Prismatic secondary battery

Abstract

The disclosed invention relates to a prismatic secondary battery, which includes: an electrode assembly, the electrode assembly including a first electrode lead portion formed in the direction of a first side surface and a second electrode lead formed in the direction of a second side surface facing the first side surface; a lower shell, the lower shell having an upper surface with an open structure and accommodating the electrode assembly therein; and an upper shell, the upper shell covering the open upper surface of the lower shell, wherein the upper shell includes: a first terminal portion, the first terminal portion is bent from a top surface corresponding to the upper surface of the lower shell and extends downward in the direction of the first side surface; and a second terminal portion, the second terminal portion is bent from the top surface and extends downward in the direction of the second side surface, the first electrode lead portion is electrically connected to the first terminal portion, and the second electrode lead portion is electrically connected to the second terminal portion.

Description

[0001] This application claims priority to Korean Patent Application No. 10-2022-0042009 filed on April 5, 2022, and the entire contents of the Korean Patent Application are incorporated as a part of this specification. Technical Field

[0002] The present invention relates to a prismatic secondary battery having an improved connection structure of a positive electrode lead and a negative electrode lead of an electrode assembly and a terminal portion of the secondary battery. Background Art

[0003] Unlike primary batteries, secondary batteries are rechargeable and have recently been widely researched and developed due to the potential for miniaturization and high-capacity applications. With the development of technology and the growing demand for mobile devices, as well as electric vehicles and energy storage systems that are gaining attention in response to environmental issues, the demand for secondary batteries as energy sources has grown rapidly and significantly.

[0004] According to the shape of the battery case, secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries. The electrode assembly installed in the battery case in the secondary battery is a power generation element capable of charging and discharging. The electrode assembly has a laminated structure of electrodes and separators.

[0005] Electrode assemblies can be roughly divided into three types: a core-wound type, which includes a positive electrode and a negative electrode wound with a sheet coated with an active material, with a separator inserted between the positive electrode and the negative electrode; a stacked type, in which a plurality of positive electrodes and negative electrodes are stacked in sequence, with a separator inserted between the positive electrode and the negative electrode; and a stacked and folded type, in which a stacked unit cell is wound with a long separator.

[0006] Conventionally, when a large-sized prismatic secondary battery is produced, an electrode assembly of a bidirectional terminal is inserted into a rectangular case with an open top surface. Then the positive and negative leads on both sides are led out on the top surface 110 and welded to the positive and negative terminals of the cap plate. Finally, the cap plate is welded to the case.

[0007] However, in the conventional prismatic secondary battery, the portion where the positive and negative electrodes are led out to the top surface occupies space, reducing the capacity of the secondary battery. In addition, there is also a risk of disconnection at the connection portion of the positive and negative electrode leads.

[0008] [Prior art literature]

[0009] (Patent Document 001) Korean Patent Publication No. 10-2019-0024290 (published on March 8, 2019) Summary of the invention

[0010] Technical issues

[0011] An object of the present invention is to improve a connection structure between a positive electrode lead and a negative electrode lead of an electrode assembly in a prismatic secondary battery and a terminal portion of the secondary battery, thereby maximizing battery capacity and reducing the risk of disconnection.

[0012] However, the technical problems to be solved by the present invention are not limited to the above problems, and those skilled in the art can clearly understand other problems not mentioned from the following description of the present invention.

[0013] Technical Solution

[0014] In one example, a prismatic secondary battery according to the present technology includes: an electrode assembly, the electrode assembly including a first electrode lead portion formed in the direction of a first side and a second electrode lead portion formed in the direction of a second side facing the first side; a lower shell, the lower shell having an open upper surface and accommodating the electrode assembly therein; and an upper shell, the upper shell covering the open upper surface of the lower shell, wherein the upper shell includes: a first terminal portion, the first terminal portion is bent from a top surface corresponding to the upper surface of the lower shell and extends downward in the direction of the first side; and a second terminal portion, the second terminal portion is bent from the top surface and extends downward in the direction of the second side, wherein the first electrode lead portion is electrically connected to the first terminal portion, and the second electrode lead portion is electrically connected to the second terminal portion.

[0015] Furthermore, a gas exhaust portion may be formed on the top surface of the upper case.

[0016] In one embodiment of the present invention, the upper case includes: a top surface covering the upper surface of the opening of the lower case; and four skirts bent from the top surface and extending downward.

[0017] Furthermore, among the four skirts, the side skirts where the first terminal portion and the second terminal portion are formed extend further downward than the other two skirts, which are the front skirt and the rear skirt.

[0018] In addition, the first electrode lead portion and the second electrode lead portion of the electrode assembly are positioned upward relative to a center height of the electrode assembly.

[0019] Further, the first and second electrode lead portions include: the first electrode lead portion and the second electrode lead portion include: a first internal terminal and a second internal terminal, the first internal terminal and the second internal terminal are arranged on the inner side of the side skirt; and a first external terminal and a second external terminal, the first external terminal and the second external terminal are electrically connected to the first internal terminal and the second internal terminal, respectively, and are exposed to the outside of the upper shell.

[0020] In addition, the first and second electrode lead portions of the electrode assembly may be directly joined and electrically connected to the first and second internal terminals, respectively.

[0021] In one embodiment of the present invention, the first external terminal and the second external terminal may be located on the side skirt, respectively.

[0022] Furthermore, according to another embodiment of the present invention, the first external terminal and the second external terminal may be respectively located on a top surface of the upper case.

[0023] Furthermore, the four skirts of the upper shell may be welded to the upper surface of the lower shell.

[0024] In addition, the upper case is coupled to the lower case in an insertion manner in a state in which the first electrode lead portion and the second electrode lead portion of the electrode assembly are integrally formed by being joined to the first terminal portion and the second terminal portion.

[0025] The electrode assembly provided in the prismatic secondary battery of the present invention may be a stacked type electrode assembly or a wound type electrode assembly.

[0026] Beneficial Effects

[0027] In the prismatic secondary battery of the present technology having the above-mentioned configuration, the electrode lead portions of the electrode assembly facing the terminal portions on both sides of the upper case are electrically connected. Therefore, it is no longer necessary to lead the positive and negative electrodes to the top surface portion as in the conventional prismatic secondary battery, so the side space of the prismatic secondary battery can be fully utilized, and the capacity of the battery can be additionally ensured.

[0028] Furthermore, since the electrode leads of the electrode assembly are directly welded to the terminal portions provided on both sides of the upper case of the prismatic secondary battery of the present invention, the risk of disconnection due to external impact or the like is significantly reduced.

[0029] However, advantageous effects of the present technology are not limited to those described above, and other effects not mentioned will be apparent to those of ordinary skill in the art from the following description of the present technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The following drawings attached to this specification illustrate preferred exemplary embodiments of the present invention and are intended to further understand the technical concept of the present invention in conjunction with the following detailed description of the present invention, and therefore the present invention should not be construed as being limited to the contents described in these drawings.

[0031] Figure 1 is an exploded perspective view of a prismatic secondary battery according to the present invention.

[0032] Figure 2 is a perspective view showing a coupling structure between an upper case and an electrode assembly.

[0033] Figure 3 2 is a diagram showing a structure in which a combination of an upper case and an electrode assembly is accommodated in a lower case.

[0034] Figure 4 It is a diagram showing a state where the upper case and the lower case are welded to each other.

[0035] Figure 5 is a diagram showing another exemplary embodiment of an upper housing.

[0036] Figure 6 It is shown Figure 5 A diagram showing a state in which the upper shell and the lower shell are welded to each other. DETAILED DESCRIPTION

[0037] The present technology may have various modifications and various examples, and therefore specific examples are shown in the drawings and described in detail in the specification.

[0038] However, it should be understood that the present invention is not limited to the specific embodiments, and includes all modifications, equivalent substitutions or alternatives within the spirit and technical scope of the present invention.

[0039] The terms "comprising", "including" and "having" are used herein to specify the presence or combination of features, quantities, steps, actions, parts or components described in the specification, and it should be understood that the possibility of the presence or addition of one or more features, quantities, steps, actions, parts, components or combinations thereof is not precluded.

[0040] Furthermore, when a portion of a layer, film, region, or plate is disposed “on” another portion, this includes not only a case where one portion is disposed “directly” “on” another portion, but also a case where a third portion is interposed therebetween. Conversely, when a portion of a layer, film, region, or plate is disposed “under” another portion, this includes not only a case where one portion is disposed “directly” “under” another portion, but also a case where a third portion is interposed therebetween. Furthermore, in the present application, “on” may include not only a case where it is disposed on an upper portion, but also a case where it is disposed on a lower portion.

[0041] In one example, a prismatic secondary battery according to the present invention includes an electrode assembly, a lower case, and an upper case.

[0042] The electrode assembly includes a first electrode lead portion formed in a direction of a first side and a second electrode lead portion formed in a direction of a second side facing the first side.

[0043] In addition, the lower case has an open upper surface structure, and a space for accommodating the electrode assembly is formed inside. The upper case covers the opened upper surface of the lower case, and the upper case includes a first terminal portion, which is bent from a top surface corresponding to the upper surface of the lower case and extends downward in the direction of the first side; and a second terminal portion, which is bent from the top surface and extends downward in the direction of the second side.

[0044] In addition, the first electrode lead portion is electrically connected to the first terminal portion, and the second electrode lead portion is electrically connected to the second terminal portion.

[0045] In the prismatic secondary battery of the present invention having the above-mentioned configuration, the electrode lead portions of the terminal portions of the electrode assembly facing both sides of the upper case are electrically connected. Therefore, it is no longer necessary to lead the positive and negative electrodes to the top surface portion as in the conventional prismatic secondary battery, so that the side space of the prismatic secondary battery can be fully utilized and the capacity of the battery can be additionally ensured.

[0046] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0047] [First embodiment]

[0048] Figure 1 is an exploded perspective view of a prismatic secondary battery 10 according to the present invention. Figure 1 The prismatic secondary battery 10 of the present invention includes an electrode assembly 200, a lower case 300, and an upper case 100. The lower case 300 and the upper case 100 are coupled to each other to form a hexahedral case of the prismatic secondary battery 10, and the size and shape of the electrode assembly 200 are set to be received in the lower case 300 and the upper case 100.

[0049] The electrode assembly 200 is composed of a plurality of stacked unit cells, and includes a first electrode lead portion 220 formed in the direction of the first side 210 and a second electrode lead portion 240 formed in the direction of the second side 230 facing the first side 210. One of the first electrode lead portion 220 and the second electrode lead portion 240 serves as a positive electrode lead, and the other serves as a negative electrode lead. If the first electrode lead portion is a positive electrode lead, it is formed as a bundle of a plurality of positive electrode tabs formed by stamping and molding the positive electrode of each unit cell of the electrode assembly 200. Similarly, the second electrode lead portion 240 as a negative electrode lead is formed as a bundle of negative electrode tabs.

[0050] The prismatic secondary battery 10 of the present invention is applied to a bidirectional electrode assembly 200, wherein the first electrode lead portion 220 and the second electrode lead portion 240 are arranged on opposite sides facing each other. With such a structure of the bidirectional electrode assembly 200, the prismatic secondary battery 10 of the present invention can use a stacked electrode assembly, a wound electrode assembly, or a hybrid electrode assembly combining the two.

[0051] In addition, the lower case 300 has an open upper surface and forms a space therein to accommodate the electrode assembly 200. Accordingly, the upper case 100 covers the open upper surface of the lower case 300 and the upper case 100 and the lower case 300 are coupled to each other to seal the inner space.

[0052] like Figure 1 As shown, the upper case 100 includes: a first terminal portion 120, which is bent from a top surface corresponding to the upper surface of the lower case 300 and extends downward in the direction of the first side 210; and a second terminal portion 130, which is bent from the top surface and extends downward in the direction of the second side 230. Therefore, the two terminal portions extending downward are provided on both sides of the upper case 100.

[0053] Figure 2 2 is a perspective view showing a coupling structure between the upper case 100 and the electrode assembly 200. Figure 2 , the first terminal portion 120 of the upper case 100 faces the first electrode lead portion 220 of the electrode assembly 200 , and similarly, the second terminal portion 130 faces the second electrode lead portion 240 .

[0054] Therefore, the first electrode lead portion 220 can be electrically connected to the opposite first terminal portion 120 by welding very simply without any additional parts. Similarly, the second electrode lead portion 240 is directly welded to the opposite second terminal portion 130 for electrical connection.

[0055] Therefore, in the prismatic secondary battery 10 of the present invention, the first electrode lead portion 220 and the second electrode lead portion 240 of the electrode assembly 200 are directly welded to the first terminal portion 120 and the second terminal portion 130 provided on both sides of the upper case 100. As a result, the risk of disconnection due to external impact, etc. is significantly reduced.

[0056] In addition, the top surface of the upper case 100 may have a vent portion 140. The vent portion 140 is designed to rupture and release gas when the internal pressure of the prismatic secondary battery 10 exceeds a certain level. It serves as a safety device to prevent the prismatic secondary battery 10 from exploding. For example, the vent portion 140 may be designed by forming a thin notch on the surface of the upper case 100, or by attaching a separate vent device.

[0057] In an exemplary embodiment of the present invention, the upper case 100 includes a top surface covering the open upper surface of the lower case 300 and four skirts 112 bent from the top surface and extending downward.

[0058] In addition, among the four skirts 112, the side skirt 113 on which the first terminal portion 120 and the second terminal portion 130 are formed may extend further downward than the other two front skirts 114 and the rear skirt 115. By making the front skirt 114 and the rear skirt 115 shorter than the side skirt 113, it provides a passage for welding the first terminal portion 120 and the second terminal portion 130 and the first electrode lead portion 220 and the second electrode lead portion 240 to each other, thereby facilitating the welding process.

[0059] In addition, the first electrode lead portion 220 and the second electrode lead portion 240 of the electrode assembly 200 may be positioned upward relative to the center height of the electrode assembly 200. Accordingly, the first terminal portion 120 and the second terminal portion 130 of the upper case 100 facing the first electrode lead portion 220 and the second electrode lead portion 240 are also positioned upward relative to the overall height of the prismatic secondary battery 10. In terms of the bidirectional terminal arrangement of the prismatic secondary battery 10, this configuration allows for a simpler implementation of a structure in which the first terminal portion 120 and the second terminal portion 130 are disposed closer to the top surface.

[0060] Meanwhile, according to an exemplary embodiment of the present invention, the first terminal portion 120 and the second terminal portion 130 may include a first internal terminal 122 and a second internal terminal 132 located inside the side skirt 113, and a first external terminal 124 and a second external terminal 134 electrically connected to the first internal terminal 122 and the second internal terminal 132, respectively, and exposed to the outside of the upper case 100. Only the first external terminal 124 and the second external terminal 134 are exposed to the outside, ensuring good sealing of the electrode assembly 200.

[0061] In addition, the first terminal portion 120 and the second terminal portion 130 are divided into the first internal terminal 122 and the second internal terminal 132 which are inwardly coupled to the first electrode lead portion 220 and the second electrode lead portion 240 of the electrode assembly 200, and the first external terminal 124 and the second external terminal 134 which are exposed to the outside of the upper case 100, thereby providing greater freedom for positioning the first external terminal 124 and the second external terminal 134. Figures 1 to 4 In the illustrated first embodiment, the first external terminal 124 and the second external terminal 134 are located on the side skirt 113 .

[0062] Figure 3 is a diagram showing a structure in which a combination of an upper case 100 and an electrode assembly 200 is accommodated in a lower case 300. The upper case 100 and the electrode assembly 200 are integrally formed by welding between the first and second terminal portions 120 and 130 and the first and second electrode lead portions 220 and 240. Therefore, the integrally formed upper case 100 and electrode assembly 200 can be easily inserted into the lower case 300.

[0063] Figure 4 1 is a diagram showing a state in which the upper case 100 and the lower case 300 are welded to each other. The four skirts 112 of the upper case 100 are welded to the upper surface of the lower case 300. The upper surface of the lower case 300 is formed into a complementary shape corresponding to the length of the four skirts 112 extending downward of the upper case 100, and a welding portion W is formed along the contact surface between the upper case 100 and the lower case 300, thereby ensuring the safety sealing of the prismatic secondary battery 10.

[0064] [Second Embodiment]

[0065] Figure 5 is a diagram showing a second embodiment of the upper case 100. The second embodiment is different from the first embodiment in the structure of the upper case 100, while the configurations of the electrode assembly 200 and the lower case 300 remain the same as the first embodiment.

[0066] In the second embodiment, the upper case 100 includes a top surface covering the upper surface of the opening of the lower case 300, and four skirts 112 bent and extending downward from the top surface. Among the four skirts 112, the side skirt 113 on which the first terminal portion 120 and the second terminal portion 130 are formed extends further downward than the other two front skirts 114 and the rear skirt 115.

[0067] The first terminal portion 120 and the second terminal portion 130 of the upper shell 100 include a first internal terminal 122 and a second internal terminal 132 located inside the side skirt 113, and a first external terminal 124 and a second external terminal 134 electrically connected to the first internal terminal 122 and the second internal terminal 132, respectively, and exposed to the outside of the upper shell 100.

[0068] Here, in the second embodiment, the first external terminal 124 and the second external terminal 134 are respectively located on the top surface of the upper case 100. That is, in the first embodiment, the first external terminal 124 and the second external terminal 134 are located on opposite sides of the upper case 100, while in the second embodiment, they are located together on the top surface of the upper case 100.

[0069] The second embodiment corresponds to a configuration in which the first and second external terminals 124 and 134 electrically connected to the first and second internal terminals 122 and 132 have been moved to the top surface of the upper case 100. Since the first and second terminal portions 120 and 130 of the upper case 100 are divided into the first and second internal terminals 122 and 132 located at the inner side interfacing with the first and second electrode lead portions 220 and 240 of the electrode assembly 200, and the first and second external terminals 124 and 134 exposed to the outside of the upper case 100, such an arrangement can be easily implemented.

[0070] In other words, the present invention can realize the second embodiment by only moving the first external terminal 124 and the second external terminal 134 to the top surface of the upper shell 100 without changing the connection structure with the first electrode lead portion 220 and the second electrode lead portion 240 of the electrode assembly 200, and thus the bidirectional secondary battery can be manufactured as a unidirectional secondary battery by only changing the upper shell 100.

[0071] Figure 6 Shows Figure 5 The upper shell 100 is welded to the lower shell 300. Figure 4 Compared with the first embodiment, only the positions of the first external terminal 124 and the second external terminal 134 are different, and all other structures are the same. Therefore, the present invention has the versatility of being applicable to both bidirectional secondary batteries and unidirectional secondary batteries, while achieving the same effect of significantly reducing the risk of disconnection due to external impact, etc. while fully utilizing the side space of the prismatic secondary battery 10.

[0072] The present invention has been described in more detail above through the drawings and embodiments. However, the configurations described in the drawings or the embodiments in the specification are merely embodiments of the present invention and do not represent all technical ideas of the present invention. Therefore, it should be understood that various equivalent substitutions and modifications may be used to replace them when submitting this application.

[0073] Industrial Applicability

[0074] The present invention provides a useful technology for enhancing the capacity and safety of a prismatic secondary battery.

[0075] [reference numerals]

[0076] 10: Prismatic secondary battery 100: Upper case

[0077] 110: top surface 112: skirt

[0078] 113: Side skirts 114: Front skirt

[0079] 115: rear skirt 120: first terminal portion

[0080] 122: first internal terminal 124: first external terminal

[0081] 130: Second terminal portion 132: Second internal terminal

[0082] 134: Second external terminal 140: Exhaust part

[0083] 200: electrode assembly 210: first side

[0084] 220: first electrode lead portion 230: second side

[0085] 240: Second electrode lead portion 300: Lower housing

[0086] W: welding part

Claims

1. A prismatic secondary battery, comprising: an electrode assembly including a first electrode lead portion formed on a first side and a second electrode lead portion formed on a second side facing the first side; a lower case having an open upper surface and accommodating the electrode assembly therein; as well as an upper shell, the upper shell covering the upper surface of the opening of the lower shell, wherein The upper housing comprises: a first terminal portion bent from a top surface corresponding to the upper surface of the lower case and extending downward on the first side; and a second terminal portion bent from the top surface and extending downward on the second side, wherein The first electrode lead portion is electrically connected to the first terminal portion, and the second electrode lead portion is electrically connected to the second terminal portion.

2. The prismatic secondary battery according to claim 1, further comprising: An exhaust portion is formed on a top surface of the upper case.

3. The prismatic secondary battery according to claim 1, wherein The upper housing comprises: a top surface covering the upper surface of the opening of the lower housing; and Four skirts are bent from the top surface and extend downward.

4. The prismatic secondary battery according to claim 3, wherein: Among the four skirts, the side skirt on which the first terminal portion and the second terminal portion are formed extends further downward than the other two skirts, which are the front skirt and the rear skirt.

5. The prismatic secondary battery according to claim 4, wherein The first electrode lead portion and the second electrode lead portion of the electrode assembly are positioned upward relative to a center height of the electrode assembly.

6. The prismatic secondary battery according to claim 5, wherein: The first electrode lead portion and the second electrode lead portion include: first and second inner terminals, the first and second inner terminals being disposed on the inner side of the side skirt; and and first and second external terminals electrically connected to the first and second internal terminals, respectively, and exposed to the outside of the upper case.

7. The prismatic secondary battery according to claim 6, wherein: The first and second electrode lead portions of the electrode assembly are directly joined and electrically connected to the first and second internal terminals, respectively.

8. The prismatic secondary battery according to claim 7, wherein: The first external terminal and the second external terminal are respectively located on the side skirt.

9. The prismatic secondary battery according to claim 7, wherein: The first external terminal and the second external terminal are respectively located on a top surface of the upper case.

10. The prismatic secondary battery according to claim 3, wherein: The four skirts of the upper shell are welded to the upper surface of the lower shell.

11. The prismatic secondary battery according to claim 10, wherein The upper case is insertedly coupled to the lower case in a state in which the first electrode lead portion and the second electrode lead portion of the electrode assembly are integrally formed by being joined to the first terminal portion and the second terminal portion.

12. The prismatic secondary battery according to claim 1, wherein The electrode assembly is a stacked electrode assembly or a wound electrode assembly.

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