KR101879869B1 - Pouch battery - Google Patents

Abstract

A pouch battery having improved overcharge safety is disclosed. The pouch battery includes an electrode assembly including a cathode plate, a cathode plate, and a separator interposed between the cathode plate and the anode plate, a lead tab extended from the electrode assembly, a pouch accommodating the electrode assembly, and a space inside the pouch And a filler disposed within the pouch together with the electrode assembly.

Description

Pouch Battery {POUCH BATTERY}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pouch battery, and more particularly, to a pouch battery having a reduced risk of ignition during overcharging and improved overcharge safety.

As the application of the pouch type secondary battery expands, the energy density and the energy storage amount in the unit cell are increasing. Particularly, in the case of a secondary battery for a vehicle, application of a high energy technology is rapidly proceeding to satisfy a demand for an increase in a mileage.

However, secondary batteries in the form of pouches may become less stable due to higher energies. In other words, as more energy is stored, risk factors such as ignition and explosion can increase.

For example, if abnormal overcharging, that is, overcharge occurs during charging of the pouch-type secondary battery, the voltage of the battery exceeds the normal range, resulting in an energy unstable state. At this time, the electrolytic solution is decomposed in the inside of the pouch battery and gas may be generated. The generated gas is a flammable gas, which increases the risk of ignition.

Accordingly, when the pouch type secondary battery is overcharged, a technique for lowering the risk of ignition is needed.

One aspect of the present invention provides a pouch battery having a reduced dead space in a pouch to reduce the risk of ignition due to overcharging.

According to another aspect of the present invention, there is provided a pouch battery having improved stability in an overcharged state by advancing a pouch vent timing due to gas generated during overcharging.

According to another aspect of the present invention, there is provided a pouch battery capable of adjusting a pouch vent timing when manufacturing a pouch battery.

According to an aspect of the present invention, a pouch battery includes an electrode assembly including a negative electrode plate, a positive electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate, a lead tab extending from the electrode assembly, a pouch accommodating the electrode assembly, And a filler disposed within the pouch together with the electrode assembly to reduce the space inside the pouch.

The filler may occupy a space inside the pouch to discharge gas generated from the electrode assembly to the outside of the pouch when overcharged.

As the number of the fillers increases, the time at which the gas generated from the electrode assembly is discharged to the outside of the pouch due to overcharging may be accelerated.

As the size of the filler increases, a time point at which gas generated from the electrode assembly is discharged to the outside of the pouch due to overcharging may be accelerated.

The filler may be configured to be inflatable according to a pressure change in the pouch.

The lead tab may include a first lead tab and a second lead tab, and the first lead tab and the second lead tab may protrude from the electrode assembly in both directions.

The filler may include a plurality of fillers, and the plurality of fillers may be disposed on both sides of the lead tab.

The filler may have a sphere shape when its volume is at its maximum.

According to an aspect of the present invention, there is provided a method of manufacturing a pouch battery, including the steps of preparing an electrode assembly, accommodating the electrode assembly, a filler provided to be inflatable according to a change in pressure in the pouch, The method comprising: injecting an electrolyte; charging and discharging the electrode assembly to activate the electrode assembly; removing gas generated during charging and discharging of the electrode assembly; and sealing the pouch. have.

In the step of housing the electrode assembly and the filler in the pouch, the filler may be disposed on both sides of the lead tab projecting from the electrode assembly.

In the step of removing the gas, the filler may be provided to increase in volume according to a pressure change inside the pouch.

According to the idea of the present invention, it is possible to provide a pouch battery which reduces the dead space in the pouch and thereby reduces the risk of ignition due to overcharging.

According to an aspect of the present invention, it is possible to provide a pouch battery in which stability in an overcharged state is improved by advancing a pouch vent timing due to gas generated during overcharging.

According to the idea of the present invention, it is possible to provide a pouch battery which can control the pouch vent timing when manufacturing the pouch battery.

1 is a view showing an appearance of a pouch battery according to an embodiment of the present invention.
2 is a plan view of the pouch battery shown in Fig.
Fig. 3 is a view showing a state before the filler is expanded in the pouch battery shown in Fig. 1. Fig.
Fig. 4 is a view showing a state after a filler is expanded in the pouch battery shown in Fig. 1. Fig.
5 is a flowchart illustrating a method of manufacturing a pouch battery according to an embodiment of the present invention.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory only and are not restrictive of the invention, as claimed, and it is to be understood that the invention is not limited to the disclosed embodiments.

In addition, the same reference numerals or signs shown in the respective figures of the present specification indicate components or components performing substantially the same function.

Also, the terms used herein are used to illustrate the embodiments and are not intended to limit and / or limit the disclosed invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more features, integers, steps, operations, elements, components, or combinations thereof.

It is also to be understood that terms including ordinals such as " first ", "second ", and the like used herein may be used to describe various elements, but the elements are not limited by the terms, It is used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as a second component, and similarly, the second component may also be referred to as a first component. The term "and / or" includes any combination of a plurality of related listed items or any of a plurality of related listed items.

The terms "front", "rear", "upper" and "lower" used in the following description are defined based on the drawings, and the shape and position of each component are not limited by these terms.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing an appearance of a pouch battery 1 according to an embodiment of the present invention.

The pouch battery 1 of the present invention includes an electrode assembly 100 including a negative electrode plate, a positive electrode plate, a separator interposed between the positive electrode plate and the negative electrode plate, a lead tab 200 extending from the electrode assembly 100, 100, as shown in FIG. The pouch 300 may include a filler 400 disposed inside the pouch 300 to reduce a dead space inside the pouch 300.

The electrode assembly 100 may include a negative electrode plate, a positive electrode plate, and a separator. The separator is provided between the positive electrode plate and the separator to insulate the positive electrode plate and the negative electrode plate. On the other hand, the electrode assembly 100 can be manufactured in the form of a rolled jelly known as a jelly roll.

The lead tab 200 may include a first lead tab 210 and a second lead tab 220. The first lead tab 210 can be welded to the negative plate, and the second lead tab 220 can be welded to the positive plate.

The lead tab 200 may be located on the short side of the electrode assembly 100 or on the long side of the electrode assembly 100. Further, the lead tabs 200 may protrude from both sides of the electrode assembly 100, respectively. Needless to say, the lead tabs 200 may protrude from one side of the electrode assembly 100 in parallel.

The pouch 300 may be provided to receive the electrode assembly 100 and the filler 400. The pouch 300 may be provided as a film of a metal material. For example, the pouch 300 may be provided with a thin aluminum alloy.

A filler 400 may be disposed within the pouch 300 to reduce dead space 310 within the pouch 300. The pillar 400 is disposed in the pouch space 300 of the pouch 300 so that the pouch 300 can be reduced in the dead space 310 by the volume of the pillar 400. A detailed description thereof will be described later.

The filler 400 may be provided so that the volume of the filler 400 changes according to a pressure change inside the pouch 300. The filler 400 may be provided as a sphere having a plastic material.

The filler 400 can be received in the pouch 300 without the air inside. In this case, the filler 400 occupies a relatively small volume inside the pouch 300. Therefore, due to the volume occupied by the filler 400, it is possible to prevent the phenomenon that the electrolytic solution overflows at the electrolyte solution instilling step to be described later.

The filler 400 may increase its volume in the degassing step of removing the gas inside the pouch 300. As a result, the space occupied by the filler 400 in the pouch 300 is increased, and the dead space 310 inside the pouch 300 is reduced as described above.

2 is a plan view of the pouch battery shown in Fig. FIG. 3 is a view showing a state before a filler is expanded in the pouch battery shown in FIG. 1, FIG. 4 is a view showing a state after a filler is expanded in the pouch battery shown in FIG. 1 to be.

As shown in FIG. 2, a sealing portion 500 may be provided on the inner periphery of the pouch 300.

The sealing part 500 may be provided to block the electrode assembly 100 from the outside of the pouch 300. The space inside the pouch 300 accommodating the electrode assembly 100 may specifically indicate a space inside the sealing part 500.

The sealing part 500 may be provided such that the distance from the side where the lead tab 200 is not provided in the electrode assembly 100 is short. On the other hand, the sealing portion 500 may have a relatively long distance from the side where the lead tab 200 is provided in the electrode assembly 100.

The distance between the short side of the electrode body 100 and the short side of the sealing part 500 is longer than the distance between the long side of the electrode assembly 100 and the long side of the sealing part 500, . This is because a lead tab weld (not shown) is provided for extending the lead tab 200 from the electrode assembly 100. That is, since a lead tab weld portion (not shown) is provided at one end of the lead tab 200, the distance between the sealing portion 500 and the electrode assembly 100 is relatively large.

The sealing part 500 may be provided to block the electrode assembly 100 from the outside of the pouch 300 as described above.

Gas may be generated in the electrode assembly 100 due to overcharging of the pouch battery 1. This gas spreads in the space inside the sealing part 500. The inside of the pouch 300 can be pressurized by the gas. Further, the pouch 300 is inflated. Gas is excessively generated inside the pouch due to overcharging or internal short circuit, and the pressure is increased. When the pressure reaches the reference pressure, the sealing part 500 may be damaged. The sealing part 500 may be randomly broken according to the mounting state of the pouch-type secondary battery mounted on a mechanical device, an electronic device, etc., and the operating state of the pouch-type secondary battery. That is, it is impossible to know exactly what area of the sealing part 500 is broken. At this time, the gas can be discharged to the outside of the pouch 300 through the damaged side of the sealing part 500. That is, gas can be vented.

Conventionally, no configuration is arranged in the space around the lead tab 200 in the space inside the pouch 300. The space around the lead tab 200 is treated as a dead space. Particularly, when gas is generated from the electrode assembly 100 during overcharging of the pouch battery 1, the gas collects in the dead space, and the vent timing of the pouch battery 1 is delayed. The temperature of the electrode assembly 100 rises and the risk of ignition of the pouch battery 1 is further increased. Therefore, it was necessary to advance the timing of the gas evolving in overcharging.

According to an embodiment of the present invention, a plurality of pillars 400 may be disposed inside the pouch 300. The pillars 400 may be disposed in the dead space 310 inside the pouch 300. The pillars 400 are disposed in the dead space 310 so that the dead space 310 can be reduced by the volume of the pillars 400.

As described above, since the dead space 310 occurs around the lead tab 200, the pillars 400 can be arranged side by side on both sides of the lead tab 200. In FIG. 2, three pillars 400 are disposed on both sides of the lead tab 200, but the present invention is not limited thereto. The number of pillars 400 may be increased or decreased in the course of designing the vent timing of the pouch battery 1. The number of the pillars 400 can be increased in order to accelerate the time of the gas vent generated when the pouch battery 1 is overcharged. Alternatively, the size of the filler 400 may be increased.

According to one embodiment of the present invention, the lead tab 200 may be provided to protrude from both sides of the electrode assembly 100. A larger dead space may be generated when the lead tab 200 protrudes from both sides of the electrode assembly 100 as compared with the case where the lead tab 200 protrudes from one side of the electrode assembly 100 . Therefore, the volume of the dead space that can be reduced by disposing the pillars is larger when the lead tab 200 protrudes from the electrode assembly 100 to both sides. That is, the filler 400 may have a relatively greater effect when the lead tab 200 protrudes from both sides of the electrode assembly 100. Needless to say, the filler 400 may be disposed inside the pouch 300 even when the lead tab 200 protrudes from one side of the electrode assembly 100.

The filler (400) of the present invention may be provided such that the volume of the filler (400) changes according to a pressure change inside the pouch (300).

3 and 4, when the filler 400 is received in the pouch 300 together with the electrode assembly 100, the filler 400 may have a minimum volume. At this time, the filler 400 may have a minimum volume 400a.

Since the filler 400 has the minimum volume 400a, when the electrolyte is injected into the pouch 300, it is possible to prevent the electrolyte from overflowing the pouch 300 due to the volume of the filler 400. [ That is, it is possible to prevent the overflow of the electrolyte.

When the filler 400 has a minimum volume 400a, the dead space 310 inside the pouch 300 may be at a maximum 310a.

The filler 400 may be bulged in a degassing step of removing gas generated during charging and discharging of the electrode assembly 100. The filler 400 may expand as the pressure inside the pouch 300 decreases, in a degassing step.

The filler 400 may have a maximum volume 400b after being subjected to a degassing process. The volume of the dead space 310 inside the pouch 300 can be minimized by having the maximum volume 400b of the pillars 400. [ That is, the dead space inside the pouch 300 can be reduced through the pillars 400.

When the dead space 310 in the pouch 300 is reduced, the time when the gas generated from the electrode assembly 100 is blown through one side of the sealing part 500 during overcharging of the pouch battery 1 can be advanced . If the gas vent timing is advanced, the temperature rise of the pouch battery 1 can be suppressed, and the risk of ignition due to overcharging of the pouch battery 1 can be reduced. That is, according to the idea of the present invention, the safety of the pouch battery 1 in overcharging can be improved.

5 is a flowchart illustrating a method of manufacturing a pouch battery according to an embodiment of the present invention.

As shown in FIG. 5, the method for manufacturing a pouch battery according to the present invention includes the steps of preparing an electrode assembly, storing a filler, which is expandable according to pressure changes in the electrode assembly, A step of injecting an electrolyte into the pouch, a step of charging / discharging the electrode assembly to activate the electrode assembly, a step of removing gas generated during charge / discharge of the electrode assembly, a step of sealing the pouch . ≪ / RTI >

The electrode assembly preparation step for manufacturing the electrode assembly 100 can be performed by winding the positive electrode plate and the negative electrode plate coated with the positive electrode active material and the negative electrode active material, respectively, together with the separator as the insulator.

Thereafter, the electrode assembly 100 and the filler 400 may be stored in the pouch 300.

After the electrode assembly 100 and the filler 400 are housed in the pouch 300 through the storing step, the electrolyte pouring step can be performed. The electrolyte solution may be injected into the pouch 300 through the pouring step. On the other hand, the volume of the filler 400 in the electrolyte injection step may be a minimum (400a). In this way, overflow of the electrolyte can be prevented even though the filler 400 is disposed inside the pouch 300.

After the injection step, the edge of the pouch 300 can be sealed. Thereafter, the electrode assembly 100 in the pouch 300 can be activated through several charge / discharge cycles. That is, the charging and discharging step of activating the electrode assembly 100 can be performed.

After the charging / discharging step, a degassing step may be performed to remove the gas generated from the electrode assembly 100 during the charging / discharging process. The degassing process can generally be done under vacuum. The degassing process may open a portion of the edge of the sealed pouch 300 to form an opening, and then evacuate gas within the pouch 300 to the opening by vacuum.

Through the degassing process, the interior of the pouch 300 becomes vacuum, so that the pressure inside the pouch 300 can approach zero. Accordingly, the filler 400 disposed inside the pouch 300 can expand. The filler 400 may expand and become bulky and the filler 400 may have a maximum volume 400b.

As the volume of the pillars 400 is increased, the dead space inside the pouch 300 can be reduced. Also, as described above, since the dead space of the pouch battery 1 is reduced by reducing the dead space, the stability of the pouch battery 1 can be improved when the battery is overcharged. In addition, the size and quantity of the filler 400 can be adjusted in order to design the vent timing of the pouch battery 1 properly. The size and quantity of the filler (400) can be changed as a design matter.

After the degassing step, a sealing step can be carried out. In the sealing step, a sealing operation for resealing the opening portion for removing gas at the degassing step can be performed. Thus, the sealing portion 500 can form a closed curve along the edge of the pouch 300. Since the sealing part 500 forms a closed curve, the electrode assembly 100 can be cut off from the outside of the pouch 300.

The foregoing has shown and described specific embodiments. However, it should be understood that the present invention is not limited to the above-described embodiment, and various changes and modifications may be made without departing from the technical idea of the present invention described in the following claims .

1: Pouch Battery
100: electrode assembly
200: Lead tab
210: first lead tab
220: second lead tab
300: Pouch
310: dead space
400: filler
500: sealing part

Claims (11)

An electrode assembly including a negative electrode plate, a positive electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate;
A lead tab extending from the electrode assembly;
A pouch having an internal space formed by a sealing portion and accommodating the electrode assembly in the internal space; And
A filler disposed in the yarn space to reduce a size of a dead space formed between the electrode assembly and the sealing unit; Lt; / RTI >
Wherein the filler is configured to receive a gas therein. The method according to claim 1,
Wherein the filler occupies a space inside the pouch so that gas generated from the electrode assembly is discharged to the outside of the pouch when the battery pack is overcharged. The method according to claim 1,
The plurality of fillers are provided,
And the gas generated from the electrode assembly is accelerated by the overcharge as the number of the fillers increases. The method according to claim 1,
Wherein the filler increases in size as the amount of gas generated from the electrode assembly is discharged to the outside of the pouch by overcharging. The method according to claim 1,
Wherein the filler is configured to be expandable according to a change in pressure inside the pouch. The method according to claim 1,
Wherein the lead tab includes a first lead tab and a second lead tab,
Wherein the first lead tab and the second lead tab protrude in both directions from the electrode assembly. The method according to claim 1,
Wherein the filler comprises a plurality of fillers,
And the plurality of fillers are disposed on both sides of the lead tab. The method according to claim 1,
Wherein the filler has a sphere shape when its volume is maximum. Preparing an electrode assembly;
The electrode assembly, and a filler for accommodating the gas in the pouch so as to be inflatable according to a change in pressure;
Injecting an electrolyte solution into the pouch;
Charging and discharging the electrode assembly for activation of the electrode assembly;
Removing gas generated during charging and discharging of the electrode assembly;
Sealing the pouch to block the electrode assembly and the filler from the outside of the pouch; Wherein the pouch is made of a conductive material. 10. The method of claim 9,
Wherein the filler is disposed on both sides of the lead tab projecting from the electrode assembly in the step of housing the electrode assembly and the filler in the pouch. 10. The method of claim 9,
Wherein the filler is provided to increase in volume with a change in pressure inside the pouch.

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