Secondary battery

Abstract

A secondary battery according to one embodiment of the present invention comprises: an electrode assembly including a first electrode plate, a second electrode plate, and a separator; a case for receiving the electrode assembly; and a cap assembly coupled to an open upper side of the case, wherein a support structure is disposed on and fixed to a lower end of the electrode assembly, and the support structure is in contact with and supported by a bottom surface of a lower side of the case.

Description

secondary batteries

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

[0002] Secondary batteries, unlike non-rechargeable primary batteries, are rechargeable and dischargeable. Low-capacity secondary batteries are used in small, portable electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while large-capacity secondary batteries are widely used as power sources for motor drives and power storage in hybrid and electric vehicles.

[0003] These secondary batteries are manufactured in various shapes, and representative shapes include cylindrical, square, and pouch shapes. They are composed of an electrode assembly formed by interposing a separator, which is an insulator, between positive and negative plates, and an electrolyte installed inside a case, and a cap plate installed on the case.

[0004] The above-described information disclosed in the background technology of this invention is only intended to improve understanding of the background of the present invention, and therefore may include information that does not constitute prior art.

[0005] The present invention provides a secondary battery capable of increasing stability and improving productivity by fixing and supporting a high-capacity electrode assembly stack inside a case.

[0006] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0007] According to one embodiment of the present invention for solving the above technical problem, a secondary battery comprises: an electrode assembly including a first electrode plate, a second electrode plate, and a separator; a case for accommodating the electrode assembly; and a cap assembly coupled to an open upper portion of the case; wherein a support structure is arranged and fixed at the lower end of the electrode assembly, and the support structure is supported by making contact with a lower bottom surface of the case.

[0008] Additionally, the electrode assembly can be formed by repeatedly stacking the first electrode plate and the second electrode plate with a separator interposed between them.

[0009] Additionally, the support structure may have a planar shape corresponding to the lower end of the electrode assembly and a height corresponding to the gap between the lower end of the electrode assembly and the lower bottom surface of the case.

[0010] Additionally, the support structure can be manufactured from a high-performance plastic material.

[0011] Additionally, the high-performance plastic material may be an engineering plastic.

[0012] Additionally, the support structure is porous, and individual pores may have a diameter of 10 mm or less.

[0013] Additionally, a resin binder is applied to at least one portion of the upper surface of the support structure so that it can be bonded to the lower portion of the electrode assembly.

[0014] According to the present invention, by fixing the electrode assembly stack inside the case, movement of the stack is suppressed and welding defects between the case and the stack are improved, thereby increasing stability and productivity.

[0015] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0016] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0017] Figure 1 is a perspective view of a secondary battery according to one embodiment of the present invention.

[0018] Figure 2 is an exploded perspective view of Figure 1.

[0019] Figures 3a and 3b are conceptual diagrams schematically illustrating only the case, electrode assembly, and support structure in Figure 1.

[0020] FIG. 4 is a cross-sectional view and a plan view of a support structure applied to a secondary battery according to one embodiment of the present invention.

[0021] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms or words used in this specification and claims should not be interpreted as limited to their typical or dictionary meanings, and should be interpreted with meanings and concepts that conform to the technical spirit of the present invention based on the principle that the inventor can appropriately define the concept of a term to best explain his or her own invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as substitutes for them at the time of filing this application.

[0022] Additionally, when used herein, the terms "comprise", "include" and / or "comprising", "including" specify the presence of stated features, numbers, steps, operations, elements, elements and / or groups thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, elements, elements and / or groups thereof.

[0023] Additionally, to facilitate understanding of the invention, the attached drawings may not be drawn to scale and some components may be exaggerated in size. Furthermore, identical components may be assigned the same reference numbers in different embodiments.

[0024] The statement that two compared objects are "identical" means "substantially identical." Therefore, "substantially identical" may include deviations considered low in the art, such as deviations of less than 5%. Furthermore, uniformity of a parameter over a given region may imply uniformity on average.

[0025] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0026] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0027] Any configuration being placed "on (or under)" or "above (or below)" a component may mean not only that any configuration is placed in contact with the upper surface (or lower surface) of said component, but also that other configurations may intervene between said component and any configuration placed on (or below) said component.

[0028] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to each other, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component. Furthermore, when it is said that a part is electrically coupled to another part, this includes not only cases where they are directly connected, but also cases where they are connected with another element in between.

[0029] - Add / delete the above commonly written contents according to the invention

[0030] When reference is made throughout the specification to "A and / or B," this means A, B, or A and B, unless otherwise stated. In other words, "and / or" includes all or any combination of the listed items. When reference is made to "C through D," this means C or more and D or less, unless otherwise stated.

[0031] The terminology used herein is for the purpose of describing embodiments of the present disclosure and is not intended to be limiting of the present disclosure.

[0032] In exemplary embodiments of [cylindrical / square / pouch] batteries according to embodiments of the present disclosure, one of the square / pouch / circular batteries is selected and the selected battery is described as having a general structure, and in the case of a generally applicable technology, the general structure of the square / pouch / circular battery is described.

[0033]

[0034] A secondary battery (100) according to an embodiment of the present invention may include an electrode assembly (110), a case (130), and a cap plate (150), as shown in FIGS. 1 and 2.

[0035] The electrode assembly (110) can be formed by laminating a first electrode plate, a separator, and a second electrode plate formed in a thin plate shape or film shape. That is, the electrode assembly (110) can be formed by repeatedly laminating the first electrode plate and the second electrode plate with a separator interposed between them.

[0036] In such a stacked electrode assembly (110), when the separator is contracted during battery implementation, a short circuit may occur due to the positive electrode plate (e.g., the first electrode plate) and the negative electrode plate (e.g., the second electrode plate) coming into contact. To prevent this, the separator may be laminated in a bonded state with the positive electrode plate. That is, a negative electrode plate is positioned on top of a positive electrode plate with a separator bonded on both sides, and a positive electrode plate with a separator bonded on both sides is again positioned on top of that. Then, a negative electrode plate is positioned on top of that, and a positive electrode plate with a separator bonded on its lower surface is again positioned on top of that. Accordingly, the electrode assembly (110) may have a structure in which a positive electrode plate, a separator, and a negative electrode plate are sequentially laminated.

[0037] The electrode assembly (110) may be housed inside the case (130) by stacking one or more electrode assemblies (110) so that their long sides are adjacent to each other, and the number of electrode assemblies (110) is not limited in the present invention. The first electrode plate of the electrode assembly (110) may serve as a cathode, and the second electrode plate may serve as an anode. Of course, the opposite is also possible.

[0038] The first electrode plate is formed by applying a first electrode active material such as graphite or carbon to a first electrode current collector plate formed of a metal foil such as copper, a copper alloy, nickel, or a nickel alloy, and may include a first electrode tab (or first uncoated region) which is a region where the first electrode active material is not applied. The first electrode tab may be a passage for current flow between the first electrode plate and the first current collector. In some examples, the first electrode tab may be formed by cutting the first electrode plate in advance so as to protrude from one side, and may protrude further from one side than the separator without separate cutting.

[0039] The second electrode plate is formed by coating a second electrode active material such as a transition metal oxide on a second electrode current collector plate formed of a metal foil such as aluminum or an aluminum alloy, and may include a second electrode tab (or second non-coated region) which is a region where the second electrode active material is not coated. The second electrode tab may serve as a passage for current flow between the second electrode plate and the second current collector. In some examples, the second electrode tab may be formed by cutting the second electrode plate in advance so as to protrude toward the other side when manufacturing the second electrode plate, and may protrude further toward the other side than the separator without separate cutting.

[0040] In some examples, the first electrode tab may be located on the left side of the electrode assembly (110), and the second electrode tab may be located on the right side of the electrode assembly (110), or may be located on one side in the same direction. Here, left and right are for convenience of explanation based on the secondary battery (100) illustrated in FIG. 1, and their positions may change when the secondary battery (100) rotates left and right or up and down.

[0041] The first electrode tab of the first electrode plate and the second electrode tab of the second electrode plate are respectively positioned at both ends of the electrode assembly (110) as described above. In some examples, the electrode assembly (110) may be housed in a case (130) together with an electrolyte. In addition, the electrode assembly (110) is positioned such that the first current collector and the second current collector are respectively welded and connected to the first electrode tab of the first electrode plate and the second electrode tab of the second electrode plate, which are exposed on both sides.

[0042] Meanwhile, the case (130) houses the electrode assembly (110). For example, the case (130) is formed in a roughly rectangular parallelepiped shape to set a space therein for accommodating the electrode assembly (110) and the electrolyte, and an opening connecting the exterior and interior spaces is formed on one surface of the rectangular parallelepiped. The opening allows the electrode assembly (110) to be inserted into the interior of the case (130).

[0043] Additionally, the case (130) may be made of a metal such as aluminum, aluminum alloy, nickel-plated steel, or a laminate film or plastic that constitutes a pouch.

[0044] Meanwhile, the cap plate (150) is installed in the opening of the case (130) to seal the opening of the case (130). For example, the case (130) and the cap plate (150) may be formed of aluminum and welded to each other.

[0045] In addition, the cap plate (150) further includes a terminal hole and an electrolyte injection port. The electrolyte injection port enables electrolyte to be injected into the interior of the case (130) after the cap plate (150) is joined and welded to the case (130).

[0046] The positive and negative terminals (151, 152) are electrically and mechanically connected to the electrode assembly (110) and installed in the terminal holes of the cap plate (150). That is, the negative and positive terminals (151, 152) are electrically connected to the negative and positive terminals of the electrode assembly (110), respectively. Accordingly, the electrode assembly (110) is extended to the outside of the case (130) through the negative and positive terminals (151, 152).

[0047]

[0048] Meanwhile, as illustrated in FIGS. 2 to 4, a support structure (170) is arranged and fixed at the bottom of the electrode assembly (110). When the electrode assembly (110) is inserted and placed in the case (130), the support structure (170) is supported by making contact with the lower bottom surface of the case (130). In other words, when the electrode assembly (110) is housed in the case (130), a gap is created between the bottom of the electrode assembly (110) and the bottom surface of the case (130). By placing the support structure (170) in the space of the gap, the empty space is filled, so that the electrode assembly (110) is fixed without shaking within the case (130), and it can serve to suppress vibration generation in the height direction.

[0049] FIG. 2 is an exploded perspective view of a secondary battery of the present invention, FIGS. 3a and 3b are conceptual diagrams schematically illustrating only the case, electrode assembly, and support structure (170) of FIG. 1, and FIG. 4 is a cross-sectional view and a plan view of a support structure (170) applied to a secondary battery according to one embodiment of the present invention. With reference to these drawings, the support structure (170) will be described in detail.

[0050]

[0051] First, the shape of the support structure (170) has a planar shape corresponding to the lower end of the electrode assembly (110), and has a height corresponding to the gap between the lower end of the electrode assembly (110) and the lower bottom surface of the case (130). The support structure (170) of the present invention is configured to prevent bending of the cap assembly when a high-capacity and high-weight electrode assembly stack is stored in the case (130), and it is preferable to configure the planar shape to correspond to the lower end of the electrode assembly (110) so as to evenly support the electrode assembly (110) upward, thereby enabling stable support of the electrode assembly (110). In addition, in order to minimize the occurrence of vibration between the electrode assembly (110) and the case (130), the gap between the electrode assembly (110) and the case (130) is intended to be filled with the support structure (170).

[0052] Meanwhile, the support structure (170) can preferably be manufactured from a high-performance plastic material, particularly an engineering plastic. Engineering plastics are high-performance plastics that can replace metals and feature superior strength, impact resistance, wear resistance, heat resistance, cold resistance, and chemical resistance. Furthermore, engineering plastics have electrical insulation properties, maintaining insulation between the electrode assembly (110) and the case (130).

[0053] In particular, engineering plastics have excellent elasticity. According to one embodiment of the present invention, the support structure (170) is made of engineering plastic to impart elasticity, thereby performing a function of mutually buffering the two components when impact or vibration occurs between the electrode assembly (110) and the case (130).

[0054] Examples of engineering plastics that can be used include polyamide (PA), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyimide (PI), and polystyrene (PS).

[0055] Meanwhile, the support structure (170) is a porous component and has a plurality of pores (171) on the inside and the surface. Since the support structure (170) is placed in the internal space of the case (130), it is exposed to the electrolyte. Since the pores (171) are provided in the support structure (170), the electrolyte can be impregnated into the pores (171). In addition, as described above, the support structure (170) is provided with elasticity due to the characteristics of the material, and since the support structure (170) has pores (171), it can be more elastically deformed in shape by external pressure, which has the advantage of being more effective in buffering. According to one embodiment of the present invention, each pore (171) preferably has a diameter of 10 mm or less, and the porosity is preferably 70% or more.

[0056]

[0057] Meanwhile, a resin-based binder (173) is applied to at least one portion of the upper surface of the support structure (170) and is bonded to the lower portion of the electrode assembly (110). The resin-based binder (173) may employ, for example, a silicone resin or an acrylic resin. These silicone-based or acrylic-based resins have excellent adhesive properties. As illustrated in FIGS. 2 and 3A, the support structure (170) is first attached to the lower portion of the electrode assembly stack, and the electrode assembly (110) with the support structure (170) attached is inserted into the case (130) and secured to the lower bottom surface of the case (130). By applying the resin-based binder (173) to the upper surface of the support structure (170), it functions to improve the adhesion to the electrode assembly (110). As illustrated, the resin-based binder (173) may be applied at equal intervals, for example, to three portions, but is not limited thereto.

[0058]

[0059] A key technological concern for electric vehicles is increasing driving range, leading to a growing demand for high-capacity secondary batteries. However, one of the persistent challenges faced in manufacturing high-capacity batteries is the warping of the cap assembly due to the high load on the electrode assembly. This warping leads to poor welding between the case (130) and the cap assembly.

[0060] To solve this problem, the present invention fills the space between the case (130) and the stack (110) by additionally arranging a support structure (170) under the high-capacity electrode assembly stack. According to this configuration, since the stack is fixed in position inside the case (130), stack movement or vibration is suppressed, stability is improved, and bending of the cap assembly is suppressed due to the fixed support of the stack, so that the problem of poor welding between the case (130) and the stack can be solved. In addition, stack alignment can be improved by bonding the support structure and the stack with a resin binder.

Claims

1. An electrode assembly including a first electrode plate, a second electrode plate, and a separator; A case for storing the above electrode assembly; and A cap assembly coupled to the open upper portion of the above case; Including, A secondary battery, characterized in that a support structure is arranged and fixed at the bottom of the electrode assembly, and the support structure is supported by contacting the lower bottom surface of the case.

2. In paragraph 1, A secondary battery, wherein the electrode assembly is formed by repeatedly stacking first and second electrode plates with a separator interposed between them.

3. In paragraph 1, A secondary battery, wherein the support structure has a flat shape corresponding to the lower end of the electrode assembly and has a height corresponding to the gap between the lower end of the electrode assembly and the lower bottom surface of the case.

4. In paragraph 1, A secondary battery, wherein the above-mentioned supporting structure is manufactured from a high-performance plastic material.

5. In paragraph 3, The above high-performance plastic material is an engineering plastic, a secondary battery.

6. In paragraph 4, A secondary battery, wherein the above-mentioned support structure is porous, and each pore has a diameter of 10 mm or less.

7. In paragraph 1, A secondary battery, wherein a resin binder is applied to at least one location on the upper surface of the support structure and is joined to the lower end of the electrode assembly.

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