Battery cell and its manufacturing method

Abstract

A battery cell according to one embodiment of the present disclosure includes: an electrode assembly formed by sequentially stacking a first separator, a negative electrode plate, a second separator, and a positive electrode plate having a rectangular shape; a negative electrode tab protruding from the negative electrode plate; and a positive electrode tab protruding from the positive electrode plate, wherein the first separator and the second separator have dimensions larger than the negative electrode plate and the positive electrode plate on all four sides, and the entire tab edge portion of the first separator and the second separator located on the side where the positive electrode tab and the negative electrode tab are formed, and a portion of the two side edge portions connected to the tab edge portion are bonded to each other, such that the inward bonding width of the tab edge portion is smaller than the inward bonding width of the tab edge portion at the two ends connected to the two side edge portions.

Description

Technical Field

[0001] Cross-references to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2020-0140347, filed on October 27, 2020, and Korean Patent Application No. 10-2021-0117898, filed on September 3, 2021, the disclosure of which is incorporated herein by reference in its entirety.

[0003] This disclosure relates to a battery cell and a method for manufacturing the same, and more specifically, to a battery cell and a method for manufacturing the same that implements sealing technology. Background Technology

[0004] In recent years, with energy prices rising due to fossil fuel consumption and growing concerns about environmental pollution, the demand for environmentally friendly alternative energy sources will inevitably play a vital role in future life. Consequently, various electricity-generating technologies, such as nuclear, solar, wind, and tidal power, are being researched, and energy storage devices for more efficient use of the generated electricity are also receiving considerable attention.

[0005] In particular, with technological advancements and increasing demand for mobile devices, the demand for batteries as an energy source has increased rapidly. Consequently, much research has been conducted on batteries that can meet diverse needs.

[0006] Typically, there is a high demand for lithium secondary batteries, such as lithium-ion batteries or lithium-ion polymer batteries, which have advantages such as high energy density, high discharge voltage, and high output stability.

[0007] Furthermore, secondary batteries can be classified based on how electrode assemblies with a structure in which a positive electrode, a negative electrode, and a separator inserted between the positive and negative electrodes are stacked. Typically, electrode assemblies may include: jelly roll (wound) type electrode assemblies in which elongated positive and negative electrodes are wound with a separator inserted between them, and stacked (laminated) type electrode assemblies in which multiple positive and negative electrodes cut to predetermined unit sizes are sequentially stacked with a separator inserted between them, etc.

[0008] Furthermore, secondary batteries are classified based on the shape of their casings as follows: cylindrical batteries with electrode assemblies mounted in a cylindrical casing, prismatic batteries with electrode assemblies mounted in a prismatic casing, and pouch batteries with electrode assemblies mounted in a pouch-shaped casing formed of aluminum laminates.

[0009] In the case of a pouch cell, an electrode assembly stacked in the order of separator, negative electrode, separator, and positive electrode is inserted into the pouch housing. The pouch housing can then be sealed together with the electrolyte, and bonding between the separators may also be required.

[0010] Figure 1 This is a diagram illustrating a method for bonding diaphragms according to related technologies.

[0011] Reference Figure 1 Conventionally, in order to press the diaphragm 20 inserted between the negative electrode plate and the positive electrode plate 10 and on one side to bond the diaphragms together, the bonding process between the diaphragms is performed by pressing the diaphragms with a straight sealing member 50 on the part where the negative electrode contact and the positive electrode contact are formed.

[0012] However, since the sealing member 50 is formed in a straight line shape at this time, a relatively weak adhesive force is applied to the corners of the diaphragm corresponding to the two ends of the sealing member 50, which can lead to diaphragm folding. In addition, the part pressed by the sealing member during the sealing process overlaps with the part where the negative or positive electrode plate is formed, which may cause interference due to the sealing member pressing on either the negative or positive electrode. Summary of the Invention

[0013] Technical issues

[0014] The purpose of this disclosure is to provide a battery cell that prevents the separator from folding during the separator bonding process and a method for manufacturing the same.

[0015] The purpose of this disclosure is not limited to the purposes described above, and those skilled in the art will clearly understand from the following detailed description other purposes not described herein.

[0016] Technical solution

[0017] To achieve the above objectives, according to one embodiment of the present disclosure, a battery cell is provided, comprising:

[0018] An electrode assembly is formed by sequentially stacking a first diaphragm, a negative electrode plate, a second diaphragm, and a positive electrode plate, all of which have a rectangular shape.

[0019] A negative electrode contact protruding from the negative electrode plate; and

[0020] The positive electrode contact formed by protruding from the positive electrode plate.

[0021] The first and second separators have dimensions larger than the negative and positive electrode plates on all four sides. The entire edge portion of the first and second separators on the sides where the positive and negative electrode contacts are formed, as well as portions of the two side edge portions connected to the edge portion, are bonded to each other. Thus, the inward bonding width at the edge portion is smaller than the inward bonding width at the ends where the edge portion connects to the two side edge portions. In this case, the inward bonding width at the edge portion can be 2% to 50% smaller than the inward bonding width at the ends where the edge portion connects to the two side edge portions.

[0022] The positive and negative electrode plates do not interfere with the bonding portion of the first and second separators. More specifically, the negative electrode plate has a larger dimension than the positive electrode plate on all four sides, and recesses corresponding to the bonding shape can be formed at the four corners of the negative electrode plate, so that the negative electrode plate does not interfere with the bonding portion of the side edge portions of the first and second separators.

[0023] To achieve the above objectives, according to another embodiment of this disclosure, a method for manufacturing a battery cell is provided, comprising the following steps:

[0024] The first separator, negative electrode plate, second separator, and positive electrode plate are sequentially stacked to form an electrode assembly; and

[0025] By pressing and bonding the first diaphragm and the second diaphragm with a sealing member, the sealing member has a bent portion because its width at both ends is wider than its width at the center.

[0026] Here, the sealing member may be formed by a sealing bar.

[0027] More specifically, in the step of pressing and bonding the first diaphragm and the second diaphragm using the sealing member, the sealing member may be formed in a shape corresponding to the edge portions of the first diaphragm and the second diaphragm where the positive electrode contacts and the negative electrode contacts are formed, thereby pressing the entire edge portion of the first diaphragm and the second diaphragm located on the side where the positive electrode contacts and the negative electrode contacts are formed, as well as a portion of the two side edge portions connected to the edge portions of the contacts.

[0028] In addition, a heating element may be formed within the sealing member.

[0029] The sealing member can press the first and second diaphragms without interfering with the positive and negative electrode plates. Prior to forming the electrode assembly, the method may further include forming recesses at the four corners of the negative electrode plate. In this case, during the step of pressing and bonding the first and second diaphragms using the sealing member, the bent portion of the sealing member can press the first and second diaphragms corresponding to the recesses at the four corners of the negative electrode plate.

[0030] According to another embodiment of this disclosure, a battery module including the above-described battery unit is provided. Attached Figure Description

[0031] Figure 1 This is a diagram illustrating a method for bonding diaphragms according to related technologies;

[0032] Figure 2 This is a diagram showing the state of the sealing member pressing the electrode assembly according to an embodiment of the present disclosure;

[0033] Figure 3 yes Figure 2 Side view. Detailed Implementation

[0034] It should be understood that the exemplary embodiments described below are illustrative examples to aid in understanding this disclosure, and this disclosure may be implemented differently from the exemplary embodiments described herein through various modifications. However, in the description of this disclosure, specific descriptions and explanations of well-known functions or components will be omitted where such specific descriptions and explanations would unnecessarily obscure the subject matter of this disclosure. Furthermore, to aid in understanding this disclosure, the drawings are not shown to scale, and the dimensions of some components may be exaggerated.

[0035] As used herein, various components may be described using terms such as first, second, etc., but these components are not limited by these terms. These terms are only used to distinguish one component from another.

[0036] Furthermore, the terminology used herein is for describing specific exemplary embodiments only and is not intended to limit the scope of this disclosure. Singular expressions include plural expressions unless the context clearly implies otherwise. It should be understood that the terms "comprising," "including," and "having" as used herein are intended to indicate the presence of the stated features, quantities, steps, constituent elements, or combinations thereof, but should be understood not to preclude the possibility of the presence or addition of one or more other features, quantities, steps, constituent elements, or combinations thereof.

[0037] Now, refer to Figure 2 and Figure 3Describes a battery cell according to an embodiment of this disclosure.

[0038] Figure 2 This is a diagram showing the state of the sealing member pressing the electrode assembly according to an embodiment of the present disclosure. Figure 3 yes Figure 2 Side view.

[0039] Reference Figure 2 and Figure 3 A battery cell according to an embodiment of the present disclosure includes: an electrode assembly formed by sequentially stacking a first separator 100, a negative electrode plate 200, a second separator 300 and a positive electrode plate 400 having a rectangular shape; a negative electrode tab 210 protruding from the negative electrode plate 200; and a positive electrode tab 410 protruding from the positive electrode plate 400.

[0040] The battery cell is a secondary battery and can be configured as a pouch-type secondary battery. Multiple such battery cells can be configured and electrically stacked together to form a battery cell stack. The battery cell may include electrode leads protruding from electrode assemblies and a pouch housing housing the electrode assemblies. The pouch housing encapsulates the electrode assemblies and may be formed of a laminate comprising a resin layer and a metal layer.

[0041] According to this embodiment, the electrode assembly may consist of a positive electrode plate, a negative electrode plate, and a separator. More specifically, as shown... Figure 3 As shown, a first separator 100, a negative electrode plate 200, a second separator 300, and a positive electrode plate 400, all having rectangular shapes, can be stacked sequentially to form an electrode assembly. In this case, the first separator 100 and the second separator 300 have dimensions larger than the negative electrode plate 200 and the positive electrode plate 400 on all four sides, thus allowing the first separator 100 and the second separator 300 to be bonded together, thereby fixing the position of the electrode assembly and the electrode contacts connected to the electrode assembly.

[0042] According to this embodiment, the first diaphragm 100 and the second diaphragm 300 are bonded by pressing with the sealing member 500, which has a bent portion 520 because its width at both ends is wider than its width at the center. Therefore, the first diaphragm 100 and the second diaphragm 300 can be formed such that the entire edge portion of the first diaphragm 100 and the second diaphragm 300 on the side where the positive electrode contact 410 and the negative electrode contact 210 are formed, and a portion of the two side edge portions connected to the edge portion of the contact, are bonded to each other, such that the inward bonding width W1 at the edge portion of the contact is about 2% to 50%, specifically, 10% to 20%, smaller than the inward bonding width W2 at the two ends where the edge portion of the contact connects to the two side edge portions.

[0043] At this point, the sealing member 500 can be formed by a sealing strip.

[0044] Furthermore, according to this embodiment, a heating element can be formed within the sealing member 500. The diaphragm is adhered by pressing the sealing member 500, and simultaneously, the diaphragm is heated via the heating element, causing the diaphragms to adhere to each other through thermal fusion.

[0045] Conventionally, for bonding between diaphragms, a diaphragm bonding process is performed, in which a straight sealing member is used to press the edge portion of the diaphragm located where the electrode tabs are formed to bond the diaphragm. However, when the sealing member is formed in a straight shape and only bonds the corners of the diaphragm at the tabs, a relatively weak adhesive force is applied to the corners of the diaphragm, which can lead to diaphragm folding.

[0046] Therefore, according to this embodiment, the sealing member 500 includes a main portion 510 and a bent portion 520 having a shape corresponding to the edge portions of the first diaphragm 100 and the second diaphragm 300 where the negative electrode contact 210 and the positive electrode contact 410 are formed. By pressing the portion where the negative electrode contact 210 and the positive electrode contact 410 are formed with the sealing member 500, the first diaphragm 100 and the second diaphragm 300 are bonded together. Thus, the sealing member 500 can apply a strong pressing force even to the corners of the diaphragms, so that the bonding between the diaphragms can be achieved normally even at the corners, and the folding of the diaphragms at the corners can be prevented.

[0047] Furthermore, according to this embodiment, the sealing member 500 is formed such that the adhesive portion of the first diaphragm 100 and the second diaphragm 300 does not interfere with the negative electrode plate 200 and the positive electrode plate 400. The first diaphragm 100 and the second diaphragm 300 are pressed so that the first diaphragm 100 and the second diaphragm 300 do not interfere with the negative electrode plate 200 and the positive electrode plate 400.

[0048] As described above, the method of forming the adhesive portion of the first diaphragm 100 and the second diaphragm 300 in a manner that does not interfere with the negative electrode plate 200 and the positive electrode plate 400 is not shown in the most basic way in the accompanying drawings. However, the dimensions of the first diaphragm 100 and the second diaphragm 300 are made to be larger than the negative electrode plate 200 and the positive electrode plate 400 on all four sides. This can be achieved by using the adhesive method of the sealing member 500 so that there is no overlap in any part.

[0049] In this case, the first diaphragm 100 and the second diaphragm 300 can be made larger than the negative electrode plate 200 and the positive electrode plate 400, or the area pressed and bonded by the sealing member 500 can be made smaller.

[0050] Or, as in this disclosure Figure 2As shown, prior to the step of forming the electrode assembly, recesses 220 corresponding to the adhesive shape can be formed at the four corners of the negative electrode plate 200, which is inserted between the first diaphragm 100 and the second diaphragm 300, so that the negative electrode plate does not interfere with the portion of the side edge portion on both sides of the first diaphragm 100 and the second diaphragm 300 that is bonded. Since the sealing member 500 is formed such that the width at both ends is wider than the width of the central portion and thus has a bent portion 520, interference may occur between the bent portion 520 of the sealing member 500 and the negative electrode plate 200 during the pressing of the first diaphragm 100 and the second diaphragm 300. Therefore, according to this embodiment, the bent portion 520 presses against the recesses 220 corresponding to the portions where the four corners of the negative electrode plate 200 are located, so that even when the sealing member 500 presses the diaphragm, the negative electrode plate 200 will not interfere with the pressed portion. Therefore, safety problems such as damage to the negative electrode plate 200 due to the pressing of the sealing member 500 can be prevented.

[0051] The aforementioned battery cells may be included in battery modules, and these battery modules may be included in battery packs. A battery pack may have a structure in which one or more battery modules according to embodiments of this disclosure are assembled and packaged together with a battery management system (BMS) and cooling devices for controlling and managing battery temperature, voltage, etc.

[0052] Battery packs can be used in a variety of devices. Such devices can be used in vehicles such as electric bicycles, electric vehicles, or hybrid vehicles, but this disclosure is not limited to these and can be used in a variety of devices that can use battery modules, which are also within the scope of this disclosure.

[0053] While preferred embodiments of the present disclosure have been shown and described above, the scope of the disclosure is not limited thereto. Those skilled in the art can devise many other modifications and embodiments that will fall within the spirit and principles of the invention as described in the appended claims. Furthermore, these modified embodiments should not be understood solely in relation to the technical spirit or ideas of the present disclosure.

[0054] [Reference Label Explanation]

[0055] 100: First diaphragm

[0056] 200: Negative electrode plate

[0057] 210: Negative electrode connector

[0058] 220: concave part

[0059] 300: Second diaphragm

[0060] 400: Positive electrode plate

[0061] 410: Positive electrode connector

[0062] 500: Sealing component

[0063] 510: Main Part

[0064] 520: The bent part.

[0065] Industrial applicability

[0066] The battery cell and manufacturing method of the present disclosure according to the embodiments provide the effect of preventing folding of the separators during the bonding process between the separators and bonding the separators without interfering with the electrodes.

[0067] The effects of this disclosure are not limited to those described above; those skilled in the art will clearly understand from the description of the appended claims any additional effects not described above.

Claims

1. A battery cell, comprising: An electrode assembly is formed by sequentially stacking a first diaphragm, a negative electrode plate, a second diaphragm, and a positive electrode plate, all of which have a rectangular shape. A negative electrode contact protruding from the negative electrode plate; as well as The positive electrode contact formed by protruding from the positive electrode plate. The first and second separators have dimensions larger than the negative and positive electrode plates on all four sides. Furthermore, the entire edge portion of the first and second separators located on the sides where the positive and negative electrode contacts are formed, as well as portions of the two side edge portions connected to the edge portion, are bonded to each other. Thus, the inward bonding width at the edge portion is smaller than the inward bonding width at the ends where the edge portion connects to the two side edge portions. in: The inward bonding width at the edge of the patch is 2% to 50% smaller than the inward bonding width at the two ends where the edge of the patch connects to the two side edge portions. The corners of the first and second diaphragms are continuously pressed and bonded by a sealing member, which has a bent portion because its width at both ends is wider than its width at the center. in: The negative electrode plate has a larger dimension than the positive electrode plate on all four sides, and recesses corresponding to the adhesive shape are formed at the four corners of the negative electrode plate. The adhesive portions of the first diaphragm and the second diaphragm are formed only in the edge portions of the tabs and the recesses at the four corners.

2. The battery cell according to claim 1, wherein: The positive electrode plate and the negative electrode plate do not interfere with the adhesive portion of the first diaphragm and the second diaphragm.

3. The battery cell according to claim 1, wherein: The negative electrode plate does not interfere with the portion of the side edge portions of the first and second diaphragms that are bonded together.

4. A method for manufacturing a battery cell, comprising the following steps: The first separator, the negative electrode plate, the second separator, and the positive electrode plate are stacked sequentially to form an electrode assembly; and By pressing and bonding the first and second diaphragms together using a sealing member, the sealing member having a bent portion due to its width at both ends being wider than its width at the center. in: In the step of pressing and bonding the first diaphragm and the second diaphragm using the sealing member The sealing member is formed in a shape corresponding to the edge portions of the first and second diaphragms where positive and negative electrode contacts are formed, thereby pressing the entire edge portion of the first and second diaphragms located on the sides where the positive and negative electrode contacts are formed, as well as a portion of the two side edge portions connected to the edge portions of the contacts. in: The inward bonding width at the edge of the patch is 2% to 50% smaller than the inward bonding width at the two ends where the edge of the patch connects to the two side edge portions. The corners of the first diaphragm and the second diaphragm are continuously pressed and bonded by the sealing member. The negative electrode plate is larger than the positive electrode plate on all four sides. Prior to the step of forming the electrode assembly, the method further includes forming recesses at the four corners of the negative electrode plate, and The adhesive portions of the first diaphragm and the second diaphragm are formed only in the edge portions of the tabs and the recesses at the four corners.

5. The method for manufacturing a battery cell according to claim 4, wherein: The sealing member is formed by a sealing strip.

6. The method for manufacturing a battery cell according to claim 4, wherein: A heating element is formed within the sealing member.

7. The method for manufacturing a battery cell according to claim 4, wherein: The sealing member presses the first diaphragm and the second diaphragm without interfering with the positive electrode plate and the negative electrode plate.

8. The method for manufacturing a battery cell according to claim 4, In the step of pressing and bonding the first diaphragm and the second diaphragm using the sealing member The bent portion of the sealing member presses against the first diaphragm and the second diaphragm in correspondence with the recesses at the four corners of the negative electrode plate.

9. A battery module comprising a battery cell according to any one of claims 1 to 3.

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