KR20220034566A - Secondary battery and devcie including the same - Google Patents

Abstract

A secondary battery according to an embodiment of the present invention includes: a jelly roll-shaped electrode assembly including an electrode tab; a battery case that accommodates the electrode assembly and has an open upper part; a cap assembly coupled to the open upper part of the battery case; and a measuring member that has one end connected to the electrode tab and the other end passing between the battery case and the cap assembly to be exposed to the outside.

Description

Secondary battery and device including same {SECONDARY BATTERY AND DEVCIE INCLUDING THE SAME}

The present invention relates to a secondary battery and a device including the same, and more particularly, to a secondary battery capable of measuring a voltage even after current cutoff and a device including the same.

Recently, an increase in the price of energy sources due to the depletion of fossil fuels, interest in environmental pollution is amplified, and the demand for eco-friendly alternative energy sources is becoming an indispensable factor for future life. Accordingly, research on various power production technologies such as nuclear power, solar power, wind power, and tidal power is continuing, and power storage devices for using the generated energy more efficiently are also of great interest.

In particular, as technology development and demand for mobile devices increase, the demand for batteries as an energy source is rapidly increasing, and accordingly, many studies on batteries capable of meeting various needs are being conducted.

Typically, there is a high demand for lithium secondary batteries such as lithium ion batteries and lithium ion polymer batteries having advantages such as high energy density, discharge voltage, and output stability.

In addition, secondary batteries are classified according to the structure of an electrode assembly in which a positive electrode, a negative electrode, and a separator interposed between the positive electrode and the negative electrode are stacked. Typically, a jelly roll-type electrode assembly having a structure in which long sheet-shaped positive and negative electrodes are wound with a separator interposed therebetween, a number of positive and negative electrodes cut into units of a predetermined size are sequentially stacked with a separator interposed therebetween. and stacked electrode assemblies. Recently, in order to solve the problems of the jelly roll type electrode assembly and the stack type electrode assembly, as a mixed type of the jelly roll type and the stack type, unit cells in which positive and negative electrodes of a predetermined unit are stacked with a separator interposed therebetween are separated A stack/folding type electrode assembly having a structure in which it is sequentially wound while placed on a film has been developed.

In addition, depending on the shape of the case, the secondary battery includes a cylindrical battery in which the electrode assembly is built into a cylindrical case, a prismatic battery in which the electrode assembly is built in a prismatic case, and a pouch in which the electrode assembly is built in a pouch-type case of an aluminum laminate sheet. It can be classified as a type battery.

On the other hand, the secondary battery can be used appropriately in the market when it has safety while satisfying the performance suitable for the intended use. When designing a secondary battery, design factors are determined by considering these performance and safety aspects at the same time. Batteries that have been designed and manufactured are subjected to performance evaluations such as lifespan, high rate characteristics, and high/low temperature characteristics, as well as safety evaluations such as overcharge, overdischarge, impact, nail test, and hot box. will proceed

Cylindrical secondary batteries among various types of secondary batteries prevent further reactions by blocking current between electrode terminals and electrode tabs when gas is rapidly generated inside the secondary battery in an abnormal state such as overcharging and the internal pressure exceeds a certain level. It may include a current interrupting member (Current Interrupt Device, CID).

1 is a partial cross-sectional view showing a cross-section of an upper portion of a conventional cylindrical secondary battery.

Referring to FIG. 1 , the electrode assembly 20 is accommodated in the cylindrical case 30 , and the cap assembly 40 is mounted on the open upper portion of the cylindrical case 30 to manufacture the cylindrical secondary battery 10 . .

The electrode assembly 20 may be a jelly roll type electrode assembly in which the first electrode 21 , the second electrode 22 , and the separator 23 are wound.

The cap assembly 40 may include an upper cap 41 , a safety vent 42 for internal pressure drop, and a current interruption member 43 (Current Interrupt Device, CID). The upper cap 41 and the safety vent 42 may form a structure in close contact with each other, and the safety vent 42 may form a structure connected to the center of the current blocking member 43 . A first electrode tab 21t protruding from the first electrode 21 may be connected to a lower end of the current blocking member 43 . Here, the first electrode 21 may be a positive electrode, and the first electrode tab 21t may be a positive electrode tab.

As described above, the upper cap 41 may be electrically connected to the electrode assembly 20 by being directly or indirectly connected to the safety vent 42, the current blocking member 43, and the first electrode tabs 21t, It can function as an electrode terminal.

Meanwhile, a gasket 70 for sealing between the cap assembly 40 and the cylindrical case 30 and a CID gasket 80 surrounding the edge of the current blocking member 43 may be disposed.

FIG. 2 is a partial cross-sectional view illustrating a state when the internal pressure of the cylindrical secondary battery of FIG. 1 is increased.

Referring to FIG. 2 , when the cylindrical secondary battery 10 is exposed to high temperatures or is in an abnormal operating state and internal pressure rises, the current blocking member 43 is separated to cut off the current. Specifically, the current blocking member 43 is divided into a portion 43a connected to the safety vent 42 and a portion 43b connected to the first electrode tab 21t, and an upper cap 41 functioning as an electrode terminal; The current between the first electrode tabs 21t is cut off.

As above, when the current blocking member 43 operates to cut off the current, the external current is no longer applied and the voltage measurement is also impossible because the circuit is disconnected. The voltage value after the current blocking member 43 operates is important information for confirming the behavior of the secondary battery after the current is cut off. Specifically, the voltage value can be used as useful information to reveal the ignition/non-ignition mechanism of the secondary battery. However, since it is impossible to measure the voltage of the secondary battery that has been circuitly disconnected, the behavior of the cylindrical secondary battery after the current blocking member 43 operates remains unknown.

Therefore, it is necessary to develop a secondary battery capable of measuring the voltage after the current is cut off in an abnormal operating condition.

An object of the present invention is to provide a secondary battery capable of measuring voltage after current is cut off in an abnormal operating situation and a device including the same.

However, the problems to be solved by the embodiments of the present invention are not limited to the above problems and may be variously expanded within the scope of the technical idea included in the present invention.

A secondary battery according to an embodiment of the present invention includes an electrode assembly in the form of a jelly roll including an electrode tab; a battery case housing the electrode assembly and having an open top; a cap assembly coupled to an open upper portion of the battery case; and a measuring member having one end connected to the electrode tab and the other end passing between the battery case and the cap assembly and exposed to the outside.

The secondary battery may further include a gasket positioned between the battery case and the cap assembly, and the measuring member may be positioned between the battery case and the gasket.

The battery case and the cap assembly may be coupled by crimping with the gasket and the measuring member interposed therebetween.

The measuring member may include a metal wire and a coating layer surrounding the metal wire.

The coating layer may include an enamel layer.

The secondary battery may further include an insulating tape positioned between the measuring member and the battery case.

The insulating tape may include at least one of polyimide (PI), polyethylene terephthalate (PET), and polypropylene (PP).

The cap assembly may include a current interrupt device (CID) and a safety vent disposed on the current interrupting member and electrically connected to the current interrupting member, wherein the electrode tab is It may be connected to the current blocking member.

The battery case may be a cylindrical case.

According to embodiments of the present invention, by introducing an additional measuring member connected to the electrode tab without passing through the current blocking member, it is possible to measure the voltage of the secondary battery even after the current is cut off by the current blocking member in an abnormal operating situation .

In addition, since the measuring member may pass between the cap assembly and the battery case, there is no need to form a separate hole. Accordingly, the behavior of the actual secondary battery in an abnormal operating situation may be accurately implemented, and accurate information may be provided for analysis.

Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a partial cross-sectional view showing a cross-section of an upper portion of a conventional cylindrical secondary battery.
FIG. 2 is a partial cross-sectional view illustrating a state in which the internal pressure of the cylindrical secondary battery of FIG. 1 is increased.
3 is a perspective view illustrating a secondary battery according to an embodiment of the present invention.
4 is an exploded perspective view of the secondary battery of FIG. 3 .
5 is an exploded perspective view illustrating a state before the electrode assembly included in the secondary battery of FIG. 4 is wound.
FIG. 6 is a partial cross-sectional view illustrating a cross-section taken along the cutting line A-A' of FIG. 3 .
7 is a partial cross-sectional view showing an enlarged portion "B" of FIG.
8 is a perspective view of a measuring member and an insulating tape according to an embodiment of the present invention.
9 is a partial cross-sectional view illustrating a state when the internal pressure of the secondary battery of FIG. 6 is increased.

Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those of ordinary skill in the art to which the present invention pertains can easily implement them. The present invention may be embodied in several different forms and is not limited to the embodiments described herein.

In order to clearly explain the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

In addition, since the size and thickness of each component shown in the drawings are arbitrarily indicated for convenience of description, the present invention is not necessarily limited to the illustrated bar. In order to clearly express various layers and regions in the drawings, the thicknesses are enlarged. And in the drawings, for convenience of description, the thickness of some layers and regions are exaggerated.

Also, when a part of a layer, film, region, plate, etc. is said to be “on” or “on” another part, it includes not only cases where it is “directly on” another part, but also cases where there is another part in between. . Conversely, when we say that a part is "just above" another part, we mean that there is no other part in the middle. In addition, to be "on" or "on" the reference part means to be located above or below the reference part, and to necessarily mean to be located "on" or "on" in the direction opposite to gravity not.

In addition, throughout the specification, when a part "includes" a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise stated.

In addition, throughout the specification, when referring to "planar", it means when the target part is viewed from above, and "cross-sectional" means when viewed from the side when a cross-section of the target part is vertically cut.

3 is a perspective view illustrating a secondary battery according to an embodiment of the present invention. 4 is an exploded perspective view of the secondary battery of FIG. 3 . 5 is an exploded perspective view illustrating a state before the electrode assembly included in the secondary battery of FIG. 4 is wound.

3 to 5 , the secondary battery 100 according to an embodiment of the present invention includes an electrode assembly 200 , a battery case 300 in which the electrode assembly 200 is accommodated, and an open top thereof, and the battery case. and a cap assembly 400 and a measurement member 500 coupled to the open upper portion of the 300 . The measuring member 500 will be described in detail together with FIGS. 6 to 8 and the like.

First, the electrode assembly 200 according to the present embodiment may include a first electrode 210 , a second electrode 220 , and a separator 230 . The first electrode 210 , the second electrode 220 , and the separator 230 may be wound together to form the jelly roll-type electrode assembly 200 . The separator 230 may be interposed between the first electrode 210 and the second electrode 220 . In addition, it is preferable that the separator 240 is additionally disposed under the second electrode 220 to prevent the first electrode 210 and the second electrode 220 from contacting each other when wound in the form of a jelly roll.

The first electrode 210 includes a first electrode current collector 211 and a first active material layer 212 formed by coating an electrode active material on the first electrode current collector 211 . Specifically, the electrode active material is applied on the first electrode current collector 211 to form the first active material layer 212 , and the electrode active material is not applied among the first electrode current collectors 211 , so the first electrode current collector ( The first electrode tab 213 may be attached to the portion where the 211 is exposed by welding or the like.

The second electrode 220 includes a second electrode current collector 221 and a second active material layer 222 formed by coating an electrode active material on the second electrode current collector 221 . Specifically, the electrode active material is applied on the second electrode current collector 221 to form the second active material layer 222 , and the electrode active material is not applied among the second electrode current collectors 221 , so the second electrode current collector ( The second electrode tab 223 may be attached to the portion where the 221 is exposed by welding or the like.

In this case, the first electrode 210 may be an anode, and the second electrode 220 may be a cathode. Accordingly, the first electrode tab 213 may be a positive electrode tab, and the second electrode tab 223 may be a negative electrode tab. Meanwhile, with respect to the wound electrode assembly 200 , the first electrode tab 213 and the second electrode tab 223 may protrude in opposite directions. The first electrode tab 213 may protrude in a direction in which the cap assembly 400 is located, and the second electrode tab 223 may protrude toward the bottom of the battery case 300 .

Meanwhile, the battery case 300 is a structure accommodating the electrode assembly 200 impregnated with the electrolyte, and may include a metal material and may be a cylindrical case.

Hereinafter, the cap assembly and the measuring member according to the present embodiment will be described in detail with reference to FIGS. 6 to 8 and the like.

6 is a partial cross-sectional view showing a cross-section taken along the cutting line A-A' of FIG. 3 . 7 is a partial cross-sectional view showing an enlarged portion "B" of FIG. 8 is a perspective view of a measuring member and an insulating tape according to an embodiment of the present invention.

First, referring to FIGS. 4 and 6 , the cap assembly 400 according to this embodiment may include an upper cap 410 , a safety vent 420 , and a current interrupting member 430 (Current Interrupt Device, CID). can The upper cap 410 and the safety vent 420 may form a structure in close contact with each other. The safety vent 420 is positioned on the current blocking member 430 and may be electrically connected to the current blocking member 430 . Specifically, the center of the safety vent 420 and the center of the current blocking member 430 may be physically and electrically connected. A first electrode tab 213 protruding from the first electrode 210 may be connected to a lower end of the current blocking member 430 .

The safety vent 420 is a thin film structure through which electric current passes, and the center thereof may be formed to protrude in a downward direction, that is, in a direction in which the current blocking member 430 is located. The current blocking member 430 is a plate member through which current passes, and a plurality of through holes for discharging gas may be formed.

The upper cap 410 , the safety vent 420 , the current blocking member 430 , and the first electrode tab 213 are sequentially connected to an electrode terminal through which the upper cap 410 guides the electrical connection of the electrode assembly 200 . can function as

Meanwhile, the battery case 300 may include a crimping unit 310 and a beading unit 320 . The beading part 320 refers to a portion in which a part of the cylindrical battery case 300 is recessed in the center direction of the electrode assembly 200 , and prevents stable coupling of the cap assembly 400 and flow of the electrode assembly 200 . is for The crimping part 310 is positioned above the beading part 320 and refers to a portion surrounding the cap assembly 400 , and is for stable coupling of the cap assembly 400 .

The sealing gasket 700 is mounted on the inner surfaces of the crimping part 310 and the beading part 320 to increase the sealing force between the cap assembly 400 and the battery case 300 . That is, the crimping part 310 may be formed by placing the gasket 700 between the battery case 300 and the cap assembly 400 and bending one end of the battery case 300 to perform crimping coupling. . Through this, the cap assembly 400 can be mounted and the secondary battery 100 can be sealed.

The CID gasket 800 may be formed to surround the edge of the current blocking member 430 . In addition, a portion of the CID gasket 800 is extended between the safety vent 420 and the current blocking member 430, so that the safety vent 420 and the current blocking member 430 come into contact with the safety vent 420 after the current blocking member 430 is separated, which will be described later. it can be prevented

Next, referring to FIGS. 6 to 8 , as described above, the secondary battery 100 according to the present embodiment includes the measuring member 500 . One end of the measuring member 500 is connected to the electrode tab, and the other end passes between the battery case 300 and the cap assembly 400 and is exposed to the outside. Here, the electrode tab may be a first electrode tab 213 protruding from the first electrode 210 .

As described above, the secondary battery 100 according to the present embodiment may further include a gasket 700 positioned between the battery case 300 and the cap assembly 400 , and the measuring member 500 is the battery case. It may be located between 300 and the gasket 700 . Specifically, the measuring member 500 connected to the first electrode tab 213 may pass between the battery case 300 and the gasket 700 and be exposed to the outside. In addition, the battery case 300 and the cap assembly 400 may be coupled by crimping with the gasket 700 and the measuring member 500 interposed therebetween.

The secondary battery 100 according to the present embodiment uses the measuring member 500 exposed to the outside through between the battery case 300 and the cap assembly 400 while maintaining the actual operating state as it is, and a current blocking member A current path connected to the first electrode tab 213 may be formed without passing through 430 .

Meanwhile, the measuring member 500 according to the present embodiment may include a metal wire 510 and a coating layer 520 surrounding the metal wire 510 . The metal wire 510 is not limited in its material as long as it includes a metal having electrical conductivity, and may include copper (Cu) as an example. Meanwhile, the coating layer 520 may include an enamel layer. Through the coating layer 520 , it is possible to prevent an unintentional current path from being formed by the metal wire 510 coming into contact with other parts in the secondary battery 100 . In addition, the coating layer 520 is not formed on both one end of the measuring member 500 connected to the first electrode tab 213 and the other end of the measuring member 500 exposed to the outside, so that the metal wire 510 is exposed. desirable. The metal wire 510 exposed at one end of the measuring member 500 may be connected to the first electrode tab 213 by welding or the like. Also, a voltage measurement may be performed through the metal wire 510 exposed at the other end of the measuring member 500 .

Meanwhile, the secondary battery 100 according to the present embodiment may further include an insulating tape 600 positioned between the measuring member 500 and the battery case 300 . The insulating tape 600 is an electrically insulating tape, and may include at least one of polyimide (PI), polyethylene terephthalate (PET), and polypropylene (PP).

Specifically, the insulating tape 600 is formed with the measuring member 500 connected thereto except for one end of the measuring member 500 connected to the first electrode tab 213 and the other end of the measuring member 500 exposed to the outside. It may extend together along the direction to cover the measurement member 500 . The insulating tape 600 prevents the battery case 300 including the crimping part 310 and the beading part 320 from coming into contact with the measuring member 500 , thereby preventing short circuits that may be caused by the measuring member 500 . risk can be blocked. Also, since the insulating tape 600 may be attached to the gasket 700 while covering the measuring member 500 , it may serve to fix the measuring member 500 in the secondary battery 100 . In addition, the insulating tape 600 protects the measuring member 500 during the crimping coupling process between the battery case 300 and the cap assembly 400 to prevent damage to the measuring member 500 . can

As described above, in the secondary battery 100 according to the embodiment of the present invention, an insulating tape 600 and a coating layer 520 were provided to prevent unintentional current path formation in the secondary battery. According to each embodiment, only one of the insulating tape 600 and the coating layer 520 may be provided, but it is also possible to provide both the insulating tape 600 and the coating layer 520 .

Hereinafter, voltage measurement using the measuring member 500 when the secondary battery 100 according to the present embodiment is placed in an abnormal operating state will be described with reference to FIG. 9 .

9 is a partial cross-sectional view illustrating a state when the internal pressure of the secondary battery of FIG. 6 is increased.

6 and 9 together, when the secondary battery 100 is exposed to high temperatures or is placed in an abnormal operating state due to overcharging or overdischarging, a large amount of gas may be generated inside. In a normal operating state, a downwardly protruding portion of the safety vent 420 is connected to the current blocking member 430 . However, when the internal pressure increases due to gas generation and the shape of the safety vent 420 is reversed, the current blocking member 430 is connected to the safety vent 420 and the portion 430a and the first electrode tab 213 ( 430b), the electrical connection between the upper cap 410 and the first electrode tab 213 is blocked.

At this time, the flow of current through the current blocking member 430 is blocked, but the secondary battery 100 according to the present embodiment uses the measuring member 500 connected to the first electrode tab 213 to the secondary battery ( 100) can be measured. That is, even after the current blocking member 430 operates, voltage information in an abnormal operating state may be provided. Except that the current blocking member 430 is separated, the voltage information may be provided while maintaining the structure of the actually operating secondary battery 100 as it is.

In particular, by passing the measuring member 500 between the crimping part 310 and the gasket 700 of the battery case 300 without providing a separate hole in the cap assembly 400 or the like, the actual secondary battery 100 ), it is possible to measure the voltage in the state in which the voltage behavior is accurately realized. Disturbance of the evaluation result can be excluded, so that accurate voltage information can be provided even in abnormal operating conditions.

If a separate hole is provided, a separate sealant for sealing between the measuring member and the hole should be interposed. In this case, there is a disadvantage that an additional space is required inside the secondary battery for interposing the sealant, and there is a problem in that the sealant is easily released due to the deformation of the sealant. Contrary to this, the measuring member 500 according to the present embodiment is provided between the crimping part 310 and the gasket 700 so that a separate hole formation is unnecessary, and it can be strongly fixed and sealed due to the crimping coupling. That is, it is possible to measure the voltage while maintaining sealing without damaging the structure of the secondary battery 100 . In addition, since one end of the measuring member 500 is connected to the first electrode tab 213 and the other end is exposed to the outside, it can be manufactured by crimping, thereby simplifying the manufacturing process.

In this embodiment, terms indicating directions such as front, rear, left, right, up, and down are used, but these terms are for convenience of explanation only, and may vary depending on the location of the object or the position of the observer. .

The secondary battery according to the present embodiment described above can be applied to various devices. Specifically, it may be applied to transportation means such as electric bicycles, electric vehicles, hybrids, etc., but is not limited thereto, and may be applied to various devices capable of using a secondary battery.

Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also provided. is within the scope of the

200: electrode assembly
300: battery case
400: cap assembly
500: measurement member

Claims (10)

A jelly roll type electrode assembly including an electrode tab;
a battery case housing the electrode assembly and having an open top;
a cap assembly coupled to an open upper portion of the battery case; and
and a measuring member having one end connected to the electrode tab and the other end passing between the battery case and the cap assembly and exposed to the outside. In claim 1,
Further comprising a gasket positioned between the battery case and the cap assembly,
The measuring member is a secondary battery positioned between the battery case and the gasket. In claim 2,
The battery case and the cap assembly are coupled to each other by crimping the gasket and the measuring member therebetween. In claim 1,
The measuring member may include a metal wire and a coating layer surrounding the metal wire. In claim 4,
The coating layer is a secondary battery comprising an enamel layer. In claim 1,
The secondary battery further comprising an insulating tape positioned between the measuring member and the battery case. In claim 6,
The insulating tape is a secondary battery comprising at least one of polyimide (PI), polyethylene terephthalate (PET), and polypropylene (PP). In claim 1,
The cap assembly includes a current interrupt device (CID) and a safety vent positioned on the current interrupt member and electrically connected to the current interrupt member;
The electrode tab is a secondary battery connected to the current blocking member. In claim 1,
The battery case is a secondary battery of a cylindrical case. A device comprising the secondary battery according to claim 1 .

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