JPH0770310B2 - Method for manufacturing cylindrical non-aqueous electrolyte battery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a cylindrical non-aqueous electrolyte battery, and more particularly to improving the utilization rate of a negative electrode and improving the utilization rate of the negative electrode terminal portion of a current collector. The present invention relates to a manufacturing method in which the spot welding process is abolished.

<< Prior Art >> A bobbin type lithium battery is conventionally manufactured through the following steps.

A cylindrical positive electrode is loaded on the inner peripheral portion of a bottomed cylindrical case that also serves as a positive electrode terminal.

On the other hand, a current collector is adhered to a sheet of metallic lithium that constitutes the negative electrode part, and this surface is inwardly formed into a cylindrical shape, and then the lead part of the current collector is spot-welded to the negative electrode terminal part.

The lithium negative electrode is loaded on the inner circumference of the positive electrode through a bottomed cylindrical separator, and the non-aqueous electrolyte is injected into the inner circumference.

The negative electrode terminal portion is crimped to the opening of the case through a sealing gasket to seal the inside of the battery.

<Problems to be solved by the invention> However, in this manufacturing method, the yield is reduced due to spot welding defects of the lead portion and the negative electrode terminal of the current collector, and the yield is 98.5% due to spot welding defects.
It is known to be about%.

In addition, the metallic lithium that constitutes the negative electrode is particularly light, and because a clearance is provided between the positive electrode and the inner circumference of the positive electrode to facilitate the loading work on the positive electrode, it floats up when the electrolyte is poured and is fixed at a fixed position. It was difficult.

Further, when a discharge test of the battery was carried out in such a state, it was found that the reaction was preferentially performed from the bottom side, the utilization factor due to discharge decreased, and the variation was large.

This invention solves the above drawbacks by positioning the negative electrode in a fixed position, improving the adhesion to the positive electrode to shorten the distance between the electrodes, and improving the utilization rate and the discharge efficiency. An object of the present invention is to provide a method for manufacturing a cylindrical non-aqueous electrolyte battery, which can eliminate a decrease in yield due to welding work by eliminating welding.

<< Means for Solving the Problems >> In order to achieve the above object, a cylindrical negative electrode made of an alkali metal is loaded on the inner circumference of a positive electrode inserted into a case through a bottomed cylindrical separator, and In a method for manufacturing a cylindrical non-aqueous electrolyte battery in which a cylindrical negative electrode and a negative electrode terminal portion are electrically connected via a current collector, a part of the cylindrical negative electrode is expanded in advance in the vertical direction toward the upper side. A slit is formed so that the diameter of the lower side is smaller than that of the upper side, and the plate-shaped current collector in which negative holes are bored inside this negative electrode is tapered so that one side is smaller than the other side. By winding and inserting from the smaller diameter side into the negative electrode, injecting a non-aqueous electrolyte, the negative electrode terminal portion is fitted into the upper opening of the case through a sealing gasket and caulked to collect the negative electrode. The upper end of the electric body is pressed against the bottom of the negative electrode terminal, and this pressure contact The diameter of the current collector is expanded, and the negative electrode is further pressed outward by the current collector having the expanded diameter to expand and divide the slit, and the negative electrode is pressed against the positive electrode through the separator. It is characterized by

<Operation> According to the above configuration, when the negative electrode is inserted into the separator, the negative electrode is inserted from the lower side of the small diameter, so that it can be inserted without high-precision radial positioning. Can be facilitated.

Further, when the current collector is inserted into the negative electrode, the current collector wound in a taper shape is inserted from the smaller diameter side,
It can be inserted without high-precision radial positioning and facilitates insertion work.

Furthermore, by crimping the negative electrode terminal portion, the upper portion of the tapered and wound current collector that is inserted inside the negative electrode is pressed, and the horizontal component force causes the lower portion of the current collector to have a small diameter. To expand, the negative electrode is pressed outward by the expanded current collector and the slit is expanded and divided, and the negative electrode is pressed against the positive electrode through the separator, thereby collecting the negative electrode terminal portion. At the same time when the current collector is pressed, the current collector and the negative electrode and the negative electrode and the positive electrode via the separator can be brought into close contact with each other.

<< Example >> An example of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a manufacturing procedure when the present invention is applied to a bobbin type lithium battery.

In FIG. 1A, the positive electrode 1 is cylindrically mounted on the inner peripheral portion of a bottomed cylindrical case 2 that also serves as a positive electrode current collector via the bottom plate 2a, and at the inner periphery of the positive electrode 1. The point that the separator 3 is loaded is no different from the conventional one.

The positive electrode 1 is formed by mixing manganese dioxide as a main component, graphite as a conductive agent, and tetrafluoroethylene as a binder into a cylindrical shape by press molding, and then charging the case 2 with the same. is there.

The separator 3 is made of polypropylene non-woven fabric and has a bottomed cylindrical shape, and is attached to the upper surface of the bottom plate 2a.

On the other hand, as shown in FIG. 2, the lithium negative electrode 4 has a sheet metal lithium formed in a cylindrical shape, and has a tapered slit 4a formed on the outer peripheral portion thereof so as to vertically expand toward the upper side. The diameter is slightly smaller than the inner diameter of the separator 3.

The lithium negative electrode 4 is fitted on the inner circumference of the separator 3 as shown in FIG. 1 (b).

Next, as shown in FIG. 1C, the negative electrode current collector 5 is fitted on the inner circumference of the lithium negative electrode 4, and the non-aqueous electrolyte solution 6 is poured onto the negative electrode current collector 5.

The current collector 5 is a punched metal such as stainless steel having a thickness of 0.15 mm and a porosity of about 40%, which is rolled into a cylindrical shape as shown in Fig. 2. The diameter of the upper side is larger than that of the lower side. It has a taper shape, and while holding this shape, the lithium negative electrode 4 is loaded to a certain depth on the inner surface, and then the cylindrical shape restriction is released, so that springback occurs and the lithium negative electrode 4 spreads to a certain diameter. Prior to the terminal portion 8, the expansion is restricted by the inner peripheral portion of the sealing gasket 7 fitted in the upper opening of the case 2.

Further, the height of the current collector 5 is a height right below the opening of the case 2, and after the liquid injection, as shown in FIG. 1 (d), a dish-shaped negative electrode terminal portion is provided inside the sealing gasket 7. When 8 is fitted, the fixed position of the negative electrode terminal portion 8 is restricted by the curl processing portion 2b formed on the upper peripheral edge of the case 2, and the current collector 5
The upper edge of is pressed against the periphery of the lower surface of the negative electrode terminal portion 8 to ensure electrical conduction.

Moreover, the current collector 5 is strongly pressed to the lower side by this pressure contact, and the horizontal component force also acts to expand the lower side of the cone shape, and the outer periphery of the current collector 5 is strongly pressed to the inner periphery of the lithium negative electrode 4. Also, good electrical contact can be obtained with respect to the lithium negative electrode 4.

Further, due to this expanding operation, the lithium negative electrode 4 is divided while expanding the slit 4a, and the lower side largely expands in the radial direction.

As a result, the lithium negative electrode 4 is strongly pressed toward the lower side of the inner circumference of the separator 3.

Then, the upper edge 2c of the case 2 is caulked inward to complete the battery as shown in FIG. 1 (e).

In the completed state, the upper edge of the current collector 5 is in a state of being strongly pressed against the lower surface of the negative electrode terminal portion 8, and the lithium negative electrode 4 is fixed at a fixed position on the inner circumference of the separator 3 in a pressure-bonded state.
The inter-electrode distance with respect to is also small, and the utilization factor of the lithium negative electrode can be improved.

Fig. 3 shows the CR17335 type battery created by the above manufacturing procedure and 10 conventional batteries each at 5.6K at 20 ° C.
6 is a graph comparing discharge characteristics until the final voltage drops to 2.0 V after continuous discharge with a load of Ω.

As a result, the average value of the discharge characteristics of the battery according to the manufacturing process of the present invention is 3620 hours, which is much larger than the conventional average value of 3360 hours, the deviation is small, and the discharge characteristics are uniform. It was confirmed.

<Effects of the Invention> As described in detail in the above examples, in the method for manufacturing a cylindrical non-aqueous electrolyte battery according to the present invention, since the negative electrode is inserted from the lower side of the small diameter, the radial height is increased. It can be inserted without precise positioning, and insertion work can be facilitated.

Further, when the current collector is inserted into the negative electrode, the current collector wound in a taper shape is inserted from the smaller diameter side,
It can be inserted without high-precision radial positioning, facilitating insertion work.

Furthermore, as the upper end of the negative electrode current collector fitted inside the negative electrode is pressed in the crimping process of the negative electrode terminal part, electrical connection can be secured, so the spot welding process can be omitted, and the number of steps and welding can be reduced. It is possible to prevent a decrease in yield due to a defect.

In addition, the current collector expands its diameter by pressure contact, secures adhesion to the negative electrode, and also the negative electrode itself is expanded and pressed against the positive electrode side through the separator, and is fixed in a fixed position. It becomes shorter, the negative electrode can be effectively used until the end of discharge, the discharge performance is improved, and at the same time, the variation in performance is reduced and a uniform product can be obtained.

[Brief description of drawings]

1 (a) to 1 (e) are half cross-sectional explanatory views showing the procedure for producing a non-aqueous electrolyte battery according to the present invention, FIG. 2 is an explanatory view showing the shapes of a lithium negative electrode and a negative electrode current collector, and FIG. 3 is a graph comparing the discharge characteristics of the present invention and a conventional battery. 1 …… Positive electrode 2 …… Case 3 …… Separator 4 …… Lithium negative electrode 4a …… Slit 5 …… Negative electrode current collector 6 …… Non-aqueous electrolyte 7 …… Sealing gasket 8 …… Negative electrode terminal

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 48-63238 (JP, A) JP 37-6223 (JP, Y1) JP 37-22956 (JP, Y1) JP

Claims (1)

[Claims] 1. A cylindrical negative electrode made of an alkali metal is loaded on the inner periphery of a positive electrode inserted in a case via a bottomed cylindrical separator, and the cylindrical negative electrode and a negative electrode terminal portion are collected. In the method of manufacturing a cylindrical non-aqueous electrolyte battery electrically connected via a body, in a part of the cylindrical negative electrode, a slit that expands in the vertical direction toward the upper side in advance is formed, and the lower side is set to the upper side. The diameter of the plate-shaped current collector having a plurality of holes formed inside the negative electrode is wound in a taper shape whose one end is smaller than the other end, and the above-mentioned small diameter side Inserted inside the negative electrode, after injecting a non-aqueous electrolyte solution, the negative electrode terminal portion is fitted into the upper opening of the case through a sealing gasket and caulked to make the upper end of the current collector the negative electrode terminal portion. Pressure contact with the bottom, and the diameter of the current collector is expanded by this pressure contact. A cylindrical non-aqueous electrolyte battery characterized in that the negative electrode is pressed outward by a sharp current collector to expand and divide the slit, and the negative electrode is pressed against the positive electrode via a separator. Manufacturing method.