JPH0624143B2 - Sealed lead acid battery - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thin sealed lead acid battery.

2. Description of the Related Art A conventional sealed lead-acid battery has a structure in which positive and negative electrode plates in which the entire surface of a lead grid and a lead sheet are filled with an active material are sandwiched with an electrolyte solution holder.

Problems to be Solved by the Invention In general, lead-acid batteries have PhO ₂ + Pb + 2H ₂ SO ₄ 2PbSO ₄ +2
The reaction proceeds with H ₂ O. That is, PbO ₂ as the active material,
Not only Pb but also H ₂ SO _{4 in} the electrolytic solution becomes the active material. Meanwhile density of the three is approximately in porous PbO ₂ 3 to 4 g / c
m ^3, a porous Pb in _{^{3~4g / cm 3, aq2H 2 SO}} 4 1.2
~ 1.3 g / cm ³ . That is, the density of the electrolytic solution is lower than the density of PbO ₂ and Pb of the electrode. The weight required for 1 Ah is 4.463 g for PbO ₂ , 3.87 g for Pb, and the specific gravity is 1.3aqH ₂ SO ₄
In because it is 9.33g, 1.12~1.48cm the active material volume PbO ₂ as a battery required 1Ah ^3, 0.97~1.29cm in Pb ^3, the 7.18Cm ³ in aqH ₂ SO ₄ of specific gravity 1.3 . As can be seen, the occupied volume of the electrolytic solution is much larger than the electrode volume.
By the way, in the case of a lead storage battery, even if a required electrolyte solution occupying space is secured, the electrolyte solution is an active material, so its diffusion is limited and cannot be effectively utilized. That is, the diffusion of the electrolytic solution becomes the controlling factor, and therefore, in the conventional sealed lead-acid battery, the active material utilization rate is 25 to 35% for PbO ₂ , 27 to 40% for Pb, and 80 to 95% for the electrolytic solution. It is designed to have a low utilization rate of active material. Therefore, the energy density cannot be improved as compared with other batteries. Therefore, it is necessary to enhance the diffusion of the electrolytic solution, which is dominant, to enhance the supply of H ₂ SO ₄ into the active material of the electrode, and to improve the energy density. In the conventional sealed lead-acid battery, the PbO ₂ active material layer, the electrolyte holding layer, and the Pb active material layer are laminated, and the diffusion and supply of H ₂ SO ₄ during battery discharge always moves in one direction. Therefore, only the surface layer is involved in the reaction without the diffusion reaction catching up and the discharge reaction not proceeding to the inside of the PbO ₂ and Pb active materials.

Means for Solving the Problems The present invention is to form a positive electrode active material on a positive electrode current collector and a negative electrode active material on a negative electrode current collector into a large number of angular shapes or circular shapes, respectively, and It is characterized in that the positive and negative electrode plates on which the electrolytic solution holders are arranged are laminated via the electrolytic solution holders and sealed together with the electrolytic solution.

Action The present invention has the above-described characteristics, so that the diffusion and supply of the electrolytic solution do not move in one direction in the conventional sealed lead-acid battery but move in the vertical and horizontal directions. Can be applied not only to the surface layer but also to the inside, greatly improving the utilization rate and improving the energy density.

Example An example of the present invention will be described.

As shown in FIGS. 1 and 2, a positive electrode current collector 2 made of lead meat is bonded onto a resin film 1, and a positive electrode active material 4 is arranged in a square shape by screen printing on the positive electrode current collector 2. A silylated gel electrolyte solution is similarly applied by screen printing as an electrolyte solution holder 3 between the substances 4 to obtain a positive electrode plate. A glass fiber non-woven fabric as the electrolytic solution holder 3 was further sandwiched between the negative electrode plate and the negative electrode plate obtained in the same manner, and the layers were laminated and heat-welded around the resin film 1, 1 ′ to form a welded portion 6
Was formed and sealed with the electrolyte. Here, a silica gel-like electrolytic solution is used as the electrolytic solution holder 3 applied on the same plane between the active materials, but of course, a glass fiber non-woven fabric may also be used here. As a product of the present invention, a sealed lead-acid battery having a thickness of 3 mm was prepared, and a positive electrode plate and a negative electrode plate, which were filled with an active material on the entire surface of a conventional current collector, were laminated with an electrolytic solution holder between them to seal a film pack. The active material utilization rate was compared when the lead acid battery was set to 100%. The discharge was performed by electric heat equivalent to 0.1 C and 2 C, and the specific gravity of the electrolyte was 1.350. Figure 3,
Each result is shown in FIG. As is apparent from the figure, in the case of 0.1 C discharge, the utilization rate of the product of the present invention increased by about 25% for PbO ₂ , about 20% for Pb, and about 5% for H ₂ SO ₄ . Especially in case of high rate discharge such as 2C discharge, it is about 35
%, 30%, 10%, and the rate of improvement in utilization rate is remarkable. Furthermore, since the electrode active material is uniformly used, the reaction is not concentrated on the surface layer unlike the conventional electrode plate, and it is expected that the life is extended.

Although the active material is formed in a square shape in the present embodiment, the same effect can be obtained by using a triangular shape, a hexagonal shape, another polygonal shape, or a circular shape, an elliptical shape, or another circular shape.

Effect of the Invention As described above, the sealed lead-acid battery of the present invention is different from the conventional battery in that the electrode active material is divided and the electrolytic solution holding body is provided between them, and the electrolytic solution holding body is also provided between the electrode and the counter electrode. Therefore, the diffusion and supply of the electrolytic solution can be obtained in the vertical and horizontal directions, the reaction can proceed to the inside of the electrode active material, and the utilization rate of the electrode active material can be improved. Therefore, it is possible to reduce the amount of the electrode active material, and it is extremely effective for improving the weight energy density. It is also expected to have a long life.

Furthermore, it can be applied to screen printing technology, can be automated and labor-saving in terms of production, and can be easily manufactured into a thin sealed lead-acid battery, which is of great industrial value.

[Brief description of drawings]

FIG. 1 is a sectional view of a sealed lead-acid battery showing an embodiment of the present invention, FIG. 2 is a plan view showing a positive electrode plate in the embodiment of the present invention, and FIG. 3 is an active material at the time of discharging 0.1 C. Utilization comparison chart,
FIG. 4 is a comparison diagram of active material utilization rates during 2C discharge. 1, 1'is a resin film, 2 is a positive electrode current collector, 3 is an electrolytic solution holder, 4 is a positive electrode active material, 5 is a negative electrode active material, 6 is a welded portion, 7 is a negative electrode current collector

Claims (1)

[Claims] 1. A positive electrode active material is formed on a positive electrode current collector, and the negative electrode active material is formed on the negative electrode current collector in a number of angular shapes or round shapes, and an electrolyte solution holder is arranged between the respective positive electrode active materials. A sealed lead-acid battery in which positive and negative electrode plates are laminated via an electrolytic solution holder and sealed together with the electrolytic solution.