JP3008722B2 - Sealed storage battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed storage battery, and more particularly to an improved pressure spacer for pressing an electrode group in a stacking direction.

[0002]

2. Description of the Related Art In a conventional sealed storage battery such as a sealed lead storage battery, an electrode plate and a retainer are laminated so that the retainer and the electrode plate are sufficiently adhered to each other and the electrolyte in the retainer permeates the electrode plate. The electrode group thus configured is placed in a cell chamber in which the inner dimension in the width direction is smaller than the thickness dimension of the electrode group, and the electrode group is pressed in the stacking direction by both walls in the width direction of the cell chamber. I have. However, in such a storage battery, when the thickness of the electrode group is smaller than the inner dimension in the width direction of the cell chamber due to variations in the dimensions of the electrode plate and the retainer, the electrode group cannot be pressurized. Therefore, a pressure spacer is disposed between the electrode group and the cell chamber wall to press the electrode group in the laminating direction. For example, in the case of using a sheet-shaped pressure spacer such as a sheet or a rubber sheet of the same material as the retainer, the required number of pressure spacers are stacked on the electrode group, and the pressure spacer is housed together with the electrode group in the cell chamber. I do. There is also a method in which a convex portion is provided on the inner wall portion of the cell chamber to serve as a pressure spacer.

[0003]

However, when a sheet-shaped pressing spacer is used, it is necessary to adjust the number of pressing spacers in accordance with the thickness of the electrode plate group, which complicates the battery assembly operation. There was a problem of becoming. In the case of conventional pressure spacers, including other pressure spacers, the electrode group must be compressed to a thickness that can accommodate the electrode group before the electrode group is housed in the cell chamber. There was a problem that was bad. Furthermore, even when the electrode group is inserted into the cell chamber with the electrode group compressed to a thickness that can be stored, the electrode group cannot be inserted into the cell chamber with the electrode group compressed to the end, and the electrode group is not inserted until the end. In the state where the compression is released, the electrode group is forcibly pushed into the cell chamber. At this time, there is a problem that an excessive force is applied to the electrode plate group to cause the active material to fall off, or the pressure spacer is biased and the pressing force is insufficient.

An object of the present invention is to provide a sealed battery in which it is not necessary to positively compress the electrode group in the stacking direction before storing the electrode group in the cell chamber, and can easily store the electrode group in the battery case. Is to provide.

Another object of the present invention is to provide, in addition to the above objects,
An object of the present invention is to provide a sealed battery capable of suppressing thermal runaway.

[0006]

According to the present invention, there is provided an electrode in a cell chamber.
A plate group and a pressure spacer for pressing the electrode plate group in the stacking direction
Pressurizing the enclosed sealed storage battery for improvement
The occupied volume is less than the specified temperature which is higher than normal temperature as a spacer.
Increase so that the occupied volume becomes smaller at a predetermined temperature or higher.
A transformation type pressurizing spacer is used.

[0007] Such a transformation type pressure spacer has a shape memory.
It can be formed of an alloy. In addition, the aforementioned predetermined temperature
The temperature is preferably set to 60 ° C. or higher.

[0008]

[Function] As in the present invention, the pressure spacer is used at room temperature.
The occupied volume increases at a high temperature lower than the predetermined temperature, and exceeds the predetermined temperature.
Transformation-type pressurized
When using a heater, change the temperature to a predetermined temperature higher than room temperature.
State in which the occupied volume is reduced by heating the pressurized spacer
And placed in the battery case together with the electrode group. Transformation type pressurization in battery case
When the temperature of the spacer becomes lower than the predetermined temperature,
The occupied volume increases, and the metamorphic pressure spacer stacks the electrode plates
Direction. Therefore, together with the electrode group
Even when the pressure spacer is inserted into the cell chamber,
Even if you do not actively compress in the stacking direction,
Can be inserted into the chamber. In addition, the electrode group and the transformation type
After storing the pressure spacers in the cell chamber,
When the sensor deforms to increase the occupied volume,
Force is applied to the electrode group to drop the active material
And the pressure spacers are biased
Is also gone. In particular, in the present invention, the battery temperature is a cause of thermal escape.
When the temperature rises above the high temperature range (for example, 60 ° C. or higher)
Since the occupied volume is small, the pressure spacer
The pressure in the high-temperature area that causes the
It is possible to suppress the chemical reaction. Predetermined temperature of transformation type pressure spacer
Forming with a shape memory alloy that fluctuates at different degrees
When the battery temperature rises above a predetermined value, the occupied volume decreases.
What is necessary is just to memorize the shape which becomes easy.

[0009]

FIG. 1 is an exploded perspective view of a reference example of a sealed lead-acid battery. In this figure, only the electrode group inserted into one cell chamber is shown. In FIG. 1, 1 is a battery case main body, 2 is an electrode plate group, 3 is a transformation type pressurizing spacer, and 4 is a lid of the battery case body. The battery case main body 1 is formed of a synthetic resin and has three cell chambers 1a. The electrode group 2 includes two anode plates 2a... And three cathode plates 2b.
Are laminated via a retainer 2c, and the anode plate 2a and the cathode plate 2b are
The ears are connected by d and 2e. The transformation type pressure spacer 3 has a flat plate shape, and is housed in the cell chamber 1a in a state of being superposed on the electrode plate group 2. This transformation type pressure spacer 3 is formed by a foam material to volume expansion and foaming at a curing temperature below the temperature of the thermosetting adhesive for joining the battery case body 1 and the lid 4 as described later . Then, the transformation-type pressure spacer is set so that the sum of the thickness A of the transformation-type pressure spacer 3 and the thickness B of the electrode plate group 2 becomes smaller than the inner dimension C in the width direction of the cell chamber 1a. 3, a thickness dimension A is determined. The lid 4 is joined to the open end of the battery case main body 1 via a thermosetting adhesive layer so as to seal the electrode plate group 2 in the cell chambers 1a.
The lid 4 is provided with a liquid injection port 4a for injecting an electrolytic solution into each of the cell chambers 1a... Corresponding to each of the cell chambers 1a.

When assembling this sealed lead-acid battery, the transformation type pressure spacer 3 and the electrode plate group 2 are superimposed,
This is stored in the cell chamber 1a. Then, an adhesive is applied to the joining end surface of the lid 4 and the battery case main body 1, and then the cover 4 is placed on the battery case main body 1, and this is placed in a curing furnace at about 60 ° C. for about 30 minutes.
Leave for a minute. In the curing furnace, the adhesive cures and the battery case body 1 and the lid 4 adhere to each other, and at the same time, the transformation type pressure spacer 3 expands about five times to increase the occupied volume. Press. After taking out the battery case main body 1 to which the lid part 4 is joined from the curing furnace, the battery case is naturally cooled, and after cooling, the electrolytic solution is injected from the liquid inlets 4a.

The transformation-type pressure spacer 3 can be made of a material other than a foam material. For example, the transformation-type pressure spacer may be formed of a material that expands by reacting with the electrolytic solution. As a specific example, powder such as lead monoxide (PbO) that expands in volume by reacting with dilute sulfuric acid is solidified into a paste and formed into a thin sheet. Can be used as In this case, when the electrolyte solution composed of dilute sulfuric acid is injected into the cell chamber, the volume of the transformation-type pressurizing spacer expands and the occupied volume increases,
As a result, the electrode group is pressed in the stacking direction.

FIG. 2 is a perspective view of a deformed pressure spacer 13 used in a sealed storage battery of another reference example before deformation. The transformation-type pressure spacer 13 is configured such that the elastic body 13a is housed in a compressed state in a synthetic resin vacuum pack 13b constituting a releasable compression means. In order to form the transformation-type pressure spacer 13, first, a sponge-like elastic body 13a is placed in a vinyl bag forming the vacuum pack 13b, and then the bag is depressurized. When the elastic body 13a is compressed to a predetermined thickness, the mouth of the bag is heat-welded to seal the elastic body 13a in the vacuum pack 13b. When the transformation-type pressurizing spacer 13 is used, the transformation-type pressurizing spacer 13 is housed in the cell chamber together with the electrode group, and then the vacuum pack 13b is used.
The elastic body 13a is expanded by making a hole in the upper part 13b1 with a needle or the like, and the electrode group is pressed in the laminating direction.

FIGS. 3A and 3B are perspective views of a transformed pressurizing spacer 23 used in the sealed battery according to the embodiment of the present invention before and after deformation. The transformation type pressure spacer 23 is formed by covering a shape memory alloy with a resin having heat resistance and elasticity. The shape memory alloy used for the transformation type pressure spacer 23 has a flat shape at a temperature of 60 ° C. or more as shown in FIG. 3A, and has a thickness direction at normal temperature as shown in FIG. The shape is stored so as to be a waveform having irregularities. In other words, higher than normal temperature
The occupied volume increases below a predetermined temperature (60 ° C or higher),
Change so that the occupied volume decreases at a constant temperature (60 ° C) or higher.
Shape of the shape memory alloy forming the pressurized spacer 23
It is remembered. When using the transformation-type pressure spacer 23, first, the transformation-type pressure spacer 23 is heated to 60 ° C. or more to make it flat, and then the transformation-type pressure spacer 23 is housed in the cell chamber together with the electrode plate group. . When the temperature of the transformation-type pressurizing spacer 23 returns to normal temperature after a lapse of time, the transformation-type pressurizing spacer 23 has a corrugated shape, and presses the electrode group in the stacking direction. If the transformation-type pressurizing spacer 23 is used, when the battery temperature rises to 60 ° C. or higher, the pressurizing spacer is deformed into a flat plate shape, and the pressing force on the electrode plate group is reduced,
There is an advantage that an electrochemical reaction in a high temperature region that causes thermal runaway can be suppressed.

[0014]

According to the present invention, the pressure spacer is always used.
The occupied volume increases at a predetermined temperature higher than the
Transformation type deformation that reduces the occupied volume above
Uses a pressure spacer so that the temperature rises above a predetermined temperature higher than room temperature.
Heating the transformation-type pressure spacer to reduce the occupied volume
If placed in the battery case together with the electrode group in a state, the transformation type in the battery case
When the pressure spacer falls below a certain temperature, the transformation pressure space
The occupied volume of the electrode increases, and the transformation type pressure spacer
Pressure is applied in the stacking direction. Therefore, one plate group
Even if the pressure spacer is inserted into the cell chamber,
Electrode group easily without compressing the group in the stacking direction
Can be inserted into the cell chamber. In addition, electrode group and metamorphosis
After the mold pressure spacer and the cell
When the spacer deforms to increase the occupied volume, the pole
An excessive force that causes the active material to fall off the plate is applied to the electrode group.
No pressure, and the pressure spacer is biased
No more. In particular, in the present invention, the battery temperature
The temperature rises above the high temperature range causing the problem (eg, 60 ° C or higher)
Occupies a smaller volume, so the electrode group of pressure spacers
In the high-temperature area where the pressure applied to the
Electrochemical reaction can be suppressed. Place a transformation type pressure spacer
Formed with a shape memory alloy that fluctuates around a constant temperature
If the battery temperature rises above a predetermined value, the occupied volume
What is necessary is just to memorize the shape which becomes smaller.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a sealed battery according to one embodiment of the present invention.

FIG. 2 is a perspective view of a deformed pressure spacer used in a sealed battery according to another embodiment of the present invention before deformation.

FIGS. 3A and 3B are perspective views of a modified pressure spacer used in a sealed battery according to still another embodiment of the present invention before and after deformation.

[Explanation of symbols]

 1a Cell chamber 2 Electrode group 3 Transformation type pressure spacer

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01M 10/06-10/18

Claims (3)

(57) [Claims] 1. A sealed storage battery in which an electrode group and a pressure spacer for pressing the electrode group in a stacking direction are housed in a cell chamber, wherein the pressure spacer is at a temperature lower than a predetermined temperature higher than room temperature. Divination
The occupied volume increases, and the occupied volume decreases above the predetermined temperature.
Hermetically sealed battery, which comprises using a transformation-type pressure spacer deforming so. 2. The pressurized transformation type spacer is a shape memory alloy.
The sealed storage battery according to claim 1, which is formed by: 3. The sealed storage battery according to claim 1, wherein said predetermined temperature is 60 ° C. or higher .