JPH083964Y2 - Flat type non-aqueous electrolyte battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a flat type non-aqueous electrolyte battery.

<Prior Art> In a flat type non-aqueous electrolyte battery, for example, a coin type lithium battery, a power generating element formed by sequentially stacking a positive electrode mixture, a separator, and a lithium negative electrode is hermetically housed by combining a positive electrode can and a negative electrode terminal plate. The configuration is adopted.

As a process for injecting an electrolytic solution (non-aqueous electrolytic solution) in the case of industrially manufacturing this coin-type lithium battery, one of the following two procedures is generally used.

That is, first, for example, in FIG. 2 (A), the separator 8 is placed on the upper surface of the positive electrode mixture 2 located on the inner bottom surface of the positive electrode can 1, and then the nonaqueous electrolysis is performed from above the separator 8. A predetermined amount of the liquid is injected with a nozzle or the like, and then, as shown in FIG. 2 (B), the negative electrode portion such as the lithium negative electrode 5 and the negative electrode terminal plate 6 and the sealing gasket 7 are combined to seal the battery. is there. In the figure, 2a is a liquid storage space for the electrolytic solution, which is usually provided in the center of the mixture. Further, by providing the liquid retaining space 2a, it is possible to store the electrolyte solution necessary and sufficient for the battery reaction in the battery, and thus it is possible to prevent the electrolyte solution from being depleted due to the swelling of the positive electrode mixture due to the progress of discharge. The rise in internal resistance of the battery is suppressed.

On the other hand, secondly, after injecting the electrolytic solution from the positive electrode mixture 2 located on the inner bottom surface of the positive electrode can 1, the separator 8 is placed on the upper surface of the mixture, and thereafter the battery is sealed in the same manner. The procedure is to do.

<Problems to be solved by the invention> However, especially a battery using a positive electrode mixture provided with a liquid retaining space (the amount of electrolyte to be injected is large in this battery)
In the case of injecting the electrolytic solution in, when performing the injection in the state where the separator is placed on the upper surface of the mixture as described above, it is difficult for the electrolytic solution to turn into this holding space, and a considerable amount of the electrolytic solution is positive electrode. Since it is in a state of being accumulated on the mixture, there is a problem that the separator is lifted and the position is likely to be displaced.

On the other hand, when the separator is placed on the poured positive electrode mixture, the surface of the mixture is wet, so the metal part of the separator holding jig that carried the separator and further the separator is placed on the upper surface of the mixture. The electrolytic solution will adhere to the metal parts of other machines and equipment used in the process up to. Since this kind of electrolytic solution (non-aqueous electrolytic solution) has a strong corrosive property, it causes corrosion and rust generation in these metal parts.

Further, if the electrolytic solution is attached to the holding jig, the step of separating the separator and placing it on the positive electrode mixture cannot be performed well, which causes a problem in the step.

To eliminate the above-mentioned metal corrosion and troubles,
It is also conceivable that the separator is placed when the electrolyte solution is sufficiently absorbed by the positive electrode mixture and the surface of the mixture has dried. However, in this case, the amount of the electrolytic solution enclosed in the battery is reduced due to the evaporation of the electrolytic solution from the surface of the mixture, and the discharge performance is deteriorated.

This invention is a flat type non-aqueous electrolyte battery that does not cause displacement of the separator as described above even when the liquid is injected with the separator placed on the upper surface of the mixture and has good discharge performance. The purpose is to provide.

<Means for Solving the Problems> The flat non-aqueous electrolyte battery of the present invention is provided with a liquid retaining space in the positive electrode mixture located on the inner bottom surface of the positive electrode can and is placed on the positive electrode mixture. The gist of the invention is that a hole smaller than the liquid retaining space is formed in a portion of the separator that faces the liquid retaining space.

In the above battery, the reason for making the pores of the separator smaller than the liquid holding space of the positive electrode mixture is that the size of the liquid holding space decreases with discharge due to swelling of the positive electrode mixture due to discharge. If the hole and the positive electrode mixture have the same diameter, there is a risk of an internal short circuit.

On the other hand, the liquid retaining space is usually provided in the central portion of the mixture and may have an appropriate shape such as a recess or a through hole.

By the way, in the case of injecting the electrolytic solution from above the separator placed on the upper surface of the mixture in the above battery, it is preferable to inject from the above hole of the separator.

Further, in the battery manufacturing process, electrolyte injection is generally performed using a liquid injection nozzle, and this liquid injection nozzle is positioned in the hole, so the hole of the separator is the diameter of the liquid injection nozzle. It may be about the same or a little larger.

<Operation> By using the separator having the holes provided at the positions facing the liquid holding space as described above, even when the separator is placed on the positive electrode mixture and the electrolytic solution is injected, the injected electrolytic solution The liquid directly reaches the liquid holding space and the surface of the mixture through this hole.

Therefore, the electrolyte solution can be quickly absorbed in the positive electrode mixture, and a sufficient amount of the electrolyte solution can be retained in the battery, so that a battery having excellent discharge performance can be obtained.

Since the separator remains in close contact with the mixture during the period from the injection to the absorption, the separator does not cause the above-mentioned positional displacement.

<Embodiment> An embodiment of the present invention will be described below.

In FIG. 1, a mixture powder containing manganese dioxide as an active material and having an outer diameter of 23 m is formed on the inner bottom surface of the positive electrode can 1 made of stainless steel.
m, the positive electrode mixture 2 obtained by molding into a hollow disk shape with an inner diameter of 8 mm,
It was crimped together with the positive electrode ring 3 fitted on the outer periphery thereof.
In the figure, 2a is a liquid holding space for holding an electrolyte.

Next, a separator 4 made of a non-woven fabric mainly made of polypropylene having an outer diameter of 21 mm and an inner diameter of 5 mm is placed on the upper surface of the positive electrode mixture 2, and a hole formed in the center of the separator 4 is placed.
From above 4a, use propylene carbonate and dimethoxyethane as the non-aqueous solvent, and add lithium perchlorate to this non-aqueous solvent.
540 μl of a non-aqueous electrolytic solution prepared by dissolving 1 mol / l was injected.

After that, on the upper bent portion of the positive electrode ring 3 located at the opening of the positive electrode can 1, the negative electrode 5 made of a lithium alloy is pressure-bonded to the inner bottom surface of the stainless steel negative electrode terminal plate 6 and the polypropylene. A flat type lithium battery of CR2450 (product of the present invention) was made by hermetically sealing the battery by fitting a sealing gasket 7 of the above. The time required from the injection of the electrolyte solution to the fitting of the negative electrode terminal plate and the sealing gasket was about 1 minute.

On the other hand, a flat lithium battery of CR2450 (comparative product A) was produced in the same manner as the product of the present invention except that a non-perforated separator made of a polypropylene nonwoven sheet having an outer diameter of 21 mm was used.

Fifty of these two types of batteries were made, respectively, and after assembling, the batteries were disassembled, and the presence or absence of separator displacement was investigated. The results are shown in Table 1, and no deviation occurred in the product of the present invention.

On the other hand, as the separator, the separator without holes used in the comparative product A was used, and the nonaqueous electrolytic solution was injected from above the positive electrode mixture that was pressure-bonded to the bottom surface of the positive electrode can, and then the wetting of the separator holding tool was minimized. After pouring the solution, leave it for 5 minutes, place the separator on the positive electrode mixture, and then fit the negative electrode terminal plate, sealing gasket, etc. on the CR2450 flat plate like the product of the present invention. Lithium battery (Comparative product B)
Was produced.

5 batteries each of the device of the present invention and the comparative product (Battery N
o.1 to 5), load each battery at a temperature of 20 ℃ 3k
The discharge duration time (hour) was examined when the discharge voltage was continuously discharged to a final voltage of 2.5 V with Ω. The results are shown in Table 2. Compared with the comparative product, the discharge duration time (average value) of the device of the present invention is 10
% Or more, and the variation (δ _n-1 ) is small.

<Effects of Device> As described above, according to this device, since the electrolyte solution in the positive electrode mixture can be absorbed quickly, and a sufficient amount of the electrolyte solution is retained in the battery, the separator is placed on the positive electrode mixture. It is possible to provide a flat type non-aqueous electrolyte battery which does not cause the above-mentioned positional displacement of the separator even when the electrolytic solution is injected while being placed on the battery, and has excellent discharge performance.

Further, since the electrolyte can be injected smoothly, there is an advantage that the battery can be easily assembled.

[Brief description of drawings]

1 (A) to (C) are explanatory views of the manufacturing procedure in the battery of the embodiment, and FIGS. 2 (A) and 2 (B) are explanatory views of the conventional battery. 1 ... Positive electrode can, 2 ... Positive electrode mixture, 3 ... Positive electrode ring, 4,
8 …… Separator, 6 …… Negative electrode terminal plate, 2a …… Liquid storage space, 4a …… Hole.

Claims (1)

[Scope of utility model registration request] 1. A liquid-retaining space is provided in a positive electrode mixture located on the inner bottom surface of a positive electrode can, and a liquid-retaining space is provided in a separator which is placed on the positive electrode mixture and which faces the liquid-retaining space. A flat type non-aqueous electrolyte battery, characterized in that pores smaller than the liquid space are formed.