Secondary battery and method for manufacturing secondary battery

Abstract

The present invention relates to a secondary battery which can be repeatedly charged and discharged, and a method for manufacturing the secondary battery. The secondary battery according to an embodiment of the present invention includes: an electrode assembly; a case accommodating the electrode assembly; an electrode lead connected to electrode tabs of the electrode assembly and partially protruding outside the case; and elastic bodies coupled to the case to press one side and the other side of the electrode lead.

Description

Secondary battery and secondary battery manufacturing method

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2024-0114615, filed August 26, 2024, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a secondary battery capable of being repeatedly charged and discharged and a secondary battery manufacturing method for manufacturing such a secondary battery.

[0005] Secondary batteries (rechargeable batteries) are rechargeable and dischargeable, unlike primary batteries, which are non-rechargeable. Low-capacity secondary batteries are used in small, portable electronic devices such as cell phones, laptops, and camcorders, while high-capacity batteries are widely used as power sources for motors in hybrid vehicles and other vehicles.

[0006] A secondary battery may have a structure in which an electrode assembly composed of electrodes and a separator is housed within a case. At this time, depending on the shape of the electrode assembly and the case housing the electrode assembly, the secondary battery may be classified into a cylindrical, square, or pouch-shaped battery.

[0007] In the case of a pouch-type battery, the battery may be composed of a laminate sheet having an insulating layer on both sides or one end of the metal layer. Specifically, the pouch-type battery may have a structure formed by joining an upper pouch and a lower pouch composed of laminate sheets.

[0008] In this case, a portion of the metal layer of the laminate sheet is inevitably exposed at the sealing portion where the upper and lower pouches are joined. However, if a conductor exists around the secondary battery, there is a problem that a short circuit occurs in the exposed metal layer. Due to the nature of the secondary battery, a conductive medium (frame) exists around it, and therefore, a secondary battery case material or structure that is advantageous for insulation is required.

[0009] The present invention has been conceived in recognition of the above problems, and an object of the present invention is to provide a secondary battery in which a case accommodating an electrode assembly is made of a material advantageous for insulation, and a method for manufacturing such a secondary battery.

[0010] A secondary battery according to the present invention may include an electrode assembly; a case made of a resin material that accommodates the electrode assembly; an electrode lead connected to an electrode tab of the electrode assembly, a portion of which protrudes outside the case; and an elastic body coupled to the case to press one side and the other side of the electrode lead.

[0011] The elastic body may include a first elastic body provided on one side of the electrode lead; and a second elastic body provided on the other side of the electrode lead.

[0012] The first elastic body and the second elastic body face each other and can press the electrode lead.

[0013] The first elastic body and the second elastic body may each include a pair of cylindrical rods.

[0014] The above case may be made of a TCP (Thermal Conductive Plastic) material having high thermal conductivity.

[0015] The above elastic body may be composed of a rubber material.

[0016] The case above has a through hole formed to connect the internal space of the case with the outside, and a plug made of an elastic material can be combined with the through hole.

[0017] A method for manufacturing a secondary battery according to the present invention includes a case preparation step of preparing an upper case made of a resin material to which a first elastic body is bonded and a lower case made of a resin material to which a second elastic body is bonded; a placement step of arranging an electrode assembly to which an electrode lead is connected between the upper case and the lower case; a sealing step of sealing a receiving space in which the electrode assembly is received by joining the upper case and the lower case; and an electrolyte injection step of injecting an electrolyte into the receiving space, wherein in the sealing step, the upper case and the lower case can be joined to each other in a state in which the first elastic body and the second elastic body face each other and press the electrode lead.

[0018] The above case preparation step may include an upper case preparation step of preparing the upper case by solidifying liquid resin; and a lower case preparation step of preparing the lower case by solidifying liquid resin.

[0019] In the upper case preparation step, the first elastic body can be insert-molded into the upper case, and in the lower case preparation step, the second elastic body can be insert-molded into the lower case.

[0020] In the above sealing step, the upper case and the lower case can be heat-sealed to each other.

[0021] The above electrolyte injection step may include a step of injecting electrolyte into the receiving space through an electrolyte injection port formed in the upper case or the lower case; and a step of sealing the electrolyte injection port using an elastic plug.

[0022] A secondary battery according to one embodiment of the present invention may include an elastic body coupled to a case made of a resin material and pressurizing one side and the other side of an electrode lead. Here, the elastic body is coupled to the case and pressurizes both sides of the electrode lead. In this case, since the case that accommodates the electrode assembly can be formed of a resin material, there is an advantageous effect of preventing a short circuit from occurring due to a surrounding conductive medium. In addition, since the elastic body that presses the electrode lead on both sides is provided, there is an advantageous effect of preventing electrolyte from leaking into a gap between the electrode lead and the case.

[0023] Figure 1 is a drawing for explaining the structure of a secondary battery according to the present invention.

[0024] Figure 2 is a drawing showing a secondary battery according to the present invention provided within a battery module.

[0025] Figure 3 is a flowchart sequentially showing each step of a secondary battery manufacturing method according to the present invention.

[0026] Figure 4 is a flowchart specifically showing the preparation steps for preparing an upper case and a lower case in a secondary battery manufacturing method according to the present invention.

[0027] Figure 5 is a flowchart specifically showing an electrolyte injection step of injecting an electrolyte into the inside of a case in a secondary battery manufacturing method according to the present invention.

[0028] FIG. 6 is a drawing for explaining in detail how the upper case and the lower case are combined in the secondary battery manufacturing method according to the present invention.

[0029] Hereinafter, with reference to the attached drawings, preferred embodiments of the present invention will be described in detail so that those skilled in the art can easily implement the invention. However, the present invention may be implemented in various different forms and is not limited or restricted by the following examples.

[0030] In order to clearly explain the present invention, a detailed description of a part that is irrelevant to the description or a related known technology that may unnecessarily obscure the gist of the present invention has been omitted, and when adding reference signs to components of each drawing in this specification, the same or similar reference signs are attached to the same or similar components throughout the specification.

[0031] In addition, terms and words used in this specification and claims should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0032] Hereinafter, a secondary battery and a method for manufacturing a secondary battery according to the present invention will be described with reference to the drawings.

[0033]

[0034] secondary battery

[0035] Figure 1 is a drawing for explaining the structure of a secondary battery according to the present invention.

[0036] Referring to FIG. 1, a secondary battery (10) according to the present invention may include an electrode assembly (100), a case (200) made of a resin material that accommodates the electrode assembly (100), an electrode lead (120) that is connected to an electrode tab (110) of the electrode assembly (100) and a portion of which protrudes outside the case (200), and an elastic body (300) that is coupled to the case (200) and presses one side and the other side of the electrode lead (120).

[0037] The electrode assembly (100) is composed of a plurality of electrodes and separators and may have various structures. For example, the electrode assembly (100) may have a laminated structure in which a plurality of electrodes and separators are alternately stacked, or a stack-folded structure in which a plurality of electrodes and separators are alternately stacked and then folded. In addition, the electrode assembly (100) may have a jelly-roll structure in which a plurality of electrodes and separators are alternately stacked and then rolled.

[0038] The electrode tab (110) is formed on each of the plurality of electrodes constituting the electrode assembly (100), and may correspond to an electrode non-conductive portion where no active material is applied among these electrodes. In addition, the electrode tab (110) may have a separate conductive rod or conductive sheet structure coupled to each of the plurality of electrodes constituting the electrode assembly (100).

[0039] The electrode tabs (110) may be provided in the same number as the electrodes included in the electrode assembly (100). The electrode tabs (110) may be welded to each other to form a bundle of electrode tabs. In this case, the positive electrode tabs may be welded to other positive electrode tabs, and the negative electrode tabs may be welded to other negative electrode tabs.

[0040] The electrode lead (120) is coupled to the electrode tab (110) to electrically connect the electrode assembly (100) and an external device, and may be configured in various ways. For example, the electrode lead (120) may be a conductive rod or conductive sheet made of the same material as the electrode tab (110), and may be welded to a bundle of electrode tabs to which the electrode tabs (110) are coupled.

[0041] The case (200) is an outer material that accommodates the electrode assembly (100) and can be configured in various ways. For example, the case (200) is a combined body in which an upper case (210) and a lower case (220) are combined, and a sealed accommodation space (S) that accommodates the electrode assembly (100) can be provided inside the upper case (210) and the lower case (220).

[0042] The upper case (210) and the lower case (220) may be composed of the same material. In particular, the upper case (210) and the lower case (220) may be composed of a resin material. When the upper case (210) and the lower case (220) are composed of a resin material, the case (200) that accommodates the electrode assembly (100) does not include a metal material, so that even when a conductive medium is positioned around the secondary battery (10), a short circuit does not occur in the case (200) of the secondary battery (10).

[0043] When the upper case (210) and the lower case (220) are made of a resin material, the upper case (210) and the lower case (220) can be joined together in various ways. For example, the upper case (210) and the lower case (220) can be joined together by heat-welding their facing surfaces.

[0044] Fig. 2 is a drawing showing a secondary battery according to the present invention provided within a battery module. Fig. 2 shows a secondary battery (10) according to the present invention provided within a housing (20) of a battery module.

[0045] Referring to Fig. 2, the case (200) of the secondary battery (10) and the housing (20) of the battery module are spaced apart by a predetermined distance (d). At this time, the housing (20) of the battery module may be made of a metal material. Since the case (200) is made of a resin material rather than a metal, even when the distance (d) between the case (200) and the housing (20) is small, a short circuit does not occur between the case (200) and the housing (20).

[0046] In this case, the secondary battery (10) can be placed close to the housing (20) of the battery module, which has the advantageous effect of minimizing dead space inside the housing (20) and thus improving the energy density of the battery module.

[0047] Meanwhile, the elastic body (300) is coupled to the case (200) and may be configured to pressurize both one side and the other side of the electrode lead (120). Specifically, the elastic body (300) may be configured with a first elastic body (310) provided on one side of the electrode lead (120) and a second elastic body (320) provided on the other side of the electrode lead (120).

[0048] The first elastic body (310) can be inserted into the lower part of the upper case (210), and the second elastic body (320) can be inserted into the upper part of the lower case (220). When the upper case (210) and the lower case (220) are combined to form a sealing space (S), the first elastic body (310) and the second elastic body (320) can face each other and press each other.

[0049] At this time, an electrode lead (120) may be provided between the first elastic body (310) and the second elastic body (320). That is, the first elastic body (310) and the second elastic body (320) may face each other and press the electrode lead (120).

[0050] Specifically, the electrode lead (120) composed of a conductor can be exposed to the outside through a sealing portion where the upper case (210) and the lower case (220) are fused. The upper case (210) and the lower case (220) are composed of a resin material, and a predetermined gap may exist between the electrode lead (120) and the upper case (210) and between the electrode lead (120) and the lower case (220), respectively.

[0051] At this time, the first elastic body (310) and the second elastic body (320) are provided in the sealing portion where the upper case (210) and the lower case (220) are fused together, and can press the upper and lower surfaces of the electrode lead (120). That is, the first elastic body (310) and the second elastic body (320) can eliminate the gap formed between the electrode lead (120) and the upper case (210) and between the electrode lead (120) and the lower case (220).

[0052] In this way, the secondary battery (10) according to the present invention is provided with first and second elastic bodies (310, 320), which has the advantageous effect of preventing electrolyte from leaking between the electrode lead (120) and the upper case (210) and between the electrode lead (120) and the lower case (220).

[0053] Additionally, the first elastic body (310) and the second elastic body (320) may be composed of a rubber material that changes shape when pressurized above a predetermined pressure. The first elastic body (310) and the second elastic body (320) composed of a rubber material may be inserted into the upper case (210) and the lower case (220) in various ways.

[0054] When the upper case (210) and the lower case (220) are manufactured by curing a liquid resin, the mold for manufacturing the upper case (210) may be provided with a first elastic body (310). Similarly, the mold for manufacturing the lower case (220) may be provided with a second elastic body (320).

[0055] Specifically, when a liquid resin is injected into a mold equipped with a first elastic body (310) and the liquid resin is cured, an upper case (210) with the first elastic body (310) inserted into one end can be prepared. In addition, when a liquid resin is injected into a mold equipped with a second elastic body (320) and the liquid resin is cured, a lower case (220) with the second elastic body (320) inserted into one end can be prepared.

[0056] Meanwhile, the first elastic body (310) and the second elastic body (320) may have various shapes and structures. For example, the first elastic body (310) may include a pair of cylindrical rods (311, 312) spaced apart from each other. Similarly, the second elastic body (320) may also include a pair of cylindrical rods (321, 322) spaced apart from each other.

[0057] Here, the load (311) provided on the inner side of the first elastic body (310) can face the load (321) provided on the inner side of the second elastic body (320). In addition, the load (312) provided on the outer side of the first elastic body (310) can face the load (322) provided on the outer side of the second elastic body (320).

[0058] In this way, if each of the first elastic body (310) and the second elastic body (320) is configured as a pair of cylindrical rods, the pressing surfaces on which the first elastic body (310) and the second elastic body (320) press the electrode lead (120) can be curved. In this case, since the pressing surface on which the electrode lead (120) is pressed does not have an angled tip portion formed, there is an advantageous effect of preventing the electrode lead (120) from being damaged by the first elastic body (310) and the second elastic body (320).

[0059] Meanwhile, the case (200) that accommodates the electrode assembly (100) may be composed of a material with high thermal conductivity. For example, the case (200) may be composed of a TCP (Thermal Conductive Plastic) material. When the case (200) is composed of a TCP material, heat can be easily dissipated to the surroundings, thereby delaying the increase in the internal temperature of the secondary battery (10) during charging and discharging of the secondary battery (10).

[0060] In addition, a through hole (211) is formed in the case (200) to connect the internal space (S) of the case (200) with the outside, and a plug (212) made of an elastic material can be combined in this through hole (211). Specifically, a through hole (211) that connects the receiving space (S) for accommodating the electrode assembly (100) with the outside can be formed in the upper case (210) or the lower case (220).

[0061] These through holes (211) can be used for various purposes. For example, the through holes (211) can be used as electrolyte injection holes for injecting electrolyte into the receiving space (S). When the injection of the electrolyte is completed, a stopper (212) is inserted into the through holes (211), and the receiving space (S) can be sealed.

[0062] This plug (212) may be made of an elastic material having substantially the same size as the through hole (211) or having a size slightly larger than the through hole (211). For example, the plug (212) may be made of a rubber material, similar to the elastic material (300) described above.

[0063]

[0064] Secondary battery manufacturing method

[0065] Figure 3 is a flowchart sequentially showing each step of a secondary battery manufacturing method according to the present invention.

[0066] Referring to FIG. 3, a secondary battery manufacturing method according to the present invention may include a case preparation step (S100) of preparing an upper case (210) made of a resin material to which a first elastic body (310) is combined and a lower case (220) made of a resin material to which a second elastic body (320) is combined, a placement step (S200) of arranging an electrode assembly (100) having an electrode lead (120) connected between the upper case (210) and the lower case (220), a sealing step (S300) of sealing a receiving space (S) in which the electrode assembly (100) is accommodated by combining the upper case (210) and the lower case (220), and an electrolyte injection step (S400) of injecting an electrolyte into the receiving space (S).

[0067] In this case, since the upper case (210) and the lower case (220) are made of a resin material, the case (200) that accommodates the electrode assembly (100) does not contain a metal material. Therefore, the secondary battery (10) manufactured by the secondary battery manufacturing method has the advantageous effect of preventing a short circuit from occurring in the case (200) even when a conductive medium is positioned around it.

[0068] Meanwhile, in the sealing step (S300) of the secondary battery manufacturing method, the upper case (210) and the lower case (220) can be joined to each other in a state where the first elastic body (310) and the second elastic body (320) face each other and press the electrode lead (120). That is, the first elastic body (310) and the second elastic body (320) can eliminate the gap formed between the electrode lead (120) and the upper case (210) and between the electrode lead (120) and the lower case (220).

[0069] Therefore, in the case of a secondary battery (10) manufactured according to the secondary battery manufacturing method described above, it is possible to prevent electrolyte from leaking between the electrode lead (120) and the upper case (210) and between the electrode lead (120) and the lower case (220).

[0070] Figure 4 is a flowchart specifically showing the preparation steps for preparing an upper case and a lower case in a secondary battery manufacturing method according to the present invention.

[0071] Referring to FIG. 4, the case preparation step (S100) may include an upper case preparation step (S110) of preparing an upper case (210) by solidifying a liquid resin, and a lower case preparation step (S120) of preparing a lower case (220) by solidifying a liquid resin.

[0072] The liquid resin used in the upper case preparation step (S110) and the lower case preparation step (S120) may be a resin made of a material with high thermal conductivity. For example, a liquid resin made of a TCP (Thermal Conductive Plastic) material may be used in the upper case preparation step (S110) and the lower case preparation step (S120).

[0073] At this time, the upper case (210) and the lower case (220) formed by hardening the TCP material are easy to release heat to the surroundings, and thus can delay the increase in the internal temperature of the secondary battery (10) when charging and discharging the secondary battery (10).

[0074] Meanwhile, in the upper case preparation step (S110), the first elastic body (310) may be insert-molded into the upper case (210), and in the lower case preparation step (S120), the second elastic body (320) may be insert-molded into the lower case (220). Specifically, when a liquid resin is injected into a mold equipped with the first elastic body (310) and the liquid resin is cured, an upper case (210) with the first elastic body (310) inserted into one end can be manufactured. In addition, when a liquid resin is injected into a mold equipped with the second elastic body (320) and the liquid resin is cured, a lower case (220) with the second elastic body (320) inserted into one end can be manufactured.

[0075] In this way, when using an insert injection process, there is an advantageous effect of being able to easily combine the first elastic body (310) and the second elastic body (320) to each of the upper case (210) and the lower case (220).

[0076] Figure 5 is a flowchart specifically showing an electrolyte injection step of injecting an electrolyte into the inside of a case in a secondary battery manufacturing method according to the present invention.

[0077] Referring to FIG. 5, the electrolyte injection step (S400) may include a step (S410) of injecting electrolyte into a receiving space (S) in which an electrode assembly (100) is accommodated through an electrolyte injection port (211) formed in an upper case (210) or a lower case (220) and a step (S420) of sealing the electrolyte injection port (211) using an elastic plug (212).

[0078] Here, the electrolyte injection port (211) is formed in the upper case (210) or the lower case (220), and may be a through hole that connects the receiving space (S) that receives the electrode assembly (100) to the outside. In addition, the plug (212) inserted into the electrolyte injection port (211) may have substantially the same size as the electrolyte injection port (211) or may be made of an elastic material that has a size slightly larger than the electrolyte injection port (211). For example, the plug (212) may be made of a rubber material.

[0079] FIG. 6 is a drawing for explaining in detail how the upper case and the lower case are combined in the secondary battery manufacturing method according to the present invention.

[0080] Referring to FIG. 6, in the sealing step (S300) where the upper case (210) and the lower case (220) are joined, the terrace portion of the upper case (210) and the terrace portion of the lower case (220) may be joined while facing each other. At this time, a first elastic body (310) may be provided on some of the terrace portions of the upper case (210), and a second elastic body (320) may be provided on some of the terrace portions of the lower case (220).

[0081] In the sealing step (S300), the upper case (210) and the lower case (220) can be combined so that the first elastic body (310) and the second elastic body (320) described above face each other. Specifically, the upper case (210) and the lower case (220) made of a resin material are heat-welded to each other, and the first elastic body (310) and the second elastic body (320) inserted into each of the upper case (210) and the lower case (220) can press the electrode lead (120) provided between the upper case (210) and the lower case (220) so that the aforementioned accommodation space (S) is sealed.

[0082] These first elastic body (310) and second elastic body (320) can be configured in various ways. For example, the first elastic body (310) can include a pair of cylindrical rods (311, 312) spaced apart from each other. Similarly, the second elastic body (320) can also include a pair of cylindrical rods (321, 322) spaced apart from each other.

[0083] Here, the load (311) provided on the inner side of the first elastic body (310) can face the load (321) provided on the inner side of the second elastic body (320). In addition, the load (312) provided on the outer side of the first elastic body (310) can face the load (322) provided on the outer side of the second elastic body (320).

[0084] In this way, if each of the first elastic body (310) and the second elastic body (320) is configured as a pair of cylindrical rods, the pressing surfaces on which the first elastic body (310) and the second elastic body (320) press the electrode lead (120) can be curved. In this case, since the pressing surface on which the electrode lead (120) is pressed does not have an angled tip portion formed, there is an advantageous effect of preventing the electrode lead (120) from being damaged by the first elastic body (310) and the second elastic body (320).

[0085]

[0086] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various embodiments are possible within the scope equivalent to the technical idea of ​​the present invention and the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

[0087]

[0088] [Explanation of symbols]

[0089] 10: Secondary battery 100: Electrode assembly

[0090] 110: Electrode tab 120: Electrode lead

[0091] 200: Case 210: Upper Case

[0092] 211: Through hole 212: Plug

[0093] 220: Lower case 300: Elastomer

[0094] 310: First elastic body 320: Second elastic body

[0095] S100: Case Preparation Stage S200: Deployment Stage

[0096] S300: Sealing stage S400: Electrolyte injection stage

Claims

1. Electrode assembly; A case made of a resin material that accommodates the above electrode assembly; An electrode lead connected to an electrode tab of the electrode assembly, a portion of which protrudes outside the case; and A secondary battery comprising an elastic body coupled to the case and pressurizing one side and the other side of the electrode lead.

2. In claim 1, The above elastic body is, A first elastic body provided on one side of the electrode lead; and A secondary battery characterized by including a second elastic body provided on the other side of the electrode lead.

3. In claim 2, A secondary battery characterized in that the first elastic body and the second elastic body face each other and press the electrode lead.

4. In claim 2, A secondary battery, characterized in that the first elastic body and the second elastic body each include a pair of cylindrical rods.

5. In claim 4, A secondary battery characterized in that the case is composed of a TCP (Thermal Conductive Plastic) material having high thermal conductivity.

6. In claim 1, A secondary battery characterized in that the elastic body is composed of a rubber material.

7. In claim 1, A secondary battery characterized in that a through hole is formed in the case to connect the internal space of the case with the outside, and a plug made of an elastic material is combined in the through hole.

8. Case preparation step of preparing an upper case made of a resin material to which a first elastic body is bonded and a lower case made of a resin material to which a second elastic body is bonded; A placement step of placing an electrode assembly with electrode leads connected between the upper case and the lower case; A sealing step of sealing a space in which the electrode assembly is accommodated by combining the upper case and the lower case; and It includes an electrolyte injection step for injecting an electrolyte into the above-mentioned receiving space, A secondary battery manufacturing method in which, in the above sealing step, the upper case and the lower case are joined to each other while the first elastic body and the second elastic body face each other and press the electrode lead.

9. In claim 8, The above case preparation steps are: An upper case preparation step of preparing the upper case by solidifying the liquid resin; and A secondary battery manufacturing method characterized by including a lower case preparation step of preparing the lower case by solidifying liquid resin.

10. In claim 9, In the upper case preparation step, the first elastic body is insert-molded into the upper case, A secondary battery manufacturing method characterized in that, in the lower case preparation step, the second elastic body is insert-molded into the lower case.

11. In claim 8, A secondary battery manufacturing method characterized in that, in the above sealing step, the upper case and the lower case are thermally fused to each other.

12. In claim 8, The above electrolyte injection step is, A step of injecting electrolyte into the receiving space through an electrolyte injection port formed in the upper case or the lower case; and A method for manufacturing a secondary battery, characterized in that it comprises a step of sealing the electrolyte injection port using an elastic plug.

Images