KR20240027290A - Electrode assembly incluidng flame resistant member, manufacturing method thereof, and secondary battery comprising the same - Google Patents

Abstract

The present invention includes an anode including a plurality of first through holes,
A cathode including a plurality of second through holes, and
A separator interposed between the anode and the cathode and including a plurality of third through holes,
The first through holes, the second through holes, and the third through holes are formed at the same position when the anode, the cathode, and the separator are stacked and are connected to each other to form a plurality of hollow portions in the stacking direction,
An electrode assembly in which a flame retardant member is located in each of the plurality of hollow parts, a manufacturing method thereof, and a secondary battery including the same are provided.

Description

Electrode assembly including a flame retardant member, manufacturing method thereof, and secondary battery including the same

The present invention relates to an electrode assembly including a flame retardant member, a manufacturing method thereof, and a secondary battery including the same.

Due to the rapid increase in the use of fossil fuels, the demand for the use of alternative or clean energy is increasing, and as part of this, the most actively researched fields are power generation and storage using electrochemistry.

Currently, secondary batteries are a representative example of electrochemical devices that use such electrochemical energy, and their use area is gradually expanding.

Recently, as technology development and demand for portable devices such as portable computers, portable phones, and cameras increase, the demand for secondary batteries as an energy source is rapidly increasing, and among such secondary batteries, they exhibit high charge/discharge characteristics and lifespan characteristics. Much research has been conducted on eco-friendly lithium secondary batteries, and they have also been commercialized and widely used.

Moreover, the secondary batteries have recently been developed into structures capable of increasingly high energy density and high output in response to user demands, and accordingly, the voltage usage range of secondary batteries is expanding to a level of 4.5V or higher.

Accordingly, the demand for secondary batteries that can be stably operated at various temperatures even within the above voltage range has increased.

Meanwhile, flame retardant members are currently being applied between batteries as a way to improve the safety of secondary batteries. However, this application is a method of ensuring safety outside the secondary battery, and on the internal side, research is being conducted in various fields such as a method to prevent short circuit between the anode and cathode to prevent ignition, and a method to discharge or collect gas when it is generated. is taking place.

However, when ignition occurs due to chemical reaction and thermal energy inside the secondary battery, the development of methods to prevent explosive ignition behavior inside the battery due to such ignition is still minimal.

Therefore, there is an urgent need to develop a secondary battery that can solve the problems of explosive ignition behavior and voltage drop when ignited by chemical reaction and thermal energy inside the secondary battery.

The problem to be solved by the present invention is to provide an electrode assembly capable of delaying ignition behavior caused by a chemical reaction between electrodes, a manufacturing method thereof, and a secondary battery including the same.

The electrode assembly according to an embodiment of the present invention to achieve this purpose,

An anode including a plurality of first through holes,

a cathode including a plurality of second through holes, and

A separator interposed between the anode and the cathode and including a plurality of third through holes,

The first through holes, the second through holes, and the third through holes are formed at the same position when the anode, the cathode, and the separator are stacked and are connected to each other to form a plurality of hollow portions in the stacking direction,

A flame retardant member is located in each of the plurality of hollow parts.

Here, the first through holes, the second through holes, and the third through holes may each have a circular, polygonal, or oval shape in plan.

Five or more of the first through holes, second through holes, and third through holes may be formed in the anode, the cathode, and the separator, respectively.

Additionally, the first through holes, second through holes, and third through holes may each be arranged regularly.

At this time, the spacing between the first through holes, the second through holes, and the third through holes may be 0.1 mm to 20 mm, and the size may be 0.1 mm to 5 mm.

The first through holes, second through holes, and third through holes may be formed in an area of 10% to 80% of the total area of the anode, cathode, and separator, respectively.

Meanwhile, the flame retardant member is a solid thermal rod, which may be a silicon rod or a carbon rod, and may be inserted into the plurality of hollow parts along the stacking direction.

At this time, the thermal rod may have a shape corresponding to the hollow part.

Alternatively, the flame retardant member may be formed by solidifying a slurry containing flame retardant particles after filling the plurality of hollow parts.

Here, the flame retardant particles may be silicon particles or carbon particles.

According to another embodiment of the present invention, the present invention prepares a separator including an anode including a plurality of first through holes, a cathode including a plurality of second through holes, and a plurality of third through holes. The first through holes, the second through holes, and the third through holes are connected to each other to form a plurality of hollow parts, and are stacked so that a separator is interposed between the anode and the cathode, and then a flame retardant member is applied. A method of manufacturing an electrode assembly formed in the plurality of hollow parts is provided.

At this time, the flame retardant member may be formed by inserting a silicon rod or a carbon rod into the plurality of hollow parts in the stacking direction.

Alternatively, the flame retardant member may be formed by filling a slurry containing flame retardant particles into the plurality of hollow parts and then solidifying it.

Meanwhile, according to another embodiment of the present invention, a secondary battery is provided in which the electrode assembly and the electrolyte are built into a secondary battery case.

As described above, according to the present invention, by positioning the flame retardant member inside the secondary battery so as to penetrate the electrode assembly in the stacking direction, ignition behavior is delayed when ignition occurs inside the battery due to chemical reaction between electrodes and thermal energy, and voltage It has the effect of preventing descent.

1 is an exploded perspective view of an electrode assembly according to an embodiment of the present invention.
Figure 2 is a cross-sectional view of an electrode assembly according to an embodiment of the present invention.
Figure 3 is a top view of an electrode assembly according to an embodiment of the present invention.

Hereinafter, the present invention will be described in more detail to facilitate understanding of the present invention.

Terms or words used in this specification and claims should not be construed as limited to their common or dictionary meanings, and the inventor may appropriately define the concept of terms in order to explain his or her invention in the best way. It must be interpreted with meaning and concept consistent with the technical idea of the present invention based on the principle that it is.

The terminology used herein is for the purpose of describing exemplary embodiments only and is not intended to limit the invention. Singular expressions include plural expressions unless the context clearly dictates otherwise.

In addition, throughout the specification, when a part is said to "include" a certain component, this means that it may further include other components rather than excluding other components, unless specifically stated to the contrary.

The electrode assembly according to an embodiment of the present invention,

An anode including a plurality of first through holes,

a cathode including a plurality of second through holes, and

A separator interposed between the anode and the cathode and including a plurality of third through holes,

The first through holes, the second through holes, and the third through holes are formed at the same position when the anode, the cathode, and the separator are stacked and are connected to each other to form a plurality of hollow portions in the stacking direction,

A flame retardant member may be located in each of the plurality of hollow parts.

Previously, flat substrates were used for the anode, cathode, and separator, and in the case of the anode and cathode, the electrode was completed by applying a maximum amount of slurry to the substrate. However, in this case, there was a problem of ignition due to a short circuit within the electrode assembly. When it occurred, there was a problem that ignition could not be delayed, resulting in explosive ignition and voltage drop.

Accordingly, after repeated in-depth research, the inventors of the present application studied a method that can delay the ignition behavior inside the battery by acting even when ignition occurs inside the secondary battery cell, and thus, the electrode and separator It was confirmed that when forming through holes and placing a flame retardant member in them, even if ignition occurs inside the battery, the flame retardant member delays internal ignition, thereby preventing explosive ignition behavior and solving the voltage drop problem. The invention has reached completion.

Accordingly, the electrode assembly according to an embodiment of the present invention will be described in detail below as shown in the drawings. Hereinafter, the description will be made based on drawings according to an embodiment to facilitate understanding, but the scope of the present invention is not limited thereto.

Specifically, the electrode assembly 100 according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3.

First, FIG. 1 shows an exploded perspective view of the electrode assembly 100 according to an embodiment of the present invention, and FIG. 2 shows a cross-sectional view of the electrode assembly 100.

Referring to FIGS. 1 and 2 together, the electrode assembly 100 according to an embodiment of the present invention includes an anode 110 including a plurality of first through holes 111, and a plurality of second through holes ( It has a structure in which a cathode 120 including a cathode 112) and a separator 130 interposed between the anode 110 and the cathode 120 and including a plurality of third through holes 131 are stacked.

In the drawing, an electrode assembly consisting of two anodes and one cathode is shown, but the number is not limited and includes structures in which anodes and cathodes are alternately stacked with a separator in between.

Meanwhile, the anode 110, the cathode 120, and the separator 130 all have a first through hole 111, a second through hole 121, and a third through hole 131, and these through holes (111, 112, 113) are formed at the same position when the anode 110, the cathode 120, and the separator 130 are stacked to form a plurality of hollow parts 150 extending in the stacking direction.

A flame retardant member 140 is located in each of the plurality of hollow parts 150 formed in this way.

An anode 110 having a plurality of first through holes 111, a cathode 120 having a plurality of second through holes 121, and a separator 130 having a plurality of third through holes 131. ) can be manufactured in a variety of ways, and the manufacturing method is not limited.

For example, the positive electrode 110 and the negative electrode 120 can be formed by applying active material to a current collector in which a through hole is formed, excluding the through hole, and then drying and rolling the applied material. Alternatively, through holes may be formed by applying an active material layer on a flat current collector in which through holes are not formed as before, and punching it during the drying and rolling process. However, when through holes are formed by punching or etching after applying the active material, problems such as waste of the active material or cracks in the active material may occur. Therefore, the active material is manufactured by applying the active material to the current collector where the through holes are formed. It is more desirable to be

The separator 130 may be a polymer substrate, specifically a polyolefin-based substrate, or may be a safety reinforced separator (SRS) structure in which a mixed layer of ceramic particles and a binder is formed on one or both sides of the polymer substrate.

The separator 130 can also be manufactured in a similar manner to the electrode to form a third through hole. In the case of a separator made of a polymer substrate, a through hole can be formed in the polymer substrate in the form of punching or etching, and in the case of SRS It can be formed by applying and drying a mixed layer containing ceramic particles and a binder on a polymer substrate on which through holes have been formed, except for the through holes, or by applying the mixed layer on a polymer substrate on which through holes have not been formed, and then applying the mixed layer together. It can also be manufactured using punching or etching.

At this time, the first through holes 111, the second through holes 121, and the third through holes 131 may each have a circular, polygonal, or oval shape in plan.

At this time, since the anode 110, the cathode 120, and the separator 130 must be positioned at the same position to form a hollow portion 150 so that the flame retardant member 140 can be inserted in the stacked state, they must have the same shape. It is desirable.

In addition, the number of first through holes 111, second through holes 121, and third through holes 131 are each 3 or more, specifically 5 or more, and more specifically 10 to improve flame retardancy properties. It may be formed abnormally.

As the number of flame retardant members 140 inserted increases, the intended effect of the present invention improves, but since the area where the active material layer is formed decreases, the number of through holes can be appropriately selected taking this into consideration.

More specifically, the first through holes 111, second through holes 121, and third through holes 131 are each arranged regularly to exert the effect of delaying heat generation in all directions. there is.

Meanwhile, Figure 3 schematically shows a top view of the electrode assembly 100 to explain the dimensions of the through holes in more detail.

Referring to FIG. 3 and FIGS. 1 and 2 , only the anode 110 is shown, but the description may also be applied to the cathode 120 and the separator 130.

The spacing (d) of the first through holes 111 may be 0.1 mm to 20 mm, specifically 1 mm to 10 mm, and more specifically 2 mm to 5 mm.

When the first through holes 111 are arranged regularly, the spacing may be selected in the above range, taking into consideration all the number of the first through holes 111, battery capacity, and safety, and each first through hole 111 The spacing between the through holes 111 may be constant.

However, when the first through holes 111 are not regularly arranged, the spacing between the first through holes 111 may each have a value within the above range.

Additionally, the size (r) of the first through holes 111 may be 0.1 mm to 5 mm, specifically 0.5 mm to 5 mm, and more specifically 1 mm to 3 mm.

At this time, the size of the first through holes 111 refers to the diameter in the case of a circular shape, the longest length between vertices in the case of a polygon, and the length in the longitudinal direction in the case of an oval shape.

In addition, the first through holes 111 have an area of 10% to 80%, specifically 20% to 70%, more specifically 30% to 60%, most specifically, based on the total area of the anode 110. may be 30% to 50%.

As described above, this area may be appropriately selected within the above range, taking into account the number of first through holes 111, battery capacity, and safety.

Outside the above range, if the spacing between the first through holes 111 is too wide, the size is too small, or the area occupied is too small, the volume occupied by the flame retardant member is too reduced, and the sufficient flame retardant effect intended by the present application is not achieved. If it cannot be applied, the gap is too small, the size is too large, or the area occupied is too large, the area where the active material can be applied relatively decreases, and the battery capacity rapidly decreases, which is not desirable.

In the above, the explanation was based on the anode 110, but the same explanation can be applied to the second through holes 121 of the cathode 120 and the third through holes 131 of the separator 130.

These first through holes 111, second through holes 121, and third through holes 131 are connected to form a plurality of hollow portions 150. Accordingly, the plurality of hollow parts 150 communicate with each other as long as the length l in the stacking direction of the electrode assembly 100.

Thereafter, the flame retardant member 140 is located in these plural hollow parts 150.

The flame retardant member 140 is not limited as long as it has a flame retardant form and is located within the hollow portions 150. For example, the flame retardant member 140 is a solid thermal rod, such as a silicon rod or It is a carbon rod, and may be inserted into the plurality of hollow parts with a length (l) in the stacking direction.

Alternatively, the flame retardant member 140 may be formed by solidifying a slurry containing flame retardant particles after filling the plurality of hollow parts.

As an example, when using a silicon rod or carbon rod as a thermal rod, the anode 110, the cathode 120, and the separator 130 are stacked, and then the thermal rod is inserted into the hollow portions 150. In its form, it can be assembled very simply. The silicon rod or carbon rod has high thermal and chemical stability, and has excellent flame retardant and thermal insulation properties, so it is very desirable for delaying heating behavior, which is the intended effect of the present invention.

These silicon rods or carbon rods may be manufactured with materials and methods similar to those of previously used silicon pads or carbon pads, and may be made of silicon or carbon, for example, calcium carbonate, mica, glass fiber, minerals, etc. It may also contain fillers such as fiber composites, inorganic carbonates, inorganic phosphates, and inorganic sulfates, nano bismuth oxides, aluminum oxide nano powders, and organic nano clays.

These thermal rods may have a shape and size corresponding to the hollow parts 150 to be inserted. That is, the thermal rod is not limited as long as it has a shape that can be inserted into the hollow parts 150, but its shape and size may be similar to the extent of insertion.

Additionally, the length at which the thermal rod is inserted may also have the length (l) of the electrode assembly 100 formed by the hollow portions 150. Therefore, when a problem such as a short circuit occurs anywhere, the flame retardant member 140 acts and can exhibit a flame retardant effect.

As another example, when the flame retardant member 140 is formed by solidifying the slurry containing flame retardant particles after filling the hollow parts 150, the hollow parts can be filled without any gaps, resulting in a good flame retardant effect.

At this time, the flame retardant particles may be silicon particles or carbon particles for the reasons described above.

Additionally, the slurry may further include fillers as described above in addition to the flame retardant particles.

In this case as well, the flame retardant member 140 can be manufactured by stacking the anode 110, the cathode 120, and the separator 130, then filling the hollow portion with the slurry and solidifying it.

in other words. As the flame retardant member 140, when using a thermal rod or filling and solidifying a slurry containing flame retardant particles, the anode 110, the cathode 120, and the separator 130 are connected through the first through holes. (111), the second through holes 121, and the third through holes 131 are all stacked so that they communicate with each other, and finally the flame retardant member 140 is placed in the plurality of hollow parts 150. It can be manufactured simply.

Therefore, according to another embodiment of the present invention, the present invention also provides a method for manufacturing an electrode assembly,

Prepare a separator including an anode including a plurality of first through holes, a cathode including a plurality of second through holes, and a plurality of third through holes, the first through holes, the second through holes, and third through holes are connected to each other to form a plurality of hollow parts, stacked so that a separator is interposed between the anode and the cathode, and then provide a method of manufacturing an electrode assembly in which a flame retardant member is formed in the plurality of hollow parts. do.

As described above, when the flame retardant member is a silicon rod or carbon rod, it can be formed by inserting a slurry containing flame retardant particles into a plurality of hollow parts in the stacking direction, and the flame retardant member is inserted into the plurality of hollow parts. It can also be formed by filling it with cattails and then solidifying it.

Other specific details are the same as described above.

As described above, according to the present invention, the flame retardant member 140 can be applied to the inside of the battery, so that it can exert a heat transfer delay effect due to ignition that occurs not only outside the battery but also inside the battery.

Furthermore, according to another embodiment of the present invention, a secondary battery is provided in which the electrode assembly and the electrolyte are built into a secondary battery case.

Since other detailed descriptions of secondary batteries are known in the art, detailed descriptions are omitted in this specification.

Those of ordinary skill in the field to which the present invention pertains will be able to make various applications and modifications within the scope of the present invention based on the above contents.

Claims (15)

An anode including a plurality of first through holes,
a cathode including a plurality of second through holes, and
A separator interposed between the anode and the cathode and including a plurality of third through holes,
The first through holes, the second through holes, and the third through holes are formed at the same position when the anode, the cathode, and the separator are stacked and are connected to each other to form a plurality of hollow portions in the stacking direction,
An electrode assembly in which a flame retardant member is located in each of the plurality of hollow portions. According to paragraph 1,
The electrode assembly wherein the first through holes, the second through holes, and the third through holes are each circular, polygonal, or oval in plan. According to paragraph 1,
An electrode assembly in which five or more first through holes, second through holes, and third through holes are formed in the anode, the cathode, and the separator, respectively. According to paragraph 1,
An electrode assembly in which the first through holes, second through holes, and third through holes are each arranged regularly. According to paragraph 1,
An electrode assembly in which the spacing between the first through holes, the second through holes, and the third through holes is 0.1 mm to 20 mm, respectively. According to paragraph 1,
The electrode assembly wherein the first through holes, the second through holes, and the third through holes each have a size of 0.1 mm to 5 mm. According to paragraph 1,
An electrode assembly in which the first through holes, second through holes, and third through holes are each formed in an area of 10% to 80% of the total area of the anode, cathode, and separator. According to paragraph 1,
The flame retardant member is a solid thermal rod, which is a silicon rod or a carbon rod, and is an electrode assembly inserted into the plurality of hollow parts along the length of the stacking direction. According to clause 8,
The thermal rod is an electrode assembly having a shape corresponding to the hollow portion. According to paragraph 1,
The flame retardant member is an electrode assembly formed by solidifying a slurry containing flame retardant particles after filling the plurality of hollow parts. According to clause 10,
An electrode assembly wherein the flame retardant particles are silicon particles or carbon particles. A method of manufacturing the electrode assembly according to claim 1, comprising:
Prepare a separator including an anode including a plurality of first through holes, a cathode including a plurality of second through holes, and a plurality of third through holes, the first through holes, the second through holes, and a method of manufacturing an electrode assembly in which third through holes are connected to each other to form a plurality of hollow parts, stacked so that a separator is interposed between the anode and the cathode, and then a flame retardant member is formed in the plurality of hollow parts. According to clause 12,
A method of manufacturing an electrode assembly in which the flame retardant member is formed by inserting a silicon rod or a carbon rod into the plurality of hollow parts in a stacking direction. According to clause 12,
A method of manufacturing an electrode assembly in which the flame retardant member is formed by filling a slurry containing flame retardant particles into the plurality of hollow parts and then solidifying it. A secondary battery in which the electrode assembly according to claim 1 and an electrolyte are built into a secondary battery case.