KR102032512B1 - An electrode assembly with improved safety in use by patterned structure of exterior materials and a lithium ion battery with the electrode assembly - Google Patents

Abstract

Secondary battery according to the present invention is an electrode assembly; And an exterior member having a structure in which an upper stamping portion and a lower stamping portion are repeatedly pressed to surround the outside of the electrode assembly, wherein the upper stamping portion and the lower stamping portion form a pleat pattern, and the electrode assembly includes a separator. At least one unit cell having a pair of electrode plates having different polarities; An electrode mixture applied on one or both surfaces of the pair of electrode plates; And electrode tabs protruding from the electrode plates at the same time, and wherein the electrode mixture is not coated, wherein the electrode tabs include tabs for parallel connection of electrodes and tabs for connecting electrode leads. At least one of the electrode tabs of the electrode parallel connection tab and the electrode lead connection tab is formed, and the gap between the corrugation patterns is different.

Description

An electrode assembly with improved safety in use by patterned structure of exterior materials and a lithium ion battery with the electrode assembly}

The present invention is to control the pattern spacing of the packaging material in order to prevent the risk of fire or explosion caused by breakage and internal short circuit, which is a mechanical problem of the battery that may be caused by the external repeated forces bending and twisting in a flexible environment The present invention relates to a technology for ensuring safety of use by inducing cutting of the outermost electrode provided with a tab for electrode lead connection and a tab for parallel connection before a breakdown of an outer material constituting a battery or an internal short occurs through the battery. .

Secondary batteries (secondary battery) is a battery that can be charged and discharged, unlike a primary battery that can not be charged, and is widely used in the field of advanced electronic devices such as cellular phones, notebook computers, camcorders. As the weight reduction and high functionality of the portable electronic devices and the Internet of things (IoT) are developed, many researches on secondary batteries used as driving power sources have been made.

In particular, lithium secondary batteries have higher voltages and higher energy densities per unit weight than nickel-cadmium batteries or nickel-hydrogen batteries, which are widely used as power sources for portable electronic equipment.

The secondary battery is a battery using an electrochemical reaction generated between the electrolyte and the electrode when the positive electrode and the negative electrode are connected with the positive electrode and the negative electrode inserted into the electrolytic material. Unlike the conventional primary battery, the electric and electronic products Since the battery can be recharged and recharged by recharging the energy consumed by the charger, the trend is spreading with the popularization of wireless electric and electronic products.

In general, a lithium electrode-type wound electrode assembly in which a separator is inserted between a positive electrode plate and a negative electrode plate and spirally wound together, or a flexible stacked electrode assembly formed by stacking a plurality of positive electrode plates and a negative electrode plate with a separator interposed therebetween is lithium. I use it a lot in a secondary battery. For example, a cylindrical battery is one that houses a wound electrode assembly in a cylindrical can, injects electrolyte, and seals it, while a square cell compresses the wound electrode assembly or stacked electrode assembly to make it flat and flat, and then stores it in a square can. It is. In the pouch type battery, the wound electrode assembly or the stacked electrode assembly is packaged together with an electrolyte in a pouch type packaging material. In such an electrode assembly, the positive electrode tab and the negative electrode tab may be respectively drawn out of the electrode assembly from the positive electrode plate and the negative electrode plate and connected to the positive electrode and the negative electrode of the secondary battery.

On the other hand, the conventional pouch type lithium secondary battery is damaged by the intentional force applied to the exterior of the lithium secondary battery by the external force, the electrolyte leakage and the inflow of the outside air contained in the exterior material occurs. Such electrolyte leakage inhibits normal operation such as corroding peripheral components such as battery protection circuits. In addition, it causes a large safety problem such as ignition due to the inflow of outside air.

As a method for improving the durability of lithium secondary batteries, electrochemical driving is stably performed even when bending, torsion, etc., which is a force repeatedly applied by improving the durability of the battery by forming the exterior pattern and forming the terminal reinforcement structure of the lithium secondary battery. To make it possible.

On the other hand, in a flexible environment, a short circuit may occur due to breakage of the exterior material and misalignment or separation of internal electrodes due to repeated bending and torsion, such that a fire or explosion may occur. The internal short circuit generates excessive heat due to excessive current flow in proportion to the contact area between the anode and the cathode. In this case, an additional secondary short circuit may occur, which may cause a risk of fire and explosion.

In the general battery structure, in the case of the winding type or the general stacked battery, all the electrodes are connected to the outside, and an internal short circuit occurs when the electrode and the separator are damaged due to an external impact.

In the case where the internal short circuit occurs as described above, even if the internal electrode or the outermost electrode, which may be any part of the electrode assembly, may have a problem that only the capacity decreases, the current flows out of the electrode assembly. There is no problem with the operation, so there is no problem with the operation of the battery. However, when the continuous use in the broken and cut state of the internal electrode may be a problem to the safety there is a seriousness.

Referring to Korean Unexamined Patent Publication No. 10-2016-0090104, in order to overcome the problems of breakage and lack of electrolyte resistance when external force is applied from an external electrode assembly included in a conventional pouch type battery, a flexible battery electrode Disclosed is the provision of a reinforcing member on one surface of the assembly to prevent breakage even when an external force is applied.

(Patent Document 1) KR10-2016-0090104 A

Accordingly, the problem to be solved by the present invention, by inducing the cutting of the outermost electrode provided with a tab for electrode lead connection before the breakage of the packaging material constituting the battery or the internal short circuit occurs by adjusting the pattern spacing of the packaging material. It is an object to provide a structure that ensures safety in use.

Lithium ion secondary battery according to the present invention for achieving the above object is an electrode assembly; And an exterior member having a structure in which an upper stamping portion and a lower stamping portion are repeatedly pressed to surround the outside of the electrode assembly, wherein the upper stamping portion and the lower stamping portion form a pleat pattern, and the electrode assembly includes a separator. At least one unit cell having a pair of electrode plates having different polarities; An electrode mixture applied on one or both surfaces of the pair of electrode plates; And electrode tabs protruding from the electrode plates at the same time, and wherein the electrode mixture is not coated, wherein the electrode tabs include tabs for parallel connection of electrodes and tabs for connecting electrode leads. At least one of the electrode tabs of the electrode parallel connection tab and the electrode lead connection tab is formed, and the gap between the corrugation patterns is different.

The electrode assembly includes an outermost negative electrode plate disposed at the outermost side and an outermost positive electrode plate integrally disposed inside the outermost negative electrode plate, and the outermost negative electrode plate and the outermost positive electrode plate respectively have tabs and electrode leads for parallel connection of electrodes. Includes all tabs for the connection.

The wrinkle pattern spacing of the packaging material is a width of each of the upper stamping portion and the lower stamping portion set to X, which is a basic pattern spacing, and a different wrinkle pattern spacing Y in the partial region of the packaging material is X <Y ≦ 5X.

The electrode assembly may further include a reinforcement tab welded and fixed on the electrode lead connection tab of any of the electrode tabs constituting the electrode assembly.

The tab lead coupling portion of the structure in which the electrode lead connection tab and the electrode lead are padded using the reinforcement tab is inserted into and aligned with the inside of the separator.

The electrode lead coupled to the electrode lead connection tab of any one of the electrode tabs constituting the electrode assembly is bent in an opposite direction to 180 ° in the state of being bonded to face the electrode assembly and bent toward the outside of the electrode assembly. It further includes a structure.

The tab-lead coupling portion to which the electrode lead connection tab and the electrode lead of the bent structure are coupled is inserted into and aligned inside the separator.

In the outermost negative electrode plates disposed at the top and bottom of the electrode assembly, the electrode mixture is coated in cross section.

According to the present invention, when tensile and compressive stresses caused by external bending on the electrode assembly are repeatedly applied, currents are interrupted by breaking and cutting portions corresponding to different patterns of the outer material of the outermost electrode constituting the electrode assembly. The structure can cause loss of battery function and safety of use.

That is, when the bending evaluation is performed at the same time as charging and discharging the electrode assembly, the outermost electrode portion facing the portion where the pattern width of the packaging material surrounding the electrode assembly is relatively larger than the basic pattern is the negative electrode which is the outermost electrode. As the separation distance between the inner anodes increases and the resistance increases, lithium remains in the outermost electrode, so that a difference in thickness occurs. It can be seen that the intentional outermost electrode can be cut at the time of repeatedly evaluating bending and bending due to an external force in a state where the electrode thickness is different.

In addition, as the charging / discharging proceeds, the electrodes undergo volume expansion and contraction, and corresponding electrode portions on patterns different from the basic pattern are continuously maintained in volume expansion, and stress is caused by repeated bending and bending outside. It is more severe locally than other parts.

In the case where the outermost electrode provided with both the electrode lead connection tab and the parallel connection tab is cut, the process of losing the function of the battery by cutting off the current by cutting off the only passage through which electrons in the active material are connected to the outside To ensure the safety of use.

The outermost electrode and the general electrodes constituting the electrode assembly according to the present invention are connected by tabs for parallel connection, and the terminal is formed on the electrode lead connection tab portion on the outermost electrode, and external forces such as bending and twisting are applied from the outside. In case of loss, the outermost electrode is preferentially damaged and cut rather than the inner general electrodes. At this time, when the outermost electrode provided with the electrode lead connection tab is cut off, the general electrodes connected by the parallel connection tab are shut down in the state where the current is cut off, and the capacity decreases rapidly and the battery returns to its original state. It doesn't work.

That is, the current blocking structure formed by inducing the cutting of the outermost electrode provided with the tab for electrode lead connection before the point of failure of the outer material or the internal short circuit by appropriately utilizing the type and arrangement of the outermost electrode constituting the electrode assembly. To ensure the safety of the battery.

Therefore, the present invention not only improves the flexibility of the battery through the shape and laminated structure of the electrode provided with the tab for parallel connection and the electrode lead connection tab at the same time, but also before the risk of internal short circuit due to breakage of the exterior material or lithium deposition. By intentionally inducing the cutting of the outermost electrode, the battery function can be lost, thereby ensuring the safety of the battery.

1 shows an exemplary configuration of an electrode assembly constituting a flexible battery according to the present invention.
2 and 3 show an exploded view of the electrode assembly with the outermost electrode disposed as a cathode according to an embodiment of the present invention.
4 and 5 show cracks and detachment of the mixture layer due to the difference in thickness occurring on the outermost cathode when the pattern spacing of the packaging material surrounding the electrode assembly is adjusted.
FIG. 6 shows a state in which cutting occurs on the outermost cell so that the other internal electrodes constituting the electrode assembly are set to a closed state.
7 shows a flexible battery having an exterior member surrounding the electrode assembly according to the present invention.
8 shows repeated bending evaluation results for the existing flexible battery and the flexible battery according to the present invention.

Hereinafter, a flexible battery according to the present invention will be described with reference to the accompanying drawings.

The following examples are detailed description to help understand the present invention, and it should be understood that the present invention is not intended to limit the scope of the present invention. Therefore, equivalent inventions that perform the same functions as the present invention will also fall within the scope of the present invention.

In addition, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

1 to 3, an embodiment of an electrode assembly having improved stability of a battery by enabling cutting of the outermost electrode by adjusting a pattern spacing of the exterior member according to the present invention will be described.

The electrode assembly is a unit cell (A) divided into the negative electrode plate 10 and the positive electrode plate 20 with the separator 30 interposed therebetween, an electrolyte that serves as an ion transfer medium between the negative electrode plate and the positive electrode plate, and protrudes from the electrode plate. The electrode tab is divided according to the parallel connection of the electrode and the electrode lead connection. At least one of the electrode plates including the negative electrode plate 10 and the positive electrode plate 20 may be spaced apart from the electrode parallel connection tab and the electrode lead connection tab on both sides. For example, any outermost negative electrode plate 10 disposed at the lowermost end of the electrode assembly 100 includes a tab 12 for negative electrode parallel connection and a tab 14 for negative electrode lead connection, and is directly connected to the outermost negative electrode plate 100. Any positive plate disposed on the top has a tab 22 for positive parallel connection and a tab 24 for positive lead connection. That is, the negative electrode and the positive electrode having both the tab for electrode parallel connection and the tab for electrode lead connection are integrally disposed at the lowermost end of the electrode assembly.

Herein, the electrode plates are applied to one or both surfaces of the electrode plate in which the electrode mixture is an electrode current collector, and the tabs for parallel connection of electrodes and the tabs for connecting electrode leads protrude from the electrode plates. Meanwhile, the electrode mixture is exposed in the uncoated state to the electrode parallel connection tab and the electrode lead connection tab.

The plurality of electrode plates are connected to the same pole through the electrode tab for parallel connection of the electrodes. That is, the plurality of negative electrode plates 10 and the plurality of positive electrode plates 20 are electrically connected in parallel by tab-tab coupling portions connecting the electrode tabs, respectively.

On the other hand, the electrode assembly has a structure that is electrically connected to the electrode lead exposed to the outside of the packaging material through the tab for connecting the electrode lead. The separator physically separates the electrode plates, but functions to pass ions included in the electrolyte.

The negative electrode plates disposed at the uppermost and lowermost ends of the electrode assembly may be in a state in which the negative electrode mixture 40 is applied only to a cross section.

The tabs 12 and 22 for parallel connection of electrodes in a state of protruding from the negative electrode plate 10 or the positive electrode plate 20 are electrically connected to each other by electrode plates having the same polarity. The parallel-connected tab-tab coupling is placed on a separator that surrounds the outer surface of the outermost electrode plate that forms the top or bottom of the electrode assembly and is finished tapered.

In the present invention, the connection between the tab-tab coupling portion in which the tabs 12 and 22 for parallel connection formed on the electrode plate are connected in parallel to each other and the tab-lead coupling portion in which the tabs 14 and 24 for connecting the electrode leads and the electrode lead are connected to each other And the joining is electrically connected through any one of the joining modes including joining by spot welding, ultrasonic welding, laser welding and conductive adhesive.

The electrodes disposed at the top and bottom of the electrode assembly are both negative electrode plates, but this is only an example and the present invention is not limited thereto. In the present invention, the uppermost and the lowermost electrodes may be disposed in the electrode assembly in any combination of a cathode / cathode, an anode / cathode, a cathode / anode, and an anode / anode.

The electrode assembly according to the present invention may reinforce a separate reinforcing tab on the electrode lead connection tabs 14 and 24 disposed on one side of the electrode assembly. By coupling the electrode leads to the reinforcing tabs, tab lead coupling portions having an overlay structure are formed using the reinforcing tabs of the electrode leads connecting tabs 14 and 24 and the electrode leads. The reinforcement bonding method for coupling the electrode leads tabs 14 and 24 and the electrode lead using the reinforcement tab corresponds to at least one of the positive electrode tab and the negative electrode.

The reinforcing tab is physically strengthened by reinforcing the strength of the connecting portions of the electrode leads connecting tabs 14 and 24 and the electrode leads. For example, the same or different metal reinforcing tabs thicker than 1 to 5 times thicker than the electrode lead connection tabs are welded on top of the electrode lead connection tabs extending from the electrode plate of the electrode assembly. Reinforcement tabs and tabs for connecting electrode leads that have been reinforced with padding have the same or different widths. The width of the reinforcing tab to be reinforced may be 3 mm to 5 mm, and the length may be 2 mm to 4 mm, but this is not limited thereto.

The electrode leads that engage with the tabs for connecting electrode leads by joining on reinforcement tabs reinforced with pads may specifically have a width of 2 mm to 3 mm and a length of 0.5 mm to 1 mm, but this is only one embodiment. It is not limited. In the present invention, the current collector of the electrode plate may be any one of a group containing aluminum, stainless steel and copper, the electrode lead may have a material of any one of the group containing aluminum, nickel and nickel coated copper. have. The tab for electrode lead connection and the reinforcing tab which reinforces on the tab-lead coupling part of the electrode lead are formed in the shape of one of a group including circles, ellipses and polygons.

On the other hand, the electrode assembly according to the present invention may be in the form of coupling the electrode lead bending structure on the electrode lead connecting tabs (14, 24).

In a state where the electrode leads are arranged side by side on the upper side of the tab for electrode lead connection, a part of the end of the electrode lead is welded to the upper end of the tab for electrode lead connection. In this state, the electrode lead is directed toward the outside of the electrode assembly from the electrode lead connection tab through the process of bending the electrode lead 180 degrees. This minimizes the local mechanical load in a flexible environment and is characterized by a joint reinforcement structure between the electrode tab and the electrode lead. The bonding method by bending the electrode lead connection tab and the electrode lead may correspond to at least one of a positive electrode tab and a negative electrode tab, and the width of the electrode lead 60 coupled to the electrode lead connection tab is 2 mm to 3 mm, the length may be 1 mm to 3 mm, but this is merely an example and not limited thereto.

Meanwhile, the tab-lead coupling portion in which the electrode leads connecting tabs 14 and 24 and the electrode lead are coupled using a reinforcing tab, and the tab-lead coupling portion in which the electrode lead coupling tab and the electrode lead of the bending tab structure are coupled to each other are separated from each other. It is inserted / aligned inwardly. This protects by preventing external exposure of the terminal portion, which is the weakest point of the flexible battery.

4 and 5 show cracks and detachment of the mixture layer due to the difference in thickness occurring on the outermost electrode when the pattern spacing of the packaging material surrounding the electrode assembly is adjusted.

The corrugation pattern formed on the packaging material shows a structure in which valleys are continuously formed along the longitudinal direction of the packaging material. In the case where the electrode assembly is provided in the packaging material of the corrugation pattern, in the region where the difference in pattern spacing is relatively wide, Local stress is applied.

Specifically, the pattern spacing may be changed on the middle region of the entire length of the packaging material, but the present invention is not limited thereto, and the pattern spacing may be varied in any region of the packaging material.

Here, in the evaluation of bending, it is possible to induce the cutting of the outermost electrode simultaneously provided with a tab for parallel connection and an electrode lead connection tab facing the exterior material having a wide pattern spacing before the breakage of the exterior material and an internal short circuit occur. Can be.

Hereinafter, referring to FIGS. 4 to 5, the result of bending and disassembling in the state in which the electrode assembly is embedded in a packaging material having a difference in pattern spacing will be described.

In general, a lithium secondary battery is inserted / desorbed into lithium ions while charging / discharging, thereby causing volume expansion and contraction of the negative electrode. State of Charge (SOC) refers to a battery capacity of a secondary battery, and represents its state at 0% to 100%. The method of measuring SOC includes a chemical method using a specific gravity and pH of an electrolyte, a voltage method, a current integration method of measuring a current of a cell and integrating it over time. Counting), there is a pressure measurement method (Pressure method) to calculate the internal pressure of the battery, but in the present invention, the voltage of the negative electrode in the fully discharged state (SOC 0%) and full charge state (SOC 100%) of the negative electrode through a voltage simply The thickness was measured. Usually, when the cathode is graphite, volume expansion of 7% on average and up to 10% occurs at full charge (SOC 100%).

In addition, it is a matter of course that the battery is disassembled in a dry room in which temperature and humidity are kept constant so that the thickness variable due to the reaction with the outside air does not work.

It can be seen that a difference in thickness occurred on the outermost electrode directly facing the portion of the surface of the packaging material that gave a difference in the wrinkle pattern spacing.

It can be seen that the gap between the electrodes in the separator is widened in the portion where the pattern interval is wide. In other words, the cathode and anode, which are the outermost electrodes, should face each other as close as possible with the separator interposed therebetween. The distance is greater and the resistance is greater.

When the electrode resistance is largely applied to the cathode and anode portions, which are the outermost electrodes, the specific capacity decreases, and lithium does not move toward the anode during discharge and remains in the cathode.

In summary, during the bending evaluation discharge of the flexible battery in which the pattern interval of the exterior material is adjusted according to the present invention, the electrode thickness t 'corresponding to the portion where the pattern interval is widened and the thickness t of the electrode which is not When the thickness difference (t'-t) occurs.

In one embodiment, the distance between the electrodes facing a different pattern of a specific region, rather than the general pattern spacing of the electrodes in the electrode assembly, due to the pattern spacing difference between the electrode portion having a pattern spacing of d and the electrode portion having a pattern spacing of 2d. Is relatively far away or less discharged due to electrode resistance, the thickness difference (t'-t) occurs in the portion, it can be seen that the sample is 2 to 4% of the thickness of the negative electrode mixture layer.

When the bending evaluation is carried out while charging and discharging, it can be seen that due to the above-described thickness difference, it is cut at about 1500-2500 bends in a relatively thick region of the electrode in the discharge state.

In addition, as charging and discharging proceeds, the electrode undergoes volume expansion and contraction. The electrode portion facing the different pattern of a specific region, not the general pattern interval, is continuously maintained in the volume expansion, and the external bending and bending repeatedly As a result, the stress acts locally more severely than in other parts. Eventually, the mixture layer is cracked and detached from the current collector and noise is generated, thereby preventing normal operation of the battery.

The pattern spacing of the packaging material may be differently arranged as X and Y as shown in FIG. 7, wherein a different pleat pattern spacing Y in some areas of the packaging material is preferably 5X wider than 5 times the basic pattern spacing X. . The reason is that according to the pattern spacing design described above, cutting of the outermost electrode can be effectively induced while maintaining a flexible performance against externally applied forces.

When Y, which is a different wrinkle pattern interval in some areas of the exterior member, is less than or equal to the basic pattern interval X, cutting of the outermost electrode cannot be effectively induced, and pattern formation of the exterior member is not easy.

Moreover, when it exceeds 5X, performance as a flexible battery cannot be implemented. The pattern repeatedly pressed on the exterior material allows the flexible battery to be compressed and stretched in bending, torsional or wrinkling operation. When it exceeds 5X, the exterior material is equivalent to bending a non-patterned battery. Of course, the electrode is damaged at the same time.

FIG. 6 shows a structure in which other internal electrodes constituting the electrode assembly are set to a closed state (shut down) by cutting occurring on the outermost cell.

Specifically, a plurality of batteries constituting the electrode assembly is connected through a tab for parallel connection on the right side, and a terminal is formed in the tab portion for electrode lead connection in the electrode plate disposed at the outermost part of the lower end of the plurality of batteries.

In this state, when external forces such as bending and torsion are applied on the electrode assembly from the outside, the electrode at the outermost portion of the lower end portion is preferentially damaged and cut rather than inside the electrode assembly.

At this time, when the outermost electrode provided with the electrode lead connection tab is cut off, the electrodes connected by the parallel connection tab are cut off, the current is closed, and the capacity decreases rapidly, thereby preventing the battery from functioning. This provides a function that prevents, in spite of the damage of the internal electrode, in contrast to the conventional battery having the risk of ignition that can occur due to internal short-circuit in continuous use.

To this end, the present invention appropriately utilizes the type and arrangement of the outermost electrode to induce cutting of the electrode provided with a tab for electrode lead connection before the breakage of the exterior material or the internal short occurs. This intended structure can be applied to devices that safeguard the battery from the risks of user carelessness or excessive bending and require the assurance and control of the performance of the flexible battery above a certain number of bends by external forces.

8 shows repeated bending evaluation results for the conventional flexible battery and the flexible battery according to the present invention. Specifically, the conventional flexible battery, the flexible battery in which the electrode is cut by different pattern intervals of the packaging material, and the crack of the mixture layer and the detached flexible battery are sequentially seen from above.

In each case, the results of charge / discharge and bending evaluation (25 cpm) of the flexible battery will be described.

The existing flexible battery shows normal electrochemical driving even over 5,000 times. However, it can be seen that the flexible battery having exterior parts having different pattern intervals in some regions generates small noise starting from discharge of 3.6V around 2,000 times, and the voltage dropped below the operating voltage at the same time as the cutting of the outermost cathode.

In the bottom graph, cracks and detachment of the mixture layer applied on the electrode were caused by a flexible battery having exterior portions having different pattern intervals in some regions, and the mixture layer was first detached from the current collector near 4.2V at the beginning of discharge. As a result, the voltage suddenly dropped and noise was continuously generated. As a result, the cracks in the mixture layer and the current collector were reduced rapidly, and the voltage dropped below the operating voltage.

As a result of many experiments as described above, by forming different wrinkle patterns formed on the exterior material, cracking or detachment of the electrode and cracking of the mixture layer may occur at local portions on the outermost electrode at a bending number of about 1,500 to 2,500. Through this, it is possible to secure the safety of the battery by designing the damage and cutting of the outermost electrode intentionally before the excessive number of bending, which is likely to damage the outer material or the internal short circuit due to lithium precipitation.

According to the present invention, when the tensile stress and the compressive stress due to external bending on the electrode assembly are repeatedly applied, the user cuts through a structure in which currents are cut off by matching portions on different patterns of the outermost material of the outermost electrode constituting the electrode assembly. It can be applied to a device that secures the battery from the danger of inadvertent or excessive bending, and requires the guarantee and control of the performance of the flexible battery above a certain number of bending times by external force.

Claims (9)

An electrode assembly; And
It includes; surrounds the exterior of the electrode assembly;
The electrode assembly,
At least one unit cell having a pair of electrode plates having different polarities with a separator therebetween;
An electrode mixture applied on one or both surfaces of the pair of electrode plates; And
Electrode tabs protruding from the electrode plates, respectively;
The electrode tab,
Tabs for parallel connection of electrodes connecting the electrode plates to one another; And
An electrode lead connection tab coupled to an electrode lead exposed to the outside of the exterior material;
So that the electrode assembly is closed by damage at the outermost part of the electrode assembly,
The electrode lead connection tab is formed on an electrode plate disposed on the outermost side of the electrode assembly,
The packaging material includes a repeating upper stamping portion and a lower stamping portion,
Of the areas facing the electrode plate disposed at the outermost side of the packaging material, the distance between the repeated upper and lower indentations in some areas is greater than the distance between the repeated upper and lower indentations in the remaining areas. Secondary battery, characterized in that formed.
The method of claim 1,
The electrode assembly includes an outermost positive electrode plate disposed to face the outermost negative electrode plate and the outermost negative electrode plate disposed between the outermost negative electrode plate and the separator interposed therebetween,
Secondary batteries are formed in the outermost negative electrode plate and the outermost positive electrode plate both tab for the electrode parallel connection and the electrode lead connection.
The method of claim 1,
In the state where the width of each of the upper and lower indentations in the remaining area is set to X, which is a basic pattern interval, Y, which is the width of each of the upper and lower indentations in the partial area, is X <Y≤ 5X secondary battery.
The method of claim 1,
The electrode assembly,
And a reinforcing tab coupled to the electrode lead connection tab.
The method of claim 1,
The electrode lead is,
The secondary battery further includes a bending structure formed on the tab for connecting the electrode leads to bend in a direction toward the outside of the electrode assembly from the side facing the electrode assembly.
The method of claim 4, wherein
The tab lead coupling portion padded by the reinforcing tab is inserted into the separator.
The method of claim 5,
And a tab-lead coupling part to which the electrode lead connection tab and the electrode lead of the bent structure are coupled are inserted into the separator.
The method of claim 1,
The outermost negative electrode plates disposed on the top and bottom of the electrode assembly is a secondary battery, the electrode mixture is coated on one side.
The method of claim 1,
Damage at the outermost side of the electrode assembly is caused by cracking of the electrode mixture or detachment from the electrode plate of the electrode mixture as the gap between the electrode plates increases in an area corresponding to the partial region. Secondary battery characterized in that the.

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