JP2001052688A - Alkaline battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the discharging characteristic by heightening the filling accuracy of an alkaline battery with a gel-form zinc negative electrode. SOLUTION: An alkaline battery is filled with a gel-form zinc negative electrode (zinc + electrolytic solution + gelation agent) through such a process that (1) a specified quantity of zinc and a specified quantity of mixture of electrolytic solution and gelation agent are weighed separately and mixed together to turn into gel form, or (2) a specified quantity of electrolytic solution and a specified quantity of mixture of zinc and gelation agent are weighed separately and mixed together to turn into gel form, or (3) a specified quantity of mixture of zinc and gelation agent and a specified quantity of mixture of electrolytic solution and gelation agent are weighed separately and mixed together to turn into gel form, and the obtained gel-form negative electrode 4 is put fully in the battery. The gel-form electrode 4 filled in this manner has a high filling accuracy to result in enhancement of the discharging characteristics of battery. Also a high anti-leakage characteristic is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention has an object to improve discharge characteristics by improving the filling accuracy of gelled negative electrode zinc as compared with the conventional gel filling method.

[0002]

2. Description of the Related Art In the manufacture of an alkaline battery using zinc as a negative electrode and an alkaline aqueous solution such as potassium hydroxide or sodium hydroxide as an electrolytic solution, the following steps must be taken. A `` gel filling method '' in which a liquid and a gelling agent are preliminarily mixed, the mixture is weighed, and then charged into a battery.
(2) Two types of methods are generally used: a "powder method" in which a mixture of zinc and a gelling agent and an electrolytic solution are separately weighed, and then separately charged into a battery and gelled in the battery. It has been done.

In general, the upper limit of the filling amount is determined based on the internal volume of the battery and the balance with the positive electrode, and the center value of the filling amount is generally determined in consideration of the variation depending on the filling method. is there.

However, in the case of the "gel filling method",
Since the viscosity of the gel to be filled varies, sufficient filling accuracy cannot be obtained, and it is necessary to manufacture a battery by reducing the central value of the negative electrode filling amount by the variation.

On the other hand, in the “powder method”, sufficient filling accuracy can be obtained in battery production, and the filling can be performed with the center value of the negative electrode filling amount set near the upper limit. Since part of the electrolyte is free before the solution has gelled in the battery, this free electrolyte crawls up the negative electrode current collector, resulting in a decrease in leakage resistance during high-temperature and high-humidity storage. Was causing it.

Further, in the "powder method", when the amount of mercury contained in the negative electrode zinc is reduced, the cause is unknown, but the zinc utilization rate is greatly reduced as compared with the "gel filling method". It has been found that a problem that the discharge characteristics are deteriorated occurs.

[0007]

As described above, two methods have conventionally been used for filling a zinc negative electrode, but the "gel filling method" generally has better battery characteristics. However, in the case of using this method, the filling accuracy of the negative electrode zinc is large as described above, so that the negative electrode zinc could not be filled to an optimum filling amount in terms of discharge characteristics.

The present invention has been made in view of the above-described circumstances, and it is intended to prevent a variation in the filling accuracy of the negative electrode zinc in the conventional “gel filling method” in an alkaline battery, and to improve the filling accuracy to the same level as the “powder method”. It is an object of the present invention to improve the discharge characteristics, thereby improving the discharge characteristics as compared with the conventional “gel filling method”.

[0009]

According to the present invention, zinc is used as a negative electrode active material, an alkaline aqueous solution is used as an electrolyte,
In an alkaline battery using a gelled negative electrode containing a gelling agent, a predetermined amount of zinc and a predetermined amount of a mixture of an electrolytic solution and a gelling agent are separately weighed and then mixed to form a gel. Then, after having a gelled negative electrode filled in the battery, or a predetermined amount of the electrolytic solution and a predetermined amount of a mixture of zinc and a gelling agent are separately weighed, these are mixed to form a gel, and then Having a gelled negative electrode filled into the battery,
After separately weighing a predetermined amount of a mixture of zinc and a gelling agent and a predetermined amount of a mixture of an electrolytic solution and a gelling agent, mixing them to form a gel, and then filling the battery with a gel It has a negative electrode.

According to the present invention, in each case, the components of the gelled negative electrode housed in the battery are weighed before gelling in advance. The accuracy of the filling amount is increased. In addition, when compared with the conventional powder system, each component is mixed and gelled before filling, so that the electrolyte does not exist in a free state in the battery, and leak-proof as in the conventional powder system. Does not degrade liquid properties.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a button-type air zinc battery PR48 (7.8 mm in diameter, 5.4 mm in total height) as a typical example of the alkaline battery of the present invention. As shown in FIG. 1, this alkaline battery has a positive electrode catalyst layer group 3 for taking in oxygen in the air as a positive electrode, and a mixture of zinc powder and an electrolytic solution (aqueous potassium hydroxide solution) was gelled as a negative electrode. It has a negative electrode gel 4. The positive electrode catalyst layer group 3 is installed in a positive electrode can 1 having an air hole 2 as shown in the figure, and a negative electrode gel 4 is contained in a negative electrode container 5 also serving as a negative electrode current collector. 5 is hermetically sealed by caulking through an insulating packing 6.

(Example 1) 6% zinc zinc oxide as a negative electrode, 35% aqueous potassium hydroxide solution as an electrolytic solution, and sodium polyacrylate as a gelling agent in a weight ratio of 100: 3.
Used at a ratio of 0: 1. In the present embodiment, a mixture of 6% of zinc calomel and the gelling agent in the above ratio and a 35% aqueous solution of potassium hydroxide are weighed in advance so as to have the above ratio, respectively, and then these are mixed. This was used as a gelled negative electrode to fill the battery.

Generally, in an air battery, zinc is changed to zinc oxide by discharge, and the volume of the negative electrode expands. Therefore, it is necessary to fill the negative electrode so that the volume of the negative electrode after discharge does not exceed 100% of the volume of the negative electrode container, and this is set as the upper limit of the negative electrode filling amount. By the way, the negative electrode volume after the discharge is a value obtained by calculating assuming that all of the filled zinc has changed to zinc oxide, and simply adding the respective volumes of the electrolytic solution and the gelling agent to the negative electrode specification (for example, , Electrolyte concentration, and rate of calcining), so it is calculated for each specification.

In this embodiment, the gelled negative electrode was filled according to the above filling process, and 100 prototypes were manufactured. The value of the dispersion σ when the negative electrode gel was filled 100 times was calculated in consideration of the variation of the gel filling amount, and 4
The value obtained by subtracting σ from the above filling upper limit was defined as the average filling amount.

[0015] Separately, a conventional gel filling method was used to perform filling to obtain a conventional example. This is a 6% zinc calomelide, 3
A 5% aqueous solution of potassium hydroxide and sodium polyacrylate were mixed at a weight ratio of 100: 30: 1 to prepare a negative electrode gel, which was weighed using a filling machine and filled into the battery. The average filling amount is calculated by taking into account the dispersion of the gel filling amount, calculating the value of the dispersion σ when the negative electrode gel is filled 100 times, and averaging the value obtained by subtracting 4σ from the above filling upper limit value in the same manner as in the above example. The filling amount was used.

(Example 2) 6% of zinc calomel was weighed, a mixture of a gelling agent and an electrolytic solution was weighed, and then these were mixed to form a gelled negative electrode, which was filled into a battery. Except for this, it was the same as Example 1.

(Example 3) The rate of calcining of zinc-melted zinc was 3%, and the other conditions were the same as in Example 1.

(Example 4) The rate of calcining of zinc-melted zinc was 1%, and the other conditions were the same as in Example 1.

(Example 5) The same zinc-free zinc was used as in Example 1 except that zinc was used.

Comparative Example 1 The filling method was the gel filling method, and the other conditions were the same as in Example 3.

(Comparative Example 2) The filling method was the gel filling method, and the other conditions were the same as in Example 4.

Comparative Example 3 The filling method was the gel filling method, and the other conditions were the same as in Example 5.

(Comparative Example 4) The filling method was the powder method, and the other conditions were the same as the conventional example.

(Comparative Example 5) The filling method was the powder method, and the other conditions were the same as in Example 3.

(Comparative Example 6) The filling method was the powder method, and the other conditions were the same as in Example 4.

(Comparative Example 7) The filling method was the powder method, and the other conditions were the same as in Example 5.

The discharge characteristics and leakage resistance characteristics of each of the above Examples, Comparative Examples and Conventional Examples were compared. The discharge characteristics are
10 prototyped batteries were stored in an environment of 20 ° C and 60% RH for 620
Continuous discharge was performed at Ω, and the average duration was taken as a characteristic value. The leak-proof characteristic was obtained by storing 50 prototype batteries for one month in an environment of 60 ° C. and 93% RH, counting how many batteries leaked, and setting the leak occurrence rate as a characteristic value. These are shown in Table 1.

Table 1 also shows the average filling amount and σ in each example. The average value and the number of samples of σ are 100.

[0029]

[Table 1]

From the results shown in Table 1, in each of the examples, the discharge characteristics were improved as compared with the conventional example and each of the comparative examples, and the liquid leakage resistance was almost the same as that of the conventional example, and was improved as compared with each of the comparative examples. You can see that there is. Also, it can be seen that even if the mercury in zinc is reduced or eliminated, the filling method of the present method can suppress a decrease in discharge characteristics as compared with the conventional powder method.

[0031]

As described above, in the alkaline battery of the present invention, the filling accuracy of the gelled negative electrode zinc is improved as compared with the conventional gel filling system, the discharge characteristics are improved, and moreover, compared with the conventional powder system. Improved liquid leakage resistance.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a zinc-air battery according to one embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Positive electrode can, 2 ... Air hole, 3 ... Positive electrode catalyst layer group, 4 ... Negative electrode gel, 5 ... Negative electrode current collector, 6 ... Insulating packing.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hideyuki Ogata 3-4-10 Minamishinagawa, Shinagawa-ku, Tokyo Toshiba Battery Corporation F-term (reference) 5H015 AA02 BB07 BB09 CC01 DD01 EE15 HH01 5H024 AA14 BB07 BB08 CC03 FF07 FF31 GG01 HH01

Claims (6)

[Claims] In an alkaline battery using a gelled negative electrode containing zinc as a negative electrode active substance, an alkaline aqueous solution as an electrolytic solution, and a gelling agent, a predetermined amount of zinc, an electrolytic solution and a gelling agent are used. An alkaline battery having a gelled negative electrode, which is separately weighed with a predetermined amount of the mixture of the above, and then mixed to form a gel, and then filled into the battery. 2. The alkaline battery according to claim 1, wherein the negative electrode zinc is a low-mercury zinc having a mercury content of 3% or less or a non-melting zinc. 3. An alkaline battery using a gelled negative electrode containing zinc as a negative electrode active substance, an aqueous alkaline solution as an electrolytic solution, and a gelling agent, wherein a predetermined amount of the electrolytic solution is
An alkaline battery having a gelled negative electrode in which a predetermined amount of a mixture of zinc and a gelling agent is separately weighed and then mixed to form a gel, and then filled into the battery. 4. The alkaline battery according to claim 3, wherein the negative electrode zinc is a low-mercury zinc having a mercury content of 3% or less or a non-molten zinc. 5. In an alkaline battery using a gelled negative electrode containing zinc as a negative electrode active substance, an alkaline aqueous solution as an electrolytic solution, and a gelling agent, a predetermined amount of a mixture of zinc and a gelling agent; An alkaline battery having a gelled negative electrode, wherein a predetermined amount of a mixture of an electrolytic solution and a gelling agent is separately weighed, mixed to form a gel, and then filled into the battery. 6. The alkaline battery according to claim 5, wherein the negative electrode zinc is a low-mercury zinc having a mercury content of 3% or less or a non-melon-free zinc.