KR20040058921A - Secondary battery with jelly-roll type electrode assembly - Google Patents

Abstract

PURPOSE: A secondary battery provided with a wound electrode assembly is provided, to reduce the shortage in the vicinity of an electrode tap and to minimize the unbalance of shape for enhancing the thermal and structural stability of a battery. CONSTITUTION: The secondary battery has an electrode assembly comprising a first electrode plate(41) where a first electrode active mass(412) containing a first electrode active material is formed in a first electrode current collector(411) and which comprises a first electrode uncoated part(413a) where the first electrode active mass is not formed at least in winding spool part; a second electrode plate(42) where a second electrode active mass(422) containing a second electrode active material is formed in a second electrode current collector(421) and which comprises a second electrode uncoated part(423a) where the second electrode active mass is not formed at least in winding spool part, and is wound together with the first electrode plate with a separator placed between the first and second electrode plates; and first and second electrode taps(44, 45) which are drawn from the first and second electrode uncoated parts of the winding spool part to one or other direction of the longitudinal direction of the each electrode assembly and are not superposed. The first electrode uncoated part(413a) does not superposed with at least the second electrode tap(45) and the second electrode uncoated part(423a) does not superposed with at least the first electrode tap(44).

Description

Secondary battery with wound electrode assembly {Secondary battery with jelly-roll type electrode assembly}

The present invention relates to a jelly roll electrode assembly having a positive electrode, a separator, and a negative electrode wound together, and a secondary battery having the same. It is about.

In general, a secondary battery refers to a battery that can be charged and discharged, unlike a primary battery that cannot be charged, and is widely used in the field of advanced electronic devices such as a cellular phone, a notebook computer, and a camcorder.

In particular, the lithium secondary battery has an operating voltage of 3.6 V, which is three times higher than that of a nickel-cadmium battery or a nickel-hydrogen battery, which is widely used as a power source for portable electronic equipment, and is rapidly expanding in terms of high energy density per unit weight. to be.

Such lithium secondary batteries mainly use lithium-based oxides as positive electrode active materials and carbon materials as negative electrode active materials. In general, a battery is classified into a liquid electrolyte battery and a polymer electrolyte battery according to the type of electrolyte, and a battery using a liquid electrolyte is called a lithium ion battery, and a battery using a polymer electrolyte is called a lithium polymer battery. Moreover, although a lithium secondary battery is manufactured in various shapes, typical shapes include cylindrical shape, square shape, and pouch type.

These secondary batteries use a jelly roll type electrode assembly in which a separator is inserted and wound between a positive electrode and a negative electrode formed by applying an active material to a substrate, drying, roll pressing and cutting the substrate. That is, the cylindrical battery is to receive the electrode assembly in a cylindrical can and inject the electrolyte, and then seal it, and the rectangular battery is to squeeze the electrode assembly to flatten it and then store it in the rectangular can.

Figure 1 shows a typical cylindrical secondary battery used in the prior art. As shown in FIG. 1, the cylindrical secondary battery is a sealed type in which an electrode assembly 3 wound in a cylindrical shape is accommodated in a cylindrical can 1, and an opening of the can 1 is sealed by a cap assembly 2. As the battery, the electrode assembly 3 is obtained by winding the positive electrode plate 31 and the negative electrode plate 32 in a jelly roll form via a separator 33.

In the electrode assembly 3, the positive electrode tab 34 and the negative electrode tab 35 are drawn out from each electrode plate, and the positive electrode tab 34 is pulled upward to seal the can 1. Is negatively connected, and the negative electrode tab 35 is drawn downward to be electrically connected to the protrusion 12 formed at the bottom of the can 1. Accordingly, the cap assembly 2 to which the positive electrode tab 34 is connected becomes the positive electrode, and the can 1 to which the negative electrode tab 35 is connected becomes the negative electrode as a whole.

In this conventional cylindrical battery, one of the positive electrode tab 34 and the negative electrode tab 35 is drawn out from the core portion of the wound electrode assembly 3, and the other from the outer peripheral portion of the electrode assembly 3. Withdrawn. However, when the electrode tab is drawn out from the outer circumferential portion of the electrode assembly, the diameter of the electrode assembly is increased, and the shape of the electrode assembly is closer to the shape of the ellipse rather than the shape of the circle, so that the inner space of the can is closed. There is a disadvantage that can not be used efficiently.

Therefore, it is preferable to pull out all the electrode tabs from the core portion of the electrode assembly 3, and in this way, when the positive electrode tab 34 and the negative electrode tab 35 are pulled out of the core portion, the possibility of a short circuit by each tab is further increased. Increases. Since the electrode tab becomes a portion through which charge is transferred to the outside, concentration and heat generation of charge occur in the electrode tab. Therefore, when both the positive electrode tab 34 and the negative electrode tab 35 are located at the core portion, the tabs and the other electrode plates meet each other with the separator as a boundary, thereby further increasing the risk of battery short circuit.

In order to prevent an increase in the risk of battery short circuit due to charge concentration and heat generation in the electrode tab portion, US Patent No. 5,508, 122 discloses that a portion of the electrode tab positioned at the core portion is disposed with an electrode plate of the same polarity with a separator interposed therebetween. The secondary battery is disclosed so that the other electrode tab is located at the outermost circumference of the electrode assembly.

However, even in the electrode assembly of the secondary battery, since only one electrode tab exists in the core portion, and the other electrode tab is disposed at the outer circumferential portion of the electrode assembly, the shape of the electrode assembly is changed as described above. It is difficult to make a circle and has a limitation that it is difficult to effectively use the space in the battery can.

In addition, in the above patent, if both electrode tabs are positioned at the core portion, the structure of the patent cannot be employed as it is. In this case, although the start positions of the electrode tabs may be wound differently from each other, since the winding form is shifted by the thickness of the electrode tabs, the shape of the electrode assembly may be deformed and collapsed during initial charging and discharging. In addition, due to the thickness of the electrode tab, the thickness of the core portion of the wound electrode assembly may be thick, thereby reducing the capacity of the battery.

The present invention is to solve the above problems, the electrode assembly that can reduce the risk of short circuit occurring in the vicinity of the electrode tab even when all the electrode tab is located in the core of the wound electrode assembly and a secondary having the same The object is to provide a battery.

Another object of the present invention is to provide a structurally more stable electrode assembly and a secondary battery having the same by minimizing the shape imbalance when all the electrode tabs are located at the core portion of the wound electrode assembly.

1 is a cross-sectional view showing a conventional cylindrical secondary battery.

Figure 2 is a cross-sectional view showing a cylindrical secondary battery according to an embodiment of the present invention,

3 is a plan view showing an electrode plate of an electrode assembly of a secondary battery according to an embodiment of the present invention;

4 is a plan view illustrating a process of manufacturing the electrode plate of FIG. 3;

5 is a partial perspective view illustrating an arrangement state of electrode plates according to FIG. 3;

6 is a view showing an arrangement state of a first electrode plate and a second electrode plate in the core portion;

7 is a view showing still another arrangement state of the first electrode plate and the second electrode plate in the core portion;

8 is a view illustrating a state of a core part of an electrode assembly of a rechargeable battery according to an exemplary embodiment of the present invention;

9 is a cross-sectional view showing an upper portion of the core part of the electrode assembly as shown in FIG. 8;

10 is a cross-sectional view showing a lower portion of the core part of the electrode assembly as shown in FIG. 8;

11 is a view illustrating a state of a core part of an electrode assembly of a rechargeable battery according to another exemplary embodiment of the present invention;

12 is a cross-sectional view illustrating an upper portion of a core part of an electrode assembly as illustrated in FIG. 11;

FIG. 13 is a cross-sectional view illustrating a lower portion of the core part of the electrode assembly as illustrated in FIG. 11;

14 to 16 are plan views showing electrode plates of an electrode assembly of a secondary battery according to another preferred embodiment of the present invention, respectively;

<Brief description of symbols for the main parts of the drawings>

1: can 2: cap assembly

4: electrode assembly 41: first electrode plate

411: first electrode current collector 412: first electrode mixture

413a, b: first electrode uncoated portion 414: first extension portion

415: first coating part 42: second electrode plate

421: second electrode current collector 422: second electrode mixture

423a, b: second electrode uncoated portion 424: second extension portion

425: second coating portion 43a, b: separator

44: first electrode tab 45: second electrode tab

In order to achieve the above object, in the present invention, the first electrode mixture including the first electrode active material is formed in the first electrode current collector, at least the first electrode uncoated portion in which the first electrode mixture is not formed in the core portion. The 2nd electrode mixture containing the 2nd electrode active material is formed in the 1st electrode plate which has, and the 2nd electrode current collector, and has a 2nd electrode non-coupling part in which the said 2nd electrode mixture is not formed in the core part at least through a separator. The first and second electrodes, which are wound with the first electrode plate, and the first and second electrode uncoated portions of the core portion, respectively, are drawn out to one side and the other in the longitudinal direction of the electrode assembly and do not overlap each other. And a second electrode tab, wherein the first electrode uncoated portion does not overlap at least the second electrode tab, and the second electrode uncoated portion does not overlap at least the first electrode tab. The provides a secondary battery comprising the electrode assembly.

According to another feature of the present invention, the first and second electrode plates may be at approximately the same position at each winding start portion thereof being wound.

According to another feature of the invention, the first electrode tab and the second electrode tab may be located on substantially the same line in the longitudinal direction.

According to another feature of the invention, the first and the second electrode plate may be the same as the starting position of each electrode mixture at its center portion.

According to another feature of the present invention, the first and second electrode tabs may be overlapped with only the first and second electrode uncoated portion and less than half the width of the first and second electrode current collector, respectively. .

According to still another feature of the present invention, a first extension portion having a predetermined width extending from the one end in the width direction of the first electrode uncoated portion in the longitudinal direction of the first electrode plate is formed at an end portion of the first electrode uncoated portion of the core portion. The first electrode tab is provided in the first extension part, and extends in the longitudinal direction of the second electrode plate from the other end in the width direction of the second electrode uncoated part to an end portion of the second electrode uncoated part of the core part. A second extension portion having a predetermined width may be formed, and the second electrode tab may be provided in the second extension portion.

In this case, the first and second extension portions may extend in parallel to the longitudinal direction of the first and second electrode uncoated portions, or may be extended to be inclined in the longitudinal direction of the first and second electrode uncoated portions.

In order to achieve the above object, the present invention also provides a first electrode mixture comprising a first electrode mixture including a first electrode active material formed on a first electrode current collector, and wherein the first electrode mixture is not formed at least in the core portion. A second electrode mixture including a first electrode plate having a portion and a second electrode active material is formed on the second electrode current collector, and at least the core portion has a second electrode non-coating portion where the second electrode mixture is not formed. The first electrode plate and the second electrode plate wound around the first electrode plate, and the first and second electrode tabs drawn out in the longitudinal direction of the electrode assembly from the first and second electrode uncoated portions of the core portion, respectively, And at least the first electrode tab and the second electrode tab in which the first and second electrode uncoated parts are positioned, both surfaces of which have an electrode plate having the same polarity through the separator, Provided is a secondary battery comprising an electrode assembly such that only a separator exists.

According to another aspect of the present invention, the first electrode uncoated portion may not be overlapped with at least the second electrode tab, and the second electrode uncoated portion may be formed without overlapping at least the first electrode tab.

According to still another feature of the present invention, each of the first and second electrode plates to be wound may have approximately the same position.

According to another feature of the invention, the first and the second electrode plate may be the same as the starting position of each electrode mixture at its center portion.

According to another feature of the invention, the first electrode tab and the second electrode tab may be located on substantially the same line in the longitudinal direction.

In this case, the first and second electrode tabs may not overlap each other, and the first and second electrode tabs may overlap only with the first and second electrode uncoated portions and a portion less than half of the width, respectively.

According to still another feature of the present invention, a first extension portion having a predetermined width extending from the one end in the width direction of the first electrode uncoated portion in the longitudinal direction of the first electrode plate is formed at an end portion of the first electrode uncoated portion of the core portion. The first electrode tab is provided in the first extension part, and extends in the longitudinal direction of the second electrode plate from the other end in the width direction of the second electrode uncoated part to an end portion of the second electrode uncoated part of the core part. A second extension portion having a predetermined width may be formed, and the second electrode tab may be provided in the second extension portion.

In this case, the first and second extension portions may extend in parallel to the longitudinal direction of the first and second electrode uncoated portions, respectively, or may extend to be inclined in the longitudinal direction of the first and second electrode uncoated portions.

And, the length from the position where the first and second extension portions start to extend from the first and second electrode uncoated portions to the first and second electrode tabs is respectively from the position of the first and second electrode tabs. It can be at least one turn long. In this case, the positions at which the first and second electrode portions extend from the first and second electrode uncoated portions may be substantially the same.

In order to achieve the above object, the present invention also provides a first electrode mixture including a first electrode active material in a band-shaped first electrode current collector having a predetermined width, wherein the first electrode mixture is formed at least in the core portion. It has a 1st electrode uncoated part which is not formed, The edge part of the 1st electrode uncoated part of the said core part has the 1st extension part of the predetermined width extended in the longitudinal direction of the said 1st electrode plate from the end of the width direction of the said 1st electrode uncoated part. A second electrode mixture containing a second electrode active material is formed on the first electrode plate and the second electrode current collector having a predetermined width, and the second electrode on which the second electrode mixture is not formed at least in the core part. A predetermined portion extending from the other end in the width direction of the second electrode uncoated portion to the end portion of the second electrode uncoated portion of the winding core portion in the longitudinal direction of the second electrode plate; A second electrode plate having a second extension portion of the first electrode plate and a separator wound through the first electrode plate and the separator, and first and second portions drawn out from the first and second extension portions in one and the other directions of the electrode assembly, respectively; It provides a secondary battery comprising an electrode assembly having a second electrode tab.

According to another feature of the invention, the first extension and the second extension may not overlap each other.

According to another feature of the invention, the first and second extension portions of the first and second electrode plates may be provided with separators and may begin to be wound from approximately the same position where they abut.

According to another feature of the invention, the first and the second electrode plate may be the same as the starting position of each electrode mixture at its center portion.

According to another feature of the invention, the first electrode tab and the second electrode tab may be located on substantially the same line in the longitudinal direction.

According to another feature of the invention, the first and second electrode tabs may not overlap each other.

According to still another feature of the present invention, the first and second extension portions may extend parallel to the longitudinal direction of the first and second electrode uncoated portions, respectively.

According to still another feature of the present invention, the first and second extension portions may extend to be inclined in the longitudinal direction of the first and second electrode uncoated portions, respectively.

In this invention, the length from the position where the first and second extension portions begin to extend from the first and second electrode uncoated portions to the first and second electrode tabs is respectively the first and second electrodes. At least one turn from the position of the tab can be at least a length, wherein the first and second extension portions of the first and second electrode uncoated portion start to extend substantially the same as each other Can be.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the present invention. In the present specification, as a preferred embodiment of the present invention, a cylindrical battery having the electrode jelly roll of the present invention will be described. However, this is not limited to a cylindrical battery, but a battery which can be provided with the same electrode jelly roll as this embodiment. Any form may be applicable. Therefore, the present invention can be applied to various methods such as a cylindrical secondary battery, a button-type secondary battery and a primary battery. In the drawings to be described below, the same components as those in FIG. 1 showing the secondary battery according to the prior art are denoted by the same reference numerals.

2 is a cross-sectional view of a cylindrical secondary battery having a wound electrode assembly according to a preferred embodiment of the present invention. As shown in FIG. 2, a wound electrode assembly wound around a separator 43 so that the first electrode plate 41 and the second electrode plate 42 are insulated from each other in the cylindrical can 1 ( 4) is housed. The cylindrical can 1 is made of a metal and can itself serve as a terminal of the first electrode plate or the second electrode plate. According to a preferred embodiment of the present invention, the cylindrical can 1 is made of aluminum or an aluminum alloy. The second electrode plate may be electrically connected to form a second electrode terminal.

As the electrode assembly 4 described later, the first electrode tab 44 and the second electrode tab 45 are drawn out from the first electrode plate 41 and the second electrode plate 42, respectively. . The first electrode tab 44 and the second electrode tab 45 are respectively drawn out from the core portion of the electrode assembly 4, and the first electrode tab 44 is drawn upwards to open the can 10. It is electrically connected to the cap assembly 2 to be sealed, and the second electrode tab 45 is drawn downward and is electrically connected to the protrusion 12 formed at the bottom of the can 1. Accordingly, the cap assembly 2 to which the first electrode tab 44 is connected functions as a first electrode terminal portion, and the can 1 to which the second electrode tab 45 is connected is entirely a second electrode terminal portion. Function. Reference numeral 11, which is not described in FIG. 2, is an insulating plate 11 for fixing the electrode assembly 4.

On the other hand, the electrode assembly 4 according to a preferred embodiment of the present invention has a first electrode plate 41 and a second electrode plate 42 as shown in FIG. According to a preferred embodiment of the present invention, the first electrode plate 41 may be provided as a positive electrode plate, the second electrode plate 42 may be provided as a negative electrode plate, but is not necessarily limited thereto. The polarity may be reversed. Hereinafter, the case where the first electrode plate 41 is provided as the positive electrode plate and the second electrode plate 42 is provided as the negative electrode plate will be described as an example.

As shown in FIG. 3, each of the electrode plates 41 and 42 is formed of electrode mixtures 412 and 422 including an electrode active material in the electrode current collectors 411 and 421. As follows.

When the electrode assembly is used as an electrode assembly of a lithium secondary battery, the first electrode plate 41 may be used as a positive electrode plate. At this time, the first electrode current collector 411 is provided with a strip-shaped metal thin plate, preferably an aluminum thin plate may be used. The first electrode mixture 412 formed on at least one surface of the first electrode current collector 411 may be formed of a mixture containing a binder, a plasticizer, a conductive material, and the like in the first electrode active material of the lithium oxide. The first electrode plate 41 may include a first electrode coating part 415 having the first electrode mixture 412 formed on at least one surface of the first electrode current collector 411, and the first electrode current collector 411. ) As the first electrode uncoated portions 413a and 413b in which the first electrode mixture 412 is not formed.

Meanwhile, in the second electrode plate 42 used as the negative electrode plate, a copper thin plate may be used as the second electrode current collector 421, and a second electrode mixture formed on at least one surface of the second electrode current collector 421 ( 422 may be a mixture containing a binder, a plasticizer, a conductive material, and the like in the second electrode active material made of a carbon material. The second electrode plate 42 includes a second electrode coating part 425 having the second electrode mixture 422 formed on at least one surface of the second electrode current collector 421, and the second electrode current collector 421. ) As the second electrode uncoated portions 423a and 423b in which the second electrode mixture 422 is not formed.

The first electrode tab 423a and the second electrode plain 423a respectively positioned at one end of the first electrode uncoated portion 423a and 423b and the second electrode uncoated portion 423a and 423b respectively have a first electrode tab. 44 and the second electrode tab 45 are bonded to each other, wherein the first electrode tab 44 is made of aluminum (Al) and the second electrode tab 45 is made of nickel (Ni). Ultrasonic welding may be performed on the uncoated portion 423a and the second electrode uncoated portion 423a, respectively. Winding starts from the part to which these 1st and 2nd electrode tab 44 and 45 were joined, and this part becomes a core part. The first and second electrode tabs 44 and 45 are welded to be drawn out in different directions, as shown in the figure.

At this time, in the electrode plates as described above, the first and second electrode uncoated portions 413a and 423a to which the electrode tabs 44 and 45 of the electrode plates 41 and 42 are bonded are formed. As can be seen in FIG. 3, the first and second extensions 414 and 424 are symmetrical to each other, and the electrode tabs 44 and 45 have these first and second extensions 414 ( 424). These first and second extension portions 414, 424 allow the shape of the electrode assembly and the more compact winding at the portion where the electrode tabs are formed even when the first and second electrode tabs are positioned at the core portion. This will be described in more detail below.

First, the first extension part 414 is located at the end of one of the first electrode uncoated parts 413a to which the first electrode tabs 44 are joined, and the width of the first extension part 414 is increased from the first electrode current collector 411. It can be extended to be narrow. At this time, the first extension part 414 is positioned in one direction in the width direction of the first electrode current collector 411. Therefore, the first extension part 414 has a shape in which a part of the first electrode uncoated part 413a is removed.

This basic structure is also applied to the second extension portion 424 as it is, except that the second extension portion is oriented opposite to the first extension portion 414 as shown in FIG. 3.

As shown in FIG. 4, the first extension part 414 and the second extension part 424 may be formed by manufacturing an electrode plate in a continuous process. In FIG. 4, the first electrode plate is illustrated, but the same is true of the second electrode plate. That is, as shown in FIG. 4, the electrode plate continuously supplied is separated due to the cutting of one electrode plate 41 and the electrode plate 41 ′ adjacent thereto. When it corresponds to the shape of 414, the first electrode uncoated portion 413b ′ corresponding to the shape of the first extension part 414 is formed in the adjacent first electrode plate 41 ′.

As shown in FIG. 5, the first electrode plate 41 and the second electrode plate 42 manufactured as described above have an inner surface of the first electrode plate 41 and the first and second electrode plates 41 and 42. The 1st and 2nd separators 43a and 43b are interposed, respectively, and wind up in the arrow direction. These first and second separators 43a and 43b mutually insulate the first electrode plate 41 and the second electrode plate 42, while active material ions are formed between the electrode plates 41 and 42. To be exchanged. Preferably, the first and second separators 43a and 43b have a sufficient width and length so as to completely insulate the electrode plates 41 and 42 even when the electrode assembly is contracted and expanded.

Although not shown in the drawings, the winding is wound using a separate winding mandrel, which is provided in a cylindrical shape having a predetermined diameter.

On the other hand, in this way, the first electrode plate 41 and the second electrode plate 42 are wound through the separators 43a and 43b. In the core part, the first electrode tab 44 and the second electrode tab 45 are wound. ) Are positioned in accordance with the present invention, in order to reduce the risk of short-circuit due to concentration of charge at the portion where these first and second electrode tabs 44 and 45 are located. 44 and the second electrode tab 45 are not overlapped with each other, and the portion where the respective electrode tabs 44 and 45 are formed is not overlapped with the electrode uncoated portion of the other polarity.

That is, in order to minimize interference due to the other electrode plate at the position where the first electrode tab 44 and the second electrode tab 45 are formed, as shown in FIG. 3, the first electrode tab 44 is formed with the first electrode tab 44. The width b1 of the extension part 414 is equal to or less than half the width a1 of the first electrode uncoated part 413a, and the width of the second extension part 424 in which the second electrode tab 45 is formed ( b2) is formed to be less than or equal to half of the width a2 of the second electrode non-coating portion 423a, and then disposed in the form as shown in FIG. 5 to be wound. As shown in FIG. 6, the first electrode tab ( Not only does the 44 and the second electrode tab 45 overlap each other, but the portions in which the respective electrode tabs 44 and 45 are formed also do not overlap with the electrode uncoated portion of the other polarity. In FIG. 6, the separators 43a and 43b are omitted to more clearly show the state in which the first electrode plate 41 and the second electrode plate 42 overlap each other, and to prevent a short circuit between the positive electrode and the negative electrode. The second electrode plate 42 serving as the cathode was provided more widely.

At this time, the widths c1 and c2 of the portions where the first and second electrode tabs 44 and 45 overlap with the first and second electrode supporting portions 413a and 423a, respectively, The first and second electrode uncoated portions 413a and 423a may be equal to or less than half the widths a1 and a2. Therefore, even if the first and second electrode tabs 44 and 45 are joined over the entire width of the first and second extension portions 414 and 424, respectively, the above interference does not occur.

In disposing and winding the first electrode plate 41 and the second electrode plate 42, it is preferable that the starting positions of the first electrode coating part 415 and the second electrode coating part 425 are the same. That is, since the capacity of the battery is determined by the area where these electrode coating portions meet via the separator, it is preferable that the starting position is the same.

On the other hand, the first electrode plate 41 and the second electrode plate 42, as can be seen in Figure 7, it can be such that the winding start portion is in the same position. Thus, when the start of the first electrode plate 41 and the second electrode plate 42 is in the same position, it is easy to adjust the shape at the core of the wound electrode assembly.

The first electrode tab 44 and the second electrode tab 45 may also be in the same position. In this way, when the positions of the first electrode tab 44 and the second electrode tab 45 are the same, it is possible to minimize the probability that the shape of the electrode assembly collapses at the portion of the electrode tab in the wound electrode assembly.

Of course, the start position of the electrode plates and the position of the electrode tabs can be variously applied according to design conditions.

When the above electrode plates are wound, the structure between the first and second electrode plates 41 and 42 at the core portion will be as shown in FIG. In FIG. 8, the separators are excluded to make the structure easier to understand, but the separator is interposed between the electrode plates. In this case, as shown in FIG. 8, the first extension part 414 to which the first electrode tab 44 is attached and the second extension part 424 to which the second electrode tab 45 is attached overlap each other. The shape at the core of the electrode assembly can be made more uniform and compact, and the interference between the electrode tabs can be reduced.

9 and 10 show the top and bottom cross-sections of the electrode assembly, respectively. In the drawings, it is shown that there is a gap between each electrode plate and the separator, but this is for convenience of description, and in fact, of course, it is more compactly wound.

9 and 10, the first electrode tab 44 drawn upward and the second electrode tab 45 drawn downward may be drawn at the same position. And, it can be seen that the upper cross-sectional structure and the lower cross-sectional structure have a structure that is exactly symmetric with each other. As such, as the lead out of the first electrode tab 44 and the second electrode tab 45 are drawn out at the same position, and as the positions of the start of the respective electrode plates 41 and 42 are the same, the electrode assembly It may have a more compact and stable winding structure, thereby allowing the electrode assembly to be more firmly supported so as not to collapse when a swelling phenomenon due to charging and discharging occurs.

However, even in the above structure, as shown in FIG. 9, the outer surface of the portion to which the first electrode tab 44 is attached is separated from the first electrode plate 41 via the separators 43a and 43b. As shown in FIG. 10, the outer surface of the portion where the second electrode tab 45 is attached meets the first electrode plate 41 via the separator 43a. Therefore, when charge concentration occurs in a portion where the second electrode tab 45 is located, a short circuit may occur due to heat generation.

Therefore, in order to solve this problem, in the secondary battery according to another embodiment of the present invention, at least the first and second electrode tabs at which the first and second electrode uncoated parts are positioned, both surfaces thereof have the same polarity through the separator. An electrode assembly is provided so as to have an electrode plate or to have only a separator.

As can be seen in FIG. 3, the lengths d1 and d2 of the first and second extension portions 414 and 424 in the longitudinal direction of the respective electrode plates 41 and 42 and the first and second lengths. The first and second electrode tabs from the starting position of the second extension portions 414 and 424, that is, the positions 414a and 424a that start to extend from the first and second electrode uncoated portions 413a and 423a. By adjusting the length up to e1) (e2) it is possible to achieve such a structure. This will be described in more detail below. However, below, the winding start part of the 1st electrode plate 41 and the 2nd electrode plate 42 is made into the substantially same position which contacted through the separator, and the 1st and 2nd electrode tab 44 and 45 are carried out. The structure to be drawn out from the approximately same position is described as an example, but is not necessarily limited thereto, and the positions may be variously modified and applied according to the design conditions of the battery.

3, when the distance e1 from the position 414a starting to extend from the first electrode uncoated portion 413a of the first extension 414 to the first electrode tab 44 is wound up, It should be at least one turn long. That is, the first extension part 414 is still present at the outer position of the first electrode tab 44 during the winding. The distance d1 of the first extension 414 should be longer than this.

This position limitation is equally applied to the case of the second electrode tab 45. However, at this time, the position 424a at which the second extension 424 begins to extend from the second electrode uncoated portion 423a starts to extend from the first electrode uncoated portion 413a. It is preferable that the position match the position 414a.

When the positions of the first and second electrode tabs 44 and 45 are determined and wound in this manner, the structure of the core portion is formed in the form as shown in FIG. 11. 11 is a structure in which the separator is omitted for convenience of description, and the first electrode plate 41 and the second electrode plate 42 are each insulated by the separator.

As can be seen in FIG. 11, in each of the first and second electrode plates 41 and 42, the positions of the first electrode tab 44 and the second electrode tab 45 are defined by the first and second extension portions ( 414 and 424 are located further inward than the starting positions 414a and 424a. Accordingly, as shown in FIG. 12, the portion where the first electrode tab 44 is located is a first extension portion extending from the first electrode uncoated portion 413a via the separators 43a and 43b to the outer surface thereof. 414 is positioned, and only the separators 43a and 43b are positioned on the inner side thereof, and as shown in FIG. 13, the portion where the second electrode tab 45 is located is also separated by the outer side thereof. A second extension portion 424 extending from the second electrode uncoated portion 423a is positioned via (43a) and 43b. FIGS. 12 and 13 illustrate another preferred embodiment of the present invention as described above. In the electrode assembly of the secondary battery according to the example is shown the cross section of the core portion of the upper and lower. In the drawings, it is shown that there is a gap between each electrode plate and the separator, but this is for convenience of description, and in fact, of course, it is more compactly wound.

In this way, the electrodes that meet each other through the separator at the position where each electrode tab is located have the same polarity, thereby preventing short circuit of the battery even when heat is generated due to charge concentration on the electrode tab.

As shown in FIG. 14, the electrode assembly of the secondary battery as described above may be manufactured by further attaching an insulating tape 46 attached to each of the electrode tabs 44 and 45, and as shown in FIG. 15, It can also manufacture by the method of integrally forming and folding up an electrode tab, without welding an electrode tab.

In addition, the first and second extension parts 414 and 424 as described above may be provided in a shape as shown in FIG. 16, that is, in a shape cut to be inclined in the longitudinal direction of each of the electrode plates 41 and 42. It may be. At this time, the inclination angle θ may be designed in consideration of problems such as interference with other electrode plates and the position where the electrode tabs are welded, and the like, and may be approximately 30 degrees to 60 degrees, and may be 45 degrees. It may be most suitable in view of problems such as interference with other electrode plates.

As described above, according to the secondary battery of the present invention, the following effects can be obtained.

First, all of the electrode tabs drawn out to the upper and lower portions of the electrode assembly may be positioned at the core part.

Second, even if the two electrode tabs are located in the core portion, it is possible to more effectively escape the interference between the electrode tabs and the interference by the other electrode plate. Therefore, even when charge concentration occurs in the electrode tab, a short circuit of the battery can be prevented.

Third, since the winding shapes of the electrode plates become uniform, it is possible to prevent the structure of the electrode assembly from collapsing during swelling due to charge and discharge.

Fourth, it is possible to further prevent the risk of battery short-circuit at the portion where the electrode tab is located by bringing the electrode plates of the same polarity through the separator on both sides of the portion where the electrode tab is located on the electrode plate or by allowing only the separator to come.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and it will be understood by those skilled in the art that various modifications and equivalent other embodiments are possible. Accordingly, the true scope of protection of the invention should be defined only by the appended claims.

Claims (30)

A first electrode plate having a first electrode mixture including a first electrode active material formed on a first electrode current collector and having at least a core portion a first electrode uncoated portion, in which the first electrode mixture is not formed; A second electrode mixture including a second electrode active material is formed in a second electrode current collector, and has at least a core portion with a second electrode non-coating portion where the second electrode mixture is not formed, and is wound with the first electrode plate via a separator. A second electrode plate; And First and second electrode tabs drawn out from the first and second electrode uncoated portions of the core portion in one and the other directions of the electrode assembly, respectively, and not overlapping with each other; And a first electrode non-coating portion not overlapping at least the second electrode tab, and the second electrode non-coating portion including an electrode assembly formed so as not to overlap at least the first electrode tab. The method of claim 1, The first and second electrode plates are secondary batteries, characterized in that the respective winding start portion is wound around the same position. The method of claim 1, And the first electrode tab and the second electrode tab are positioned on substantially the same line in the length direction thereof. The method of claim 1, The first and second electrode plates are secondary batteries, characterized in that the starting position of each of the electrode mixture in the center portion of the same. The method of claim 1, And the first and second electrode tabs overlap only the portions of the first and second electrode uncoated portions and the width of the first and second electrode current collectors less than or equal to half. The method according to any one of claims 1 to 5, A first extension portion having a predetermined width extending from the one end in the width direction of the first electrode uncoated portion in the longitudinal direction of the first electrode plate is formed at an end portion of the first electrode uncoated portion of the core portion. It is provided with a 1st extension part, The 2nd extension part of the predetermined width extended in the longitudinal direction of the said 2nd electrode plate from the other end of the width direction of the said 2nd electrode support part is formed in the edge part of the 2nd electrode support part of the said core part, And the second electrode tab is provided in the second extension part. The method of claim 6, And the first and second extension portions extend parallel to the longitudinal direction of the first and second electrode uncoated portions, respectively. The method of claim 6, And the first and second extension portions extend to be inclined in the longitudinal direction of the first and second electrode uncoated portions, respectively. A first electrode plate having a first electrode mixture including a first electrode active material formed on a first electrode current collector and having at least a core portion a first electrode uncoated portion, in which the first electrode mixture is not formed; A second electrode mixture including a second electrode active material is formed on a second electrode current collector, and has at least a core portion with a second electrode non-coating portion where the second electrode mixture is not formed, and is wound with the first electrode plate via a separator. A second electrode plate; And And first and second electrode tabs drawn out from the first and second electrode uncoated portions of the core portion in one direction and the other in the longitudinal direction of the electrode assembly, respectively, and including at least a first portion of the first and second electrode uncoated portions. The secondary battery, characterized in that the portion in which the first electrode tab and the second electrode tab is located includes an electrode assembly such that both sides of the electrode plate having the same polarity, or only the separator is present through the separator. The method of claim 9, And the first electrode uncoated portion does not overlap at least the second electrode tab, and the second electrode uncoated portion is formed not to overlap at least the first electrode tab. The method of claim 9, The first and second electrode plates are secondary batteries, characterized in that the respective winding start portion is wound around the same position. The method of claim 9, The first and second electrode plates are secondary batteries, characterized in that the starting position of each of the electrode mixture in the center portion of the same. The method of claim 9, And the first electrode tab and the second electrode tab are positioned on substantially the same line in the length direction thereof. The method of claim 13, Secondary battery, characterized in that the first and second electrode tabs do not overlap each other. The method of claim 14, And the first and second electrode tabs overlap only the first and second electrode uncoated parts and a portion less than half of the width, respectively. The method according to any one of claims 9 and 15, A first extension portion having a predetermined width extending from the one end in the width direction of the first electrode uncoated portion in the longitudinal direction of the first electrode plate is formed at an end portion of the first electrode uncoated portion of the core portion, and the first electrode tab is formed in the first electrode tab. It is provided with a 1st extension part, The 2nd extension part of the predetermined width extended in the longitudinal direction of the said 2nd electrode plate from the other end of the width direction of the said 2nd electrode support part is formed in the edge part of the 2nd electrode support part of the said core part, And the second electrode tab is provided in the second extension part. The method of claim 16, And the first and second extension portions extend parallel to the longitudinal direction of the first and second electrode uncoated portions, respectively. The method of claim 16, And the first and second extension portions extend to be inclined in the longitudinal direction of the first and second electrode uncoated portions, respectively. The method of claim 16, At least one length from the position of the first and second electrode tabs to the first and second electrode tabs from the position where the first and second extension portions start to extend from the first and second electrode uncoated portions is respectively. Secondary battery, characterized in that to be more than the length of the turn. The method of claim 19, A secondary battery, wherein the positions at which the first and second extension portions begin to extend from the first and second electrode uncoated portions are substantially the same. The first electrode mixture including the first electrode active material is formed on a band-shaped first electrode current collector having a predetermined width, and has at least a core portion having a first electrode non-coating portion in which the first electrode mixture is not formed. A first electrode plate having a first extension part having a predetermined width extending from the one end in the width direction of the first electrode uncoated part in the longitudinal direction of the first electrode plate at the end of the first electrode uncoated part of the first electrode uncoated part; The second electrode mixture including the second electrode active material is formed on the band-shaped second electrode current collector having a predetermined width, and has at least a core portion with a second electrode non-coating portion in which the second electrode mixture is not formed. An end portion of the second electrode non-coated portion of the second electrode non-coated portion has a second extension portion having a predetermined width extending in the longitudinal direction of the second electrode plate from the other end in the width direction of the second electrode non-coated portion, and wound around the first electrode plate and the separator. A second electrode plate; And And an electrode assembly having first and second electrode tabs extending from the first and second extension portions to one and the other in the longitudinal direction of the electrode assembly, respectively. The method of claim 21, The secondary battery, characterized in that the first extension portion and the second extension portion do not overlap each other. The method of claim 21, And the first and second extension portions of the first and second electrode plates are provided with separators and start to be wound from approximately the same positions in contact with each other. The method of claim 21, The first and second electrode plates are secondary batteries, characterized in that the starting position of each of the electrode mixture in the center portion of the same. The method of claim 21, And the first electrode tab and the second electrode tab are positioned on substantially the same line in the length direction thereof. The method of claim 21, Secondary battery, characterized in that the first and second electrode tabs do not overlap each other. The method of claim 21, And the first and second extension portions extend parallel to the longitudinal direction of the first and second electrode uncoated portions, respectively. The method of claim 21, And the first and second extension portions extend to be inclined in the longitudinal direction of the first and second electrode uncoated portions, respectively. The method according to any one of claims 21 to 28, At least one length from the position of the first and second electrode tabs to the first and second electrode tabs from the position where the first and second extension portions start to extend from the first and second electrode uncoated portions is respectively. Secondary battery, characterized in that to be more than the length of the turn. The method of claim 29, A secondary battery, wherein the positions at which the first and second extension portions begin to extend from the first and second electrode uncoated portions are substantially the same.