KR100536227B1 - Secondary battery and plate using the same - Google Patents

Abstract

According to an embodiment of the present invention, a secondary battery includes: an electrode group formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween; A can for accommodating the electrode group; A cap assembly assembled to the can to seal the cap assembly and electrically connected to the electrode group; And a current collector plate selectively contacting the electrode group, wherein at least one of the pole plates is provided with a non-contact portion contacting the current collector plate, and the current collector plate connected to the non-contact portion includes a recess and an iron portion. Unevenness is formed.

Description

Secondary Battery and Electrode Assembly Used Thereof {SECONDARY BATTERY AND PLATE USING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a secondary battery, and more particularly, to a secondary battery having improved weldability and improved current collection efficiency, and an electrode assembly used therefor.

The secondary battery is a low-capacity secondary battery (hereinafter, referred to as a 'small battery') in which one or several battery cells are packaged and used in a pack form, and a battery pack unit in which dozens of battery cells are used. It can be classified into a large capacity secondary battery (hereinafter, referred to as a 'large battery') for motor driving.

Dual batteries are mainly used as power sources for small electronic devices such as cellular phones, notebook computers and camcorders, and large batteries are used as power sources for driving motors as in hybrid vehicles.

When a small battery is composed of one cell, it is mainly formed in a cylindrical or rectangular shape, and is wound around a vortex by separating a separator on the strip between the cathode and the negative electrode, and forming an electrode assembly (or jelly roll). ) And inserted into a cylindrical can to construct a cell.

The positive and negative plates each have a conductive tab attached to each of the lead terminals, that is, currents generated from the positive and negative plates when the battery is in operation, and the conductive tabs are attached to the electrode assembly by welding or the like. The current generated in the positive and negative plates respectively is induced to the positive and negative terminals.

When the structure of a small battery configured as described above is applied to a large battery as it is, it does not satisfy the operation characteristics of the large battery in terms of capacity and output. Therefore, a multi-tap structure in which a plurality of tabs are attached between electrode assemblies is used. It is proposed in patent 2003-7346. The secondary battery has a structure in which a plurality of tabs are formed in one direction of the electrode assembly, and the tabs are coupled with an inner terminal connecting the outer terminal.

However, such a multi-tap structure has a problem that a lot of work maneuver is required. In particular, since the unit area of the tab is small, there is a limit that does not satisfy the desired output characteristics in a large battery.

Another example of a tab is a plate collector. Since the current collector plate has a larger unit area than the above-described multi-tap, the current collector efficiency can be increased more than before, and the energy density per unit volume can be increased by reducing the space occupied by the tab.

By the way, in the case of the plate-shaped current collector plate is fixed between the pole plate and the current collector plate by welding, there is a disadvantage that the fixing thereof is not solid. Moreover, in the case of a large battery, the electrode plate is wound up by winding the electrode plate about 5 meters in length, and the part in which the plain part is formed becomes uneven. Accordingly, the contact between the uncoated portion and the current collector plate is only partially, so that poor welding occurs frequently, and further, the current collector efficiency is lowered, thereby causing a problem of degrading the performance of the battery.

Accordingly, the present invention is to provide a secondary battery of the present invention that has been solved to solve the above-described problems, to improve the weldability of the tab to secure the fixing between the pole plate and the current collector plate.

Another object of the present invention is to provide a secondary battery of the present invention, which is improved to increase the current collecting efficiency by increasing the contact area between the electrode plate and the plain portion.

Still another object of the present invention is to provide a secondary battery that can be applied to an industrial field requiring a large battery, such as a hybrid electric vehicle by improving the instantaneous output.

In order to achieve the above object, the secondary battery of the present invention,

An electrode group formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween;

A can for accommodating the electrode group;

A cap assembly assembled to the can to seal the cap assembly and electrically connected to the electrode group; And,

And a current collector plate selectively contacting the electrode group.

At least one of the pole plates is formed with a non-contact portion in contact with the current collector plate, the current collector plate is connected to the uncoated portion is formed with an uneven portion consisting of recesses and convex portions.

In addition, the secondary battery of the present invention,

An electrode group formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween;

A can for accommodating the electrode group;

A cap assembly assembled to the can to seal the cap assembly and electrically connected to the electrode group; And,

And a current collector plate selectively contacting the electrode group.

At least one of the pole plates is formed with a non-coating portion in contact with the current collector plate, the current collector plate is formed of at least two or more partial current collector plates in partial contact with the non-coated portion, each of the partial current collector plate with recesses and concave parts The irregularities formed may be formed.

In this case, the uncoated portion is selectively formed along the longitudinal end of the positive electrode plate or the negative electrode plate, and the current collector plate made of a plate is fixed to the uncoated portion through surface contact.

Preferably, the uncoated portion is formed on the positive electrode plate and the negative electrode plate in a direction facing each other, and the current collector plate is fixed to each of the uncoated portions to form a secondary battery.

On the other hand, the irregularities formed in the current collector plate is alternately arranged with the concave portion toward the center of the electrode group, the current collector plate and the electrode group is connected by welding across the thus formed irregularities.

At this time, the uneven portion of the uneven portion is in contact with a relatively long uncoated portion of the uncoated portion, the relatively small uncoated portion of the convex portion is in contact with each other to increase the contact area between the uncoated portion and the current collector plate than before.

In the secondary battery provided in the present embodiment, the electrode group is preferably formed in the shape of a cylindrical jelly roll so that the shape of the secondary battery is formed in a cylindrical shape, and a plurality of secondary cells of such a cell unit are connected in series to the hybrid electric vehicle ( It is preferably used for HEV: Hybrid Electric Vehicle.

In addition, the invention provided in another embodiment of the present invention is an electrode assembly for a secondary battery,

An electrode group formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween;

An uncoated portion formed on the positive electrode plate and the negative electrode plate without applying an active material along an end portion in a longitudinal direction; And,

Concave-convex and concave-convex is formed, the current collector plate is electrically connected to the uncoated region through the concave-convex.

In another form,

An electrode group formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween;

An uncoated portion formed on the positive electrode plate and the negative electrode plate without applying an active material along an end portion in a longitudinal direction; And,

At least two or more partial current collector plates are partially fixed to the non-coated portion, and each partial current collector plate includes a current collector plate having irregularities formed of recesses and convex portions.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

1 is a cross-sectional view of a rechargeable battery according to an exemplary embodiment of the present invention. Referring to this, the secondary battery of the present invention will be described.

The secondary battery of this embodiment is formed by winding a positive electrode plate 23 and a negative electrode plate 22 in a can 11 having a rectangular shape such as a cylindrical shape or a hexahedron with a separator 21 serving as an insulating material interposed therebetween. One electrode assembly 20 is inserted, and an open portion of the can 11 is sealed with the cap assembly 30 via the gasket 32. At this time, the end portions of the positive electrode plate 23 and the negative electrode plate 22 are formed so that the uncoated parts 23b and 22 protrude out of the electrode group, and the contact area is in contact with the concave and convex portions of the uneven collector plate 70 and 50. The electrode assembly 20 is formed in an expanded state.

In the present embodiment, the can 11 is made of a conductive metal material such as aluminum, aluminum alloy or nickel plated steel, and the shape thereof is formed in a cylindrical shape having a space in which the electrode assembly 20 can be inserted and seated. Preferred but not limited to this.

Next, the electrode assembly 20 includes an electrode group 25 formed by winding the separator 21 between the positive electrode plate 23 and the negative electrode plate 22 and twisting it, and the longitudinal end portion of the electrode group 25. It includes the positive and negative electrode current collector plates 70 and 50 selectively connected to the plain portions 22b and 23b formed on the top and bottom of the figure. This electrode assembly 20 of the present embodiment will be described in detail below with different drawings.

Meanwhile, FIG. 1 illustrates a case in which a jelly roll type electrode assembly 20 is positioned in the can 11, and will be described below with reference to the present invention, but the present invention is not limited thereto.

The cap assembly 30 includes a cap plate 31 having an external terminal 31a and a gasket 32 that insulates the can 11 from the cap plate 31. The cap assembly 30 has a space for buffering internal pressure, and may further include a vent plate 33 having a safety valve (not shown) configured to break at a predetermined pressure to release gas.

In addition, the gasket 32 is made of an insulating material to seal the can 11 while insulating the cap assembly 30 of the positive electrode and the can 11 of the negative electrode. This will be described later in detail below.

The cap assembly 30 configured as described above is electrically connected to the electrode assembly 20 according to the present invention through the lead wire 60.

Hereinafter, the electrode group constituting the electrode assembly 20 will be described with reference to FIG. 2. Next, the electrode assembly formed by coupling a current collector plate to the electrode group will be described.

In the present embodiment, the electrode group 25 is alternately formed with the separators 21 interposed therebetween in the state in which the uncoated portions 22b and 23b are formed along the ends in the longitudinal direction on the positive electrode plate 23 and the negative electrode plate 22. It's done by resentment.

In more detail, the positive electrode and the negative electrode active materials 23a and 22a are coated on the respective current collectors 231 and 221 to form the positive electrode plate 23 and the negative electrode plate 22, and the electrodes are wound in a jelly roll type. Group 25 is formed. At this time, the end portions of the current collector to form the uncoated portion (23b, 22b) without applying the active material, the uncoated portion (23b, 22b) is the positive electrode solid in one direction when the pole plates (23, 22) are wound The part 23b is arrange | positioned so that it may come out of an electrode group, and it arrange | positions so that the negative electrode uncoated part 22b may come out in the direction which opposes the said positive electrode uncoated part 23b.

In the state in which the electrode group 25 is configured as described above, the positive electrode current collector plate 70 is placed on the electrode group 25 so as to be in contact with the positive electrode non-coating portion 23b, and the negative electrode current collector plate 50 is disposed below the negative electrode solid material. In the state which contacted the part 22b, the electrode assembly 20 is completed by welding and fixing these to the electrode group 25. As shown in FIG.

At this time, in order to enlarge the contact area between the plain portions 23b and 22b arranged irregularly and convexly, and the current collector plates 50 and 50, the present embodiment forms irregularities in the current collector plate 3 so as to form this unevenness. It consists of a structure which arrange | positions the said plain part between.

This will be described in detail with reference to FIGS. 3 and 4. 5 and 6, another embodiment of the collector plate structure partially disposed will be described.

 First, referring to FIGS. 3 and 4, in the positive electrode current collector plate 70 of the present embodiment, protrusions and protrusions 73 are formed to form recesses 73b and convex portions 73a on a plate 71 having a disc shape. In the center, an electrolyte injection hole 75 is formed. In addition, a plurality of holes 77 may be further provided on the plate 71. At this time, the electrolyte is also provided through the hole 77 in the same manner as the hole 75.

Here, the plate 70 is made of a metal such as aluminum, the shape of which is shown in the figure in a circle, but is not limited to this, of course, may be made of a polygon, such as a triangle, a square. In addition, the unevenness 73 may be formed by beading or pressing the plate 70 formed of a disc. In addition, the concave-convex 73 is preferably formed in the direction from the center toward the outer side so as to be matched to the transverse direction of the electrode group. By forming the concave-convex 73, the uncoated portion 23b having different sizes may be disposed therebetween along the curvature of the concave-convex formed in the same direction. It can be aligned along the concave portion (73b) and convex portion (73a) of the), thereby increasing the contact area between the plain portion (23b) and the current collector plate (70). That is, due to the size difference between the uncoated portion 23b, the small uncoated portion 23b, which is not in contact with the current collector plate 70, also comes into contact with the concave portion 73a, so that the entire uncoated portion 23b and the current collector plate ( 70) the area of contact between the two is increased (see FIG. 4). In addition, since the focusing area between the current collector plate 70 and the uncoated portion 23b is increased, current collection efficiency of current is also better than before.

In this way, an electrolyte injection hole 75 is formed in the center of the plate 71 provided with the unevenness 73. In addition, a plurality of holes 77 may be further formed to secure a sufficient passage for the injection of the electrolyte. At this time, these holes 77 are evenly disposed on the plate 71. In this way, a uniform electrolyte is provided to the electrode group 25 through the holes 77 to impregnate the electrode group.

The structure of this collector plate can be similarly applied to the collector plate 50 for the negative electrode.

The collector plates 70 and 50 configured as described above are combined with the plain portions 23b and 22b through laser welding. In this case, the laser welding is made to cross the irregularities formed in the current collector plate. By performing laser welding in this way, welding is uniformly applied to the entire uncoated portion in contact with each of the uneven portion and the concave portion of the unevenness, so that the contact area between the current collector plate and the uncoated portion can be increased than before.

As described above, the electrode assembly 20 is completed with the respective collector plates 50 and 70 fixed to the upper and lower sides of the electrode group 25, and the positive electrode current collector plate 70 is attached to the outer can 11. 30 so as to face. Therefore, the negative electrode current collector plate 50, which is connected to the negative electrode plate 22, contacts the bottom surface of the outer can 11, and in this state, the negative electrode current collector plate 50 and the bottom surface are fixed by resistance welding. .

At this time, a resistance welding bar is inserted into the can 11 through the hole 77 formed in the center of the positive electrode current collector plate 70 to fix the negative electrode current collector plate 50 to the can 11. As a result, the can 11 forms a negative electrode of the battery.

Alternatively, the negative electrode of the battery may be formed by directly contacting the negative electrode uncoated portion 22b with the outer can 11 without using the negative electrode current collector plate 50.

Next, the electrolyte is supplied into the can 11 through the holes 75 and 77 of the positive electrode current collector plate 70 to impregnate the electrode assembly 20. In addition, the positive electrode current collector plate 70 electrically connected to the positive electrode plate 23 is electrically connected to the cap assembly 30 through the lead wire 60. As a result, the cap assembly 30 forms the positive electrode of the battery.

On the other hand, Figure 5 shows the structure of the current collector plate according to another embodiment of the present invention, the collector plate of this embodiment is a convenient (片 利) structure of at least two or more partial collector plates (70a ~ 70d) gathered The current collector plate 70 of the battery is formed.

That is, the partial collector plates 70a to 70d on which the same irregularities 73 are formed as described above are combined with the plain portions 23b in a state in which they are disposed at mutually symmetrical positions for evenly dividing the plain portions. By arranging the partial collector plates in this way, it is possible to prevent the potential difference in accordance with the position of the partial collector plate.

In addition, by arranging the partial current collectors as described above, an empty space in which the uncoated portion 23b of the electrode group 25 is exposed is provided between the partial current collector plates. Can impregnate the army.

In addition, since the partial collector plates 70a to 70d are connected to the uncoated portion 23b through surface contact, the current collector efficiency can be improved by reducing the contact resistance than before.

In the collector plate configured as described above, separate lead wires 60a to 60d are connected to each of the partial collector plates 70a to 70d to electrically connect the electrode assembly and the partial collector plate (see FIG. 6).

Meanwhile, in FIG. 5, a case in which four partial collector plates are configured is illustrated. However, the present invention is not limited thereto and any two or more partial collector plates may be used.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

According to the present invention, the contact area between the current collector plate and the electrode group is increased to reduce the contact resistance, whereas the current collector efficiency is increased.

In addition, the above-mentioned problem can be solved to accommodate the operation characteristics required by a large-sized battery, and the fixing between the current collector and the electrode assembly can be more firmly solved. Allow discharge to occur.

1 is a cross-sectional view of a rechargeable battery according to an exemplary embodiment of the present invention.

2 is a perspective view showing a state of an electrode group according to an embodiment of the present invention.

3 is a perspective view showing a state of a positive electrode current collector plate according to an embodiment of the present invention.

FIG. 4 is an enlarged view showing a contact relationship between the positive electrode current collector plate and the positive electrode non-coating portion shown in FIG. 3.

5 is a view showing a state of a positive electrode current collector according to another embodiment of the present invention.

FIG. 6 is a cross-sectional view of a rechargeable battery including the positive electrode current collector plate illustrated in FIG. 5.

Claims (25)

An electrode group formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween; A can for accommodating the electrode group; A cap assembly assembled to the can to seal the cap assembly and electrically connected to the electrode group; And, And a current collector plate selectively contacting the electrode group. A secondary battery having at least one of the pole plates formed with an uncoated portion in contact with the current collector plate, and the current collector plate connected with the uncoated portion forms an uneven portion formed with recesses and convex portions. The method of claim 1, And the non-coating portion is selectively formed along the longitudinal end of the positive electrode plate or the negative electrode plate, and the current collector plate having a plate shape is fixed to the non-coating portion through surface contact. The method of claim 2, The non-charged portions are formed in the positive and negative electrodes in opposite directions, respectively, and the current collector plate is fixed to each of the non-coated portions. The method of claim 3, A secondary battery comprising the recesses and recesses formed alternately toward the center. The method of claim 4, wherein A secondary battery, wherein the fixing of the electrode plate and the uncoated portion is made by welding across the unevenness. The method of claim 4, wherein The recessed part of the uneven part is in contact with a relatively long uncoated part of the non-coated parts, the secondary battery is a relatively small uncoated parts made of a state in contact with each other. The method of claim 1, The secondary battery of the electrode group is formed in the shape of a cylindrical jelly roll. The method of claim 1, A secondary battery for which the secondary battery is for a hybrid electric vehicle (HEV). An electrode group formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween; A can for accommodating the electrode group; A cap assembly assembled to the can to seal the cap assembly and electrically connected to the electrode group; And, And a current collector plate selectively contacting the electrode group. At least one of the pole plates is formed with a non-coating portion in contact with the current collector plate, the current collector plate is formed of at least two or more partial current collector plates in partial contact with the non-coated portion, each of the partial current collector plate with recesses and concave parts Secondary battery formed by the irregularities formed. The method of claim 9, And the non-coating portion is selectively formed along the longitudinal end of the positive electrode plate or the negative electrode plate, and the current collector plate having a plate shape is fixed to the non-coating portion through surface contact. The method of claim 10, The non-charged portions are formed in the positive and negative electrodes in opposite directions, respectively, and the current collector plate is fixed to each of the non-coated portions. The method of claim 11, A secondary battery comprising the recesses and recesses formed alternately toward the center. The method of claim 12, A secondary battery, wherein the fixing of the electrode plate and the uncoated portion is made by welding across the unevenness. The method of claim 13, The recessed part of the uneven part is in contact with a relatively long uncoated part of the non-coated parts, the secondary battery is a relatively small uncoated parts made of a state in contact with each other. The method of claim 9, The secondary battery of the electrode group is formed in the shape of a cylindrical jelly roll. The method of claim 9, A secondary battery for which the secondary battery is for a hybrid electric vehicle (HEV). An electrode group formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween; An uncoated portion formed on the positive electrode plate and the negative electrode plate without applying an active material along an end portion in a longitudinal direction; And, Concave-convex formed of concave portion and convex portion is formed, the current collector plate electrically connected to the uncoated portion through the concave-convex electrode assembly for a secondary battery comprising a. The method of claim 17, The electrode assembly for a secondary battery, wherein the recesses and protrusions are alternately formed toward the center of the electrode group. The method of claim 18, A secondary battery electrode assembly, wherein the fixing between the electrode plate and the uncoated portion is made by welding across the unevenness. The method of claim 18, A relatively long uncoated portion of the uncoated portion is in contact with a main portion of the current collector plate, and a relatively small uncoated portion is fixed to the convex portion in contact with each other. An electrode group formed by winding a positive electrode plate and a negative electrode plate with a separator interposed therebetween; An uncoated portion formed on the positive electrode plate and the negative electrode plate without applying an active material along an end portion in a longitudinal direction; And, At least two or more partial current collector plates are partially fixed to the uncoated portion, and each of the partial current collector plates includes a current collector plate having irregularities formed of recesses and convexities. The method of claim 21, And the partial collector plates are arranged symmetrically with each other at positions where the non-coating portions are evenly divided. The method of claim 21, The electrode assembly for a secondary battery, wherein the recesses and protrusions are alternately formed toward the center of the electrode group. The method of claim 23, A secondary battery electrode assembly, wherein the fixing between the electrode plate and the uncoated portion is made by welding across the unevenness. The method of claim 23, A relatively long uncoated portion of the uncoated portion is in contact with a main portion of the current collector plate, and a relatively small uncoated portion is fixed to the convex portion in contact with each other.