JPH06111795A - Sealed type secondary battery - Google Patents

Abstract

PURPOSE:To suppress swell of a battery jar generated during charge/discharge cycles. CONSTITUTION:Among wall parts of a battery jar 10 surrounding cell chambers 17a-17f, a pair of wall parts (11 and 16a, 12 and 16e, etc.) confronting in the laminate direction of a group 19 of electrode plates are coupled together by coupling walls 18.... These coupling walls 18... stretch in the laminate direction of the group 19 of electrode plates and the vertical direction of the battery jar 10. The plate group 10 is provided with slits 23 in which the coupling walls 18... are fitted. Each slit 23 is formed from a split groove 23a furnished in electrode plates 20, 22 and a split groove 23b provided in a retainer 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealed secondary battery in which a group of electrode plates is arranged in a cell chamber of a battery case made of synthetic resin in a state of being pressed in the stacking direction.

[0002]

2. Description of the Related Art In a known sealed secondary battery such as a sealed lead storage battery, an electrode plate group is housed in a cell chamber provided in a battery case made of a synthetic resin such as PP resin or ABS resin. The electrode plate group is pressed in the stacking direction by a pair of wall portions of the battery case surrounding the cell chamber that face each other in the stacking direction of the electrode plate group.

[0003]

However, in the sealed secondary battery, the gas generated by the charge / discharge cycle is accumulated in the battery case, so that the internal pressure in the battery cell increases.
Due to this increase in internal pressure, the wall portion that pressurizes the electrode plate group expands, and the pressing force of the electrode plate group decreases. When the pressure applied to the electrode plate group decreases, the adhesion between the electrode plate and the retainer deteriorates, and a layer of the electrolytic solution is formed between the retainer and the electrode plate. When such a layer of electrolyte solution is formed, a stratification phenomenon occurs in this layer, a concentration difference occurs in the electrolyte solution in the vertical direction of the electrode plate, and the charge / discharge reaction becomes uneven, resulting in a battery However, there is a problem that the life of the device is shortened.

An object of the present invention is to provide a sealed secondary battery which can prevent the battery container from expanding.

[0005]

DISCLOSURE OF THE INVENTION The object of the present invention is to improve a sealed secondary battery in which electrode plates are arranged in a cell chamber of a battery case made of synthetic resin in a state of being pressurized in the stacking direction. . Claim 1
In the invention, the pair of wall portions facing each other in the stacking direction among the wall portions of the battery case surrounding the cell chamber are connected to each other by at least one connecting wall portion extending in the stacking direction and the vertical direction of the battery case. Then, a slit into which the connecting wall portion is fitted is formed in the electrode plate group.

According to the second aspect of the present invention, each of the positive electrode plate, the negative electrode plate and the retainer forming the electrode plate group is formed with a dividing groove which is laminated to form a slit, and the width dimension of the dividing groove formed in the retainer is set. It is made smaller than the width dimension of the dividing groove formed in the positive electrode plate and the negative electrode plate.

[0007]

When the pair of wall portions that press the electrode plate group are connected to each other by the connecting wall portion, the connecting wall portion suppresses the bulging of the pair of wall portions even if the internal pressure in the battery case rises. It is possible to suppress a decrease in the pressing force of the electrode plate group. As a result, according to the present invention, the battery life can be extended by suppressing the expansion of the battery case during the charge / discharge cycle.

If the width of the dividing groove formed in the retainer is narrowed as in the second aspect of the invention, even if a slit is provided in the electrode plate group, a short circuit between the electrode plates through the slit can be prevented.

[0009]

Embodiments of the present invention will now be described in detail with reference to the drawings. 1A to 1E show schematic configurations of a battery case body, an electrode plate group, an electrode plate and a retainer used in an embodiment in which the present invention is applied to a sealed lead storage battery. In this embodiment, the battery case body 10 integrally formed of synthetic resin having the structure shown in FIGS. 1 (A) and 1 (B) is used. The structure of the lid (not shown) that covers the opening of the battery case body 10 may be the same as the conventional structure. The battery case body 1 has a side wall 11 having four peripheral walls.
14 to 14, and has a structure in which one end of the peripheral wall portion is closed by the bottom wall portion 15. The battery case body 1 is partitioned by partition wall parts 16a to 16e connected to a pair of side wall parts 13 and 14 and a bottom wall part 15 inside the battery case body. Walls 16a-1
Cell chambers 17a to 17f for accommodating the electrode plate group are formed between two adjacent wall portions 6e.

In each of the cell chambers 17a to 17f, two connecting wall portions 18 are provided so as to divide each cell chamber.
Are provided at a predetermined interval. Each connecting wall 18
... are a pair of side wall parts 11 and 12 and a partition wall part 16a-.
16e is connected to two adjacent wall portions and the bottom wall portion 15 and extends in the stacking direction of the electrode plate group inserted into the cell chambers 17a to 17f and the vertical direction of the battery case body 1. Connection wall 1
The upper ends of 8 ... Terminate before the upper end opening of the battery case body 1. The number, the vertical length, the thickness, and the mounting position of the connecting wall portions 18 ...
It may be appropriately determined depending on how much the mechanical strength of 1, 12, 16a to 16e is increased.

FIG. 1C shows a schematic perspective view of a part of the electrode plate group 19 inserted into each of the cell chambers 17a to 17f. In the figure, 20 is a negative electrode plate, 21 is a retainer, 2
2 is a positive electrode plate, 23 is a connecting wall portion 18 provided on the battery case body 1, ...
Is a slit into which is inserted. The slit 23 extends so as to penetrate the stacked negative electrode plate 20, retainer 21, and positive electrode plate 22 in the stacking direction. The slit 23 is
As shown in FIG. 1 (D), wide dividing grooves 23a formed in each electrode plate and narrow dividing grooves 23 formed in the retainer 21.
b ... are formed in alignment when the electrode plates 20 and 22 and the retainer 21 are laminated. Each division groove 23a ... and 23b
Has a slender rectangular shape that opens at the lower end and in the thickness direction. The dividing groove 23b formed in the retainer 21
Since the width dimension of is smaller than the thickness dimension of the dividing groove 23a and the connecting wall portion 18 of the electrode plate, the positive electrode plate and the negative electrode plate are not short-circuited through the dividing groove 23b.

Next, the test results of the characteristics of the lead storage battery of the above embodiment will be described. In this test, the electrode plate group housed in each cell chamber was an electrode plate group consisting of three positive electrode plates, four negative electrode plates, and six retainers, and the electrolytic solution had a specific gravity of 1.32.
0 (20 ° C.) dilute sulfuric acid was used. And the battery capacity is
It was 30Ah-12V (5HR). For comparison,
A conventional product having the same capacity was prepared, and a cycle life test was conducted on the example of the present invention and the conventional product. The test conditions were that the ambient temperature was 35 ° C. and the discharge was 0.25 CA (7.5 A).
The battery is charged for 3 hours at a current value of 0.17 CA (5.1
Constant current charging was carried out for 5 hours with the current value of A), and these discharging and charging were set as one cycle. Then, the capacity was confirmed every 50 cycles under the condition that the ambient temperature was 25 ° C. and the final voltage was 1.70 V at 0.2 CA (6 A), and when the capacity became 80% or less of the rated capacity, it was judged as the life. FIG. 2 shows the result of the cycle life test for the example of the present invention and the conventional product. In FIG. 2, a curve A is the test result of the example of the present invention, and a curve B is the test result of the conventional product. From the test results, it was found that the conventional product reached the end of life at 300 cycles, whereas the example of the present invention reached the end of life at 450 cycles. At the time of reaching the end of life, the wall portion for pressing the electrode plate group was expanded by 3.0 mm in the conventional product, whereas in the embodiment of the present invention, it was expanded by only 1.4 mm,
It is considered that this difference in swelling resulted in a difference in cycle life characteristics.

In the above embodiment, two cells are provided for each cell chamber.
Although two connecting wall portions are provided, at least one connecting wall portion may be provided. Further, although the present invention is applied to the sealed lead-acid battery in the above-mentioned embodiment, it is needless to say that the present invention may be applied to other secondary batteries. Connection wall portion 18 of the above embodiment
Are formed so as to be orthogonal to the connecting wall portions 11, 12, 16a to 16e, but if the angle allows the electrode plate group 19 to be inserted, the connecting wall portion 18 ... Etc. can be connected at any angle.

[0014]

According to the first aspect of the present invention, since the pair of wall portions for pressing the electrode plate group are connected to each other by the connecting wall portion, the connecting wall portion is formed even if the internal pressure in the battery case rises. The bulging of the pair of wall portions can be suppressed, and the decrease in the pressure applied to the electrode plate group can be suppressed. As a result, according to the present invention, there is an advantage in that the battery life can be extended by suppressing the expansion of the battery case during the charge / discharge cycle.

According to the invention of claim 2, since the width of the dividing groove formed in the retainer is narrowed, it is possible to prevent a short circuit between the electrode plates through the slits even when a slit is provided in the electrode plate group. There is.

[Brief description of drawings]

1A is a side view of a battery case body used in an embodiment of the present invention, FIG. 1B is a sectional view taken along line BB of FIG. 1A, and FIG. 1C is used in an embodiment of the present invention. FIG. 3 is a perspective view of an electrode plate group, (D) is a front view of a negative electrode plate, and (E) is a front view of a retainer.

FIG. 2 is a diagram showing cycle life characteristics of an example of the present invention and a conventional product.

[Explanation of symbols]

 10 Battery Case Body 11 to 14 Side Wall Part 15 Bottom Wall Part 16a to 16e Partition Wall Part 17a to 17f Cell Chamber 18 Connecting Wall Part 19 Electrode Plate Group 20 Positive Electrode Plate 21 Retainer 22 Negative Electrode Plate 23 Slits 23a, 23b Dividing Groove

Claims (2)

[Claims] 1. A sealed secondary battery in which a group of electrode plates is arranged in a cell chamber of a synthetic resin battery case under pressure in the stacking direction, and a wall of the battery case surrounding the cell chamber. A pair of wall parts facing each other in the stacking direction are connected to each other by at least one connecting wall part extending in the stacking direction and the vertical direction of the battery case, and the electrode plate group includes the at least one A sealed secondary battery, wherein a slit into which two connecting wall portions are fitted is formed. 2. Each of the positive electrode plate, the negative electrode plate, and the retainer constituting the electrode plate group is formed with a dividing groove that is laminated to form the slit, and the dividing groove formed in the retainer is formed. The sealed secondary battery according to claim 2, wherein the width dimension is smaller than the width dimension of the dividing grooves formed in the positive electrode plate and the negative electrode plate.