KR20200077304A - Pouch-type Battery Case Comprising Asymmetrical Concave Part - Google Patents

Abstract

The present invention relates to a pouch type battery case made of a laminate sheet including a metal layer. The pouch type battery case includes a lower case having a concave unit for accommodating an electrode assembly and an electrolyte and an upper case positioned above the lower case. A distance between the upper case and the lower case is that a size of the distance at a first sealing unit in a first direction in which the electrolyte is injected is larger than a size of the distance at a sealing unit in the other direction. By forming the concave unit for housing the electrode assembly in an asymmetrical structure, the injectability of the electrolyte may be improved.

Description

Pouch-type Battery Case Comprising Asymmetrical Concave Part}

The present invention relates to a pouch-type battery case including an asymmetrical recess for easy electrolyte injection. Specifically, the gap between the upper case and the lower case in the sealing prediction direction in the electrolyte injection direction is relatively large, or It is for a pouch-shaped battery case having a relatively low side wall of the recess in the same direction.

As an energy source capable of repetitive charging and discharging of portable electronic products such as mobile phones, tablet PCs, vacuum cleaners, etc., the demand for secondary batteries is rapidly increasing, and applied to devices that require high capacity and high efficiency, such as electric vehicles and power storage devices. Development and research of a secondary battery for the purpose is being conducted.

Among the secondary batteries, lithium secondary batteries having advantages such as high energy density, high voltage, high power, and excellent life characteristics are widely used.

The secondary battery is classified into a pouch type, a cylindrical shape, and a square shape according to the type of the exterior material. The pouch type secondary battery has a structure in which the electrode assembly is embedded in a pouch case of a laminate sheet containing a metal layer, which is easy to manufacture and has a manufacturing cost. It has a low advantage.

The pouch-type secondary battery, after receiving the electrode assembly in the battery case, seals the remaining outer periphery except for the outer periphery of one side and injects an electrolyte through the outer periphery of the one side.

However, in order to manufacture a compact sized secondary battery, it is common to design the upper case and the lower case to be in close contact, and when forming a pouch-type battery case, the radius of curvature between the outer periphery of the electrode assembly housing and the side wall of the storage is the same It is difficult to secure a wide electrolyte injection passage because it is molded or molded so that the side wall height of the storage portion is constant in the entire portion.

Due to this, when the injection rate is faster than the speed at which the electrolyte solution moves to the electrode assembly housing part, a problem occurs that the electrolyte solution overflows, and if the gas collecting part is designed wide to prevent this, the battery case part cut after bending increases the economic efficiency. There is a losing problem.

In this regard, Patent Document 1 relates to a flat battery in which a laminated electrode is embedded in an exterior case of a laminate sheet, wherein the radius of curvature, the depth of the concave portion, and the side wall of the concave portion of the rectangular electrode accommodation concave opening corner where the laminated electrode is accommodated And the numerical range of the radius of curvature of the bottom corner composed of the bottom wall.

However, Patent Literature 1 discloses a flat cell having a constant depth and curvature radius on all four sides of the electrode accommodating concave portion, and has not disclosed a structure for facilitating injection of an electrolyte.

Patent document 2 discloses an electrolyte injection device that is inserted into the injection portion of the pouch case to inject the electrolyte into the inside of the pouch case. However, Patent Document 2 only discloses a method for easily and effectively injecting an electrolyte into a pouch case using the electrolyte injection device, and a method of using shape deformation of a battery case is not disclosed or recognized.

As described above, the need for a pouch-type secondary battery having a structure capable of easily injecting electrolyte into the pouch-type secondary battery without using a separate additional device while using the manufacturing process of the conventional pouch-type secondary battery This is a high situation.

Japanese Patent Application Publication No. 2000-208110 (2000.07.28) Korea Patent Publication No. 2015-0089557 (2015.08.05)

The present invention is to solve the problems as described above, in order to easily and effectively inject the electrolyte in the pouch-type battery case, the pouch-type battery case in the form of increasing the gap between the upper case and the lower case that is an electrolyte injection passage and the same It is an object to provide a pouch type secondary battery.

An embodiment according to the present invention for achieving this object is a pouch-shaped battery case made of a laminate sheet comprising a metal layer, wherein the pouch-shaped battery case is a lower case formed with a recess for receiving the electrode assembly and the electrolyte, and It includes an upper case located on the upper portion of the lower case, the gap between the upper case and the lower case is in the first sealing projection portion located in the first direction in which the electrolyte is injected in the sealing projection portion located in the remaining direction It may be a pouch-shaped battery case of a size larger than the size of the.

The concave portion of the lower case may have a structure in which the height of the sidewall in the first direction is lower than the height of the sidewall in the other direction.

The electrode assembly is a unidirectional electrode assembly in which the positive electrode terminal and the negative electrode terminal protrude in the same direction, and the sealing prediction portion formed on the outer periphery of the concave portion is opposite to the first sealing prediction portion and the first sealing prediction portion located in the first direction. A curvature radius (R1) of the curved surface formed by the first side wall of the concave portion connected to the first sealing predecessor and the first sealing predecessor includes a second sealing predecessor positioned in the direction. And a curvature radius R2 of the curved surface formed by the second side wall of the concave portion connected to the second sealing prediction unit.

In addition, the size of the radius of curvature R1 may be 1.5 to 5 times the radius of curvature R2.

The electrode assembly is a bidirectional electrode assembly in which the positive electrode terminal and the negative electrode terminal protrude in opposite directions, and the sealing prediction portion formed on the outer periphery of the concave portion is the first sealing prediction portion located in the direction in which the electrolyte is injected, and the electrode terminal protrudes. A curvature radius (R1) of the curved surface formed by the first side wall of the concave portion connected to the first sealing predecessor and the first sealing predecessor, including the third sealing predecessor formed in both directions to be the third sealing It may have a shape larger than the radius of curvature R3 of the curved surface formed by the third side wall of the concave portion connected to the predetermined portion and the third sealing projection.

The upper case and the lower case may have an integral structure in which one side is bent and connected.

The upper case may have a shape in which a concave portion for receiving the electrode assembly is formed.

The first sealing prediction unit may have a shape in which the gap between the upper case and the lower case is larger than the size on the outer periphery only in a portion where the electrolyte injection port is formed.

The electrolyte injection hole may be formed at the center of the first sealing projection.

The present invention provides a pouch type secondary battery manufactured using a pouch type battery case, and a battery pack including the pouch type secondary battery.

As described above, since the pouch-type battery case according to the present invention forms the gap between the upper case and the lower case in the direction in which the electrolyte is injected, larger than the gap in the other outer periphery, the electrolyte injection path is widened to thereby increase the electrolyte injection process. Can solve the problem of overflowing electrolyte.

In addition, since the injection passage of the electrolyte can be prevented from clogging, the gas collecting portion can be formed relatively narrowly, so that the portion removed by cutting in the process of manufacturing the secondary battery can be reduced.

In addition, the curvature radius of the curved surface formed by the sealing predictor and the side wall positioned in the direction in which the electrolyte is injected is larger than the curvature radius formed by the sealing predictor and the side wall in the other direction, and the electrolyte flows in the direction of the electrode assembly storage unit. Can induce an effect.

1 is a plan view of a pouch-type battery case according to the first embodiment.
FIG. 2 is a vertical sectional view taken along line A-A' in FIG. 1;
3 is a vertical cross-sectional view of a pouch type battery case according to the second embodiment.
4 is a plan view of a pouch-type battery case according to a third embodiment.
5 is a partially enlarged view of FIG. 4.
6 is a partial perspective view of a pouch type battery case according to the fourth embodiment.
7 is a vertical sectional view of a pouch type battery case according to a fifth embodiment.

Hereinafter, exemplary embodiments in which a person having ordinary skill in the art to which the present invention pertains may easily implement the present invention will be described in detail with reference to the accompanying drawings. However, in the detailed description of the operating principle of the preferred embodiment of the present invention, when it is determined that a detailed description of related known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description will be omitted.

In addition, the same reference numerals are used for parts having similar functions and functions throughout the drawings. Throughout the specification, when a part is connected to another part, this includes not only the case of being directly connected, but also the case of being connected indirectly with another element in between. In addition, the inclusion of any component does not exclude other components unless specifically stated otherwise, means that other components may be further included.

The present invention will be described as detailed examples according to the drawings.

1 is a plan view of a pouch type battery case according to the first embodiment, and FIG. 2 is a vertical cross-sectional view taken along line A-A' in FIG. 1.

1 and 2, the battery case 110 is composed of an upper case 121 and a lower case 122, the upper case 121 is a flat structure, the lower case 122 is an electrode assembly 101 ) Is formed with a recess 109 for receiving. The electrode assembly 101 is accommodated in the concave portion 109, and the electrode assembly 101 is a unidirectional electrode assembly in which the positive electrode terminal 102 and the negative electrode terminal 103 protrude upward.

The electrode assembly 101 is a jelly-roll electrode assembly having a structure in which long sheets of positive and negative electrodes are wound in a state in which a separator is interposed, and a plurality of positive and negative electrodes cut in units of a predetermined size are sequentially in a state via a separator. Stacked electrode assemblies stacked in a stack, stacked/folded electrode assemblies having a structure in which unit cells stacked in a state in which a positive electrode and a negative electrode of a predetermined unit are interposed with a separator sheet are stacked in a state in which the separator cells are stacked or folded/folded. It may be a lamination / stack-type electrode assembly of the bonded structure.

The battery case 110 is a form in which the lower outer periphery 105 of the concave portion 109 in which the electrode assembly is accommodated is bent, and is divided into the upper case 121 and the lower case 122, and the first direction in which the electrolyte is injected. The first sealing predictor 111 located at is not sealed, and the second sealing predictor 112 and the electrode tab positioned in the second direction opposite to the first sealing predictor 111 protrude in the direction in which the electrode tab protrudes. The electrolyte solution is injected through the first sealing predictor 111 in a state where the third sealing predictor 113 located is sealed and forms a sealing part.

The distance D1 between the upper case 121 and the lower case 122 in the first sealing predictor 111 is upper in the second sealing predictor 112 located in the opposite direction of the first sealing predictor 111. The height D1 between the case 121 and the lower case 122 is greater, and the height H1 of the first side wall 131 into which the electrolyte is injected is smaller than the height H2 of the second side wall 132.

Specifically, after the battery case is molded and before sealing the sealing projections, the spacing between the upper case 121 and the lower case 122 is formed in all the sealing projections, and the spacing is the first sealing prediction 111 ), the distance D1 between the upper case 121 and the lower case 122 is greater than the distance D2 between the upper case 121 and the lower case 122 in the second sealing prediction part 112.

In addition, in the remaining sealing predictors except for the first sealing predictor 111, sealing is performed to form a sealing part and an electrolyte is injected through the first sealing predictor 111 in an open state.

As described above, the sealing portions on the outer periphery except for the first sealing preliminary portion are sealed to form a sealing portion, and the gap between the upper case and the lower case in the sealing portions on the outer periphery may be zero.

In addition, the radius of curvature R1 of the curved surface formed by the first sealing predictor 111 and the first side wall 131 is the radius of curvature of the curved surface formed by the second sealing predictor 112 and the second side wall 132. (R2).

Specifically, the size of the curvature radius R1 of the curved surface formed by the first sealing predictor 111 and the first side wall 131 is the curved surface formed by the second sealing predictor 112 and the second side wall 132. It may be molded within a range of 1.5 to 5 times the radius of curvature of R2, for example, R1 may be 1.4 and R2 may be 0.5. When R2 is the radius of curvature of a typical pouch-type battery case, the curvature radius (R1) of the curved surfaces formed by the first sealing predictor 111 and the first side wall 131 is the second sealing predictor 112 and the second. When the curvature radius R2 of the curved surface formed by the side wall 132 is less than 1.5 times, it is difficult to obtain an improvement effect of the process of injecting the electrolytic solution, and when it is greater than 5 times, insertability is poor when the electrode assembly is stored. It is not preferable because there is a problem that the fairness decreases.

The pouch-shaped battery case 110 is in a state before sealing the upper case 121 and the lower case 122, the distance between the upper case and the lower case (D1) and the height of the first side wall (H1) in the direction of the first sealing prediction. ) Is the same as the sum of the gap (D2) between the upper case and the lower case and the height (H2) of the second side wall in the direction of the second sealing prediction.

However, when the upper case and the lower case are sealed, the D1 and D2 become 0, so the height of the battery case may be formed on the second side wall 132 relatively higher than on the first side wall 131 side. Therefore, in order to prevent this, the first side wall 131 side is a battery case in a sealed state, such as bending the upper case 121 to the lower side or performing a heat-sealing sealing in a state in which the lower case 122 is bent upward. It is preferable to seal considering that the thickness of the film is uniform throughout.

3 is a vertical cross-sectional view of a pouch type battery case according to the second embodiment.

Referring to FIG. 3, the pouch-type battery case includes an upper case 221 and a lower case 222 that are connected in a state in which one side of the laminate sheet is bent at a predetermined angle, and a recess 209 in the lower case 222 ) Is formed.

The distance D1 between the upper case 221 and the lower case 222 in the first sealing predictor 211 is the distance D2 between the upper case 221 and the lower case 222 in the second sealing predictor 212. ).

However, in order to inject the electrolyte, when the sealing portions are formed by sealing the remaining sealing portions other than the first sealing portion 211, the gap D2 becomes as the second sealing portion prediction portion 212 becomes the second sealing portion. The interval D1 between the upper case 221 and the lower case 222 in the first sealing prediction part 211 that is 0 and has not yet been sealed may be changed according to the material and thickness of the battery case.

If the gap between the upper case 221 and the lower case 222 in the second sealing predictor 212 before sealing is formed to be the same as the gap between the upper case and the lower case in the conventional battery case, the first sealing predictor 211 ) In the bar (D1) of the upper case 221 and the lower case 222 is formed larger than the gap in the conventional battery case, the injection of the electrolyte can be easily made.

Unlike the battery case 110 of FIGS. 1 and 2, the battery case of FIG. 3 has a height H1 of the first side wall 231 equal to a height H2 of the second side wall 232. Therefore, as shown in FIG. 3, in the state before sealing the upper case 221 and the lower case 222, the battery case thickness D1+H1 in the first side wall 231 direction is the battery case in the second side wall 232 direction. Although thicker than the thickness D2+H2, D1 and D2 become 0 when the upper case 221 and the lower case 222 are heat-sealed, so that the thickness of the battery case is uniform throughout.

In the case of the pouch-type battery case accommodating the unidirectional electrode assembly shown in FIGS. 1 to 3, the height of the first side wall is lower than that of the second side wall as well as the third side wall excluding the first side wall and the second side wall. A step difference according to a height difference between the side walls may be formed at the connection portion between the three side walls and the first side wall. Alternatively, the third side wall may be formed in an inclined shape so that the height gradually decreases from the second side wall to the first side wall.

4 is a plan view of a pouch-type battery case according to a third embodiment, and FIG. 5 is a partially enlarged view of FIG. 4.

4 and 5, the electrode assembly 301 is housed in the concave portion 309 of the pouch type battery case, and the positive electrode terminal 302 and the negative electrode terminal 303 are opposite to each other in the electrode assembly 301. It is a bidirectional electrode assembly that protrudes.

The outer periphery of the concave portion 309 includes a first sealing predictor 311 positioned in the direction in which the electrolyte is injected, and a third sealing predictor 313 formed in both directions in which the electrode terminal protrudes. The battery case is bent in the lower outer periphery 305, which is in the opposite direction of the sealing prediction unit 311, and is divided into an upper case and a lower case.

Since the pouch-type battery case according to the third embodiment includes a bidirectional electrode assembly, it is difficult to estimate the gap between the upper case and the lower case because it is bent in the opposite direction of the first sealing projection in which the electrolyte is injected. Accordingly, the radius of curvature R1 of the curved surface formed by the first sealing predictor 311 and the first side wall 331 is the radius of curvature of the curved surface formed by the third sealing predictor 313 and the third side wall 333. It may be formed larger than (R3).

As described above, since R1 is largely formed, it is possible to induce the electrolyte injected in the direction of the first sealing prediction unit 311 to move in the direction of the electrode assembly storage unit.

6 is a partial perspective view of a pouch type battery case according to the fourth embodiment.

Referring to FIG. 6, the pouch-type battery case is a battery case of the same shape as in FIG. 1, and the first sealing predictor, which is the direction in which the electrolyte is injected, partially has a different curvature radius.

That is, the height of the first side wall 431 of the recess 409 for receiving the electrode assembly is the same as the height of the third side wall 433 and the first side wall 431b and the relatively low first side wall 431a. Consisting of, the distance between the upper case and the lower case in the first sealing prediction part 415 connected to the first side wall 431a is upper in the first sealing prediction part 411 connected to the first side wall 431b. It may be larger than the size of the gap between the case and the lower case.

Specifically, in the pouch type battery case of FIG. 6, the first sealing prediction unit 415 secures the electrolyte injection passage without sealing the upper case and the lower case in the first sealing prediction unit 415, but the first sealing prediction unit 411 ) May be sealed together when the second sealing predictor and the third sealing predictor are sealed.

In addition, the radius of curvature of the curved surface to which the first sealing predictor 415 and the first side wall 431a are connected is formed larger than the curvature radius of the curved surface to which the first sealing predictor 411 and the first side wall 431b are connected. As can be done, it is possible to induce the flow of the electrolyte in the direction of the concave portion through the unsealed portion of the first sealing projection portion 415.

As illustrated in FIG. 6, the first sealing predictor 415 and the first sealing predictor 411 are formed with a step difference according to a difference in height between the first side wall 431a and the second side wall 431b. It can be a structure.

The position of the first sealing predictor 415 may be selectively applied among all parts of the first sealing predictor, and may be formed in the center of the first sealing predictor in consideration of uniform electrolyte impregnation properties of the electrode assembly.

To seal the first sealing projections 411 and 415, a sealing tool may be used to pressurize and heat the sealing property due to the stepped structure.

Accordingly, the sealing tool can be prevented from being deteriorated by using a sealing tool having a stepped structure corresponding to the stepped structure of the first sealing prediction unit as the sealing tool.

As shown in FIG. 6, when the first sealing predictor having a relatively large gap between the upper case and the lower case is formed to be small, it means that the injection path of the electrolyte is limited to the first sealing predictor 415. Since the first sealing predictor 411 is sealed before the electrolyte is injected, it is possible to prevent the first sealing predictor 411 from contacting the electrolyte. Therefore, the sealing property of the pouch type battery case can be secured.

On the other hand, the present invention, unlike the pouch-type secondary battery described above, the upper case also includes a pouch-type battery case having a structure in which a recess for storing an electrode assembly is formed, and FIG. 7 is a pouch-type battery case according to the fifth embodiment It shows a vertical cross section of.

Referring to FIG. 7, the pouch-shaped battery case includes an upper case 521 in which a concave portion 510 is formed and a lower case 522 in which a concave portion 509 is formed.

The curvature radius R1 of the curved surfaces formed by the first sealing predictor 511 and the first side wall 531 positioned in the recesses 509 and 510 in the direction in which the electrolyte is injected is the second sealing predictor 512 And the second side wall 532 is larger than the radius of curvature R2 of the curved surface.

In addition, FIG. 7 shows a state before sealing the pouch-type battery case, and the gap D1 between the upper case 521 and the lower case 522 in the first sealing projection part 511 is the second sealing example. It is larger than the gap D2 between the upper case 521 and the lower case 522 at the top portion 512.

For example, when the distance D2 between the upper case 521 and the lower case 522 in the second sealing predictor 512 of FIG. 7 is the same as the interval in the conventional battery case, the second sealing predictor Even if the gap D2 between the upper case 521 and the lower case 522 in the second sealing part is zero because the 512 is sealed, the upper case 521 and the lower case in the first sealing prediction part 511 ( The spacing D1 of 522 is larger than the spacing in the conventional battery case. In addition, since a pouch-shaped battery case in which the radius of curvature R1 is formed larger than the radius of curvature R2 is used, injection of the electrolyte solution can be easily and quickly performed.

In addition, in the pouch-type battery case of FIG. 7, the descriptions of FIGS. 1 to 6 may be equally applied to the intervals between the upper case and the lower case, the side wall height of the concave portion, and the radius of curvature.

Those skilled in the art to which the present invention pertains will be able to perform various applications and modifications within the scope of the present invention based on the above.

101, 301: electrode assembly
102, 302: positive terminal
103, 303: negative terminal
105, 305: lower outer periphery
109, 209, 309, 409, 509, 510: recess
110: battery case
111, 211, 311, 411, 415, 511: First Shilling Government
112, 212, 512: Second Ceiling Prediction
113, 313, 413: 3rd Sealing Government
121, 221, 521: upper case
122, 222, 522: lower case
131, 231, 331, 431, 431a, 431b, 531: first side wall
132, 232, 532: Second side wall
333, 433: Third side wall
D1: The gap between the upper case and the lower case in the first sealing plan
D2: The gap between the upper case and the lower case in the second sealing prediction
H1: First side wall height
H2: Second side wall height
R1: radius of curvature of the curved surface formed by the first sealing projection and the first side wall
R2: The radius of curvature of the curved surface formed by the second sealing projection and the second side wall
R3: The radius of curvature of the curved surface formed by the third sealing projection and the third side wall

Claims (11)

A pouch-type battery case made of a laminate sheet comprising a metal layer,
The pouch-shaped battery case includes an electrode assembly and a lower case in which a concave portion for storing an electrolyte is formed, and an upper case located on an upper portion of the lower case,
The gap between the upper case and the lower case is a pouch-type battery case characterized in that the size in the first sealing predictor located in the first direction in which the electrolyte is injected is larger than the size in the sealing predictor positioned in the other direction. The pouch-type battery case according to claim 1, wherein the recessed portion of the lower case has a side wall height in a first direction lower than a side wall height in the other direction. According to claim 1, The electrode assembly is a unidirectional electrode assembly in which the positive electrode terminal and the negative electrode terminal protrude in the same direction,
The sealing prediction portion formed on the outer periphery of the concave portion includes a first sealing prediction portion located in the first direction and a second sealing prediction portion located in the opposite direction of the first sealing prediction portion,
The radius of curvature R1 of the curved surface formed by the first side wall of the recess connected to the first sealing predictor and the first sealing predictor is a concave portion connected to the second sealing predictor and the second sealing predictor. A pouch-type battery case characterized in that the curvature radius (R2) of the curved surface formed by the second side wall is larger. The pouch-type battery case according to claim 3, wherein the radius of curvature (R1) is 1.5 to 5 times the radius of curvature (R2). The electrode assembly of claim 1, wherein the electrode assembly is a bidirectional electrode assembly in which positive and negative terminals protrude in opposite directions.
The sealing projection formed on the outer periphery of the concave portion includes a first sealing projection positioned in a direction in which the electrolyte is injected, and a third sealing projection formed in both directions in which the electrode terminals protrude,
The radius of curvature R1 of the curved surface formed by the first side wall of the recess connected to the first sealing predictor and the first sealing predictor is a concave portion connected to the third sealing predictor and the third sealing predictor. Pouch-shaped battery case characterized in that the curvature radius (R3) of the curved surface formed by the third side wall. The pouch-type battery case according to claim 1, wherein the upper case and the lower case are integral structures connected by bending one side. The pouch-shaped battery case according to claim 1, wherein a recess is formed in the upper case for receiving the electrode assembly. The pouch-type battery case according to claim 1, wherein the first sealing preliminary, the gap between the upper case and the lower case is larger than the rest of the outer periphery only in a portion where the electrolyte injection hole is formed. 9. The pouch-type battery case according to claim 8, wherein the electrolyte injection hole is formed at the center of the first sealing projection. A pouch type secondary battery manufactured using the pouch type battery case according to any one of claims 1 to 9. A battery pack comprising a pouch-type secondary battery according to claim 10.

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