Secondary battery, manufacturing method thereof, and device including the same

Abstract

A secondary battery according to one embodiment of the present invention comprises an electrode assembly; a first battery case housing the electrode assembly; and a second battery case covering the first battery case, wherein the second battery case is formed to have a color different from that of the first battery case.

Description

Technology Field

[0001] The present invention relates to a secondary battery and a device including the same, and more specifically, to a secondary battery and a device including the same in which expansion of the secondary battery is easily confirmed. Background Technology

[0002] Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has increased rapidly, and the development of electric vehicles, energy storage batteries, robots, and satellites has accelerated, much research is being conducted on secondary batteries used as their power sources.

[0003] Secondary batteries are classified according to the shape of the battery case into cylindrical batteries, in which the electrode assembly is embedded in a cylindrical metal can; prismatic batteries, in which the electrode assembly is embedded in a rectangular metal can; and pouch-type batteries, in which the electrode assembly is embedded in a pouch-type case made of aluminum laminate sheets.

[0004] The electrode assembly embedded in the battery case is a rechargeable power generator composed of a stacked structure of a positive electrode, a separator, and a negative electrode, and is classified into jelly-roll type, stack type, and stack / folding type. The jelly-roll type is a form in which a separator is interposed between long sheet-shaped positive and negative electrodes coated with active material and wound; the stack type is a form in which multiple positive and negative electrodes of a predetermined size are sequentially stacked with a separator interposed; and the stack / folding type is a composite structure of the jelly-roll type and the stack type. Among these, the jelly-roll type electrode assembly has the advantages of being easy to manufacture and having a high energy density per unit weight.

[0005] Meanwhile, secondary batteries include, for example, nickel-cadmium batteries, nickel-hydrogen batteries, nickel-zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries are widely used in the field of advanced electronic devices due to their advantages, such as the ability to freely charge and discharge with almost no memory effect compared to nickel-based secondary batteries, a very low self-discharge rate, high operating voltage, and high energy density per unit weight.

[0006] Furthermore, secondary batteries may experience swelling due to gas generation caused by the decomposition of the electrolyte or side reactions within the battery during cycling. By assessing the degree of gas generation as the cycle progresses, it is possible to identify performance degradation of the secondary battery. However, conventional secondary batteries have lacked a method to clearly detect swelling visually.

[0007] Therefore, as it is necessary to clearly visually confirm the presence or absence of the aforementioned swelling phenomenon and to verify the degree of expansion, there is a need for a new structure capable of solving the above problem. The problem to be solved

[0008] The problem that the present invention aims to solve is to provide a secondary battery that facilitates the verification of battery expansion and a device including the same.

[0009] However, the problems that the embodiments of the present invention aim to solve are not limited to the problems described above and can be expanded in various ways within the scope of the technical ideas included in the present invention. means of solving the problem

[0010] A secondary battery according to one embodiment of the present invention comprises an electrode assembly; a first battery case housing the electrode assembly; and a second battery case covering the first battery case, wherein the second battery case is formed to have a color different from that of the first battery case.

[0011] A groove may be formed in the second battery case above.

[0012] The above-mentioned grooves may be formed in multiple numbers on the second battery case.

[0013] The plurality of grooves mentioned above may be formed on the second battery case so as to be spaced apart from each other.

[0014] The portion of the second battery case where the groove is formed may rupture when the battery expands.

[0015] As the second battery case ruptures, the groove can be connected to the first battery case.

[0016] As the second battery case ruptures, the first battery case may be exposed to the outside.

[0017] The first battery case and the second battery case may be formed to have different materials.

[0018] The first battery case above can be formed to have greater deformability than the second battery case.

[0019] A method for manufacturing a secondary battery according to another embodiment of the present invention comprises the steps of: housing an electrode assembly in a first battery case; and covering the first battery case in which the electrode assembly is housed with a second battery case, wherein the second battery case is formed to have a color different from that of the first battery case.

[0020] A groove may be formed in the second battery case above.

[0021] A device according to another embodiment of the present invention includes the secondary battery. Effects of the invention

[0022] According to embodiments of the present invention, the first battery case and the second battery case are formed in different colors, and a groove is formed on the second battery case so that the expansion of the secondary battery can be visually confirmed.

[0023] In addition, the degree of expansion can be confirmed through the change in the size of the groove formed as the second case is torn.

[0024] The effects of the present invention are not limited to those mentioned above, and other unmentioned effects will be clearly understood by those skilled in the art from the description in the claims. Brief explanation of the drawing

[0025] FIG. 1 is a perspective view showing a pouch-type battery among secondary batteries according to one embodiment of the present invention. FIG. 2 is a perspective view showing a cylindrical battery among secondary batteries according to one embodiment of the present invention. FIG. 3 is a perspective view showing a prismatic battery among secondary batteries according to one embodiment of the present invention. FIG. 4 is a partially exploded perspective view of a pouch-type battery according to one embodiment of the present invention. FIG. 5 is a drawing showing a secondary battery according to an embodiment of the present invention that combines the components of FIG. 4 and includes a second battery case. Figure 6 is a drawing showing a cross-section cut along the A-A' cutting line of Figure 5. Figure 7 is an enlarged view of section C of Figure 6. Figure 8 is a diagram showing the secondary battery of Figure 6 when it expands. Figure 9 is an enlarged view of section D of Figure 8. FIG. 10 is an enlarged view of part B of FIG. 5, illustrating the appearance of the first and second battery cases that change due to the expansion of the secondary battery. Specific details for implementing the invention

[0026] Hereinafter, various embodiments of the present invention will be described in detail with reference to the attached drawings so that those skilled in the art can easily implement the present invention. The present invention may be embodied in various different forms and is not limited to the embodiments described herein.

[0027] To clearly explain the present invention, parts unrelated to the explanation have been omitted, and the same reference numerals are used for identical or similar components throughout the specification.

[0028] Furthermore, the size and thickness of each component shown in the drawings are depicted arbitrarily for convenience of explanation, and thus the present invention is not necessarily limited to what is illustrated. Thicknesses have been enlarged in the drawings to clearly represent various layers and regions. Additionally, for convenience of explanation, the thickness of some layers and regions has been exaggerated in the drawings.

[0029] Furthermore, when a part such as a layer, membrane, region, or plate is said to be "on" or "on" another part, this includes not only the case where it is "directly on" another part, but also the case where there is another part in between. Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between. Also, saying that a part is "on" or "on" a reference part means that it is located above or below the reference part, and does not necessarily mean that it is located "on" or "on" facing the opposite direction of gravity.

[0030] Furthermore, throughout the specification, when a part is described as "including" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components.

[0031] Additionally, throughout the specification, "planar" means when the subject part is viewed from above, and "cross-sectional" means when the cross-section obtained by vertically cutting the subject part is viewed from the side.

[0033] Hereinafter, a secondary battery according to one embodiment of the present invention will be described with reference to FIGS. 1 to 4.

[0034] FIG. 1 is a drawing showing a pouch-type battery among secondary batteries according to one embodiment of the present invention. FIG. 2 is a drawing showing a cylindrical battery among secondary batteries according to one embodiment of the present invention. FIG. 3 is a drawing showing a prismatic battery among secondary batteries according to one embodiment of the present invention. FIG. 4 is a partially exploded perspective view of an example of a pouch-type battery according to one embodiment of the present invention.

[0035] Referring to FIGS. 1 and FIGS. 4, the secondary battery (100) according to the present embodiment is a pouch-type secondary battery and can be manufactured by housing an electrode assembly (105) inside a first battery case (110) and then sealing it.

[0036] The electrode assembly (105) may include a positive electrode, a negative electrode, and a separator disposed between the positive and negative electrodes. Each of the positive electrode and the negative electrode includes a positive electrode tab and a negative electrode tab, and a positive lead (111) connected to the positive electrode tabs and a negative lead (112) connected to the negative electrode tabs may be exposed outside the first battery case (110). At this time, the positive lead (111) and the negative lead (112) may function as electrode terminals. The positive lead (111) and the negative lead (112) may be collectively referred to as electrode leads (111, 112).

[0037] The first battery case (110) is made of a laminate sheet and may include a resin layer for heat fusion and a metal layer for preventing material penetration.

[0038] This first battery case (110) may include an upper case (110a) and a lower case (110b). A separate storage portion may be formed in each of the upper case (110a) and the lower case (110b) to accommodate an electrode assembly (20).

[0039] Meanwhile, the pouch-type battery (100) is illustrated as a bidirectional battery in which the positive lead (111) and the negative lead (112) protrude in opposite directions, but the pouch-type battery (100) of the present invention is not limited to such a form and includes a unidirectional battery in which the positive lead (111) and the negative lead (112) protrude in the same direction, and a stepped battery in which a step is formed in the electrode assembly housing. In particular, referring to FIG. 4, a stepped battery in which a step is formed in the electrode assembly housing can be seen.

[0040] Referring to FIG. 2, the cylindrical battery (200) includes a cylindrical first battery case (210) made of a metal material and a cylindrical second battery case (220) covering the cylindrical first battery case (210).

[0041] In the cylindrical battery (200), the upwardly protruding top cap functions as the positive electrode terminal (211), and the crimping portion (212) functions as the negative electrode terminal. Accordingly, the second battery case (220) can cover the remaining portion excluding the entire top cap functioning as the electrode terminal and a part of the crimping portion (212).

[0042] Referring to FIG. 3, the rectangular battery (300) includes a rectangular first battery case (310) made of a metal material and a rectangular second battery case (320) covering the rectangular first battery case (310).

[0043] A rectangular battery (300) is positioned so that electrode terminals (311) are exposed on its upper surface. A rectangular second battery case (320) can be formed on the upper surface excluding the portion where electrode terminals (311) are exposed, the entire side surface of the rectangular first battery case (310), and the entire lower surface of the rectangular first battery case (310). That is, the rectangular second battery case (320) can cover the rectangular first battery case (310) excluding the electrode terminals (311).

[0045] Hereinafter, with reference to FIGS. 5 to 10, a second battery case formed in a secondary battery according to an embodiment of the present invention will be described in detail. Although the description focuses on a pouch-type battery, forms in which the pouch-type battery is modified into a cylindrical battery and a prismatic battery as shown in FIGS. 2 and 3 are also included within the scope of the present invention.

[0046] FIG. 5 is a drawing showing a secondary battery according to an embodiment of the present invention that combines the components of FIG. 4 and includes a second battery case. FIG. 6 is a drawing showing a cross-section cut along the A-A' cutting line of FIG. 5. FIG. 7 is a drawing showing an enlarged view of section C of FIG. 6. FIG. 8 is a drawing showing the secondary battery of FIG. 6 when it expands. FIG. 9 is a drawing showing an enlarged view of section D of FIG. 8. FIG. 10 is a drawing showing an enlarged view of section B of FIG. 5, illustrating the appearance of the first and second battery cases that change due to the expansion of the secondary battery.

[0047] Referring to FIGS. 5 and 6, a secondary battery (100) according to the present embodiment includes an electrode assembly (105), a first battery case (110) that houses the electrode assembly (105), and a second battery case (120) that covers the first battery case (110). At this time, the second battery case (120) is formed to have a color different from that of the first battery case (110).

[0048] Specifically, the first battery case (110) and the second battery case (120) can be formed with a combination of various colors, and complementary colors can be used or colors such as black, yellow, and red can be selected to ensure high visibility. Therefore, as described below, when the second battery case (120) ruptures as the secondary battery (100) expands and the color of the first battery case (110) is exposed to the outside, it can be easily distinguished by the naked eye. In addition, the degree of expansion of the secondary battery (100) can be predicted based on the degree of exposure of the color of the first battery case (110).

[0050] Meanwhile, referring to FIG. 7, a groove (125) may be formed in the second battery case (120). A plurality of grooves (125) may be formed on the second battery case (120), and each groove (125) may be formed on the second battery case (120) so as to be spaced apart from each other.

[0051] At this time, referring to FIG. 5, the distance between each electrode lead (111, 112) of the secondary battery (100) can be defined in the length direction of the secondary battery (100). Accordingly, the groove (125) can be formed on the second battery case (120) of the secondary battery (100) along the said length direction of the secondary battery (100). In addition, the groove (125) may be formed to be spaced apart from each other along the width direction of the secondary battery (100), which is a direction perpendicular to the length direction.

[0052] Additionally, when the groove (125) is formed, the groove (125) may be formed on the second battery case (125) such that a portion of the second battery case (120) exists between the groove (125) and the first battery case (110). Accordingly, the groove (125) may be formed so that the first battery case (110) is not exposed.

[0053] When gas is generated as the electrolyte inside the secondary battery (100) decomposes or side reactions occur, causing the secondary battery (100) to expand and a swelling phenomenon to occur, the second battery case (120) may rupture. Specifically, a groove (125) is formed on the second battery case (120), and the part of the second battery case (120) where the groove (125) is formed may be formed with a thinner thickness compared to other parts. Therefore, when swelling occurs in the secondary battery (100), the part of the second battery case (120) where the groove (125) is formed may rupture due to the expansion force caused by the swelling phenomenon.

[0054] At this time, referring to FIGS. 8 and 9, as the second battery case (120) ruptures, the portion of the second battery case (120) between the groove (125) and the first battery case (110) can be removed. At this time, being removed means that as the second battery case (120) ruptures, the portion of the second battery case (120) formed between the groove (125) and the first battery case (110) is not left. Accordingly, as the portion of the second battery case (120) located between the groove (125) and the first battery case (110) is removed, the groove (125) can be connected to the first battery case (110).

[0055] In addition, as the groove (125) and the first battery case (110) are connected as described above, the first battery case (110) can be exposed to the outside. Therefore, as the first battery case (110), which has a different color from the second battery case (120), is exposed to the outside, it is possible to visually determine whether swelling of the secondary battery (100) has occurred. Furthermore, since the area of ​​the first battery case (110) exposed by the groove (125) varies depending on the degree of swelling, the degree of swelling and the degree of battery expansion can be predicted based on the said area.

[0056] Meanwhile, the first battery case (110) and the second battery case (120) may be formed to have different materials. Specifically, compared to the first battery case (110), the second battery case (120) may be formed to have a small deformability to expansion force, so that it cannot respond to the expansion of the secondary battery (100) and ruptures. However, even if the second battery case (120) ruptures, the first battery case (110) remains intact without rupturing, so that the performance of the secondary battery (100) can be maintained.

[0057] Therefore, the first battery case (110) may be formed to have greater deformability than the second battery case (120). Additionally, a material may be selected to have such deformability.

[0058] Referring to FIG. 10, as described above, when swelling occurs and expands in the secondary battery (100), the first battery case (110) may be exposed between the second battery case (120). At this time, due to the characteristics of the cell swelling phenomenon, the first battery case (110) may begin to be exposed from the center of the secondary battery (100). In addition, when overall swelling occurs in the secondary battery (100), the first battery case (110) may be exposed at multiple locations through the multiple grooves (125) formed on the second battery case (120) as shown in FIG. 10. Depending on the exposure location and degree of exposure of the first battery case (110), the location and degree of swelling of the secondary battery (100) can be confirmed visually, and the degree of swelling and the performance degradation of the secondary battery can be predicted through the area where the first battery case (110) is exposed.

[0060] Hereinafter, a method for manufacturing a secondary battery according to another embodiment of the present invention will be described. Since the technical details regarding the secondary battery described above may also be applied to this embodiment, redundant details will be omitted.

[0061] A method for manufacturing a secondary battery according to the present embodiment includes the step of housing an electrode assembly (105) in a first battery case (110); and the step of covering the first battery case (110) housing the electrode assembly (105) with a second battery case (120). At this time, the second battery case (120) is formed to have a color different from that of the first battery case (110).

[0062] Additionally, a groove (125) may be formed in the second battery case (120), and as described above, when swelling and expansion occur in the secondary battery (100), the second battery case (120) ruptures and the first battery case (110) is exposed, making it possible to identify the issue visually.

[0063] In particular, the groove (125) formed on the second battery case (120) is formed along the longitudinal direction of the secondary battery (100) and can be deformed by the expansion of the secondary battery (100) when swelling occurs.

[0065] In this embodiment, terms indicating directions such as front, back, left, right, up, and down have been used; however, these terms are for convenience of explanation only and may vary depending on the location of the object or the observer.

[0066] The secondary battery according to the embodiment described above can be applied to various devices. Specifically, it can be applied to means of transportation such as electric bicycles, electric vehicles, and hybrids, but is not limited thereto and can be applied to various devices capable of using secondary batteries.

[0067] Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention. Explanation of the symbols

[0069] 100: Secondary battery 105: Electrode assembly 110: First battery case 120: Second battery case 125: Homeboo

Claims

Claim 1 A secondary battery comprising: an electrode assembly; a first battery case housing the electrode assembly; and a second battery case covering the first battery case, wherein the second battery case is formed to have a color different from that of the first battery case, a groove is formed in the second battery case, and the second battery case is such that when the battery expands, the portion of the second battery case where the groove is formed ruptures. Claim 2 delete Claim 3 In claim 1, the above-mentioned groove portion is a secondary battery formed in plurality on the second battery case. Claim 4 In paragraph 3, the plurality of grooves are formed on the second battery case so as to be spaced apart from each other. Claim 5 delete Claim 6 In claim 1, as the second battery case ruptures, the groove portion is connected to the first battery case, a secondary battery. Claim 7 In claim 1, the secondary battery in which the first battery case is exposed to the outside as the second battery case ruptures. Claim 8 A secondary battery according to claim 1, wherein the first battery case and the second battery case are formed to have different materials. Claim 9 In claim 8, the secondary battery is formed such that the first battery case has greater deformability than the second battery case. Claim 10 A method for manufacturing a secondary battery comprising: a step of housing an electrode assembly in a first battery case; and a step of covering the first battery case in which the electrode assembly is housed with a second battery case, wherein the second battery case is formed to have a color different from that of the first battery case, a groove is formed in the second battery case, and the second battery case is such that when the battery expands, the portion of the second battery case in which the groove is formed ruptures. Claim 11 delete Claim 12 A device including a secondary battery according to claim 1.

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