KR20150124215A - Prismatic secondary battery with improved safety - Google Patents

Abstract

In the present invention, disclosed is a prismatic secondary battery with improved safety, capable of preventing the secondary battery from being exploded or ignited by inducing the prismatic secondary battery to be symmetrically folded and to ultimately induce the prismatic secondary battery into a safe short mode if the prismatic secondary battery is folded by an external force applied to the prismatic secondary battery. The prismatic secondary battery according to the present invention includes an electrode assembly on which an anode plate and a cathode plate are arranged to face each other, a battery can which receives the electrode assembly in an inner space, and a cap plate which is combined with the upper end of the battery can, seals an opening part formed on the upper end of the battery can, and includes a folding groove formed in a region.

Description

[0001] The present invention relates to a prismatic secondary battery with improved safety,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a prismatic secondary battery, and more particularly, to a prismatic secondary battery having improved safety in inducing symmetric folding and ultimately leading to a safe short mode when the prismatic secondary battery is folded due to external pressure .

2. Description of the Related Art In recent years, demand for portable electronic products such as notebook computers, video cameras, and portable telephones has been rapidly increased, and electric vehicles, storage batteries for energy storage, robots, and satellites have been developed in earnest. Are being studied actively.

The secondary rechargeable batteries are nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium secondary batteries. Among them, lithium secondary batteries have almost no memory effect compared to nickel- It is very popular because of its low self-discharge rate and high energy density.

These lithium secondary batteries mainly use a lithium-based oxide and a carbonaceous material as a cathode active material and an anode active material, respectively. The lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate each coated with such a positive electrode active material and a negative electrode active material are disposed with a separator interposed therebetween, and a jacket for sealingly storing the electrode assembly together with the electrolyte solution.

Meanwhile, the lithium secondary battery can be classified into a can type secondary battery in which an electrode assembly is embedded in a metal can, and a pouch type secondary battery in which an electrode assembly is embedded in a pouch of an aluminum laminate sheet, depending on the shape of the battery case. The can-type secondary battery can be classified into a cylindrical battery and a prismatic battery depending on the shape of the metal can. The casing of such a rectangular or cylindrical secondary battery has a cap assembly which is hermetically sealed to the case having an open end, that is, the battery can and the open end of the battery can.

Among these, the prismatic secondary battery has a shape of a rectangular parallelepiped, has a variety of advantages such that it is easy to laminate a plurality of secondary batteries, and is widely used.

1 is a schematic view of a prismatic secondary battery according to the prior art. The prismatic secondary cell shown in Fig. 1 is a rectangular prismatic secondary cell having a long side portion 1 and a short side portion s when viewed from above, and is one of the generally used prismatic secondary cells.

However, when an external force is applied to the prismatic secondary battery, the prismatic secondary battery may be folded. This folding phenomenon occurs at the long side portion (l) of the rectangular secondary battery (s) rather than the short side portion (s). If such a folding phenomenon occurs, there is a possibility that the battery can 20 penetrates the electrode assembly housed in the battery can 20 to cause ignition or explosion.

Particularly, when asymmetrical folding occurs in the long side portion 1 of the prismatic secondary battery, the electrode assembly and the battery can 20 are immediately energized to become a very dangerous short-circuit state (hereinafter, dangerous short-circuit mode). Such a dangerous short-circuiting mode is caused by the asymmetric folding phenomenon of the long side portion 1, and the asymmetric folding phenomenon mainly occurs around the electrolyte injection opening 11 of the cap assembly 10. The cap assembly 10 is provided with an electrolyte injection port 11 for injecting an electrolyte solution. The electrolyte injection port 11 is provided with a hole in the cap assembly 10.

As shown in FIG. 2, when an external force is applied to the prismatic secondary battery, the portion where the hole is formed has a lower mechanical strength than the portion where the hole is not formed, so that there is a great possibility that a folding phenomenon (i.e., asymmetric folding) occurs around such a hole. Therefore, when the prismatic secondary battery according to the prior art is subjected to an external force, it is very likely to be folded asymmetrically and to be led to a dangerous short-circuit mode.

SUMMARY OF THE INVENTION The present invention has been made to overcome the above problems, and it is an object of the present invention to provide a prismatic secondary battery which is folded symmetrically when an external force is applied to the prismatic secondary battery, To thereby prevent the secondary battery from being ignited or exploded, and to provide a prismatic secondary battery having improved safety.

Other objects and advantages of the present invention will become apparent from the following description, and it will be understood by those skilled in the art that the present invention is not limited thereto. It is also to be understood that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations thereof.

According to an aspect of the present invention, there is provided a prismatic secondary battery including: an electrode assembly having an electrode plate and a cathode plate facing each other; A battery can accommodating the electrode assembly in an internal space; And a cap plate coupled to an upper end of the battery can to close an opening formed at an upper end of the battery can and having a folding groove formed in a part of the cap.

The folding groove may be formed at a long side of the cap plate.

The folding groove may be formed at the center of the long side portion.

The folding groove may have a ratio of a distance between one end of the long side portion which meets the short side of the cap plate and a distance from the other side of the long side portion opposite to the one end of the long side portion to 2: And a distance of 1: 2 between the distance between the long side edge and the short side edge.

Further, the folding grooves may be formed in a long side portion on either side of both side long side portions.

A guide groove may be formed in the battery can in a lower end direction from an upper end opening of the battery can.

The guide groove is formed on the outer surface of the battery can, and is formed along the folding groove. A guide groove is further formed on the inner surface of the second long side plate facing the first long side plate of the battery can having the guide groove formed therein .

The prismatic secondary battery further includes a terminal plate disposed on the lower surface of the cap plate and electrically connected to the electrode tab of the electrode assembly. The folding groove may be located within a longitudinal range of the terminal plate.

Further, two or more folding grooves may be formed.

Further, the folding grooves may be V-shaped.

At least a part of the lower end of the cap plate is inserted into the battery can through an opening of the battery can and is formed on the outer surface of the long side of the lower end of the cap plate inserted into the battery can, Shaped fixing projections or fixing grooves are provided on the inner surface of the battery can, and corresponding grooves or corresponding protrusions corresponding to the fixing protrusions or fixing grooves may be provided on the inner surface of the battery can.

A battery pack according to another aspect of the present invention includes the prismatic secondary battery described above.

According to the present invention, even if an external force is applied to the prismatic secondary battery to cause a folding phenomenon, folding is performed along the folding grooves formed in the cap plate, so that symmetric folding can be induced. Thus, asymmetrical folding can be avoided, thereby minimizing the risk of ignition or explosion due to a hazardous short-circuit mode.

More specifically, the prismatic secondary battery is folded symmetrically along the folding grooves, so that the terminal plate and the battery can become in contact with each other before the battery can penetrates the electrode assembly, resulting in a short circuit between the terminal plate and the battery can. Safe short-circuit mode). This makes it possible to prevent a dangerous short-circuit mode in which the battery can is immediately energized with the electrode assembly.

According to an aspect of the present invention, by appropriately adjusting the position and shape of the folding grooves, symmetric folding can be induced more effectively.

According to another aspect of the present invention, the guide groove is formed in the rectangular case body so as to correspond to the position of the folding groove, so that symmetric folding can be more easily achieved.

According to another aspect of the present invention, a fixing protrusion or a fixing groove is formed on an outer surface of a long side portion of a lower end portion of a cap plate, and a corresponding groove or a corresponding projection is formed inside the rectangular type case body corresponding to the fixing protrusion or the fixing groove The cap plate can be prevented from being detached from the rectangular case body. Therefore, another risk factor that may be caused by the cap plate being detached from the rectangular case body can be prevented in advance.

The above and other effects of the present invention can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. It is also to be understood that the objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations thereof.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention given below, serve to further the understanding of the technical idea of the invention, And should not be construed as limiting.
1 is a schematic view of a prismatic secondary battery according to the prior art.
FIG. 2 is a view showing a state in which a prismatic secondary battery according to the prior art is folded asymmetrically around an electrolyte injection port.
3 is an exploded perspective view of a prismatic secondary battery according to an embodiment of the present invention.
4 is an assembled perspective view of a prismatic secondary battery according to an embodiment of the present invention.
5 is a top view of a cap plate according to an embodiment of the present invention.
6 is an assembled perspective view of a prismatic secondary battery according to another embodiment of the present invention.
Fig. 7 is an example of a folded secondary battery of Fig. 6; Fig.
8 is another example of the shape of the prismatic secondary battery of Fig. 6 folded.
9 is a top view of a cap assembly according to an embodiment of the present invention.
10 is a front view of the cap assembly of FIG.
11 is an exploded perspective view of a prismatic secondary battery according to another embodiment of the present invention.
12 is a reference view showing that the cap assembly does not easily detach from the battery can when an external force is applied to the prismatic secondary battery according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be construed as meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined.

Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

The embodiments of the present invention are provided to explain the present invention more fully to the ordinary artisan, so that the shape and size of the components in the drawings may be exaggerated, omitted or schematically shown for clarity. Thus, the size or ratio of each component does not entirely reflect the actual size or ratio.

FIG. 3 is an exploded perspective view of a prismatic secondary battery according to an embodiment of the present invention, and FIG. 4 is an assembled perspective view of a prismatic secondary battery according to an embodiment of the present invention.

Referring to FIGS. 3 and 4, the prismatic secondary battery according to an embodiment of the present invention includes an electrode assembly, a battery can 200, and a cap assembly 100.

The prismatic secondary battery according to an embodiment of the present invention may have a rectangular parallelepiped shape as a whole and may have a rectangular shape as viewed from above. Therefore, the prismatic secondary battery according to an embodiment of the present invention may have two long side portions 1 and two short side portions s. Here, the long side portion 1 means a portion having a relatively longer length than the short side portion s. That is, in other words, the short side s means a portion having a shorter length than the long side portion l.

The electrode assembly is configured such that the positive electrode plate and the negative electrode plate are opposed to each other, and a separator may be interposed between the positive electrode plate and the negative electrode plate. Such an electrode assembly may be formed in a state where a plurality of positive electrode plates and negative electrode plates are stacked with a separator interposed therebetween, or one positive electrode plate and negative electrode plate may be wound with a separator interposed therebetween. In the drawings, the present invention will be described with reference to a wound electrode assembly, but the present invention is not limited to such an electrode assembly.

The electrode plates (positive electrode plate, negative electrode plate) of the electrode assembly are formed with a structure in which active material slurry is applied to the current collector. The slurry is usually agitated in the state where a granular active material, an auxiliary conductor, a binder and a plasticizer are added with a solvent . Each of the electrode plates may have an uncoated portion to which no slurry is applied, and an electrode tab corresponding to each electrode plate may be formed on the uncoated portion. One or more of these electrode tabs, that is, the positive electrode tab and the negative electrode tab, may be formed on the positive electrode plate and the negative electrode plate, respectively. The positive electrode tab or the negative electrode tab may protrude from the positive electrode plate or the negative electrode plate and may be formed of the same material as the positive electrode collector or the negative electrode collector, respectively.

One of the electrode taps may be electrically connected to the electrode terminal 130 to be described later, and the other electrode tab may be electrically connected to the cap plate 110 or the battery can 200 to be described later. For example, when the positive electrode tab is energized with the electrode terminal 130, the electrode terminal 130 becomes positive polarity, and the negative electrode tab is energized with the cap plate 110 or the battery can 200, ) Or the battery can 200 has negative polarity. When the negative electrode tab is energized with the electrode terminal 130, the positive electrode tab is electrically connected to the cap plate 110 or the battery can 200 and the positive electrode tab is electrically connected to the cap plate 110, Or the battery can 200 has positive polarity.

The battery can 200 provides a space for accommodating the electrode assembly and the electrolyte therein. Therefore, the battery can 200 can accommodate the electrode assembly and the electrolyte in the inner space.

The battery can 200 may be made of a conventional metal plate known in the art and may be made of a conductive metal such as aluminum, stainless steel or an alloy thereof without limitation.

For example, the battery can 200 may be manufactured by deep drawing a metal plate, or may be manufactured by various other methods. The material and the manufacturing method of the battery can 200 of the prismatic secondary battery are widely known, and a detailed description thereof will be omitted.

The cap assembly 100 may be coupled to the battery can 200 in a state where the cap assembly 100 is disposed in an opening formed in the upper end of the battery can 200. At this time, the cap assembly 100 can be coupled to the battery can 200 in various ways. For example, the cap assembly 100 may be welded to the battery can 200.

The cap assembly 100 may include a cap plate 110, a terminal plate 120, a gasket 140, and an electrode terminal 130.

The cap plate 110 may be connected to one of the electrode tabs. For example, when the positive electrode tab is connected to the cap plate 110, the cap plate 110 has positive polarity. On the contrary, when the negative electrode tab is connected to the cap plate 110, the negative electrode of the cap plate 110 is polarized. At this time, the electrode tabs may be connected to the cap plate 110 by welding or the like, and this connection method is one example, and the present invention is not limited to this connection method.

In addition, the cap plate 110 may be provided with a battery through hole 112 and an electrolyte injection hole 113a.

The battery through hole 112 provides a space through which the electrode terminal 130 and the gasket 140, which will be described later, can be inserted. The electrode terminal 130 is inserted into the battery through hole 112 in a state surrounded by the gasket 140 and is electrically connected to the terminal plate 120 to be described later. The terminal plate 120 is electrically connected to one of the positive electrode tab and the negative electrode tab. That is, any one of the electrode tabs is electrically connected to the electrode terminal 130 through the terminal plate 120. Therefore, the electrode terminal 130 has the same polarity as the polarity of the electrode tab connected to the terminal plate 120.

The gasket 140 is disposed between the electrode terminal 130 and the cap plate 110 in order to prevent current from flowing between the electrode terminal 130 and the cap plate 110. Therefore, it is preferable that the gasket 140 is made of an insulating material. 3, the gasket 140 is inserted into the battery through hole 112 of the cap plate 110 while surrounding the electrode terminal 130. As shown in FIG.

The electrolyte injection hole 113a provides a hole through which the electrolyte can be injected. The electrolyte injection hole 113a is sealed by the sealing member 113b after the electrolyte is injected. Therefore, after the electrolyte injection hole 113a is sealed by the sealing member 113b, the electrolytic solution does not flow out to the outside.

According to an embodiment of the present invention, a folding groove 111 may be formed in a part of the cap plate 110. This folding groove 111 is a component for guiding the folding of the prismatic secondary battery when an external force is applied to the prismatic secondary battery. Therefore, it is preferable that the folding grooves 111 are formed in the long side portion 1 of the cap plate 110, which is a portion where the folding phenomenon mainly occurs.

Further, in order to induce symmetrical folding, the folding grooves 111 are preferably formed at the center of the long side portion 1.

For example, the folding grooves 111 may be formed at a distance from one end of the long side portion 1 which meets the short side portion s of the cap plate 110, (1) a distance between the point where the ratio of the distance from the other end is 2: 1 and one end of the long side portion (1) and a distance between the long side portion (1) and the other end is 1: 2.

5 is a top view of a cap plate according to an embodiment of the present invention. Referring to FIG. 5, a part of the cap plate 110 is shaded, and folding grooves 111 may be formed in the shaded areas.

In other words, in FIG. 5, shading is processed in the area between the portions denoted by c1 and c2. Here, c2 is a point where the ratio of the distance between one end t1 of the long side portion meeting the short side portion of the cap plate 110 and the other side long side portion t2 opposite to the one end of the long side portion is 2: y = 2: 1). c1 is a point where the ratio of the distance between one end t1 of the long side portion and the other end t2 of the long side portion is 1: 2 (i.e., z: w = 1: 2). 5, the folding groove 111 is formed at a point where the ratio of the distance between the one end t1 of the long side portion and the other end t2 of the long side portion is 2: 1, the one end t1 of the long side portion and the other end t2 ) Is 1: 2.

There is no limitation on the number of the folding grooves 111, and therefore, it is not necessarily formed only one. Accordingly, two or more folding grooves 111 may be formed on the cap plate 110. [

FIG. 6 is an assembled perspective view of a prismatic secondary battery according to another embodiment of the present invention, FIG. 7 is an example of a folded rectangular secondary battery of FIG. 6, and FIG. 8 is a cross- It is another example of appearance.

Referring to FIG. 6, two folding grooves 111 are formed in the cap plate 110. Each of the folding grooves 111 is formed on two long sides 1 of the cap plate 110. The folding grooves 111 are formed in the long side portion 1 of the cap plate 110 in the front direction of FIG. 6 and the long side portion 1 of the cap plate 110 in the back side direction of FIG. As shown in Fig. According to this embodiment, when an external force is applied to the prismatic secondary battery, the prismatic secondary battery may be folded in the form shown in Fig. 7, or the prismatic secondary battery may be folded in the form shown in Fig.

Preferably, the folding groove 111 is formed in a V-shape as shown in FIG. 2 or the like so as to induce a folding phenomenon. However, the shape of the folding grooves 111 is not limited to the V shape but may be formed in other shapes (for example, U shape).

The terminal plate 120 may be disposed on a lower surface of the cap plate 110 and may be electrically connected to one of the electrode tabs of the electrode assembly. Also, the terminal plate 120 may be electrically connected to the electrode terminal 130 as described above. One of the electrode taps of the electrode assembly is electrically connected to the electrode terminal 130 through the terminal plate 120 and the electrode terminal 130 has the same polarity as the polarity of the electrode tab electrically connected to the terminal plate 120. [ . 3 and the like, since the electrode tab to be energized with the terminal plate 120 is a negative electrode tab, the electrode terminal 130 is provided as a negative electrode terminal having negative polarity. However, this is an example, and the electrode terminal 130 may be electrically connected to the positive electrode tab through the terminal plate 120 and may be provided as a positive electrode terminal.

Preferably, the first insulating plate 150 may be provided on the upper surface of the terminal plate 120. The first insulating plate 150 is made of an insulating material and interposed between the cap plate 110 and the terminal plate 120 to prevent the terminal plate 120 and the cap plate 110 from being energized.

Also, preferably, a second insulating plate (not shown) may be provided on the lower surface of the terminal plate 120. The second insulating plate is made of an insulating material and interposed between the terminal plate 120 and the electrode assembly to prevent the electrode assembly from being connected to the terminal plate 120 or the like to be energized.

The first and second insulating plates 150 and 150 are merely reference numerals used for distinguishing the first and second insulating plates 150 and 150 from each other. no.

Preferably, the folding grooves 111 are located within the longitudinal range of the terminal plate 120.

FIG. 9 is a top view of a cap assembly according to an embodiment of the present invention, and FIG. 10 is a front view of the cap assembly of FIG.

9 and 10, a gasket 140 and an electrode terminal 130 are inserted into the battery through hole 112 of the cap plate 110. A terminal plate 120 is attached to the lower surface of the cap plate 110 Lt; / RTI > A first insulating plate 150 is interposed between the cap plate 110 and the terminal plate 120. The first insulating plate 150 is omitted in FIG. Is shown in dashed lines in Fig.

Here, the folding grooves 111 may be located within a range of the longitudinal direction of the terminal plate 120 (a range indicated by an arrow), as shown in the figure. According to this embodiment, when the prismatic secondary battery receives an external force and the folding of the cap plate 110 and the battery can 200 is induced along the folding groove 111, the end portion 120t of the terminal plate can contact the battery can 200 So that a short circuit occurs between the terminal plate 120 and the battery can 200 (safe short-circuit mode). Then, the battery can 200 penetrates the electrode assembly, and the battery can 200 and the electrode assembly are short-circuited. That is, according to this embodiment, the terminal plate 120 and the battery can 200 are short-circuited before the battery can 200 penetrates the electrode assembly and is short-circuited with the electrode assembly. Therefore, the electrode assembly and the battery can 200 are immediately energized to prevent the battery from exploding.

Also, the folding grooves 111 may be formed in the long side portion 1 of either side of the both side long side portions 1. 3 and 4, the folding grooves 111 are formed only in the long side portion 1 in the front direction, and the folding grooves 111 are not formed in the long side portion 1 in the back direction . According to this embodiment, when an external force is applied to the prismatic secondary battery, it is possible to induce a folding phenomenon to occur in one direction.

More preferably, the battery can 200 is formed with guide grooves 201 and 202 in the lower end direction from the upper end opening of the battery can 200. That is, as shown in FIGS. 3 and 4, the guide grooves 201 and 202 are formed in the battery can 200 to more effectively induce the folding phenomenon. For this purpose, the guide groove may be formed along the folding groove 111. In other words, as shown in FIG. 4, when the folding groove 111 and the guide groove 201 are formed at positions corresponding to each other and the cap plate 110 and the battery can 200 are coupled to each other, . For this purpose, the guide groove 201 may be formed on the outer surface of the battery can 200 when the guide groove 201 is formed along the folding groove 111. When the guide groove 201 is formed on the outer surface of the battery can 200 as described above, it is possible to have a shape corresponding to the folding groove, so that the folding groove 111 and the guide groove 201 can form a single groove have.

In addition, more preferably, the guide groove 202 is further formed on the inner surface of the long-side plate facing the long-side plate of the battery can 200 having the guide groove 201 described above. A long side plate of the battery can 200 having a guide groove formed on the outer surface of the battery can 200 along the folding groove 111 is called a first long side plate and a long side plate facing the first long side plate is called a second long side plate, Long plate can be named. 3, the long-side plate of the battery can 200 positioned in the front direction is the first long-side plate, and the long-side plate of the battery can 200 located in the backward direction is the second long-side plate.

According to the above-mentioned naming, the guide groove 202 is further formed on the inner surface of the second long-side plate to effectively induce the folding phenomenon in one direction. That is, according to this embodiment, it is possible to induce folding in the form similar to the prismatic secondary battery shown in FIG.

According to an aspect of the present invention, it is possible to prevent other dangerous factors that may be caused by detaching the cap assembly 100 from the battery can 200 when an external force is applied to the prismatic battery and the secondary battery is folded .

To this end, the prismatic secondary battery according to an aspect of the present invention may include a cap plate 110 having protrusions or grooves and a battery can 200.

For example, the outer surface of the long side portion 1 of the cap plate 110 may be provided with a bar-shaped fixing protrusion or a fixing groove formed along the long side portion 1 direction. The inner surface of the battery can 200 may be provided with a corresponding protrusion corresponding to the fixing protrusion or the fixing groove of the cap plate 110.

At least a part of the cap plate 110 is inserted into the battery can 200 through the opening of the battery can 200 so that the cap plate 110 and the battery can 200 can be coupled to each other. At this time, the fixing protrusions or fixing grooves provided on the outer surface of the long side portion 1 of the cap plate 110 may be coupled with corresponding grooves or corresponding protrusions in the battery can 200. Here, the fixing protrusions or fixing grooves are elongated in a bar shape along the direction of the long side portion 1. Therefore, even if an external force is applied to the prismatic secondary battery, the cap assembly 100 including the cap plate 110 can not easily be detached from the battery can 200 even if a folding phenomenon occurs. This can prevent other hazards that may be caused by the removal of the cap assembly 100 from the battery can 200 in advance.

11 is an exploded perspective view of a prismatic secondary battery according to another embodiment of the present invention. 11, a bar-shaped fixing protrusion 114 is formed on the outer surface of the long side portion 1 of the lower end of the cap plate 110 along the longitudinal direction of the long side portion 1. As shown in FIG. The fixing protrusion 114 is provided between the folding groove 111 and the short side s of the cap plate 110. The fixing protrusion 114 is also provided on the outer surface of the short side s.

On the inner surface of the battery can 200, corresponding grooves 203 corresponding to the fixing protrusions 114 are formed. In Fig. 11, the corresponding groove 203 is formed on the inner surface of the battery can 200 and does not directly appear in Fig. Therefore, in Fig. 11, the corresponding groove 203 is shown by a dotted line.

12 is a reference view showing that the cap assembly 100 is not easily detached from the battery can 200 when an external force is applied to the prismatic secondary battery according to another embodiment of the present invention. Referring to FIG. 12, the cap plate 110 and the battery can 200 are firmly coupled through the fixing protrusions 114 and the corresponding grooves 203 (see the dotted line in FIG. 12). Accordingly, even if an external force is applied to the prismatic secondary battery to cause a folding phenomenon, the cap assembly 100 may be detached inward of the battery can 200 (see the downward arrow in FIG. 12) (See the upper arrow in Fig. 12) in the outer direction of the housing 200 can be prevented. Thereby, another risk factor that may occur when the cap assembly 100 is detached from the battery can 200 can be prevented in advance.

11 and 12, a fixing protrusion is formed on the cap plate and a corresponding groove is formed in the battery can. However, the present invention is not limited to these embodiments. That is, it is to be understood that a coupling manner such as that a fixing groove is formed in the cap plate and a corresponding projection is formed in the battery can is also within the scope of the present invention.

A battery pack according to an embodiment of the present invention includes the prismatic secondary battery described above. The battery pack may further include not only a prismatic secondary battery but also a battery pack management device for monitoring and controlling the state of the prismatic secondary battery.

On the other hand, in the present specification. Direction, such as up, down, left, right, inside, outside, etc., are used, but these terms are only for convenience of description, and are used for explanation object, target viewer's position, It will be apparent to those skilled in the art that various modifications and variations can be made thereto.

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

100: cap assembly
110: cap plate
111: folding groove 112: cell through hole
113a: electrolyte injection hole 113b: sealing member
114: Fixing projection
120: terminal plate
130: Electrode terminal
140: Gasket
150: first insulating plate
200: Battery cans
201, 202: Guide groove
203: corresponding groove
300: electrode assembly
310: negative electrode tab 320: positive electrode tab

Claims (12)

An electrode assembly disposed such that the positive electrode plate and the negative electrode plate are opposed to each other;
A battery can accommodating the electrode assembly in an internal space; And
And a cap plate coupled to an upper end of the battery can to close an opening formed in an upper end of the battery can and having a folding groove formed in a part of the cap. The method according to claim 1,
Wherein the folding groove is formed in a long side portion of the cap plate. 3. The method of claim 2,
Wherein the folding groove is formed at a central portion of the long side portion. 3. The method of claim 2,
The folding-
A ratio of a distance between one end of the long side portion that meets the short side portion of the cap plate and a distance from the other long side portion opposite to the one end of the long side portion is 2:
The ratio of the distance between the long side portion and the long side portion is 1: 2
Wherein the first and second electrodes are formed between the first electrode and the second electrode. 3. The method of claim 2,
Wherein the folding groove is formed on a long side portion of either one of the two side long side portions. 6. The method of claim 5,
Wherein the battery can has a guide groove formed in a lower end direction from an upper end opening of the battery can. The method according to claim 6,
Wherein the guide groove is formed on the outer surface of the battery can and is formed along the folding groove,
And a guiding groove is formed on an inner surface of the second long side plate facing the first long side plate of the battery can having the guide groove formed therein. 3. The method of claim 2,
And a terminal plate disposed on a lower surface of the cap plate and electrically connected to the electrode tab of the electrode assembly,
Wherein the folding groove is located within a longitudinal range of the terminal plate. The method according to claim 1,
Wherein the folding grooves are formed in two or more. The method according to claim 1,
Wherein the folding grooves are V-shaped. The method according to claim 1,
At least a part of the lower end of the cap plate is inserted into the battery can through an opening of the battery can,
A bar-shaped fixing protrusion or fixing groove is formed on an outer surface of a long side portion of a lower end portion of the cap plate inserted in the battery can,
And a corresponding groove or a corresponding projection is provided on the inner surface of the battery can corresponding to the fixing protrusion or the fixing groove. A battery pack comprising a prismatic secondary battery according to any one of claims 1 to 11.

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