JPS59219854A - Lead storage battery - Google Patents

Abstract

PURPOSE:To reduce the electric resistance of a lead storage battery without increasing the weight of the plate by adjusting the ratio (A/B) of the height (A) of the plate to its width (B) to be within a specified range. CONSTITUTION:In a lead storage battery, a plate 3 is installed in which the ratio (A/B) of its height (A) to its width (B) is 0.67-0.76. As a result, the internal resistance of the battery can be minimized without increasing the weight of a grid, thereby enabling the voltage of the battery during its high-rate discharge to be increased. Consequently, a light battery having a good starting performance can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in lead-acid batteries, and in particular to the shape of plates for lead-acid batteries, for example plates using expanded lattices.

Conventionally, lead-acid batteries have used book mold type cast grids for their electrode plates, but in recent years, in order to meet the demand for smaller and lighter batteries, electrode plates have become thinner. In place of the casting method, which is unsuitable for forming objects into shapes, an expanded lattice manufacturing method is being adopted. With the grid made by the expanded method, the desired thickness of the grid can be obtained by changing the thickness of the lead alloy sheet used in the expanded process, so the electrode plate can be made thinner by making the grid thinner. becomes easier.

However, although batteries using thin expanded electrode plates can achieve weight reduction, they have the disadvantage that voltage characteristics during high rate discharge are inferior to conventional batteries. This is a very serious drawback, especially for applications where startability is important, such as automobile batteries. This is due to the fact that by making the lattice body thinner, the cross-sectional area of the bones of the lattice body is reduced, which increases the electrical resistance, and also because the thickness of the active material layer is reduced in the thin electrode plate, so the active material The cause is an increase in the electrical resistance of the layer. Therefore, it is currently an important issue to improve the fullE characteristics while achieving weight reduction.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a lead-acid battery equipped with electrode plates that can reduce electrical resistance without increasing the weight of the electrode plates.

It has been found that the voltage characteristics of lead-acid batteries during high-rate discharge almost depend on the internal resistance of the battery, and that there is a linear relationship between internal resistance and battery voltage, especially up to about 5 seconds at the beginning of discharge. The main components of a battery's internal resistance are the internal resistances of the anode plate, cathode plate, and electrolyte, and these can be considered to be arranged in series. In order to reduce the internal resistance of the battery, we focused on the external dimensions of the electrode plate and found that there is a range in which the internal resistance of the battery is minimized at the ratio A/B of the total height A and width B of the electrode plate. .

Therefore, in order to achieve the above object, the main points of the present invention are as follows:
The ratio A/B of the total height A and total width B of the electrode plate is 067 to 076
It is to have an electrode plate that is

Examples will be explained below.

Figure 1 shows an outline of the electrode plate using an expanded lattice. Here, l is the current collecting ear of the electrode plate, 2 is the bone of the expanded lattice body, 3 is the active material, A is the total height of the electrode plate, B is the total width of the electrode plate, and C is the current collected from one end of the electrode plate. This is the distance to the center of the electric ear.

In order to determine the internal resistance of each of the anode plate, cathode plate, and electrolyte, first calculate the electrical resistance of the grid body mathematically based on the constant current model, and then use the grid body to calculate the open circuit voltage of approximately 2 using the conventional method. The battery (2) was assembled and the internal resistance of the battery was measured at -15°C by the AC bridge method. FIG. 2 shows internal resistance changes in the battery for anode grids having various electrical resistances. Here, the cathode grid used had a certain electrical resistance.

The grid dimensions are 120 m for A and I 05 mm for B, the anode grid weight is 349, and the cathode grid weight is 23 g. The specific gravity of the electrolyte is 1.280 (20°C). As can be seen from FIG. 2, an extremely good linear relationship was obtained, proving that the electrical resistance value of the grid body determined based on the constant current model can be put to practical use.

To briefly explain how to calculate the electrical resistance based on the constant current model, it is assumed that a constant current flows into or out of all the intersection points of the bones 2 of the lattice body (hereinafter referred to as lattice points). Since the resistance at each grid point can be measured, the potential at each grid point can be found by formulating an equation using Kirchhonff's law with only the potential at each grid point as an unknown, and solving this for each grid point. Using the potential of each grid point and the electrical resistance between each grid point, find the sum of the losses (watts) between each grid point, and then divide by the square of the sum of the currents flowing through each grid point. Find resistance.

In the straight line in Figure 2, the slope of the straight line is a coefficient for determining the internal resistance of the anode plate from the electrical resistance of the grid, and the slope of the straight line multiplied by the electrical resistance of the grid is the coefficient for determining the internal resistance of the anode plate from the electrical resistance of the grid. This is the internal resistance of the anode plate itself when in use. The y-intercept of the straight line is the sum of the internal resistance of the cathode plate and the internal resistance of the electrolyte.

Using the same method as above, use an anode grid with a certain electrical resistance, and determine the internal resistance If of a battery using cathode grids with various electrical resistances, and obtain the relationship shown in Figure 2. After finding a linear relationship, the internal resistance of the cathode plate can be found from the slope of that straight line. Therefore, the internal resistance of the electrolyte can be separated and found from the y-intercept of the straight line shown in FIG.

Figure 3 shows an example of the internal resistance changes of the anode plate ta+, the cathode plate (bl), and the electrolyte (C) at -15°C when the total height A of the electrode plate is changed. Overall width B
is constant at IO'5+im, and the heavy charges of the anode and cathode grids are constant at 349.23.9, respectively. The specific gravity of the electrolyte is 1.280 (20°C).

As can be seen from Figure 3, as the total height A of both the anode and cathode plates decreases, the internal resistance decreases, but the electrolyte (
On the contrary, the internal resistance of c+ is increasing.

Since the internal resistance of the battery is the sum of these three factors as described above, Table 1 shows the ratio A/B of the total height A and the total width B of the electrode plate.

Table 1 As can be seen from Table 1, A/B becomes the minimum at 067 to 076. The A/B of the lattice body conventionally used is 1.
Since it is about 0.05 to 1.20, it means that the internal resistance of the battery has decreased considerably. In addition, the data shown in Table 1 is the ratio C/B of the position C of the current collecting ear to the total width B of the electrode plate.
is 0.04. Even if C/B increases, the absolute value of the internal resistance of the battery decreases, but the minimum A/B range remains unchanged. Similarly, even if the total width of the electrode plate and the weight of the grid body change, the A/H range does not change.

Although this embodiment has been described only with respect to an expanded grid body, the effect will not be reduced in any way even if the present invention is applied to a grid body having other current collecting ears.

As described above, according to the present invention, the battery voltage during high rate discharge can be improved without increasing the weight of the lattice body, and it is possible to create a battery that is lightweight and has excellent startability, and has no industrial value. Very expensive.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of the expanded grid, Figure 2 is a diagram of the relationship between the electrical resistance of the anode grid and the internal resistance of the battery at -15°C, and Figure 3 is the relationship between the total height of the electrode plate and the battery's internal resistance at -15°C. FIG. 3 is a relationship diagram between the internal resistance of the anode plate, cathode plate, and electrolyte in FIG. A is the total height of the plate, B is the total width of the plate, and the patent applicant

Claims (1)

[Claims] The ratio A/B of the total height A and total width B of the electrode plate is 0.67 to 07
6. A lead-acid battery comprising: 6 electrode plates.