JP2572964B2 - Separator for sealed storage battery, sealed storage battery as well as its manufacturing equipment - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a separator suitable mainly for use in a sealed lead-acid battery, a manufacturing device thereof, and a sealed storage battery which is a method of using the same.

(Prior art) As a conventional sealed lead-acid battery, as a separator,
For example, a separator obtained by cutting a papermaking sheet having a predetermined uniform density into a predetermined size by a papermaking method or the like by mixing an acid-resistant synthetic fiber or a synthetic pulp with glass fiber alone or this as a main component, and forming an anode plate. There is a well-known type in which a group of electrodes is assembled by assembling between a metal plate and a cathode plate, assembled into a battery case, and a separator is impregnated with a dilute sulfuric acid electrolytic solution.

(Problems to be Solved by the Invention) In the above-mentioned conventional sealed lead-acid battery, the amount of the electrolyte in the separator becomes smaller toward the upper part of the separator under the influence of gravity. Also, since the storage battery is charged and discharged during use, the sulfuric acid in the electrolyte reacts with the electrode plate active material by discharging, the concentration decreases, and the concentration released from the electrode plate active material by charging increases. In this process, the sulfuric acid with a high concentration sinks downward due to its high specific gravity, and the concentration of the electrolyte in the separator gradually decreases at the upper part and increases at the lower part. A battery is formed, and the characteristics of the storage battery are significantly reduced. This tendency is more pronounced in a storage battery having a higher height, resulting in a shorter life.

In view of the above situation, there is a demand for an excellent sealed storage battery in which the distribution of the electrolyte in the vertical direction is uniform and the electrolyte concentration does not stratify.

(Means for Solving the Problems) The present invention provides a sealed storage battery separator which satisfies such a demand, a manufacturing device thereof and a sealed storage battery thereof. A separator having a density gradient directed to the other side, wherein the separator having a higher density has a higher rank.

The second invention provides an apparatus for producing the above separator, wherein the inside of a papermaking tank of a paper machine is divided into at least two sections by at least one partition, and each of the sections is separated from each other for papermaking having different densities. It constitutes a tank.

The third invention is to provide a separator for a sealed type storage battery which does not have the above-mentioned conventional drawbacks. The sealed invention comprises a battery case in which an electrode group having a separator interposed between an anode plate and a cathode plate is incorporated in a battery case. In the type storage battery, a separator having a density gradient from one side to the other side is used, and the separator is interposed between the anode plate and the cathode plate with the higher density side being higher, and the electrolyte Impregnated.

(Example) Next, an example of the present invention will be described.

Separators to be manufactured are glass fiber, synthetic fiber,
Made from plant fiber alone or mixed fiber, synthetic pulp,
It is made with or without the addition of additives such as glass powder and binder. Such a material is used to constitute the separator of the present invention having a density gradient from one side to the other side.
That is, for example, generally, glass fibers selected from the range of 0.3 to 2 μm in average fiber diameter alone, or mainly containing glass fibers having an average fiber diameter of 3 to 30 μm.
According to the present invention, a papermaking machine, for example, a round-mesh papermaking machine as shown in FIG. 1 (1) is used for papermaking in which a small amount of any one of glass fiber, acid-resistant synthetic fiber and synthetic pulp is mixed. In the filter layer (2), the inflow path of the semi-cylindrical material liquid between the rotating circular net (3) and the tank (2) is divided into right and left to divide each material solution passage. A partition wall (4) is provided at the center thereof for forming, and the respective partition tank sections (2
Raw supply ducts (5) and (6) communicating with a) and (2b)
A paper machine of the present invention is used in which the left and right combined paper layers on the rotary mesh (3) are formed on one common coach roll (not shown) on the outflow side. That is, for example, using glass fiber having an average fiber diameter of 1 μ, two kinds of stock solutions having different paper-drain concentrations are prepared, and these are respectively supplied from the supply ducts (5) and (6) of the paper machine (1). The left and right halves, which are supplied to the left and right partition layers (2a) and (2b) and are combined at the center at the center of the rotating circular net (3), have some thickness mutually. A different paper layer is obtained, this is made up by a couched roll, the wet paper web is sucked, and then the thickness is made uniform by a pressure roll, and then heated and dried to obtain a paper making.

Next, the papermaking sheet is cut into a predetermined size as shown by a chain line in FIG. 3 to obtain a separator for a lead storage battery. In this way, glass fiber having an average fiber diameter of 1μ is used as a raw material, and the mutual density of the right and left paper types is changed in various ways. Various types of separators having the same thickness were prepared as a whole, and several examples are shown as NO.1 to NO.6 in Table 1 below. For comparison,
A glass fiber having an average fiber diameter of 1 μm was prepared using a conventional paper machine as a raw material. No.7 paper separator with the same thickness
As shown.

In addition, the boundary area between the left half and the right half of the center of the NO.1 to NO.6 separators generally has a substantially intermediate density in which the exchanges are mixed.

Each of the above separators was interposed between an anode plate and a cathode plate, assembled as an electrode plate group, and impregnated with a predetermined amount of an electrolytic solution to produce test batteries having the components shown in Table 2 below. In this case, each of the separators No. 1 to No. 6 was interposed between the negative anode plates (5) and (6) with the higher density side as the upper side as shown in FIG. (7) shows the bottom wall of the battery case of the sealed storage battery.

For these sealed lead-acid batteries, a life test and a self-discharge test were performed.

Life test: In the life test, discharge for 3 hours at a current of 0.25C, and then charge for 5 hours at a current of 0.17C in an atmosphere of 40 ° C.
The capacity was measured at a discharge test of 0.2C at 25 ° C every 5 times, and the time when the capacity reached 40% of the initial value was regarded as the end. The results were as shown in FIG.

As is apparent from FIG. 2, the test battery No. 1 incorporating the separators NO. 1 to NO. 6 having different densities as described above as compared with the test battery NO. 7 incorporating the conventional separator NO.
~ NO.6 is recognized to have an extended life.
That is, in the conventional battery No. 7, the number of charge / discharge cycles is about 110
On the other hand, the battery life of the battery of the present invention is 1 to NO.
It is recognized that the service life is extended to about 125 times or more, and in particular, for the batteries No. 1 to No. 4, the capacity of 70% or more can be maintained even when the number of charge cycles is 150.

Self-discharge test: The self-discharge test is performed at 45 ° C after performing 0.2C discharge 5 times.
Was left in the atmosphere for 30 days, and then discharged at 25 ° C. at 0.2 C. The capacity was measured. The results are shown in Table 3 below. As is clear from Table 3, the battery showed the same tendency as the result of the self-discharge test, and the battery No.
~ NO.6 shows excellent results, and above all, NO.1 ~ NO.4 are recognized to be particularly excellent.

The reason that such an excellent battery as described above can be obtained is that when a separator having substantially half the densities different from each other is incorporated into the battery with the relatively high density half being higher in the battery, The upper part is considered to be because the relatively high density makes the retention of the electrolytic solution extremely good, and the upper part does not easily deposit on the lower part due to gravity or the like, and the liquid distribution in the vertical direction becomes uniform. . As a result of many experiments, the density ratio of the left and right halves of the separator was 1: 1.
It has been found that the above object can be achieved in the range of 1-2, preferably 1: 1.1-1.5. In addition, it was found that the lower limit of the bottom density is preferably 0.1 g / cm ³ and the upper limit of the high density is preferably 0.3 g / cm ³ , from the relation of electrolytic retention and the like.

Figure 3 shows a separator A of Table 1 sample NO.3, halves A ₁ of the 1-way has a bottom density of 0.14 g / cm ^3, its other half portion A ₂ of 0.19g It has a high density of / cm ³ and a density ratio of about 1.3.

In the above-described embodiment, the separator A is formed so as to have a density gradient composed of two areas having two different densities. In this case, as shown in FIG. The boundary area is not limited to the one having the same surface area on both sides thereof, and the boundary area is located above or below the center, that is, in the illustrated example, the high-density area A ₂ on the right and the left bottom surface area ratio of the density region part a ₁ is 6: 4, 7: can be configured so that the 3 or the like, or vice versa.

Further, as described above, the separator of the present invention is divided into an appropriate number such as two, three, four, five, etc., and the density increases or decreases sequentially from one side to the other side. There are various types configured to have the following density gradient. FIG. 5 shows a separator A of the present invention divided into three parts, from one side to the other side, and from the lower side to the upper side in the drawing, a relatively lower density area A ₃ , so that the density gradually increases.
₄ shows a density gradient separator having a middle density region A ₄ and a high density region A ₅ . Its density ratio, for example, medium density region part A ₄ to the bottom density region part A ₃ 1 1.3, and the high-density region part A ₅ are 1.5. Generally, each boundary area of these areas A ₃ A ₄ A ₅ is formed to have an intermediate value between the densities of both areas, and is obtained as a whole having a gentle density gradient.

When the separator manufacturing apparatus is provided at the position shown by the dashed line instead of the central position of the partition wall (4) of the apparatus shown in FIG. It is possible to produce a separator comprising a high and low density region divided into two different parts. In the case where a separator divided into three or more parts and having different densities is manufactured stepwise, two or more partition walls are arranged at a desired interval, and three or more partition walls are interposed therebetween. Alternatively, it can be obtained by forming a papermaking tank portion more than that, and allowing papermaking types having different densities to flow into the respective tank portions. The partition wall (4) may be changed to a fixed type, and may be detachable or movable to change its position. For example, an upward comb-shaped fitting portion is provided in the width direction of the papermaking tank (2), and the partition wall (4) is detachably fitted to the fitting portion so that the position is appropriately changed. . The density of each surface area of the separator can be changed depending on the amount of fibers in papermaking, the presence or absence of additives, the amount thereof, the degree of compression of papermaking, and the like.

(Effect of the Invention) As described above, when using the separator for a sealed storage battery of the present invention, a separator having a density gradient from one side to the other side is provided, with a configuration in which the higher density side is higher. Therefore, when used in a sealed storage battery, it has the effect of extending the life of the storage battery. In addition, in the case of using the sealed storage battery of the present invention, the separator of the present invention having a density gradient from one side to the other side is prepared, and this is incorporated into the storage battery with the higher density side as the higher order, thereby shortening the life. This has the effect of obtaining a storage battery having an extended length. Furthermore, according to the manufacturing apparatus of the present invention, at least one partition wall is provided inside the papermaking tank and at least two partition tank parts are provided, so that at least two surface area parts are arranged from one side. This has the effect of obtaining the separator of the present invention having a density gradient directed to the other side.

[Brief description of the drawings]

FIG. 1 shows one of the paper machines for producing the separator of the present invention.
FIG. 2 is a top view of a main part of the example, FIG. 2 is a graph showing life characteristics, FIG. 3 is a perspective view of a separator of one example of the present invention, FIG.
The figure is a partial cross-sectional view of a main part of one example of the sealed storage battery of the present invention, and FIG. 5 shows a separator of the present invention in a modified example. (1) ... paper machine, (2) ......漉槽(4) ...... Kukaku wall A .... present invention separator A _1, A ₃ ... bottom density region part, A ₄ ... medium density region part A ₂ , A ₅ …… High density area

Claims (9)

(57) [Claims] 1. A separator for a sealed storage battery, wherein the separator has a density gradient from one side to the other side, wherein the higher density side is higher. 2. The separator according to claim 1, wherein said density gradient is constituted by at least two areas having different densities. 3. A separator made of a glass fiber, a synthetic fiber, a vegetable fiber alone or a mixed fiber, and containing or not containing additives such as synthetic pulp, glass powder, and a binder, sequentially from one side to the other side. 2. The separator according to claim 1, comprising at least two areas of increasing or decreasing density. 4. The separator according to claim 1, wherein the density ratio of the high density area to the low density area of the separator is 1: 1.1 to 2, preferably 1: 1.1 to about 1.5. 5. The upper limit of the density of the high-density region of the separator is
Until 0.3 g / cm ^3, separator according to claim 1 of the appended claims limit the density of the low density region part is up to 0.1 g / cm ^3. 6. An apparatus for manufacturing a separator for a sealed storage battery, wherein the inside of a papermaking tank of a papermaking machine is divided into at least two sections by at least one partition wall, each of which is a papermaking tank section having a different density from each other. 7. The manufacturing apparatus according to claim 6, wherein said partition can be set at a predetermined position in the width direction of the papermaking tank. 8. A sealed storage battery comprising an electrode plate group having a separator interposed between an anode plate and a cathode plate incorporated in a battery case, wherein the separator has a density gradient from one side to the other side. A sealed storage battery that is used between the anode plate and the cathode plate, with the denser side being higher, and impregnated with an electrolytic solution. 9. The sealed storage battery according to claim 8, wherein a separator having a density gradient of 1.1 to 1.5 times is used.