JPH01195665A - Ready to use type lead-acid battery - Google Patents

Abstract

PURPOSE:To keep the instant use performance at a high level over a long period without accelerating the generation of a high-resistance material on the interface between the substrate and active material of a positive electrode plate in storage by setting the moisture quantity of the positive electrode plate to 0.25wt.% or below and storing a constituted electrode plate group in a battery jar. CONSTITUTION:An electrode plate group using a positive electrode plate with the moisture quantity of 0.1-0.25wt.% when measured on the dry condition of 120 deg.C.1hr is stored and sealed in a battery jar. The moisture accelerating the reduction of the instant use performance is mainly the physical absorption water, it is important to remove this physical absorption water, the growth of a high-resistance material on the interface between a positive electrode plate substrate and an active material is suppressed when the moisture of the positive electrode plate is set to 0.1-0.25wt.% or below, and the instant use performance is kept at a high level over a long period.

Description

[Detailed description of the invention] Industrial applications This invention relates to improvements in ready-to-use lead acid batteries.

Conventional technology Conventional ready-to-use lead-acid batteries have chemically formed anode plates and cathode plates.
In this battery, after washing and drying, the electrode plate group is stored and sealed in a battery case, and an electrolyte is injected when it is used. The required performance of a ready-to-use lead-acid battery is that it has enough voltage and capacity to start a car engine within a few minutes after injection, and securing the voltage is especially important. The ready-to-use performance of a ready-to-use lead-acid battery gradually deteriorates during storage due to the formation of a high resistance material at the substrate-active material interface of the anode plate. Deterioration of ready-to-use performance is accelerated by temperature, moisture, etc. Therefore, in order to suppress the deterioration of ready-to-use performance, methods have been adopted, such as storing batteries at low temperatures or thoroughly drying the electrode plates and storing the electrode plates in a battery case.

Problems to be Solved by the Invention In a ready-to-use lead-acid battery, a charged anode plate and a cathode plate are washed and dried, and then a group of electrode plates is stored and sealed in a battery case. However, when a battery is manufactured with the electrode plate, especially the anode plate, containing moisture, the formation of a high-resistance element at the interface between the substrate and active material of the anode plate is accelerated, leading to an early decline in the ready-to-use performance. It had the following drawback. Table 1 shows the amount of water contained in the components of 36820 series ready-to-use lead-acid batteries. However, the water content of the anode plate is expressed as the difference in weight before and after drying at 120° C. for 1 hour as a ratio to the amount of active material (all other cases were measured in the same manner). In the case of the cathode plate, it was vacuum dried at 120° C. to prevent oxidation and calculated in the same manner. In the case of a separator, drying was performed at 60'.

Moisture content of constituent members in Table 1 () is wtχ Amount of active material (for 55Q, as is clear from Table 1, the anode plate has more moisture and the separator has less moisture, and the cathode contains almost no moisture. Therefore, It can be seen that the moisture content of the anode plate is important.

Figure 1 shows the anode plate of a 36B20 series battery placed in the atmosphere after drying (
The graph shows the change in moisture content when the sample was left at a temperature of 25°C and a relative humidity of 6096. The water content is 1 as shown in Table 1.
This was determined from the difference in weight before and after drying at 20°C. Immediately after drying, the moisture content of the anode plate is very low at 0.15 wt%, and most of the physically adsorbed water has been removed, but if left in the atmosphere, moisture in the atmosphere will be adsorbed to the anode plate very quickly. , increases to about 0.50 wt% after 30 minutes. If a group of electrode plates is stored in a battery case in such a state, even if it is not sufficiently dried, the performance for immediate use will be greatly reduced during storage.

Means for Solving the Problems The present invention eliminates the above-mentioned drawbacks by reducing the moisture content of the anode plate to 0.25 wt% or less, and storing the constructed electrode plate group in a battery case.

The ready-to-use performance is maintained at a high level for a long period of time without accelerating the formation of a high-resistance material at the substrate-active material interface of the anode plate during operation and storage.

Example After washing the anode plate after chemical formation in running water for 30 minutes, it was heated to 120°C.
, and dried for 30 minutes. The water content at this time is 0.15Wt96
It is. Immediately after drying, this anode plate was placed in a battery case in the form of an electrode plate group, and the container was sealed to prevent the moisture content from increasing by absorbing moisture from the atmosphere.

If the relative humidity is 30% or less, the moisture content of the anode plate will hardly change even if the temperature changes, and the influence of temperature will be small. When storing anode plates, similar conditions must be used to prevent moisture adsorption. Obtained by the present invention:
36 B Accelerated storage test of 20 series battery A at 60°C (
After storage, 15OA discharge was performed at 0°C. As a comparison,
At the same time, a conventional battery B consisting of an anode plate, a cathode plate, and a separator 1 was subjected to a test in the atmosphere (20° C. 6096° C.) as before.

The results are shown in FIG. Battery A obtained by the present invention had a terminal voltage of about 8.5V at the 5th second on the 7th day, whereas the conventional battery B had a terminal voltage of about 8V on the 2nd day and decreased to about 7V on the 7th day. However, it can be seen that battery A obtained according to the present invention shows little deterioration in ready-to-use performance during storage.

Next, batteries were fabricated by changing the moisture content of the anode plate, and
Ready-to-use performance after storage for 7 days at ℃ (150A discharge at 0℃)
is shown in Figure 3. The temperature for measuring moisture content is 100
℃・120℃・140℃. At 100℃, there is a linear relationship between the moisture content of the anode plate and the 5th second terminal voltage, and the moisture content is Q.
It shows the highest value when approaching wt96. In the case of 120℃,
When the moisture content is 0.25 wt % or less, it is constant at about 8.5 V, but in the range of 0.25 Wt 96 or more, as the moisture content increases, the 5th second terminal voltage decreases. At 140℃, 0
．． Below 45wt96, it is constant at around 8.5v,
As expected, if the content is 0.45 wt% or more, the immediate performance will be significantly degraded. Qwt96 at 100℃.0.25w at 120℃
The water content of 0.45Wt96 at t% and 140° C. indicates a low level with no adsorption of physically adsorbed water, and the water content below this level includes weight loss due to chemically adsorbed water and decomposition of the active material. Therefore, since the moisture that accelerates the deterioration of ready-to-use performance is mainly physically adsorbed water, it is important to remove this physically adsorbed water. At 100℃, the moisture content is 3wt9
Although it is intended to be 46 or less, it is not possible to measure 0wt% or less. Moreover, in the case of 140° C., the influence of decomposition of the active material becomes large, and the amount of water, that is, the amount of physically adsorbed water, cannot be measured accurately and the variation becomes large. In the case of 120° C., a stable region is found in the range of 0.25 Wt96, where physically adsorbed water is removed, to 0.1 wt %, where some chemically adsorbed water is removed, and batteries may be manufactured within this range. At each temperature, as the moisture content decreases, the ready-to-use performance deteriorates because the performance is low even before storage due to excessive drying.

Effects of the Invention As described above, according to the present invention, the moisture content of the anode plate can be reduced to
By controlling the content to 0.25 wt% or less, the growth of high-resistance elements at the anode plate substrate-active material interface is suppressed, and immediate performance is maintained at a high level for a long period of time, which has great industrial value. .

[Brief explanation of the drawing]

Figure 1 is a moisture absorption characteristic diagram of the anode plate, Figure 2 is a comparison diagram showing the results of a storage test at 60°C between a battery obtained by the present invention and a conventional battery, and Figure 3 is the moisture content of the battery positive plate. and 60℃
- It is an explanatory diagram showing the relationship between ready-to-use performance after storage for 7 days. Time (minutes) Storage time (town ff
f & board moisture 1 (wt%)

Claims (1)

[Claims] In a ready-to-use storage battery, the anode plate and the cathode plate are chemically formed, washed with water, dried, and then the electrode plate group is stored and sealed in a battery case.12
Moisture content is 0.1 when measured under drying conditions of 0°C and 1 hour.
A ready-to-use lead-acid battery characterized in that a group of electrode plates using ~0.25 wt% of anode plates is housed and sealed in a battery case.