KR20130064228A - Secondary battery having electrode lid and electrode tab connected by slit - Google Patents

Abstract

PURPOSE: A secondary battery is provide to stabilize an adhesive structure of an electrode tab and an electrode lead by introducing a coupling structure through a slit, thereby minimizing the short due to the external impact. CONSTITUTION: A secondary battery(100) comprises a cell assembly(220) in which at least two or more unit cells including a positive electrode plate, separator, and a negative electrode plate are laminated; an electrode tab(230) protruded from the positive electrode plate and a negative electrode plate of the unit cell; and an electrode lead(240) attached to the electrode tab. The connection of the electrode lead and the electrode tab are conducted in a state which a slit(260) is inserted into the opposite side. When the slit is formed on the electrode lead, the electrode tab is attached to the electrode lead in the state of being inserted into the slit.

Description

Secondary battery comprising electrode leads and electrode tabs connected using slits {SECONDARY BATTERY HAVING ELECTRODE LID AND ELECTRODE TAB CONNECTED BY SLIT}

The present invention relates to a connection structure of a lead and a tab in a secondary battery, and more particularly, to a secondary battery in which a structure capable of improving bonding stability of a lead and a tab is introduced.

In recent years, due to exhaustion of fossil energy and environmental pollution, there is a growing interest in electric products that can be driven by electric energy without using fossil energy.

Accordingly, the demand for secondary batteries as an energy source is rapidly increasing due to the increase in technology development and demand for mobile devices, electric vehicles, hybrid vehicles, power storage devices, and uninterruptible power supplies. In particular, secondary batteries used in electric vehicles or hybrid vehicles are high-power, high-capacity secondary batteries, and many studies on them have been conducted.

Commercially available secondary batteries include nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, and lithium secondary batteries. In particular, lithium secondary batteries include conventional lead acid batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. Compared with other secondary batteries such as batteries, the energy density per unit weight is high and rapid charging is possible, thereby increasing the use thereof actively. In addition, lithium secondary batteries have a three times higher operating voltage than nickel-cadmium batteries or nickel-metal hydride batteries, and are also rapidly being used because of their excellent energy density per unit weight.

The lithium secondary battery may be classified into a lithium ion battery using a liquid electrolyte and a lithium ion polymer battery using a polymer solid electrolyte according to the type of electrolyte. In addition, secondary batteries are classified into pouch type, cylindrical type, and rectangular type according to the type of exterior material.

A pouch type secondary battery, which is an example of a secondary battery, includes a pouch type case made of an aluminum laminate sheet, and a cell assembly in which a plurality of electrochemical cells including an anode, a separator, and a cathode are housed inside the pouch type case. .

The cell assembly includes a plurality of positive and negative electrode tabs extending from each positive and negative electrode. Since the positive electrode tab and the negative electrode tab are made of a very thin metal thin film like the positive electrode plate and the negative electrode plate, when a shock is applied to the pouch type secondary battery, it is more likely to be disconnected before other components. Therefore, the electrode tab is bonded to the electrode lead having higher mechanical strength than the electrode tab without directly connecting to an external device.

Since the electrode lead has a thickness of about 0.3 mm thicker than the electrode tab, it is more resistant to impact than the electrode tab. In addition, since the electrode lead is bonded to the pouch case through a heat fusion process during manufacture of the pouch type secondary battery, the position of the electrode lead is less likely to flow when an external shock is applied.

In order to connect the electrode tab and the electrode lead, first, the plurality of positive electrode tabs and the negative electrode tabs are welded to each other, and then additional welding is performed to bond the bound electrode tabs to the corresponding electrode leads. However, over time, when the welding force is weakened or the welding part is dismantled by an external impact applied to the secondary battery, electrical connection of the secondary battery is broken. In addition, an internal short circuit may occur due to the dissipated electrode tab, and the internal short circuit may cause a safety accident such as a secondary battery explosion. Therefore, there is a continuous need for a method of improving the bonding stability of the electrode tab and the electrode lead.

The present invention has been made in view of the above-described problems of the related art, and an object thereof is to provide a secondary battery in which a structure capable of improving bonding stability between an electrode lead and an electrode tab is introduced.

According to an aspect of the present invention, there is provided a secondary battery including: a cell assembly including at least two unit cells including a positive electrode plate, a separator, and a negative electrode plate; Electrode tabs protruding from the positive and negative plates of each unit cell; And an electrode lead bonded to the electrode tab, wherein the electrode lead and the electrode tab are bonded in the state in which the other is inserted into a slit formed in one of them.

According to an aspect of the present invention, the slit is formed on the electrode lead, and the electrode tab is bonded to the electrode lead while being inserted into the slit. Preferably, the electrode lead is bonded to one surface of the upper surface or the lower surface of the electrode tab inserted into the slit. More preferably, the electrode lead is joined to both the upper and lower surfaces of the electrode tab inserted into the slit.

According to another aspect of the present invention, the slit is formed on the electrode tab, and the electrode lead is bonded to the electrode tab while being inserted into the slit of the electrode tab. Preferably, the electrode tab is bonded to any one surface of the upper surface or the lower surface of the electrode lead inserted into the slit. More preferably, the electrode tab is joined to both the upper and lower surfaces of the electrode lead inserted into the slit.

According to another aspect of the present invention, two or more slits are formed in the electrode lead, and the electrode tabs are inserted to pass through the two or more slits and are bonded to the electrode lead.

According to another aspect of the present invention, two or more slits are formed in the electrode tab, and the electrode leads are inserted to pass through the two or more slits and are bonded to the electrode tabs.

According to another aspect of the present invention, a first slit is formed in the electrode tab, a second slit is formed in the electrode lead, the electrode tab is inserted into the second slit, and the electrode lead is inserted into the first slit. The electrode tab and the electrode lead are joined in the attached state.

The technical problem of the present invention is a cell assembly in which at least two unit cells including a positive electrode plate, a separator, and a negative electrode plate are stacked; An electrode tab protruding from the positive and negative plates of each unit cell and having a first slit formed at one end thereof; An electrode lead electrically connected to the electrode tab and having a second slit formed at one end thereof; And a connection member inserted into the first slit and the second slit and bonded to the electrode tab and the electrode lead.

In the present invention, the bonding of the electrode lead and the electrode tab may be made by ultrasonic welding, resistance welding, laser welding or conductive adhesive.

According to an aspect of the present invention, the bonding structure of the electrode lead and the electrode tab can be stabilized by introducing the bonding structure through the slit.

According to another aspect of the present invention, since the junction structure of the electrode lead and the electrode tab is stabilized, it is possible to provide a secondary battery having a low possibility of disconnection from external impact.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention given below, serve to further the understanding of the technical idea of the invention, And should not be construed as limiting.
1 is a planar view of a secondary battery having a structure bonded to an electrode lead in a state where an electrode tab is inserted into a slit formed in an electrode lead according to an exemplary embodiment of the present invention.
FIG. 2 is a partially enlarged cross-sectional view illustrating various bonding states of an electrode lead and an electrode tab in the embodiment illustrated in FIG. 1.
3 is a planar projection view of a secondary battery having a structure in which an electrode lead is inserted into a slit formed in an electrode tab and bonded to the electrode tab according to another embodiment of the present invention.
4 is a partially enlarged cross-sectional view illustrating various bonding states of an electrode lead and an electrode tab in the embodiment shown in FIG. 3.
5 is a planar projection view of a secondary battery having a structure in which an electrode lead and an electrode tab are joined using two slits provided in the electrode lead according to another exemplary embodiment of the present invention.
6 shows a first slit in an electrode tab, a second slit in an electrode lead, an electrode tab is inserted into the second slit, and an electrode lead is inserted into the first slit according to another embodiment of the present invention. It is a planar projection view of a secondary battery having a bonded structure.
7 is a secondary battery having a structure in which a first slit is formed on an electrode tab and a second slit is formed on an electrode lead, and a connection member is inserted into and joined to the first and second slits according to another embodiment of the present invention. Is a planar projection of.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the common or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention. Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 is a secondary battery having a structure in which an electrode tab 230 is inserted into a slit 260 formed in an electrode lead 240, and thus, the electrode lead 240 and the electrode tab 230 are bonded to each other. 100 is a planar projection view.

Referring to FIG. 1, a secondary battery 100 according to an embodiment of the present invention includes an electrode tab 230 and an electrode lead 240.

The electrode lead 240 is formed with a slit 260 for forming a junction structure with the electrode tab 230. The electrode tab 230 is inserted into the slit 260 and bonded to the electrode lead 240. The width and length of the slit 260 can be adjusted according to the size of the electrode tab 230 is inserted. Preferably, the electrode tab 230 and the electrode lead 240 are bonded at an interface in contact with each other.

2 is a partially enlarged cross-sectional view illustrating various bonding states of the electrode lead 240 and the electrode tab 230 in the embodiment shown in FIG. 1.

As shown in (a) and (b) of FIG. 2, the electrode lead 240 may be bonded to any one surface of the upper or lower surface of the electrode tab 230 inserted into the slit 260. In addition, as shown in FIG. 2C, the electrode lead 240 may be bonded to both the upper and lower surfaces of the electrode tab 230 inserted into the slit 260.

Reference numerals 270 of FIGS. 1 and 2 schematically show a point where the electrode tab 230 and the electrode lead 240 are bonded to each other using an ultrasonic welding technique. It is apparent that the bonding between the electrode tab 230 and the electrode lead 240 may be made by resistance welding, laser welding, or conductive adhesive in addition to ultrasonic welding. In addition, the junction point and junction area of the electrode tab 230 and the electrode lead 240 may be variously modified according to the characteristics of the secondary battery.

3 is a planar view of a secondary battery 100 having a structure in which an electrode lead 240 is inserted into a slit 260 formed in an electrode tab 230 and bonded to the electrode tab 230 according to another exemplary embodiment of the present invention. to be.

Referring to FIG. 3, unlike the above-described embodiment, the slit 260 may be formed in the electrode tab 230. In this case, the electrode lead 240 may be bonded to the electrode lead 240 while being inserted into the slit 260 of the electrode tab 230.

4 is a partially enlarged cross-sectional view illustrating various bonding states of the electrode lead 240 and the electrode tab 230 in the embodiment illustrated in FIG. 3.

As shown in the figure, the bonding position of the electrode tab 230 and the electrode lead 240 may be variously modified. That is, the electrode tab 230 may be bonded to an upper surface and / or a lower surface of the electrode lead 240 inserted into the slit 260.

FIG. 5 illustrates a structure in which the electrode tab 230 is bonded to the two slits 260 provided in the electrode lead 240 so that the electrode tab 230 passes through the slits 260. A planar projection view of the secondary battery 100.

Referring to FIG. 5, unlike the above-described embodiment, two slits 260 may be formed in the electrode lead 240. In this case, the electrode tab 230 is bonded to the electrode lead 240 in a state where the electrode tab 230 is inserted to pass through both slits 260.

On the other hand, the number of the slits 260 formed in the electrode lead 240 can be increased to three or more, the spacing of the slits 260 can also be variously adjusted. In addition, as shown in FIG. 5, two or more slits 260 are formed in the electrode tab 230, and the electrode leads 240 are inserted to pass through the two or more slits 260. Embodiments to be bonded to the electrode tab 230 may be any number.

6 is a plan view of a secondary battery 100 according to another embodiment of the present invention.

Referring to FIG. 6, unlike the above-described exemplary embodiment, the first slit 261 may be formed on the electrode tab 230, and the second slit 262 may be formed on the electrode lead 240. In this case, the electrode tab 230 and the electrode lead 240 are inserted into the second slit 262 and the electrode lead 240 is inserted into the first slit 261. Can be spliced.

7 is a plan view of a secondary battery 100 according to another embodiment of the present invention.

Referring to FIG. 7, when the first slit 261 is formed on the electrode tab 230 and the second slit 262 is formed on the electrode lead 240, separate connection members 280 may be formed in the first and second slits. A structure in which the electrode tab 230, the electrode lead 240, and the connection member 280 are joined to each other in the state of being inserted into the 261 and 262 is also possible.

The connection member 280 may be made of a metal having the same material as that of the electrode lead 240. Alternatively, the connection member 280 may be made of a metal having better elasticity and ductility than the electrode lead 240. In this case, the possibility of disconnection of the electrode tab 230 and the electrode lead 240 is reduced due to the drop of the secondary battery 100 or an impact applied from the outside.

The secondary battery 100 according to the present invention described above includes a battery case 200 and a cell assembly 220 as common components.

The battery case 200 serves to protect the cell assembly 220. The battery case 200 may be formed of a pouch film having a structure in which a thermal fusion film / metal film / protective film is sequentially stacked. In this case, the battery case 200 has a sealing line 210 formed at the edge through a heat fusion process.

The present invention is not limited by the type of battery case 200. Therefore, it is apparent that the present invention can be applied as much as the battery case 200 is changed to a can-type case.

The battery case 200 includes an electrolyte required for the operation of the secondary battery. The electrolyte varies depending on the type of the secondary battery. For example, a liquid electrolyte, a solid electrolyte, a gel electrolyte, or the like including a lithium salt may be used.

The cell assembly 220 sealed in the battery case 200 includes at least two unit cells including a positive electrode plate, a separator, and a negative electrode plate. The positive electrode plate and the negative electrode plate are not particularly limited as long as they are metal materials having different redox potentials. For example, the positive electrode plate may be made of aluminum, and the negative electrode plate may be made of copper. The positive electrode plate and the negative electrode plate are coated with an active material required for operation of the secondary battery. The active material is not particularly limited as long as it is a material capable of inserting and detaching a specific cation during charging and discharging of a secondary battery. There may be. The separator is not particularly limited as long as it is a porous insulating membrane that ensures the movement of a specific cation. For example, the separator may be made of a porous polyolefin membrane. The separator may be provided with a coating layer of inorganic particles on the surface in order to improve the safety of the secondary battery.

A portion of the positive electrode plate is provided with a positive electrode tab, and the positive electrode tab may have a shape in which the positive electrode plate extends. Alternatively, the conductive material may be bonded to a predetermined portion of the positive electrode plate by welding or the like. In addition, the positive electrode material may be applied to a portion of the outer circumferential surface of the positive electrode plate and dried to form a positive electrode tab. The positive electrode tab is electrically connected to the positive lead through the slit 260 according to the present invention. The anode lead is not particularly limited as long as it is a metal having excellent electrical conductivity. For example, the anode lead may be formed of an aluminum plate.

The negative electrode plate is also provided with a negative electrode tab in a portion, and may be implemented in a form extending from the negative electrode plate, as described above, may also be connected by a method such as welding a member of a conductive material to a predetermined portion of the negative electrode plate. It is also possible to form the negative electrode material in a manner such as coating and drying on a portion of the outer peripheral surface of the negative electrode plate. The negative electrode tab is electrically connected to the negative electrode lead through the slit 260 according to the present invention. The negative electrode lead is not particularly limited as long as the metal has excellent electrical conductivity. For example, the negative electrode lead may be formed of a nickel plated copper plate.

The cell assembly 220 may have a simple stack structure, a stack / fold structure, a jelly roll structure, and the like according to a stacking method of unit cells. The stack / folding structure refers to a structure in which the unit cells are inserted between the folding films by disposing unit cells on a separate folding film at regular intervals and winding the unit cells in one direction together with the folding film. The jelly roll structure refers to a structure formed by disposing a unit cell having a structure extending in a winding direction on a separate winding film and winding the unit cell in a roll form together with the winding film.

 The secondary battery according to the present invention may further include an insulating tape 250. The insulating tape 250 serves to improve adhesion between the battery case 200 and the electrode lead 240. The insulating tape 250 is not particularly limited as long as it is an insulating material while improving the adhesion between the electrode lead 240 and the battery case 200. For example, the insulating tape 250 may be made of polyethylene, polyacetylene, PTFE, nylon, polyimide, polyethylene talephthalate, polypropylene, or a synthetic material thereof.

According to an aspect of the present invention, the bonding structure of the electrode lead and the electrode tab can be stabilized by introducing the bonding structure through the slit. In addition, since the junction structure between the electrode lead and the electrode tab is stabilized, a secondary battery having a low possibility of disconnection from external shock can be provided.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not to be limited to the details thereof and that various changes and modifications will be apparent to those skilled in the art. And various modifications and variations are possible within the scope of the appended claims.

100: secondary battery 200: battery case
210: sealing line 220: cell assembly
230: electrode tab 240: electrode lead
250: insulating tape 260: slit
261: first slit 262: second slit
270: joining point 280: connection member

Claims (12)

A cell assembly including at least two unit cells including a positive plate, a separator, and a negative plate;
Electrode tabs protruding from the positive and negative plates of each unit cell; And
An electrode lead bonded to the electrode tab;
Bonding of the electrode lead and the electrode tab is a secondary battery, characterized in that the other side is inserted into the slit formed in any one. The method of claim 1,
The slit is formed in the electrode lead,
And the electrode tab is bonded to the electrode lead while the electrode tab is inserted into the slit. The method of claim 2,
The electrode lead is bonded to any one of the upper surface or the lower surface of the electrode tab inserted into the slit. The method of claim 2,
The electrode lead is secondary battery, characterized in that bonded to both the upper surface and the lower surface of the electrode tab inserted into the slit. The method of claim 1,
The slit is formed on the electrode tab,
And the electrode lead is bonded to the electrode tab while being inserted into a slit of the electrode tab. The method of claim 5,
The electrode tab is secondary battery, characterized in that bonded to any one of the upper surface or the lower surface of the electrode lead inserted into the slit. The method of claim 5,
The electrode tab is secondary battery, characterized in that bonded to both the upper surface and the lower surface of the electrode lead inserted into the slit. The method of claim 1,
Two or more slits are formed in the electrode lead,
And the electrode tab is inserted to pass through the two or more slits and bonded to the electrode lead. The method of claim 1,
Two or more slits are formed in the electrode tab,
And the electrode lead is inserted to pass through the two or more slits and bonded to the electrode tab. The method of claim 1,
A first slit is formed in the electrode tab, and a second slit is formed in the electrode lead.
The electrode tab is inserted into the second slit, the secondary battery, characterized in that the electrode tab and the electrode lead is bonded in the state inserted into the first slit. A cell assembly including at least two unit cells including a positive plate, a separator, and a negative plate;
An electrode tab protruding from the positive and negative plates of each unit cell and having a first slit formed at one end thereof;
An electrode lead electrically connected to the electrode tab and having a second slit formed at one end thereof; And
And a connection member inserted into the first slit and the second slit and bonded to the electrode tab and the electrode lead. 12. The method according to any one of claims 1 to 11,
Bonding of the electrode lead and the electrode tab is a secondary battery, characterized in that made by ultrasonic welding, resistance welding, laser welding or conductive adhesive.

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