40252 (JP, A) JP-A-63-40253 (JP, A) JP-A-63-40254 (JP, A) JP-A-61-114662 (JP, U) JP-A-62-98159 (JP, U) JP-A-62-98160 (JP, A) JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 2/26 H01M 10/28

Claims (3)

(57) [Claims] An active material is filled into holes of an electrode base made of a three-dimensional porous metal body, and an ultrasonic horn is pressed from one side of the base to remove the active material by ultrasonic vibration to collect a current collecting terminal. after forming the, to prepare an electrode attached to the current collector terminal to the mounting part, then, constitutes a spiral electrode body by winding an electrode to the surface pressed against an ultrasonic horn facing the outer circumferential direction A method for producing a battery provided with a spiral electrode body, characterized in that: 2. An ultrasonic horn according to claim 1, wherein an edge portion at an end of the ultrasonic horn is tapered or rounded to continuously reduce the plate compression ratio of the active material removing portion from a central portion to a peripheral portion. Item 7. A method for manufacturing a battery comprising the spiral electrode body according to Item 1. 3. The method for manufacturing a battery provided with a spiral electrode body according to claim 1, wherein an adhesive tape is attached so as to cover the entire surface of the current collector terminal mounting portion.