JP2002324568A - Cell having a plurality of wound pole plates - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cell of high efficiency which has an excellent function to suppress temperature rise even at discharging and which is excellent in charging/discharging cycle. SOLUTION: The cell has a positive pole plate, a separator, and a negative pole plate stacked and wound into a plurality of wound pole plates held between a positive pole collecting terminal and a negative pole collecting terminal. A core of the pole plate is exposed on one side of the positive pole plate and the negative pole plate, and the core of the exposed positive pole plate and that of the negative pole plate are allowed to protrude from a facing wound end surfaces of the pole plates. The protruded core, the positive plate collecting terminal, and the negative plate collecting terminal are welded at the engagement part. A sheet holding an electrolyte abuts on the outer peripheral surface of a plurality of wound pole plates.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery of an electrolytic solution limiting type (hereinafter referred to as a "liquid limiting type"), comprising a plurality of wound electrode groups, and a plurality of wound electrode plates. A power generator connected in parallel by holding the group between a pair of opposed positive and negative electrode current collector terminals (the power generator referred to here is a part involved in power generation or storage of a battery). And a collection of electrode plates and current collecting terminals). Here, the battery of the liquid limiting type refers to a battery in which the amount of the electrolytic solution is almost limited to a value corresponding to the liquid holding amount of the electrode plate group, and the presence of a free electrolytic solution is suppressed as much as possible.

[0002]

2. Description of the Related Art FIG. 6 shows the internal structure of a battery provided with a conventional stacked electrode group. In FIG. 6, the power generator 60 is connected to a negative electrode plate 64 and a positive electrode plate 66 via a separator 62 as shown in FIG.
And a plate-like negative electrode current collecting terminal 70 and a positive electrode current collecting terminal 72 joined to one end of the negative electrode plate 64 and one end of the positive electrode plate 66, respectively.

The negative electrode current collecting terminal 70 and the positive electrode current collecting terminal 72 are arranged in contact with the core projecting surfaces of the negative electrode plate 64 and the positive electrode plate 66, and the negative electrode current collecting terminal 70 and the positive electrode current collecting terminal 72 are arranged. The surface 70A, 72A (hidden on the back surface) is irradiated with a laser beam or an electron beam, or joined to the cores of the negative electrode plate 64 and the positive electrode plate 66 by resistance welding. It is stored in a tank 78.

[0004] In the case of a battery provided with the above-mentioned conventional stacked electrode group, the electrode group is not fixed until the electrode group is housed in the battery case, and there is no risk of displacement. Therefore, after laminating the positive electrode plate, the separator and the negative electrode plate, the electrode plate group is pressed from both sides to prevent positional displacement until the electrode plate group is completely inserted into the battery container including the step of joining the current collecting terminals. Carry.

[0005] Next, a predetermined amount of electrolyte is injected to obtain a liquid-limited battery. The liquid-limited battery is superior in leak-proof performance and lighter in weight than a battery filled with an electrolytic solution in a battery case (hereinafter referred to as a “liquid battery”). Excellent absorption function.

However, the liquid-limited type battery has a smaller heat capacity and lower heat conductivity from the electrode plate group to the outside than the liquid-type battery.
For this reason, when a high load is applied, the heat generated in the electrode group is trapped and the battery temperature tends to increase. For example, in the case of a battery for a hybrid electric vehicle, the discharge current is 200 A
Reach In the case of a liquid-limited battery, when the battery is discharged at such a high rate, the battery temperature rises more remarkably than in a liquid battery.

[0007] A battery system having an assembled battery in which a plurality of batteries are combined is applied to an application requiring a large output and a large energy, such as a power supply for an electric vehicle. This battery system is air-cooled or water-cooled. A mechanism is provided to cool the battery and prevent the battery temperature from rising too high. However, in the case of the battery provided with the conventional stacked electrode group, the function of dissipating heat from the electrode group to the outside is not sufficient, and when discharging at a high rate, the heat radiation does not catch up with the heat generation, and the battery temperature increases. There were drawbacks.

[0008]

When the high-rate discharge is completed in a short time, the battery cooling mechanism is activated, and the battery temperature is maintained within the specified range. However, when a large load is continuously applied to the electric vehicle power supply, such as when climbing a hill or accelerating, the cooling function may not catch up with the heat generated by the battery, and the battery temperature may increase.

[0009] An increase in battery temperature causes deterioration of battery performance and an increase in battery internal pressure, which is not preferable in terms of performance and safety. In particular, in the case of a nickel-hydrogen storage battery or a nickel-cadmium battery, the regenerative charging efficiency is reduced, and oxygen is generated at the positive electrode during charging. The internal pressure of the battery rises due to the generation of oxygen, and when the pressure exceeds a specified value, the gas discharge valve operates to release oxygen to the outside. Further, oxygen oxidizes the hydrogen storage alloy and cadmium of the negative electrode. The release of the gas and the oxidation of the negative electrode are not preferable because they cause a decrease in capacity.

In the case where the stacked electrode group is applied as described above, if the stacked state is to be maintained without causing the electrode group to be misaligned, the positive electrode plate, the separator, and the negative electrode plate must be consistently stacked after being stacked. It was necessary to press and hold the electrode plate group, and there was a disadvantage that the larger the electrode plate, the more difficult it was to hold the laminate. For this reason, in a battery having a large capacity, application of an electrode plate group in which a stacked electrode plate or a separator is unlikely to be displaced has been demanded.

The present invention has been made in view of the above-mentioned drawbacks of the conventional battery. In addition to the battery cooling mechanism provided in the conventional battery, the present invention has been made by improving the structure of the electrode group in the battery. The purpose of the present invention is to improve the heat dissipation function of the above and further facilitate the maintenance of the laminated state of the electrode group, and to solve the drawbacks of the conventional battery.

[0012]

The battery according to the present invention is a battery provided with a plurality of wound type electrode groups formed by stacking and winding a positive electrode plate, a separator and a negative electrode plate. The core body and the core body of the negative electrode plate are exposed at one end surface of the electrode plate group, and the core body of the positive electrode plate and the core body of the negative electrode plate protrude from two opposing surfaces of the electrode plate group. , The electrode plate group is sandwiched between a pair of positive and negative electrode current collecting terminals facing each other and facing each other, and the current collecting terminal and the core are welded at an engaging portion. Provided with a plurality of wound electrode plates.

[0013] In the battery according to the present invention, a wound electrode group is applied in order to easily maintain the laminated state of the electrode group. In the case of the plate-type laminated electrode group, if the electrode group is not pressed and held from both sides and the electrode plate and the separator are misaligned, in the case of the wound electrode group, the winding end portion is fixed. As long as this is done, there is an advantage that the displacement of the electrode plate and the separator can be prevented without the winding being loosened.

In the battery of the present invention, an electrode group having a wound end face other than a circular shape, an elliptical shape, or a flat shape can be applied as a wound type electrode plate group. Then, in order to prevent heat generated due to energization from being trapped in the electrode plate group, the diameter (when the wound end surface shape is circular) or the short diameter (the wound end surface shape) of the wound electrode plate group is used. (When is an ellipse or flat). At the same time, a predetermined capacity is ensured by providing a plurality of electrode plate groups.

In the case of a wound electrode group having a wound end surface having a circular shape, since the outer peripheral surface is in an arc shape, a plurality of electrode groups are brought into contact with each other (that is, the interval between the outer peripheral surfaces of the electrode group and the electrode group is reduced. 0 mm), it is point contact even if it is arranged, and there is a gap between the two. If the distance between the electrode groups is too large, not only the volume efficiency is reduced but also the cycle performance is adversely affected as described later. When the shape of the wound end face is circular, it is desirable to set the interval to less than 8 mm, and more preferably to 5 mm or less.

When an electrode group having an elliptical or flat wound end face is applied, a plurality of electrode groups are arranged such that the long axis of the wound end face is parallel so that the volumetric efficiency of the battery is as high as possible. Place. If a plurality of elliptical or flat electrode plates are arranged such that the outer peripheral surfaces parallel to the long axis are in contact with each other, unlike the circular case, a gap is secured between the electrode plates. May not be possible. In this case, it is desirable to provide an interval of 1 mm or more and less than 8 mm, more preferably 1 to 5 mm, between the electrode groups for the reasons described below. Here, the interval refers to the shortest distance between the outer peripheral surfaces of the two electrode groups.

Further, the present invention relates to a liquid-limited battery. In the battery of the present invention, an electrolyte is held on the surface of each of the plurality of wound electrode groups. The sheet that has been made to abut is brought into contact. By contacting the sheet held by the electrolyte with the surface of the electrode group, it is possible to prevent the electrode group from drying out. To facilitate the transfer of the electrolyte from the electrolyte impregnated sheet into the electrode group, the band-shaped separator constituting the electrode group is set to be longer than the electrode plate, and the separator is provided on the outer peripheral surface of the wound electrode group. , And the electrolyte-impregnated sheet is preferably brought into contact with the exposed portion of the separator.

As described above, by bringing the electrode group into contact with the electrolyte impregnated sheet, when the electrode group generates heat and abnormally rises in temperature, the electrolyte contained in the sheet evaporates. Since the latent heat is taken from the electrode group, there is an effect of cooling the electrode group.

[0019]

FIG. 1 is a perspective view of a wound electrode plate group 10. FIG. In the figure, the strip-shaped separator 12 is replaced with the strip-shaped negative electrode plate 1.
4 and a belt-like positive electrode plate 16 and wound around the core 18 to form an electrode plate group. On the upper side of the figure, the core 17 is projected on one side (upper side in the figure) of the positive electrode plate, and the core 15 is projected on one side (lower side in the figure) of the negative electrode plate. In the electrode group, unlike the flat-type electrode group, the end of the winding is fixed with an adhesive tape or the like so that the winding is not loosened.

FIG. 2 shows four wound electrode plates 10 each having a circular wound end face as shown in FIG. 1, and the electrode plate 10 is narrowed to the negative current collecting terminal 1 and the positive current collecting terminal 2. FIG. 3 is a view showing a power generator of the cell held by the battery (a negative electrode current collecting terminal is intentionally separated in order to prevent the electrode group 10 from being hidden behind a current collecting terminal). The core of the positive electrode plate protruding from the wound end face of the electrode plate group and the positive current collecting terminal, and the engaging portion of the core of the negative electrode plate and the negative current collecting terminal are joined by welding to form a power generator. Protrusions are provided on the upper sides of the negative and positive electrode current collector terminals, and the protrusions are provided with through holes for mounting inter-cell connecting members or external terminals.

In the example shown in FIG. 2, the electrode groups are arranged apart from each other. However, when a wound electrode group having a circular wound end surface is applied, the electrode groups are brought into contact with each other. Is also good. Since the outer peripheral surface of the electrode group is arc-shaped, a gap is secured between adjacent electrode groups even when the electrode groups are brought into contact with each other. In the case of the battery according to the present invention, a sheet impregnated with an electrolyte described below is brought into contact with the outer peripheral surface of the electrode group, and a power generator is inserted into the battery case 4 to constitute a cell.

FIG. 3 is an explanatory view for explaining the structure of a power generating body to which a wound electrode plate group 10 having an elliptical or flattened wound end face is applied. The structure of the wound electrode group applied here is basically the same as that of the cylindrical electrode group.
Further, there is also a structure of a power generating body in which a plurality of wound electrode groups are arranged between a pair of a positive electrode current collecting terminal and a negative electrode current collecting terminal, and the core of the electrode plate and the current collecting terminal are joined by welding. It is the same as that shown in FIG. However, unlike the case where the wound end surface is circular, the side surface of the electrode plate group parallel to the long diameter becomes nearly flat. Therefore, when the electrode groups are brought into contact with each other, a gap cannot be secured between the electrode groups. Therefore, in the electrode group in which the shape of the wound end surface is elliptical or flat, so that heat does not remain in the electrode group,
It is desirable to provide an interval of 1 mm or more and less than 8 mm, and more preferably 1 to 5 mm between the electrode plate groups.

FIG. 4 is a front view of a power generator provided with the four wound electrode plates shown in FIG. The separator is longer than the electrode plate, and at least one round of the separator is wound around the outer peripheral surface of the electrode plate group. At least one round of the periphery of the four electrode groups 10 is surrounded by a sheet 5 impregnated with the electrolytic solution, and the electrode group 10 and the electrolyte impregnated sheet 5
Is abutted.

FIG. 5 is a diagram for explaining the inside of a monobloc battery in which six cells are housed in one battery case 4. Each cell contains the power generator shown in FIG. 4 (the electrolyte impregnated sheet is omitted for clarity), and the adjacent cells and cells are located at the protrusion of the current collecting terminal and the partition of the battery case. They are connected in series by inter-cell connecting members (not shown for clarity) mounted through the provided through holes. Also,
The negative electrode current collecting terminal 30c and the positive electrode current collecting terminal 30b of the cells at both ends.
Are equipped with a negative electrode terminal and a positive electrode terminal, respectively.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on an embodiment using an alkaline storage battery as an example. In addition, the shape of the present invention, the material of the parts, and the like are not limited to the examples described below.

(Example 1) A thickness of 0.1 mm, a thickness of 0.6 mm having a core exposed portion having a width of 2 mm provided at an end of a side edge,
A sintered nickel positive electrode plate having a width of 40 mm and a length of 180 mm is sandwiched between folded 150-μm-thick polypropylene strip separators, and the positive electrode is exposed to a thickness of 0.06 mm and a core exposed portion having a width of 2 mm provided on a side. 0.4m thick with
m, a width of 40 mm, and a length of 200 mm, a paste-type hydrogen-absorbing alloy negative electrode plate was arranged such that the respective core exposed portions protruded on both sides, and the electrode plate and the separator were wound, as shown in FIG. A wound electrode plate group having a diameter of 15 mm and a width of 42 mm and having a circular wound end surface was prepared. The strip-shaped polypropylene separator was made longer than the electrode plate, and a wound portion of only one turn of the separator was provided on the outer peripheral surface of the electrode plate group.

The four wound type electrode plates were arranged in a line so that the interval between them was 3 mm. A nickel current collecting terminal having a thickness of 0.6 mm, a width of 15.2 mm, and a length of 85 mm was brought into contact with the core of the positive electrode plate protruding from one of the wound end surfaces of the electrode plate group, and was joined by laser welding. Furthermore, a negative electrode current collector terminal of the same size and the same material as described above was joined to the core of the negative electrode plate protruding from the opposing surface to form a power generator having four electrode groups. Around a circumference of the four electrode plate groups, a nonwoven fabric made of polypropylene having a thickness of 120 μm and subjected to a hydrophilic treatment is rotated twice,
The edge of the sheet was fixed.

[0028] Six sets of power generating bodies, each of which is provided with four wound electrode groups, and in which the non-woven fabric impregnated with the electrolytic solution is wound on the outer peripheral surface of the electrode groups, are inserted into a battery case, and the cells are connected to each other. The members were connected in series to form a monoblock battery composed of 6 cells. After injecting a predetermined amount of an alkaline electrolyte containing a caustic potassium aqueous solution of a predetermined concentration as a main component into each cell, a lid equipped with a gas discharge valve was attached and sealed, and the voltage was 7.2 V and the capacity was 6.5 Ah.
Liquid limiting type battery.

(Embodiment 2) In Embodiment 1, the interval between the electrode groups is 0 mm (the outer peripheral surfaces of the electrode groups are in contact with each other).
It was arranged so that it might become. Otherwise, a battery having the same configuration as in Example 1 was produced.

(Example 3) In Example 1, the electrode plates were arranged so that the interval between them was 5 mm. Otherwise, a battery having the same configuration as in Example 1 was produced.

(Example 4) In Example 1, the electrode groups were arranged so that the interval between them was 8 mm. Otherwise, a battery having the same configuration as in Example 1 was produced.

Comparative Example 1 A monoblock battery having the same structure as in Example 1 except that no polypropylene nonwoven fabric was arranged on the outer peripheral surface of the electrode plate group was prepared.

(Comparative Example 2) Thickness 0.1 mm, width 2 on the side
0.6mm thickness, 40mm width, exposing the core material of mm
A sintered nickel positive electrode plate having a height of 70 mm and a core material having a thickness of 0.06 mm and a width of 2 mm exposed on the side sides and a thickness of 0.4.
A paste-type hydrogen storage alloy negative electrode plate having a thickness of 40 mm and a width of 40 mm and a height of 70 mm, and a polypropylene nonwoven fabric separator having a thickness of 150 μm were prepared. Twelve positive electrode plates and thirteen negative electrode plates were laminated with a separator interposed therebetween to form a laminated electrode group having a thickness of 15 mm, a width of 42 mm, and a height of 60 mm. The positive electrode current collector terminals are respectively provided on the positive electrode plate core and the negative electrode plate core protruding to the side while holding the electrode group so that the positions of the electrodes and the separator of the laminated electrode group do not shift. Then, the negative electrode current collecting terminals were brought into contact with each other and joined by laser welding to form a group of electrodes of a unit cell. Six electrode plates were prepared, and a monoblock-type liquid-limited battery in which six cells were connected in series as in Example 1 was produced. As in the case of the example battery, the battery voltage was set to 7.2.
V and the capacity were set to 6.5 Ah.

(Activation of batteries) Each of these batteries was heated at a temperature of 25 ° C. for 0.2 It (A) ＡNote 1 It (A)
= C5 (Ah) / 1h}. The charge / discharge operation was repeated five times to activate the battery.

(Investigation of Battery Temperature During Discharge) The activated battery was discharged at various rates, and the battery temperature at that time was measured. The discharge test was performed at an ambient temperature of 25 ° C. and a discharge current of 1.0 It (A).
To 15 It (A), and the discharge end voltage was set to 4.8 V. The temperature was measured by disposing a temperature sensor at the center of the electrode group surface in the width direction of the electrode group.

FIG. 5 shows the measurement results. In FIG. 5, the battery temperature is represented by a rising temperature. As shown in the figure, in the case of the battery of the present embodiment, the battery rise temperature is kept low even when the battery is discharged at an extremely high rate of 15 It (A). As in the present embodiment, when the shape of the wound end face is circular, even in the case of Embodiment 2 in which the interval between the electrode groups is 0 mm, the temperature rise is 2
It is kept at 3 ° C. The temperature rise in Examples 1, 3 and 4 in which an interval is provided between the electrode groups is even lower than in Example 2. On the other hand, in the case of Comparative Example 2, the temperature rise under the same discharge condition showed a high value of 35 ° C. This is a result of the laminated electrode plate having a low heat dissipation function and being easily trapped in the electrode group.

In the case of the battery provided with the wound electrode group according to the above embodiment, the electrode group is divided into four.
Since the gap between the electrode groups is secured, the heat radiation function is enhanced, and the Joule heat generated by the discharge is dissipated without a cage, so that the temperature rise may be suppressed to a small level.

Although the difference is not large in the present experimental example, the temperature rise value of Comparative Example 1 is higher than the temperature rise value of Example 1. In the case of the first embodiment, it may be the result that the cooling effect by the sheet impregnated with the electrolytic solution brought into contact with the outer peripheral surface of the electrode plate group appears.

Although detailed data is omitted, when the diameter or the short diameter of the wound electrode group is increased, the heat radiation function is reduced and heat is easily stored. The diameter or minor diameter of the electrode group is 35m
If m or less, the temperature rise at the time of discharge is equivalent to that of the above-described embodiment, whereas if it exceeds 35 mm, the temperature rise becomes remarkable. In the case of a wound electrode group, the diameter of the core is 3 mm.
Since the diameter or the short diameter of the electrode plate group is 12
If it is less than mm, the volume ratio of the core in the electrode plate group becomes large, and there is a disadvantage that the volume efficiency is reduced. For the above reasons, the diameter or the short diameter of the wound electrode group according to the present invention is:
It is desirable to set it within the range of 12 to 35 mm.

Further, part of the heat generated in the electrode group during the discharge is dissipated through the current collecting terminal. Therefore, when the width of the wound electrode plate is increased, the heat dissipation function due to the conduction is reduced. In the configuration of the electrode group according to the present invention, if the width of the electrode group is 50 mm or less, the temperature rise during discharge is substantially the same as in the above-described embodiment. However, when the width exceeds 50 mm, the temperature rise becomes remarkable. Further, in the case of the battery according to the present invention, plate-shaped current collecting terminals are provided on both sides of the electrode plate group, and the side wall of the battery case is located outside the terminal. The thickness of the collecting terminal is 0.5 ~
Requires 2 mm. When the width of the electrode group is less than 25 mm, the volume ratio of the current collecting terminals in the power generator increases, and the volume efficiency decreases. For the above reasons, it is desirable that the width of the wound electrode plate group according to the present invention be within the range of 25 to 50 mm.

(Charge / discharge cycle test)
It was subjected to a charge / discharge cycle test at 5 ° C. Current 1It
After charging for 1 hour in (A), charge and discharge were repeatedly performed at the same current under the condition of a final voltage of 1.0 V.

The batteries of Examples 1, 2 and 3 maintained a capacity of 78 to 80% even after 500 cycles. In the case of Example Battery 4, the capacity was reduced to 65% after 500 cycles. On the other hand, in Comparative Example 1, the capacity was exhausted before reaching 500 cycles. Comparative Example 2 showed 82 after 500 cycles.
% Capacity was maintained.

In the case of Comparative Example 1, the battery after the test showed a phenomenon of electrolyte drying. It is considered that the impedance increased due to the drying up and the capacity decreased. The cycle performance of Example 4 was changed from Examples 1 to 3 and Comparative Example 2.
Is slightly inferior to. In the battery of Example 4, an increase in impedance was observed as compared with the batteries of the other examples.
In the case of the fourth embodiment, a nonwoven fabric filled with an electrolyte is disposed on the surface of the electrode plate group. However, since the interval between the electrode plate groups is increased, there is a possibility that the evaporation of water may occur.

As described above, in the configuration of the electrode group of the battery according to the present invention, a sheet containing an electrolyte is brought into contact with at least a part of the outer peripheral surface of the electrode group. This is extremely effective as a measure for preventing the electrode group from drying out.

As described above, the interval between the electrode groups is 8
When it is increased to mm, the cycle performance is reduced.
Further, since the filling volume of the active material is reduced, the volume efficiency is reduced. For this reason, the interval between the electrode groups is 8 m.
It is desirable that the thickness be less than m, and more preferably 5 mm or less.

When the wound end face is elliptical or flat,
As described above, the plurality of electrode plates are arranged such that the long axes of the wound end surfaces are parallel. At this time, one between the electrode groups
It is desirable to provide an interval of not less than 8 mm and less than 8 mm, and more preferably, an interval of 1 to 5 mm. If there is no interval, heat may be trapped in the electrode plate group. There is a possibility that heat may be trapped in the electrode plate group and the battery performance such as cycle life may be adversely affected. When the distance between the electrode groups is 8 mm or more, the charge / discharge cycle characteristics are adversely affected as described above, and there is a disadvantage that the volume efficiency is reduced.

[0047]

As described in detail above, according to the first aspect of the present invention, it is possible to provide a battery having a small temperature rise even when high-rate discharge is performed and having excellent charge-discharge cycle performance.
According to claims 2 and 3 of the present invention, the effect of claim 1 can be further enhanced.

[0048]

[Brief description of the drawings]

FIG. 1 is a perspective view of a wound electrode group according to the present invention.

FIG. 2 is a view showing a power generator provided with a plurality of circularly wound electrode plates according to the present invention.

FIG. 3 is a view showing a power generator including a plurality of elliptical or flat wound electrode plates according to the present invention.

FIG. 4 is a view showing a power generator in which an electrode group is wrapped in a sheet containing an electrolyte;

FIG. 5 is a diagram showing a structure of a monoblock battery having a plurality of cells according to the present invention.

FIG. 6 is a view showing a conventional laminated electrode group.

FIG. 7 is a graph showing the temperature rise of a battery when discharged.

FIG. 8 is a graph showing the charge / discharge cycle performance of the battery of the present invention and a comparative battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Negative electrode current collecting terminal 2 Positive electrode current collecting terminal 5 Sheet impregnated with electrolyte 10 Rolled electrode group

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H028 AA06 AA08 BB05 CC08 HH05 HH06

Claims (3)

[Claims] 1. A plurality of wound electrode groups each comprising a strip-shaped positive electrode plate, a separator and a negative electrode plate, wherein the plurality of wound electrode groups are formed by a pair of a positive electrode current collector terminal and a negative electrode current collector. A battery sandwiched between terminals, wherein a core of an electrode plate is exposed on one side of the positive electrode plate and the negative electrode plate, and the exposed core of the positive electrode plate and the core of the negative electrode plate are exposed. Projecting from opposed winding end faces of the electrode plate group, and joining the projected core and the positive electrode current collecting terminal and the negative electrode current collecting terminal at their engaging portions, A battery in which a sheet holding an electrolyte is brought into contact with the outer peripheral surface of each of the rotating electrode plates. 2. The method according to claim 1, wherein the distance between the plurality of electrode groups is 8 mm.
The battery according to claim 1, wherein an interval of less than is provided. 3. The wound electrode group having a diameter or a short diameter of 12
The battery according to claim 1, wherein the battery has a diameter of 25 to 50 mm.