HK1025185B - Battery - Google Patents

Description

Battery with a battery cell

Technical Field

The present invention relates to a battery having an electrode group welded with a collector plate to improve high-efficiency discharge characteristics.

Background

Fig. 1 shows an exploded view of the electrode connection collector plate of the counter electrode group. The battery equipped with the electrode assembly 4 and the current collector 6 shown in the figure is suitable for improving the high-efficiency discharge characteristic and discharging with a large current. In the structure in which the lead plate 6A is partially welded as in the electrode plate shown in the expanded view of fig. 2, current is collected in the lead plate 6A and a current flows, so that it is difficult to improve the large-current discharge characteristic. The electrode assembly 4 shown in fig. 1 has a plurality of pairs of collector plates 6 connected to the upper edge of the electrode assembly, thereby equalizing the current distribution in the electrodes.

Fig. 3 is a sectional view of a battery in which a current collecting plate 6 is connected to the upper surface of the electrode group 4. The battery of this structure is such that the collector plate 6 is connected to the lower surface of one of the plates in a multi-part manner. In order to connect the one electrode plate to the current collector plate 6, the one electrode plate protrudes upward from the other electrode plate. The projecting portion of the electrode plate is a strip-like connection portion 7 which projects a substrate 9 in a strip-like manner.

As shown in fig. 4, the collector plate 6 is pressed against the electrode group 4 having this structure, and the collector plate 6 is resistance-welded to the upper surface. The electrode plate connected to the current collector plate 6 is not filled with an active material or the active material is removed, a band-shaped connection portion 7 protruding from a part of the substrate 9 in a band shape is provided, and the band-shaped connection portion 7 is connected to the current collector plate 6. The substrate 9 to which the current collector plate 6 is connected is a porous metal body such as foamed nickel so as to contact the active material over a larger area.

It is very difficult to connect the substrate of the porous metal body and the current collecting plate in an ideal state. The following publications disclose the realization of this technology.

Japanese patent publication No. 61-61230

Japanese laid-open patent publication No. 62-139251

(iii) Japanese patent laid-open publication No. 63-4562

Japanese unexamined patent publication No. 2-220365

First and second publications describe a structure in which an active material unfilled portion is crushed into a foamed nickel or the like as a base sheet to form a high-density strip-shaped connection portion, and the strip-shaped connection portion is connected to a current collecting plate. The battery disclosed in the first publication is provided with a high-density strip-shaped connecting portion for crushing the substrate in the lateral direction. ② the battery of the publication is provided with high-density ribbon-shaped connecting portions crushing the substrate in the longitudinal direction.

The third and fourth publications describe a structure in which a metal thin plate is welded to a strip-shaped connection portion of a substrate that is not filled with an active material, and the connection portion is connected to a current collecting plate.

Even the technique described in the above publication cannot connect the strap-like connection portion of the substrate to the current collecting plate in an ideal state. In particular, in order to reliably connect a plurality of portions of the band-shaped connection portion to the collector plate, it is necessary to press the band-shaped connection portion with a considerable pressure and to electrically resistance-weld the collector plate. When the pressing force of the current collector plate is weakened, the resistance between the current collector plate and the connection portion of the band-shaped connection portion increases, and normal electric welding cannot be performed. When the collector plate and the band-shaped connection portion are electrically welded by resistance in a state where the resistance is large, the welding machine passes a constant current, and thus the voltage applied between the collector plate and the band-shaped connection portion increases. When a high voltage is applied, the resistance between the collector plate and the ribbon coupling portion drops rapidly as in the case of arc discharge, and a large power is applied to the welded portion to cause the contact portion to be instantly dissolved and scattered, thereby presenting a state called "pop-off". When this state is reached, the current collecting plate and the ribbon coupling portion cannot be normally connected.

To avoid this disadvantage, when the current collecting plate is strongly press-welded to the ribbon-shaped connecting portion, as shown in fig. 5 and 6, the ribbon-shaped connecting portion 7 bends, causing an internal short circuit. This is because the bent portion punctures the separator 3 and contacts the other electrode. In particular, the discontinuous portion of the band-shaped joint 7 is weakened and has a property of being easily bent at the filling boundary. This disadvantage is that the laminated metal sheet 10 is welded to the strip-shaped connecting portion 7, or that the crushed substrate cannot be released even at high density. The substrate 9 is a discontinuous boundary. In particular, in the non-sintered electrode in which the active material is filled in the substrate 9 of the porous metal body, the substrate 9 is weak in strength and is easily broken when strongly pressed.

Then, in the battery having the band-shaped connection portion, a plurality of current collecting plates are welded, and all the connection portions are not welded by pressing with the same pressure. The plurality of through holes are provided, and the protrusions are provided below the periphery of the through holes, and the protrusions are brought into contact with the electrically welded current collecting plate of the ribbon coupling portion. Therefore, the belt-shaped coupling portion is likely to be strongly pressed and bent, which is also a cause of easy internal short-circuiting, similarly to the case where the lower surface of the charging plate is a flat surface.

Disclosure of Invention

The present invention has been made to solve the above disadvantages. The main object of the present invention is to provide a battery in which a current collecting plate and a band-shaped connecting portion can be connected in a more ideal state.

The battery of the present invention comprises an electrode group 4 in which a 1 st electrode plate 1 and a 2 nd electrode plate 2 composed of a positive electrode plate and a negative electrode plate are laminated via a separator 3, a case 5 for housing the electrode group 4, and a collector plate 6 electrically connecting the 1 st electrode plate 1 and the 1 st electrode plate 1 to one side terminal 12. In the battery of the present invention, the 1 st electrode plate 1 is preferably a positive electrode plate, and the 2 nd electrode plate 2 is preferably a negative electrode plate. However, it goes without saying that the 1 st electrode plate may be a negative electrode plate and the 2 nd electrode plate may be a positive electrode plate.

The 1 st electrode plate 1 is a non-sintered electrode in which an active material is filled on a substrate 9 of a porous metal body. The substrate 9 of the 1 st electrode plate 1 has a strip-like connection portion 7 and an active material filling portion 8 which expose the substrate 9. The band-shaped connecting portion 7 connects a plurality of portions of the current collector plate 6 by welding.

In the battery of the present invention 1, the 2 nd electrode plate 2 is protruded from the filling boundary between the band-shaped connecting portion 7 and the active material filling portion 8, and the filling boundary of the 1 st electrode plate 1 is opposed to the 2 nd electrode plate 2 via the separator 3. The structure in which the filling boundary of the 1 st plate 1 faces the 2 nd plate 2, in other words, the structure in which the filling boundary of the 1 st plate 1 is sandwiched between the 2 nd plates 2 is maintained. The filling boundary of the 1 st electrode plate 1 held between the 2 nd electrode plates 2 is hard to bend even if pressed against the current collecting plate 6. Therefore, the current collecting plate 6 is pressed against the strong band-shaped connecting portion 7, and the internal short circuit caused by the rupture of the separator 3 due to the bending of the filling boundary can be reliably prevented at the time of welding.

The battery of the present invention 2 has a structure in which the spirally wound electrode group 4 composed of the 1 st electrode plate 1 and the 2 nd electrode plate 2 is laminated by the separator 3 as a spiral electrode.

The battery of the invention 3 is characterized in that the substrate 9 of the 1 st polar plate 1 is made of metal foaming nickel and a nickel fiber porous body.

In the battery of the present invention 4, a metal thin plate 10 is laminated on a base plate 9 of a 1 st electrode plate 1 as a strip-shaped connecting portion 7 to the base plate 9, and the metal thin plate 10 is welded to a current collecting plate 6.

The battery of the present invention 5 is formed by pressing the base sheet 9 of the first electrode plate 1 into a high-density compressed base sheet 9 at the ribbon-shaped connecting portion 7.

In the battery of the present invention 6, a protective tape 13 is applied to one or both surfaces of the strip-shaped connecting portion 7, and the strip-shaped connecting portion 7, which is prevented from being deformed by the protective tape 13, breaks the separator 3 to prevent an internal short circuit.

Drawings

Fig. 1 is an exploded perspective view showing a state in which a current collecting plate is connected to a plate of an electrode group incorporated in a battery.

Fig. 2 is a plan view showing an example of a plate to which a lead plate is welded.

Fig. 3 is a partial sectional front view of a conventional battery.

Fig. 4 is an enlarged cross-sectional view showing a state where the collector plate is pressed against the electrode group.

Fig. 5 is an enlarged cross-sectional view showing an example of an internal short circuit caused by bending of the ribbon-shaped coupling portion and the filling boundary.

Fig. 6 is an enlarged cross-sectional view showing another example of an internal short circuit caused by bending of the ribbon-shaped coupling portion and the filling boundary.

Fig. 7 is a partial cross-sectional front view of a battery according to an embodiment of the invention.

Fig. 8 is an expanded view of the 1 st plate of the battery shown in fig. 7.

Fig. 9 is an enlarged cross-sectional view of the stacked structure of the electrode groups of the battery shown in fig. 7.

Fig. 10 is a cross-sectional view showing another example of the belt-like connecting portion of the 1 st electrode plate.

Fig. 11 is a cross-sectional view showing another example of the belt-like connecting portion of the 1 st electrode plate.

Fig. 12 is a development view of the current collecting plate of the battery shown in fig. 7.

Fig. 13 is an enlarged cross-sectional view of the collector plate shown in fig. 12.

Fig. 14 is a plan view showing an example of the method for manufacturing the 1 st electrode plate.

Fig. 15 is a cross-sectional view showing the positional relationship between the 1 st electrode plate and the 2 nd electrode plate of the battery of example 1 of the present invention.

Fig. 16 is a cross-sectional view showing the positional relationship between the 1 st electrode plate and the 2 nd electrode plate of the battery of example 2 of the present invention.

Fig. 17 is a cross-sectional view showing the positional relationship between the 1 st electrode plate and the 2 nd electrode plate of the battery of example 3 of the present invention.

Fig. 18 is a cross-sectional view showing the positional relationship between the 1 st electrode plate and the 2 nd electrode plate of the battery of example 4 of the present invention.

Fig. 19 is a plan view showing the 1 st electrode plate of the battery according to example 5 of the present invention.

Fig. 20 is a cross-sectional view showing the positional relationship between the 1 st electrode plate and the 2 nd electrode plate of the battery of comparative example 1.

Fig. 21 is a cross-sectional view showing the positional relationship between the 1 st electrode plate and the 2 nd electrode plate of the battery of comparative example 2.

The following description of the symbols

1-the 1 st polar plate; 2-the 2 nd polar plate; 3-a separator; 4-electrode group; 5-a housing; 6-a collector plate; 6A-lead plate; 6B-center hole; 6C-groove; 6D-through holes; 6E-protrusions; 7-a ribbon linkage; 8-an active material filling part; 9-a substrate; 10-a metal sheet; 11-sealing plate; 12-a terminal; 13-protective band.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the following examples are given by way of illustration of a battery embodying the technical idea of the present invention, and the present invention is not limited to the following batteries.

In addition, in the present specification, the components mentioned in the specification are denoted by reference numerals for easy understanding of the components of the embodiments corresponding to the technology of the present invention. However, the components shown in the present invention are by no means specified in

The components of the examples.

The battery shown in fig. 7 includes a cylindrical case 5 hermetically sealed with a sealing plate 11, an electrode group 4 inserted into the case 5, and a current collecting plate 6 connecting the electrode group 4 to a terminal 12 through the sealing plate 11. In the battery shown in the figure, the case 5 is cylindrical, and the case 5 of the battery not specified in the present invention is cylindrical. Although not shown, the housing may have a quadrangular cylindrical shape or an elliptical cylindrical shape, for example.

The shell 5 is made of iron and the surface is plated with nickel. The material of the case 5 is selected from the most suitable metals in consideration of the kind and characteristics of the battery. The case 5 is also made of, for example, stainless steel, aluminum, or an aluminum alloy, and the metal case 5 has an opening at the upper end hermetically sealed by a sealing plate 11. The sealing plate is configured by caulking the case 5 with the sealing plate 11, or by hermetically fixing the boundary between the case 5 and the sealing plate 11 by a method such as laser welding. The sealing plate 11 fixes a terminal 12 at one end of the battery. The terminal 12 is fixed to the housing 5 in an insulated manner.

The cell of the present invention is a cell equipped with a non-sintered electrode, such as a nickel-metal hydride cell. However, the present invention does not specify the battery as a nickel-metal hydride battery. For example, a nickel cadmium battery, a lithium ion battery, or the like may be used. Hereinafter, a nickel-metal hydride battery will be described in detail as a preferred embodiment.

The electrode group 4 is formed by rewinding the 1 st electrode plate 1 and the 2 nd electrode plate 2 through the separator 3. The illustrated battery has the 1 st electrode plate 1 connected to the current collector plate 6 as a positive electrode plate, and the 2 nd electrode plate 2 as a negative electrode plate. However, in the present invention, the 1 st electrode plate may be a negative electrode plate and the 2 nd electrode plate may be a positive electrode plate. The 1 st electrode plate 1 and the 2 nd electrode plate 2 laminated to each other with the separator 3 are formed as a spirally wound electrode group 4. The spiral electrode group 4 is inserted into a cylindrical case 5. The spiral electrode group is deformed into an elliptical shape by pressing from both sides and can be inserted into the elliptical housing 5. The electrode group inserted into the horn-shaped case is formed by laminating a plurality of 1 st and 2 nd electrode plates cut into a plate shape with separators.

The separator 3 uses a polyethylene nonwoven fabric. However, a microporous film made of a synthetic resin such as polyethylene may be used as the separator 3. The separator 3 may insulate the 2 nd plate 2 of the 1 st plate 1 stacked on both sides, and may use a thin plate material that may be impregnated with the electrolyte entirely.

The 1 st electrode plate 1 is a non-sintered electrode in which an active material is filled in a substrate of a porous metal body. The porous metal substrate is a porous metal body such as a porous foamed nickel body or a porous nickel fiber body. The 1 st plate 1 fills these substrates with an active material.

As shown in the developed view of fig. 8, the substrate of the first electrode plate 1 has a strip-shaped connecting portion 7 provided on the upper portion of the substrate 9, and the other portion is an active material filling portion 8 filled with an active material. The ribbon-shaped connecting portion 7 is not filled with an active material, or the substrate 9 from which the filled active material is removed is exposed. The strip-shaped connecting portion 7 is electrically connected reliably by the current collecting plate, and a thin metal plate 10 such as a nickel lath plate is fixed thereto as shown in the sectional view of fig. 9. The metal thin plate 10 is fixed to the belt-like coupling portion 7 by welding or electrically connecting with a conductive adhesive.

The thin metal plate 10 is not necessarily fixed to the belt-like coupling portion 7. For example, as shown in fig. 10 and 11, the exposed substrate 9 may be pressed by the strap connecting portion 7 to connect the high-density compressive collector plate. The tape-like connecting portion 7 shown in fig. 10 presses the exposed substrate 9 in the longitudinal direction at high density. The exposed substrate 9 is compressed at a high density by lightly pressing the tape-like connecting portions 7 in the lateral direction in fig. 11. The base sheet 9 of the high-density compressed metal porous body is directly connected to the current collecting plate without using a metal thin plate.

As shown in the cross-sectional view of fig. 9, the belt-shaped connecting portion 7 has an upper end edge protruding from the 2 nd electrode plate 2, and the filling boundary of the active material filling portion 8 is located below the upper end of the 2 nd electrode plate 2, in other words, the upper end of the 2 nd electrode plate 2 protrudes beyond the filling boundary, and the filling boundary is disposed at a position facing the 2 nd electrode plate 2 via the separator 3. The overlapping width of the filling boundary and the upper end edge of the 2 nd plate 2 is set to about 0.8mm, for example. When the width of the lap is wide, the width of the active material-filled portion 8 of the 1 st electrode plate 1 is narrow, and the capacity of the battery becomes small, although both sides of the band-shaped connecting portion 7 can be sufficiently held by the 2 nd electrode plate 2. On the other hand, when the overlapping width is small, the band-shaped connecting portion 7 cannot be sufficiently held by the 2 nd electrode plate 2. Therefore, the lapping width is preferably set to an optimum value in the range of 0.5 to 1mm in consideration of the effect of holding the 2 nd plate 2.

The first electrode plate 1 in fig. 9 has protective tapes 13 applied to both surfaces of the strip-shaped connecting portion 7. The protective strip 13 extends the lower edge until further below the filling boundary. The purpose of press-welding the current collecting plate to the strip-shaped connecting portion 7 is to prevent the filling boundary from bending and bursting the separator 3. Here, the battery with the holding strap 13 attached thereto has a feature of preventing an internal short circuit and surely connecting the current collecting plate to the band connecting portion 7. In particular, as shown in the figure, the structure in which the protective tapes are applied to both surfaces of the tape-shaped connecting portion has a feature that the internal short circuit can be prevented most effectively. The protective tape may be applied to one surface of the strip-like connecting portion. A protective tape is applied to one surface of the belt-like connecting portion, and is applied to the opposite surface of the welded metal sheet or to the surface of the welded metal sheet. However, the battery of the present invention may be configured such that the band-shaped connecting portion is connected to the current collecting plate without using a protective tape.

As shown in fig. 7 and 12, the current collector plate 6 is formed by cutting a metal plate into a disc shape smaller than the inner shape of the case 5, and the lead plate 6A is protruded. The current collecting plate 6 is provided with grooves 6C on both sides of the center hole 6B in order to reduce the reactive current during resistance welding. A plurality of through holes 6D are formed. As shown in the enlarged cross-sectional view of fig. 13, the through-hole 6D has a protrusion 6E protruding downward at its peripheral edge, and the protrusion 6E is connected to the belt-like connection portion 7 of the 1 st electrode plate 1. The lead plate 6A of the collector 6 is connected to the terminal 12 of the opening of the insulating fixing case 5.

Example 1

An electrode group inserted into a nickel-metal hydride battery case was produced in the following procedure.

Positive plate for making No. 1 polar plate

(1) The porous metal body was produced by the following procedure.

A sponge-like organic porous body of polyurethane foam having open cells is subjected to an electrical conduction treatment, and then immersed in a plating solution in an electrolytic bath to carry out plating. The plated organic porous body is fired at a temperature of 750 ℃ for a predetermined time to remove the resin component of the organic porous body, and then sintered in a reducing atmosphere to produce a metal porous body. The porous metal body produced by this step has a mesh opening of about 600g/m²Porosity 95% foamed nickel having a thickness of about 2.0 mm.

(2) The following raw materials were mixed to prepare an active material slurry for a positive electrode.

Nickel hydroxide powder: 90 parts by weight

(containing 2.5 wt% of zinc and 1 wt% of cobalt as coprecipitated components).

Cobalt powder: 10 parts by weight

Zinc oxide powder: 3 part by weight

Hydroxypropyl cellulose 0.2 wt% aqueous solution: 50 parts by weight

(3) The prepared positive electrode active material slurry was filled in the voids of the porous metal body. Filling amount

The density of the active material after calendering was adjusted to about 2.9 g/ml.

Then, the substrate was dried, rolled to a thickness of about 0.70mm, cut into a rectangular shape, and the active material was removed by ultrasonic peeling from one end in the longitudinal direction, whereby the strip-shaped connecting portion 7 where the substrate 9 was exposed was used as the first electrode plate 1 as shown in fig. 8.

The 1 st plate 1 can also be used to manufacture an active material in the following process. As shown in fig. 14, the porous metal body is rolled in parallel with a predetermined width before being filled with the active material. The rolled width is about 5mm which is 2 times the width of the ribbon-shaped coupling portion 7, and the thickness after pressing is about 0.5 mm. The substrate 9 of the thus rolled porous metal body is filled with and rolled with the above active material slurry. Then, the first plate 1 in a rectangular shape is cut at the position indicated by the arrow in fig. 14 to produce a first plate 1.

Then, compressed air is sprayed along the thin-rolled portion of the ribbon coupling portion 7, or the active material is removed with a brush or the like to expose the substrate 9.

(4) The metal thin plate 10 is connected to the exposed strip-like connecting portion 7 of the substrate 9 by resistance welding. The metal thin plate 10 uses nickel laths having a thickness of 0.1mm and a width of 3 mm.

Negative plate for producing the 2 nd polar plate 2

(1) Preparation and pulverization of hydrogenated alloys

A misch metal (a mixture of rare earth elements such as La, Ce, Nd, and Pr) and nickel, cobalt, aluminum, and manganese were mixed in a ratio of 1.0: 3.4: 0.8: 0.2: 0.6, and the mixture was placed in a crucible, melted in a high-frequency melting furnace, and cooled to prepare a hydrogenated alloy electrode having the following composition formula.

Mm.1.0 Ni3.4 Co0.8 Al0.2 Mn0.6

Then, the obtained hydrogenated alloy ingot was roughly pulverized and then pulverized in an inert gas to obtain particles having an average particle diameter of 60 μm.

(2) Preparation of hydrogenated alloy slurry

To the pulverized hydrogenated alloy powder, polyethylene oxide powder as a binder was added, and then ion-exchanged water was added to mix into slurry. The amount of the binder polyethylene oxide powder added was 1.0 wt% based on the hydrogenated alloy.

(3) The slurry is applied to both sides of a substrate of punched metal. The coating amount was adjusted so that the density of the active material after calendering was 5 g/ml. Then, after drying and rolling, the resultant was cut into a predetermined size to obtain a negative electrode plate of the 2 nd electrode plate. The paste is applied to the lower edge of the punched metal, leaving a strip-shaped connection portion at the lower edge. Alternatively, the tape-shaped connecting portion may be provided by applying a paste to all surfaces of the punching metal, drying the paste, and then removing the active material on the lower edge.

The 1 st and 2 nd electrode plates 1 and 2 produced in the above steps are rewound into a spiral electrode group 4 through a separator 3 made of polyethylene nonwoven fabric. The 1 st plate 1 and the 2 nd plate 2 are rewound as shown in the positional relationship of fig. 15.

Disc-shaped current collecting plates are electrically resistance welded to the upper and lower sides of the obtained electrode group. 100 electrode groups were prepared in the above procedure, and the number of internal short circuits contacting the 1 st and 2 nd electrode plates was counted, and only 1 electrode group was internally short-circuited, and the remaining 99 electrode groups were free of internal short circuits. The short-circuited portion is a filling boundary between the strip-shaped connecting portion and the active material filling portion, and the foamed nickel skeleton of the 1 st electrode plate protrudes at the short-circuited portion and passes through the separator to contact the 2 nd electrode plate.

Example 2

100 electrode groups to which current collecting plates were connected were prepared in the same manner as in example 1, except that the width of the metal thin plate 10 was narrowed as shown in fig. 16 for the 1 st plate 1 and the 2 nd plate 2, and a gap of 0.5mm was formed between the metal thin plate 10 and the filling boundary. When the number of internal short circuits of 100 electrode groups formed was counted, only 1 electrode group was short-circuited, and the remaining 99 electrode groups were free of internal short circuits. The short-circuited portion was the same as in example 1.

Example 3

100 electrode groups to which current collecting plates were connected were prepared in the same manner as in example 1, except that the 1 st electrode plate 1 and the 2 nd electrode plate 2 were covered with the protective tape 13 in the tape-shaped connecting portion 7 as shown in fig. 17. The protective tape 13 was a polypropylene hot-melt adhesive tape having a thickness of 200 μm. When the number of internal short circuits of 100 electrode groups prepared was counted, the electrode group having no internal short circuit proved to have an effect of suppressing the internal short circuit due to the protrusion of the substrate skeleton at the filling boundary.

Example 4

As shown in fig. 18, 100 electrode groups to which current collecting plates were connected were prepared in the same manner as in example 1, except that the sheet metal was not fixed to the strip-shaped connecting portion 7 in which the electrode sheet 9 of the 1 st electrode sheet 1 was pressed in the compression longitudinal direction 1/3 in the strip-shaped connecting portion 7 and the base sheet 9 was exposed. The figure shows the substrate 9 before compression by means of a dashed line. When the number of internal short circuits in 100 electrode groups produced in this step was counted, only 1 electrode group was internally short-circuited, and the remaining 99 electrode groups were not internally short-circuited. The short circuit was the same as in example 1.

Example 5

As shown in fig. 19, 100 electrode groups to which the current collecting plates were connected were prepared in the same manner as in example 1, except that punched metal, which was a perforated metal sheet, was resistance-welded to the strip-shaped connecting portions 7 exposed on the base sheet of the 1 st electrode plate 1. When the number of internal short circuits in 100 electrode groups produced in this step was counted, there were no electrode groups with internal short circuits. In this embodiment, punching metal as a punched metal sheet is welded to the strip-shaped connecting portion, and the punched metal sheet may be an expanded alloy instead of the punching metal.

Comparative example 1

As shown in FIG. 20, the upper end of the 2 nd plate 2 is 0.2mm higher than the filling boundary of the substrate 9 of the 1 st plate 1. In other words, 100 electrode groups to which the collector plates were connected were prepared in the same manner as in example 1, except that the upper end of the 2 nd electrode plate 2 was 0.2mm lower than the filling boundary. When the number of internal short circuits of the 100 electrode groups prepared was counted, the number of internal short-circuited electrode groups was 25. As shown in fig. 5 or 6, the short circuit portion mostly has the strip-like connecting portion 7 in contact with the 2 nd electrode plate 2.

Comparative example 2

As shown in fig. 2, 100 electrode groups to which the collector plates were connected were prepared in the same manner as in example 1, except that the base sheet 9 of the 1 st electrode plate 1 was pressed so as to compress the ribbon-shaped connecting portion 7 in the longitudinal direction 1/3, and the upper end of the 2 nd electrode plate 2 was 0.2mm lower than the filling boundary of the 1 st electrode plate 1 in the same manner. When the number of internal short circuits in the 100 electrode groups prepared was counted, the number of internal short circuit electrode groups was 31. The state of the internal short circuit was the same as in comparative example 1.

The present invention provides a battery which can be manufactured in a nearly ideal state and has a high efficiency and good discharge characteristics. In particular, the current collector plate is strongly pressed against the band-shaped connecting portion of the electrode group, so that the current collector plate and the band-shaped connecting portion can be welded reliably, and internal short circuit of the 1 st electrode plate and the 2 nd electrode plate can be effectively reduced. This is because the battery of the present invention is such that the 2 nd electrode plate disposed to the 1 st electrode plate passing through the separator is protruded from the filling boundary between the ribbon-shaped connecting portion and the active material filling portion. In the battery in which the 2 nd electrode plate is protruded from the filling boundary of the 1 st electrode plate, the filling boundary of the 1 st electrode plate is supported by the 2 nd electrode plate, and when the strip-shaped connecting part of the 1 st electrode plate is press-welded, the internal short circuit caused by the bending of the filling boundary is effectively prevented.

In the battery of the present invention 4, the 2 nd electrode plate is protruded from the filling boundary of the 1 st electrode plate, and the metal sheet having the hole such as a metal sheet or a punching metal is attached to the strip-shaped connecting portion of the first electrode plate. The battery of this structure has an excellent characteristic of most effectively preventing an internal short circuit. This is because the metal sheet can effectively prevent the substrate from being bent when the current collecting plate is pressed and connected while the strip-shaped connecting portion and the metal sheet are spirally wound together when the 1 st electrode plate and the 2 nd electrode plate are spirally wound together through the separator. Further, since the metal sheet is made of a metal having a hole such as punched metal, the metal sheet has sufficient flexibility, and even if the electrode group is spirally rewound, the metal sheet is not broken, and internal short-circuiting is extremely effectively prevented.

Claims (7)

1. A battery includes an electrode group (4) in which a 1 st electrode plate (1) and a 2 nd electrode plate (2) composed of a positive electrode plate and a negative electrode plate are stacked by a separator (3), and a case (5) housing the electrode group (4), and a 1 st electrode plate (1) is electrically connected, and a collector plate (6) on one side terminal (12) is electrically connected to the 1 st electrode plate (1), characterized in that:

the 1 st electrode plate (1) is a non-sintered electrode in which a substrate (9) of a porous metal body is filled with an active material, and has a strip-shaped connecting part (7) and an active material filling part (8) that expose the substrate (9), the strip-shaped connecting part (7) being electrically connected to a plurality of portions of a current collecting plate (6) by welding;

the 2 nd electrode plate (2) protrudes beyond the filling boundary between the strip-shaped connecting portion (7) and the active material filling portion (8), and the filling boundary faces the 2 nd electrode plate (2) through the separator (3).

2. The battery according to claim 1, wherein the electrode group (4) is a spiral-shaped electrode that is wound back in a spiral shape in which a 1 st plate (1) and a 2 nd plate (2) are laminated through the separator (3).

3. The battery according to claim 1, wherein the substrate (9) of the metal porous body is a metal foamed nickel porous body or a nickel fiber porous body.

4. The battery according to claim 1, wherein the porous metal base sheet (9) is formed by attaching a thin metal sheet (10) or an open-pore thin metal sheet (10) to the ribbon-shaped connecting portion (7) of the porous metal base sheet (9), and the thin metal sheet (10) or the open-pore thin metal sheet (10) is welded to the current collecting plate (6).

5. The battery according to claim 1, wherein the substrate (9) of the porous metal body is a substrate (9) of a porous metal body which is pressed at the band-shaped connecting portion (7) to be a high-density compressed substrate.

6. The battery according to claim 1, wherein the protective tape (13) is applied to one or both surfaces of the ribbon-like connecting portion (7).

7. The battery according to claim 2, wherein the electrode group (4) is rolled back with the thin metal plate (10) welded to the band-shaped connecting portion (7) as an inner side.