JP2000251923A - Rectangular storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rectangular storage battery capable of preventing short- circuiting between positive and negative electrode plates even if a dead space required in a conventional rectangular storage battery for prevention of short- circuiting between the positive and negative electrode plates is eliminated, and furthermore having increased energy density impossible so far to achieve in the conventional rectangular storage battery. SOLUTION: An end part 1a of a strip separator 1 is bent to form an upwardly bent end part 1b, and it is then zigzagged. The desired number of positive electrode plates P and negative electrode plates N are alternately laminated with the intervention of cross separators 1s, 1s... disposed and formed in its longitudinal direction, and each positive electrode plate P inserted between surfaces having the upwardly bent end part 1b of each cross separator 1s is placed on the upwardly bent end part 1b facing it, on the other hand, the negative electrode N is inserted between the surfaces having no upwardly bent end part 1b of each cross separator 1s, to form a group of electrode plates 2, and the group of the electrode plates 2 is stored in a rectangular battery jar 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prismatic storage battery used for electric vehicles and the like.

[0002]

2. Description of the Related Art As shown in FIG. 7, a conventional prismatic storage battery includes a group of various electrode plates B such as a nickel hydrogen battery, a nickel cadmium battery, and a nickel zinc battery in a prismatic battery container A.
Is housed, an alkaline electrolyte is injected, and a lid (not shown) is provided. Such an alkaline storage battery has a higher energy density, a higher durability against overcharge and overdischarge, a better life performance, and a better power supply for EVs than a lead storage battery.
It is widely used as portable equipment and emergency power supply. FIG. 7 shows a general configuration of the prismatic storage battery, in which the width of the band-shaped separator B is larger than the height of the positive electrode plate P and the negative electrode plate N.
, And a predetermined number of positive plates P and negative plates N are alternately stacked via transverse separators b, b,... Disposed opposite to each other in the longitudinal direction thereof, and the upper end of each transverse separator. A group of electrodes C, whose parts and lower end protrude above and below the upper and lower ends of the positive electrode plate P and the negative electrode plate N, are housed in the rectangular battery case A in a state where they are pressed in the stacking direction.

[0003]

As described above, in the conventional prismatic storage battery, as shown in FIG. 7, the strip-shaped separator B constituting the electrode plate group C is composed of adjacent positive and negative electrode plates P and N. In order to prevent a short circuit between them, the width thereof, that is, the dimension in the height direction of the electrode plate is increased, and each of the transverse separators b, b,
.. Are accommodated in the rectangular battery case A by contacting the lower end of the band-shaped separator B with the bottom surface a of the battery case A so as to protrude slightly above and below the upper and lower end surfaces of the positive and negative plates. Type battery case A
Between the bottom plate a and the electrode plate group C, the separators b, b,
Are formed below the positive and negative electrode plates P, N by the height protruding downward from the lower ends of the positive and negative electrode plates P, N, respectively, so that dead spaces D, D,. When charging / discharging is repeated, each positive electrode plate P repeatedly expands and contracts, and as a result, the active material that has fallen from the positive electrode plate P is placed in the dead space D below the positive electrode plate P in the bottom surface of the battery case A. a, the belt-like separator B,
That is, short-circuiting due to side short-circuiting between the adjacent positive and negative plates via the gap between the left and right side surfaces of the transverse separator b and the inner surface of the battery case A is prevented. However, in order to increase the battery capacity per unit volume of the battery case A, in order to reduce the height of the dead space D, use positive and negative plates which are higher than those shown in the figure. The lower end is lowered to the vicinity of the lower end of each transverse separator b to assemble the electrode group, which is accommodated in the battery case A, and the height of the dead space D from the lower end of each electrode plate to the bottom surface a of the battery case A. When a battery with increased battery capacity was created and battery charge and discharge were repeated, short-circuiting due to side short-circuit with an adjacent negative electrode plate via the dropped and deposited positive electrode active material occurred early, and the battery life was shortened. Was found to be shorter. As described above, in the conventional prismatic storage battery having the above-mentioned electrode plate group, a required relatively large dead space is required in order to prevent a short circuit. It has been found that there is a disadvantage that the plate cannot be incorporated and therefore the energy density cannot be increased. Therefore, based on the above findings, it is possible to eliminate the disadvantages of the conventional rectangular storage battery and reliably prevent a short circuit between the positive and negative plates even if the conventional dead space is eliminated, and further increase the battery capacity as desired. It is desired to develop a rectangular prismatic storage battery.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned disadvantages and to provide a rectangular storage battery which satisfies the above-mentioned demands. An electrode plate group formed by alternately stacking a desired number of positive plates and negative plates via respective transverse separators disposed opposite to each other in the longitudinal direction and containing the plates in a rectangular battery case. In the rechargeable battery, the lower end of the strip separator is bent to form an upwardly bent end, and the positive electrode plate is placed between opposing surfaces having the upwardly bent end of each of the transverse separators formed by squeezing the lower end. It is characterized in that the negative electrode plate is inserted between the flat surfaces of the respective transverse separators that do not have the bent ends, while being inserted and placed on the opposite bent ends. Further, the present invention provides a prismatic storage battery having an increased capacity.In the prismatic storage battery described above, a negative electrode plate having a height higher than the positive electrode plate is used as each negative electrode plate, and the lower end of the negative electrode plate is used as the positive electrode plate. It is characterized in that it is located near or at the same position as the lower end of the transverse separator below the lower end. Further, the present invention provides a prismatic storage battery constituted by using a large number of plate-shaped separators instead of the band-shaped separator.
Prepare a desired number of leaf-shaped separators having an area larger than the vertical and horizontal dimensions of the negative electrode plate, fold the lower end of each leaf-shaped separator, insert it between the positive and negative electrode plates, and have its upward bent end. Insert each positive electrode plate between the surfaces and place it on the opposing upward bent end, and insert each negative electrode plate between the opposing flat surfaces that do not have the upward bent end of each leaf-shaped separator. It is characterized by having.

[0005]

1 to 4 show an example of an embodiment of the present invention. In the drawings, reference numeral 1 denotes a long strip separator used in the present invention. According to the present invention, there is prepared a belt-like separator 1 in which the lower end portion 1a is bent to form an upward bent end portion 1b. The width, that is, the height of the strip-shaped separator 1 is formed to be higher than the heights of the positive electrode plate P and the negative electrode plate N, and when the electrode plate group is formed by being interposed between the positive and negative electrode plates P and N, Generally, the upper and lower ends of the positive and negative plates P and N are made to protrude above the upper and lower ends to prevent electrical insulation between adjacent positive and negative plates. The length in the length direction is, as is apparent in FIGS.
A large number of transverse separators 1s,
1s,..., A desired number of negative electrodes N and positive electrodes P are alternately stacked to have a length sufficient to assemble the electrode group 2. N1 is a lug of each negative electrode plate N protruding and aligned on one side of the upper surface of the electrode group 2, and P1 is a lug of each positive electrode plate P protruding and aligned on the other side of the upper surface of the electrode group 2. Show ears.

The desired number of transverse separators 1 formed in the longitudinal direction of the strip-shaped separator 1 according to the present invention, which is formed by folding the band-shaped separator 1 with its lower end portion 1a bent.
s, 1s,... have their ends 1b, 1b,.
.. Are obtained by alternately forming surfaces having no bent end portions 1b, 1b,. Thus, according to the present invention, the transverse separator 1
s, 1s,..., between the surfaces of the transverse separators 1s facing the upwardly bent ends 1b, 1b.
And the positive electrode plate P is placed on the opposed bent ends 1b, 1b, while the negative plate N is placed between the opposed flat surfaces without the upwardly bent ends 1b, 1b of each transverse separator 1s. Was inserted. Thus, electrical insulation at the lower end side of each adjacent positive electrode plate P and negative electrode plate N is favorably performed by the upward bent ends 1b, 1b. The number of the negative electrode plates N constituting the electrode plate group 2 is larger than that of the positive electrode plate P by one, and the flatness of the transverse separators 1s, 1s without the bent end portions 1b, 1b located at the outermost end thereof is used. Negative electrode plates N, N were laminated on the outer surface of the surface. In the illustrated example, the height dimension of each positive electrode plate P arranged in this manner is such that the upper end of the positive electrode plate P is placed on the upward bent ends 1b, 1b at the upper end edge of the strip separator 1. In other words, while the separators lower than the transverse separators 1s, 1s are used, each negative electrode plate N also has an upper end lower than the upper end edge of the strip-shaped separator 1, and is used between the adjacent positive and negative electrode plates. Prevention of short circuit due to contact on the upper end side was secured.

As shown in FIGS. 2 to 4, the electrode plate group 2 assembled as described above is firmly inserted into the rectangular battery case 3 with both ends in the stacking direction between the inner wall surfaces of the facing battery case 3. And
The rectangular storage battery 4 of the present invention is obtained by being housed in a compressed state.
After that, according to a conventional method, a strap for connecting ear rows of positive and negative plates arranged on both sides of the upper surface and positive and negative terminals rising from the strap are formed on the prismatic storage battery 4 according to a conventional method. It goes without saying that the electrolyte is injected and a lid (not shown) is provided on the upper surface thereof.

As shown in FIG. 3, the thus constructed prismatic storage battery 4 of the present invention has a lower end of each positive electrode plate P of the electrode plate group 2 housed in the rectangular battery case 3. The bottom surface 3a of the battery case 3
, Upper ends 1b, 1b of the lower ends 1a, 1a of the transverse separators 1s, 1s on both sides thereof intervene, and the positive electrode plate P is connected to the upper ends 1b, 1b.
1b, the opposite sides of which are mounted on the transverse separator 1
so that grooves 1c, 1c formed between the vertical lower end portion 1a and the upward bent end portion 1b of each transverse separator 1s are positioned below and sandwiched by the flat surfaces of the horizontal separators 1s, 1s. I made it. Thus, the prismatic storage battery 4
Even if the active material falls off from both surfaces due to expansion and contraction of the positive electrode plate P due to the repetition of the charge and discharge, the active material is collected by the grooves 1c and 1c below the active material. The dead space below is effectively used as a collecting part for the falling active material, and the cause of the short circuit caused by the conventional falling active material is solved beforehand, which helps to extend the battery life. In this case, the height of the upward bent end portion 1b is about half the height of the dead space D below the positive electrode plate P of the conventional storage battery shown in FIG. However, a positive electrode plate P having a high height can be incorporated as shown. As described above, the effective bent end portions 1b, 1b as described above are provided at the useless space formed between the lower end of the conventional positive electrode plate and the bottom surface of the battery case, that is, the dead space. As a result, not only can the dead space be changed to a useful space for preventing a short circuit between the positive and negative plates adjacent to the bearing of the positive plate, but also the height of the positive plate can be increased, which is advantageous. .

The negative electrode plate N used in the prismatic storage battery 4 of the present invention may have the same height as the positive electrode plate P. However, as described above, the active material falling off from the positive electrode plate P ,
Grooves 1c, 1 inside the upward bent ends 1b, 1b
c, and short-circuiting with the adjacent negative electrode plate N is well prevented, so that a higher plate than the conventional positive electrode plate P shown in FIG. 7 can be provided. For example, as shown in FIG. 3, a negative electrode plate N having a height higher than the height of the positive electrode plate P is incorporated, and the lower end of the negative electrode plate N approaches the lower end of the transverse separator 1s or reaches the same position. Then, as shown in FIG. Thus, the dead space between the lower end of the negative electrode plate N and the bottom surface 3a of the battery case 3 can be filled with the lower end of the negative electrode plate N, thereby not only eliminating the dead space that has conventionally occurred, but also The positive and negative plates P,
Since the height dimension of both N can be increased, the prismatic storage battery 4 with improved energy density can be configured.

FIGS. 5 and 6 show another embodiment of the present invention. In this embodiment, a case where a leaf-shaped separator s having a size corresponding to the transverse separator is used as shown in FIG. That is, the vertical and horizontal dimensions of the leaf-shaped separator s are:
It is made larger than the vertical and horizontal dimensions of the positive and negative electrodes, and its lower end sa is bent to form a groove sc between the upward bent end sb and the vertical lower end 1a inside the bent end sb. In the same manner as in the previous embodiment, a positive electrode plate P and a negative electrode plate N are alternately laminated, and when assembling the electrode plate group 2, each of the In this case, the surfaces having the bent ends sb, sb of the leaf-shaped separators s, s,... Interposed therebetween are arranged so as to face each other, and the opposite bending is performed. Inserting between the leaf-shaped separators s, s with the respective positive plates P placed on the ends sb, sb, while inserting the respective negative plates N between the inner surfaces of the bent ends sb, sb. As a result, the electrode plate of the present invention is similar to that of the previous embodiment. By 2 constitutes a, to accommodate the compression state it to square electrodeposition tank 3, square battery 4 of the present invention
It is what constituted. FIG. 6 shows a top view of the prismatic storage battery 4. Thus, in the dead space between the lower end of each positive electrode plate P and the bottom surface 3a of the rectangular battery case 3, the extended portion of the positive electrode plate P and the separator S are provided as shown in FIG. , S are interposed between opposing bent ends sb, sb. As a result, the positive electrode plate P is stably supported, and the active material that has fallen off from both surfaces thereof has its grooves 1c,
1c, the height of the conventional dead space D shown in FIG. 7 can be reduced, and even if the positive electrode plate is lowered by the reduced amount, a short circuit between the positive and negative electrode plates is well prevented. On the other hand, the bottom surface 3a of the battery case 3 below the lower end of each positive electrode plate P
Can be used as an effective space by interposing the opposed bent ends sb, sb. Also in this case, as the negative electrode plate N,
As in the previous embodiment, it is preferable to arrange so as to be higher than the positive electrode plate P and to reach the same position as the vicinity of the lower end or the lower end of the leaf-shaped separator s. The dead space between the lower end of each positive electrode plate and negative electrode plate of the electrode plate group 2 and the bottom surface of the rectangular battery case 3 can be eliminated, and the size can be increased together with the positive electrode plate P, so that the energy density of the battery can be improved. Is the same as in the previous embodiment.

Next, a more specific embodiment will be described together with a conventional example. Conventional example Width, that is, height 74 mm, length 1620 mm, thickness 0.
A 3 mm PP band-shaped separator is folded in a zigzag, and 15 paste-type Ni plates as a positive electrode plate and 16 MH plates as an anode plate are alternately provided through the many transverse separators, and MH plates are provided at the outermost end. Assemble the electrode group by stacking them so that they are positioned, and store them in a state where they are pressed against a predetermined rectangular battery case to form a rectangular storage battery, inject an alkaline electrolyte by a conventional method, and cover the battery. Fifty cells of the prismatic storage battery were produced. In addition, the upper and lower end portions of the flat-shaped separator interposed between the positive and negative electrode plates of the electrode group housed in the rectangular battery case have upper and lower ends of the positive and negative electrode plates, respectively. It protrudes upward and downward by 4 mm, respectively, and the height of the dead space between the lower end of each electrode plate and the bottom surface of the battery case is 4 mm. The structure of the rectangular storage battery corresponds to that shown in FIG. . The Ni electrode plate was prepared by filling a foamed nickel substrate with an active material mixture paste mainly composed of nickel hydroxide powder, drying and applying pressure to dimensions of 66 mm in length, 50 mm in width and 0.75 mm in thickness. . The MH electrode plate is mainly composed of a hydrogen storage alloy powder in a punching metal, a small amount of a conductive material is added thereto, and the mixture is kneaded with a CMC aqueous solution, an active material mixture paste is applied, dried and pressed to a length of 66 mm. 50mm in width,
It was manufactured to have a thickness of 0.55 mm. Comparative Example For comparison, an MH electrode plate was 70 mm long and 50 m wide.
m, having a thickness of 0.55 mm and leaving the lower end substantially at the same position as the lower end of the transverse separator so that there is no dead space between each MH electrode plate and the bottom surface of the rectangular battery case. Except that it was arranged in the same manner as in the conventional example, to produce 50 square storage batteries. That is, the structure of the prismatic storage battery is M
The structure was the same as that shown in FIG. 7 except that the lower end of the H-electrode plate reached the bottom of the battery case. Example The width, ie height 76 mm, length 1620 mm, thickness 0.
One end in the width direction of a 3 mm PP band-shaped separator is 2 m
After being bent into a width of 74 mm, this was folded in a zigzag manner, and the bent end was positioned at the lower end thereof.
An electrode group is assembled by alternately stacking 15 electrode plates and 16 MH electrode plates, and each Ni electrode plate is inserted between the surfaces having the upwardly bent ends of the transverse separator and opposed to each other. The MH plate is placed so as to be placed on the upward bent end, and the MH plate is inserted between flat surfaces having no upward bent end of the transverse separator, and the MH plates at both ends are After assembling into a group of electrode plates stacked so as to be positioned outside the flat surface of the outermost transverse separator, this is housed in the same predetermined battery case as in the conventional example in a compressed state to form a prismatic storage battery Then, an alkaline electrolyte is injected in the same manner as in the conventional example, and the battery is covered.
A cell was prepared. The Ni electrode plate is 68 mm long and 50 m wide.
m and a thickness of 0.75 mm were used. The MH plate is
Same as the comparative example, length 70 mm, width 50 mm, thickness 0.55
mm. In addition, the top of the tabular folding separator interposed between the positive and negative electrodes of the electrode group housed in the battery case protrudes 4 mm from the upper end of the positive electrode plate. Protrudes 2 mm from the positive electrode plate, reaches the bottom of the battery case, and supports the lower end of the positive electrode plate at its upward bent end. The structure of the prismatic storage battery corresponds to that shown in FIG. .

Each of the 50 cells of the conventional example, the comparative example, and the example manufactured as described above was
00 cells are prepared, charged at 2 A for 7.5 hours, and charged at 10 A for 1 hour.
A life test for discharging to V and the presence or absence of a short circuit were performed. The results are shown in Table 1 below.

[0013]

[Table 1]

According to the present invention, since the lower end portion is bent upward as a separator, thereby supporting the positive electrode plate, the fallen active material can be captured at the bent end portion. , The short circuit can be reliably prevented. In addition, by enlarging the dimensions of the negative electrode plate and the positive electrode plate, the battery capacity is significantly increased as compared with the conventional rectangular storage battery. As in the comparative example, in the structure of the conventional rectangular storage battery, if the dead space below the electrode plate is eliminated, a short circuit occurs at an early stage, the battery life is shortened, and the practicality is lost. In the above embodiment, the thicknesses of the positive and negative plates were made the same as those of the conventional example in order to compare with the comparative example and the conventional example. Therefore, the volume ratio of the Ni electrode plate / MH electrode plate of this example was about 1.32, but considering the charging characteristics etc., a combination of 0.76 mm thick Ni plate and 0.54 mm thick MH plate, with a volume ratio of about 1.36 Is generally used, and needless to say, this brings about the same effect as in the above embodiment.

[0015]

As described above, according to the present invention, a strip-shaped separator or a leaf-shaped separator in which the lower end is bent is prepared, and a desired number of positive and negative plates are alternately provided through the separator. In assembling the plate group, each of the positive electrode plates was supported by the opposed upwardly bent end portion, so when the electrode plate group was immovably accommodated in a rectangular battery case to form a rectangular storage battery, Since the active material that has fallen off the plate can be captured by the groove inside the upwardly bent end portion that faces downward on both sides of the positive electrode plate, a short circuit between the positive and negative electrode plates can be positively prevented. Therefore, even if the lower end of the negative electrode plate is placed near or at the same position as the lower end of the separator, a short circuit between the positive and negative electrode plates can be effectively prevented, and the dead space between the lower end of the negative electrode plate and the bottom surface of the rectangular battery case can be prevented. Resulting in a battery with increased energy density.

[Brief description of the drawings]

FIG. 1 is a front view of a rectangular storage battery according to an embodiment of the present invention, in which a middle portion of a band-like separator is omitted.

FIG. 2 is a top view of the prismatic storage battery according to one embodiment of the present invention, in which an intermediate portion is omitted.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 2;

FIG. 5 is a front view of a leaf separator used in a prismatic storage battery according to another embodiment of the present invention.

FIG. 6 is a top view of a prismatic storage battery according to another embodiment of the present invention, in which an intermediate portion is omitted.

FIG. 7 is a vertical cross-sectional view of a conventional prismatic storage battery in which an intermediate portion is omitted.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 strip separator 1a lower end of strip separator 1s transverse separator 1b upward bent end 1c groove s leaf separator sa lower end of leaf separator sb upward bent end sc groove 2 electrode plate group 3 square battery case 3a square Bottom of battery case P Positive electrode plate N Negative electrode plate

Claims (3)

[Claims] 1. A desired number of positive and negative electrode plates are alternately formed by folding a strip-shaped separator wider than the height of the positive and negative electrode plates and interposing transverse separators formed in the longitudinal direction so as to face each other. In a rectangular storage battery in which a stacked electrode group is accommodated in a rectangular battery case, the lower end of the band-shaped separator is bent to form an upwardly bent end, and the bent end is bent and formed. A positive plate is inserted between the opposing surfaces having the upwardly bent ends of each transverse separator and placed on its opposite folded ends, while the opposing flats without the folded ends of each transverse separator. A prismatic storage battery comprising an electrode group, wherein a negative electrode plate is inserted between the surfaces. 2. The prismatic storage battery according to claim 1,
Each of the negative plates is a negative plate having a height higher than that of the positive plate, and the lower end is located near or at the same position as the lower end of the transverse separator below the lower end of the positive plate. Storage battery. 3. A desired number of leaf-shaped separators having an area larger than the vertical and horizontal dimensions of the positive and negative electrode plates are prepared in place of the strip-shaped separators, and the lower ends of the leaf-shaped separators are bent to form positive and negative electrode plates. Each positive electrode plate is inserted between the surfaces having the upwardly bent end portions and is placed on the opposite upwardly bent end portion, while each leaf-shaped separator has an upwardly bent end portion. A prismatic storage battery comprising an electrode plate group, wherein each negative electrode plate is inserted between opposed flat surfaces.