Secondary battery

Abstract

To provide a secondary battery in which an adhesive agent of a cover tape surrounding an outer surface of a battery cell is not exposed.SOLUTION: A secondary battery includes an electrode assembly, a pouch that accommodates the electrode assembly, and a cover tape that is attached so as to cover at least a part of two surfaces of the pouch. The cover tape is set so that the adhesive power of an adhesive agent is different in a fixed region attached to a first surface of the pouch and a dot region attached to a second surface of the pouch.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a secondary battery.

Background Art

[0002] Unlike non-rechargeable primary batteries, secondary batteries can be charged and discharged. Small-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, notebook computers, digital cameras, and camcorders, and large-capacity secondary batteries are widely used as power sources for motor drives such as hybrid vehicles and electric vehicles, and batteries for power storage. Such secondary batteries include an electrode assembly composed of a positive electrode and a negative electrode, a case for housing the same, electrode terminals connected to the electrode assembly, and the like.

[0003] The above-described information disclosed in the technology that is the background of such an invention is only for improving the understanding of the background of the present invention, and thus may include information that does not constitute the prior art.

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present invention is to provide a secondary battery in which the adhesive of a cover tape surrounding the outer surface of a battery cell is not exposed.

[0005] However, the technical problems to be solved by the present invention are not limited to the above-described problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

Means for Solving the Problems

[0006] A secondary battery according to an embodiment of the present invention for solving the above technical problem includes an electrode assembly, a pouch for accommodating the electrode assembly, and a cover tape adhered to cover at least a part of two surfaces of the pouch. The cover tape is set such that the adhesive force of the adhesive is different between a fixed region adhered to the first surface of the pouch and a dot region adhered to the second surface of the pouch.

[0007] Here, the fixed region of the cover tape may be formed to surround the side surface of the pouch, and the dot region of the cover tape may be formed to surround at least a part of the upper surface of the pouch.

[0008] Also, the adhesive of the dot region may be formed to have a lower adhesive force than the adhesive of the fixed region.

[0009] Also, the cover tape may be adhered to the lower surface of the pouch and may include a base region having a first adhesive force.

[0010] Also, the secondary battery may include a first dot region extending from the base region to one side surface and having a second adhesive force, a second dot region formed along an edge of a part of the first dot region and having a first adhesive force, and a first fixed region formed along an edge of the second dot region and having a third adhesive force.

[0011] Also, the cover tape may be adhered to the lower surface of the pouch and may include a base region having a first adhesive force, a second fixed region extending from the other side surface of the base region and having a third adhesive force, and a third dot region extending along the outside of the second fixed region and having a second adhesive force.

[0012] Also, the second adhesive force may be set to be lower than the first adhesive force.

[0013] Also, the third adhesive force may be set to be higher than the first adhesive force.

[0014] Also, the first adhesive force can be 0.20 to 0.50 [kgf / 25 mm].

[0015] Also, the second adhesive force can be 0.05 to 0.25 [kgf / 25 mm].

[0016] The third adhesive force can be 1.10 to 1.40 [kgf / 25 mm].

[0017] Also, a finishing area where no adhesive is applied may be further formed at the end of the first fixing area or the third dot area.

[0018] Also, the finishing area may be formed on the outermost side along the edge of the first fixing area or the third dot area.

[0019] Also, the finishing area can have a thickness different from that of the base material of the cover tape.

[0020] Also, the finishing area is formed thicker than the base material of the cover tape and can contact the upper surface of the pouch.

Advantages of the Invention

[0021] The secondary battery according to the present invention attaches a cover tape to a part of the lower surface, side surface, and upper surface of the battery cell, and reduces the adhesive force for the second dot area and the third dot area that cover the upper surface to form it, so that the adhesive can be prevented from being exposed from the upper surface of the battery cell.

[0022] Also, by forming a finishing area where no adhesive is applied at the ends of the second dot area and the third dot area, it is possible to prevent the adhesive in the second dot area and the third dot area from being exposed.

[0023] Further, by forming the thickness of the tape base material thicker with respect to the finishing region to produce a dam structure, it is possible to prevent the adhesive in the second dot region and the third dot region from moving and to ensure that they are not exposed either.

[0024] However, the effects obtained by the present invention are not limited to the above-described effects, and other technical effects not mentioned will be clearly understandable to those skilled in the art from the description of the invention described below.

[0025] The drawings attached to this specification illustrate preferred embodiments of the present invention and serve to enable a more detailed understanding of the technical idea of the present invention together with the detailed description of the present invention to be described later. Therefore, the present invention should not be construed as being limited only to the matters described in those drawings.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to the detailed description, terms and words used in this specification and claims should not be construed as being limited to their ordinary or dictionary meanings. In accordance with the principle that the inventor can appropriately define the concept of terms in order to explain their invention in the best way, they should be construed in a meaning and concept consistent with the technical idea of the present invention. Therefore, the embodiments described in this specification and the configurations shown in the drawings are only some of the preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. It should be understood that there may be various equivalents and modifications that can replace these at the time of this application. Also, as used in this specification, "comprise" and / or "including" identify the presence of the recited shape, number, step, operation, member, element, and / or group thereof, and do not exclude the presence or addition of one or more other shapes, numbers, operations, members, elements, and / or groups. Further, when describing embodiments of the present invention, the phrases "can be" and "may be" can include "one or more embodiments of the present invention".

[0028] Also, to assist in understanding the invention, the accompanying drawings are not shown at actual scale, and the dimensions of some components may be exaggerated. Also, the same reference numerals can be assigned to the same components in different embodiments.

[0029] A reference that two comparison targets are "identical" means "substantially identical". Therefore, substantial identity can include cases having a deviation considered to be a low level in the art, for example, a deviation within 5%. Also, that a parameter in a given region is uniform can mean that it is uniform from an average perspective.

[0030] For example, terms such as first, second, etc. are used to describe various components, but it goes without saying that these components are not limited to these terms. These terms are merely used to distinguish one component from another, and it goes without saying that, unless otherwise stated, the first component can be the second component.

[0031] Throughout the specification, unless otherwise stated, each component can be singular or plural.

[0032] Saying that any configuration is disposed "above (or below)" a component or "on (or under)" a component means not only that any configuration is disposed in contact with the upper (or lower) surface of the component, but also that other configurations can be interposed between the component and any configuration disposed on (or under) the component.

[0033] Also, when a component is described as being "coupled", "connected", or "joined" to another component, it should be understood that the components can be directly coupled or connected to each other, but other components can be "interposed" between the respective components, or the respective components can be "coupled", "connected", or "joined" through other components. Also, when a part is said to be electrically coupled to another part, this includes not only the case where they are directly connected, but also the case where other elements are interposed therebetween.

[0034] Throughout the specification, when "A and / or B" is mentioned, this means A, B, or A and B, unless otherwise stated. That is, "and / or" includes all combinations or any combination of the plurality of listed items. When "from C to D" is mentioned, this means from C or more to D or less, unless otherwise stated.

[0035] Hereinafter, a secondary battery according to an embodiment of the present invention will be described in more detail.

[0036] FIG. 1 shows an exploded perspective view of a pouch-type battery constituting a secondary battery according to an embodiment of the present invention.

[0037] The battery cell 100 can be composed of a pouch-type battery and include an electrode assembly, a first current collector, a first terminal, a second current collector, a second terminal, a case, and a cap assembly.

[0038] The battery cell is composed of an electrode assembly 110 and a pouch 130 that houses the electrode assembly 110.

[0039] The electrode assembly 110 includes a negative electrode plate 112 that is a first electrode plate, a positive electrode plate 114 that is a second electrode plate, and a separator 116 interposed therebetween. The negative electrode plate 112 is provided with a negative electrode tab 112a that is electrically connected to a non-coated portion of the negative electrode, and the positive electrode plate 114 is provided with a positive electrode tab 114a that is electrically connected to a non-coated portion of the positive electrode. The negative electrode tab 112a and the positive electrode tab 114a are welded to the negative electrode lead 152 and the positive electrode lead 154 of the external terminal and are electrically connected to the outside. A tab film 156 for insulation from the pouch 130 is attached to the negative electrode lead 152 and the positive electrode lead 154.

[0040] The pouch 130 is sealed by the sealing portions 132 at the periphery abutting against each other in a state where the electrode assembly 110 is housed. Here, it is sealed in a state where the tab film 156 is disposed between the sealing portions 132. As shown in FIG. 1, a form in which the tab film 156 is attached to each of the negative electrode tab 112a and the positive electrode tab 114a is defined as a "separated tab film" (such a sealing structure is defined as a separated sealing structure).

[0041] The sealing portion 132 of the pouch 130 is made of a heat-sealing material and has a structure that is sealed by adhering the heat-sealing layers to each other. Since the heat-sealing material generally has weak adhesiveness to metal, the thin film-like tab film 156 is attached to the tab and then fused to the pouch 130. However, in the separable sealing structure, after attaching the tab film 156 to each tab, it has to be welded to the tab and further heat-sealed to the pouch 130, which causes problems such as poor workability and productivity.

[0042] FIG. 2 is a perspective view showing a secondary battery according to an embodiment of the present invention, and FIG. 3 is an enlarged view of part A in FIG. 2.

[0043] Referring to FIGS. 2 and 3, a secondary battery 10 according to an embodiment of the present invention can include a battery cell 100 and a cover tape 200 coupled to the outer surface of the battery cell 100.

[0044] The basic structure of the battery cell 100 has been described above with reference to FIG. 1. The negative electrode lead 152 and the positive electrode lead 154 of the battery cell 100 are exposed outside the sealing portion 132 of the pouch 130 and can be connected to the lead tab 160 as shown in FIG. 2. Therefore, the battery cell 100 can be connected to an external device such as a charge and discharge device via the lead tab 160.

[0045] The cover tape 200 can function to protect and insulate the pouch 130 of the battery cell 100. The cover tape 200 can be coupled to the outside of the battery cell 100, specifically, to the outside of the pouch 130. The cover tape 200 can be coupled so as to cover at least one surface of the battery cell 100.

[0046] For example, the cover tape 200 can be coupled to both adjacent side surfaces with reference to one side surface of the side surfaces of the battery cell 100 where the lead tab 160 is formed. In addition, the coupling force to the battery cell 100 can be improved by the wing portion formed on one side of the cover tape 200.

[0047] On the other hand, in the case of the adhesive formed on the inner surface for attaching the cover tape 200, it may be exposed during the attachment process of the cover tape 200 or during the use process of the secondary battery 10. And when the adhesive is exposed, problems such as a decrease in the assemblability and productivity of the secondary battery 10, adhesion of foreign matter, or movement to an external device to cause defects may occur.

[0048] In the case of the cover tape 200 used for the secondary battery 10 according to an embodiment of the present invention, such problems can be solved by preventing the adhesive, particularly the adhesive located at the edge of the cover tape 200, from being exposed.

[0049] Hereinafter, the detailed configuration of the cover tape 200 used for the secondary battery 10 according to an embodiment of the present invention will be described.

[0050] FIG. 4 is a plan view showing a cover tape provided in a secondary battery according to an embodiment of the present invention.

[0051] Referring to FIG. 4, the cover tape 200 can be adhered to the lower surface of the battery cell 100 by the first adhesive force and include a base region 210 that is basic in the overall structure.

[0052] Also, based on the base region 210, a first dot region 220 that is coupled to the base region 210 in one side direction (the left side in FIG. 4) and is formed by a second adhesive force having an adhesive force lower than the first adhesive force, a second dot region 230 that is formed outside the first dot region 220 and is formed by the first adhesive force, and a first fixing region 240 that is formed at the edge of the second dot region 230 and has a third adhesive force higher than the first adhesive force can be formed. Further, at the edge of the first fixing region 240, a finishing region 250 having no adhesive can be further provided.

[0053] Also, based on the base region 210, a second fixing region 260 that is coupled to the base region 210 in the direction of the other side (the right side in FIG. 4) and has a third adhesive force, and a third dot region 270 that is formed outside the second fixing region and has a second adhesive force, can be formed. Further, a finishing region 280 having no adhesive can be provided at the edge of the third dot region 270.

[0054] Specifically, the base region 210 can be entirely attached to one surface of the battery cell 100, for example, the lower surface. In the case of the adhesive formed on the inner surface of the base region 210, it has a first adhesive force, and the first adhesive force can be defined as 0.20 to 0.50 [kgf / 25 mm]. Also, the base region 210 can entirely protect the lower surface of the battery cell 100 and keep the position of the cover tape 200 constant.

[0055] The first dot region 220 is coupled in the left direction based on the base region 210. In the case of the adhesive formed on the inner surface of the first dot region 220, it can have a second adhesive force that is lower than the first adhesive force. Here, in the case of the adhesive, the dot size of the adhesive can be specified in the manufacturing process, and it can be manufactured to have a second adhesive force that is lower than the first adhesive force. In this case, the second adhesive force can be defined as 0.05 to 0.25 [kgf / 25 mm]. Although the range of the second adhesive force is defined to partially overlap with the range of the first adhesive force, when configuring the cover tape 200, the second adhesive force can be set to a value lower than the first adhesive force. Therefore, the first dot region 220 can be attached to the battery cell 100 with a relatively lower adhesive force compared to the base region 210.

[0056] The second dot region 230 is formed outside the first dot region 220 and can be formed to have a first adhesive force. The second dot region 230 is formed to surround one side surface of the battery cell 100 and can be bent to surround a part of the upper surface of the battery cell 100. Here, the second dot region 230 can be attached to the outer surface of the battery cell 100 with a stronger adhesive force compared to the first dot region 220.

[0057] The first fixing area 240 is formed along the edge of the second dot area 230 and may have a third adhesive force. In this case, the third adhesive force can be defined as 1.10 to 1.40 [kgf / 25 mm]. Therefore, since the first fixing area 240 adheres to the battery cell 100 with the strongest adhesive force at the outermost edge of the cover tape 200, the form and position in which the cover tape 200 is coupled can be maintained. Further, by providing the wing part 241 at the end of the first fixing area 240, it can be further adhered to the side surface where the lead tab 160 of the battery cell 100 is formed and the opposite side surface.

[0058] On the other hand, the finishing area 250 is formed at the edge of the first fixing area 240 and may not include an adhesive. Since such a finishing area 250 does not have an adhesive, when pressure is applied for the adhesion of the first fixing area 240 in the process, even if the adhesive of the first fixing area 240 is extruded, the adhesive can be accommodated in the finishing area 250. Therefore, it is possible to prevent the adhesive from being exposed to the outside of the cover tape 200.

[0059] Also, the second fixing area 260 is coupled to the base area 210 in the right direction with respect to the base area 210, and the adhesive formed on the inner surface may have a third adhesive force. The second fixing area 260 can be coupled along the right side surface of the battery cell 100 and can be stably coupled by an adhesive having a high adhesive force. Here, since the second fixing area 260 is coupled to the entire right side surface in the longitudinal direction of the battery cell 100, it is adhered over a wide area. Therefore, by providing the second fixing area 260 having an adhesive with a relatively high third adhesive force, it can be strongly adhered to the battery cell 100. Further, by providing the wing part 261 at the end of the second fixing area 260, it can be further adhered to the opposite side surface of the side surface where the lead tab 160 of the battery cell 100 is formed.

[0060] The third dot region 270 is formed outside the second fixed region, and the adhesive may have a second adhesive force. Here, in the case of the adhesive, the dot size of the adhesive can be specified in the manufacturing process, and it can be manufactured with a second adhesive force lower than the first adhesive force. In particular, in the case of the third dot region 270, since it is formed long along the second fixed region 260 in the longitudinal direction of the battery cell 100, even if the adhesive of the second fixed region 260 moves, it can be accommodated within the second fixed region 260 and thus will not be exposed. Also, in the case of the adhesive constituting the third dot region 270, since it has a second adhesive force lower than the first adhesive force, it is possible to reduce the exposure of the adhesive of the third dot region 270 to the outside during the manufacturing process.

[0061] Also, along the edge of the third dot region 270, a finishing region 280 without an adhesive can be further provided. Since the finishing region 280 does not have an adhesive on the inner surface of the tape base material, even if the adhesive extruded from the third dot region 270 moves during the manufacturing process or the like, it can be accommodated within the finishing region 280. Thus, it is possible to prevent the adhesive from being exposed to the outside.

[0062] On the other hand, in the case of the finishing regions 250 and 280, although they have been described only as non-adhesive regions without an adhesive, in some cases, by making the thickness of the base materials of the finishing regions 250 and 280 thicker, they can serve as dams against the adhesive. In this case, since the finishing regions 250 and 280 prevent the adhesives of the first fixed region 240 and the third dot region 270 from being extruded, it is still possible to prevent the exposure of the adhesive.

[0063] Hereinafter, in the structure of a secondary battery according to an embodiment of the present invention, a configuration in which a cover tape is bonded to a battery cell will be described.

[0064] FIG. 5 is a side view seen in the B direction of FIG. 2.

[0065] The structure of FIG. 5 shows the state in which the cover tape 200 is attached to the battery cell 100 as viewed in the B direction. As described above, the base region 210 can be attached to the entire lower surface of the battery cell 100.

[0066] In addition, the first dot region 220 and the first fixing region 240 cover one side surface (the left side surface in FIG. 4) of the battery cell 100, and the first dot region 220 can further surround a part of the upper surface of the battery cell 100. Also, the wing portion 241 of the first fixing region 240 can be bent and attached to the opposite side surface (the side surface visible in FIG. 5) of the side surface where the lead tab of the battery cell 100 is formed. Further, the second dot region 230 extends and is joined from the first dot region 220 on the upper surface of the battery cell 100, and by providing the finishing region 250 at the end of the second dot region 230, it is possible to prevent the adhesive from being exposed.

[0067] Similarly, the second fixing region 260 covers the other side surface (the right side surface in FIG. 5) of the battery cell 100, the wing portion 261 of the second fixing region 260 is bent, and can be attached to the opposite side surface (the side surface visible in FIG. 4) of the side surface where the lead tab of the battery cell 100 is formed. Also, the third dot region 270 can further surround a part of the upper surface of the battery cell 100. Further, by providing the finishing region 280 at the end of the third dot region 270, it is possible to prevent the adhesive from being exposed.

[0068] As described above, the secondary battery 10 according to an embodiment of the present invention attaches the cover tape 200 to a part of the lower surface, side surfaces, and upper surface of the battery cell 100, and by reducing the adhesive force with respect to the second dot region 230 and the third dot region 270 that cover the upper surface, it is possible to prevent the adhesive from being exposed from the upper surface of the battery cell 100.

[0069] Further, by forming finishing regions 250 and 280 where no adhesive is applied at the ends of the second dot region 230 and the third dot region 270, it is possible to prevent the adhesives in the second dot region 230 and the third dot region 270 from being exposed.

[0070] Also, by forming the thickness of the tape base material thicker for the finishing regions 250 and 280 to produce a dam structure, it is possible to prevent the adhesives in the second dot region 230 and the third dot region 270 from moving, and still prevent the adhesives from being exposed. Here, the structures of the finishing regions 250 and 280 are configured to be in direct contact with the upper surface of the battery cell 100, that is, the pouch 130, so that it is possible to prevent the adhesives from being exposed.

[0071] Although the present invention has been described above based on the limited embodiments and drawings by taking the present invention as an example, the present invention is not limited thereto, and it goes without saying that various modifications and variations are possible within the equivalent scope of the technical idea of the present invention and the scope of the claims described below by those having ordinary knowledge in the technical field to which the present invention belongs.

Explanation of Reference Numerals

[0072] 10 Secondary battery 100 Battery cell 200 Cover tape 210 Base region 220 First dot region 230 Second dot region 240 First fixing region 241 Flange 250 Finishing region 260 Second fixing region 270 Third dot region 271 Flange 280 Finishing region

Claims

1. An electrode assembly, a pouch for housing the electrode assembly, and a cover tape adhered so as to cover at least a part of two surfaces of the pouch, wherein the cover tape is a secondary battery in which the adhesive force of the adhesive is set to be different between a fixed region adhered to the first surface of the pouch and a dot region adhered to the second surface of the pouch.

2. The secondary battery according to claim 1, wherein the fixed region of the cover tape surrounds the side surface of the pouch, and the dot region of the cover tape is formed so as to surround at least a part of the upper surface of the pouch.

3. The secondary battery according to claim 2, wherein the adhesive of the dot region is formed to have a lower adhesive force than the adhesive of the fixed region.

4. The secondary battery according to claim 1, wherein the cover tape is adhered to the lower surface of the pouch and includes a base region having a first adhesive force.

5. The secondary battery according to claim 4, further including a first dot region extending from the base region to one side surface and having a second adhesive force, a second dot region formed along a part of an edge of the first dot region and having the first adhesive force, and a first fixed region formed along an edge of the second dot region and having a third adhesive force.

6. The secondary battery according to claim 4, wherein the cover tape extends to the other side surface of the base region and includes a second fixed region having a third adhesive force and a third dot region extending along the outside of the second fixed region and having the second adhesive force.

7. The secondary battery according to claim 5 or 6, wherein the second adhesive force is set to be lower than the first adhesive force.

8. The secondary battery according to claim 5 or 6, wherein the third adhesive force is set to be higher than the first adhesive force.

9. The secondary battery according to claim 5 or 6, wherein the first adhesive force is 0.20 to 0.50 [kgf / 25 mm].

10. The secondary battery according to claim 5 or 6, wherein the second adhesive force is 0.05 to 0.25 [kgf / 25 mm].

11. The secondary battery according to claim 5 or 6, wherein the third adhesive force is 1.10 to 1.40 [kgf / 25 mm].

12. The secondary battery according to claim 5 or 6, wherein a finishing region where no adhesive is applied is further formed at an end of the first fixed region or the third dot region.

13. The secondary battery according to claim 12, wherein the finishing area is formed outermost along an edge of the first fixing area or the third dot area.

14. The secondary battery according to claim 12, wherein the finishing area has a thickness different from that of the base material of the cover tape.

15. The secondary battery according to claim 12, wherein the finishing area is formed thicker than the base material of the cover tape and contacts the upper surface of the pouch.

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