Improved safety of secondary batteries

Abstract

The disclosed invention relates to a prismatic secondary battery including a hexahedral metal case and one or more electrode assemblies inserted into the case through an open surface formed on an upper surface of the case. In one example, a concave surface is formed on at least one of a front surface and a rear surface of the case, the electrode assembly is supported in contact with the concave surface, and the insertion end of the electrode assembly is wedge-shaped.

Description

[Technical Field]

[0001] The present invention relates to a secondary battery, and more particularly to a secondary battery that can prevent an electrode assembly housed in a case from shaking and can suppress deformation of the case due to swelling of the electrode assembly.

[0002] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0065161, filed May 27, 2022, and all contents disclosed in the documents of said Korean patent application are incorporated herein by reference. [Background technology]

[0003] Unlike primary batteries, secondary batteries are rechargeable and have the potential to be small and have large capacities, which has led to extensive research and development in recent years. Demand for secondary batteries as an energy source is rapidly increasing due to the increasing technological development and demand for mobile devices, as well as the emergence of electric vehicles and energy storage systems in response to modern demands for environmental protection.

[0004] Secondary batteries are classified into coin-type batteries, cylindrical batteries, prismatic batteries, and pouch-type batteries depending on the shape of the battery case. The electrode assembly installed inside the battery case of a secondary battery is a power generating element that can be charged and discharged and is made up of a laminated structure of electrodes and a separator.

[0005] Electrode assemblies can be broadly classified into a jellyroll type in which a sheet-like positive electrode and negative electrode coated with an active material are wound up with a separator interposed between them; a stack type in which multiple positive electrodes and negative electrodes are stacked in sequence with a separator interposed between them; and a stack & folding type in which stack-type unit cells are wound up with a long separator film.

[0006] Prismatic secondary batteries enclose an electrode assembly in a metal case, but because a certain amount of space is required for the electrical connection between the electrode tabs and electrode terminals of the electrode assembly, this space causes the electrode assembly to vibrate within the case. When prismatic secondary batteries are used in a stable environment, the degree of looseness of the electrode assembly is not a major issue. However, when used in an environment with high vibrations, such as an electric vehicle, the vibration of the electrode assembly can pose a significant safety risk. For example, repeated stress on the electrode tabs can cause short circuits, shortening the life of the secondary battery, or can cause an internal short circuit, resulting in a fire or explosion.

[0007] Furthermore, when a secondary battery is used for a long period of time, swelling may occur, causing the prismatic secondary battery to gradually expand and deform. Such deformation of the case also adversely affects safety.

[0008] Therefore, in order to maintain the safety of the secondary battery for a long period of time, an effective method for preventing the electrode assembly from shaking is required. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Korean Patent Publication No. 10-2013-0128344 Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention aims to prevent various problems caused by shaking of an electrode assembly housed inside a prismatic secondary battery, thereby maintaining the safety of the prismatic secondary battery for a long period of time.

[0011] However, the technical problems that the present invention aims to solve are not limited to the above-mentioned problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below. [Means for solving the problem]

[0012] The present invention relates to a prismatic secondary battery including a hexahedral metal case and one or more electrode assemblies housed in the case and inserted through an open surface formed on an upper surface of the case. In one example, a concave surface is formed on at least one of a front surface and a rear surface of the case, the electrode assembly is supported in contact with the concave surface, and the insertion end of the electrode assembly is wedge-shaped.

[0013] In one embodiment of the present invention, the concave surface is formed along one of the width direction and the height direction.

[0014] Here, the concave surface may be formed continuously from one end to the other end in either the width direction or the height direction of the case.

[0015] The concave surface may be a curved surface or a flat surface.

[0016] According to an embodiment of the present invention, the concave surface may be connected to both ends in a height direction or width direction intersecting with the extending direction of the concave surface by a curved surface or a flat surface.

[0017] Alternatively, the concave surface may form a stepped surface.

[0018] In some embodiments of the present invention, the concave surface may be formed in a central portion of at least one of the front and rear surfaces of the case, and in this case, the concave surface is connected to the corners of the case by a continuous inclined surface.

[0019] In addition, the insertion end of the electrode assembly may not contact the concave surface.

[0020] Meanwhile, the prismatic secondary battery of the present invention may further include a heat absorber disposed in the space formed by the recessed surface.

[0021] The outer packaging material of the heat absorber is a pouch, and the pouch seals an absorbent material impregnated with a liquid that absorbs external heat and vaporizes.

[0022] The absorbent material may then comprise a superabsorbent matrix, such as a superabsorbent polymer (SAP) or a superabsorbent fiber (SAF). [Effects of the Invention]

[0023] In the prismatic secondary battery of the present invention having the above-described configuration, the electrode assembly is supported in contact with the concave surface formed in the case, thereby preventing various problems such as damage to the electrode tabs caused by the electrode assembly moving within the case.

[0024] In addition, even if a swelling phenomenon occurs in the electrode assembly of the prismatic secondary battery of the present invention, deformation of the case, whose structural rigidity is improved due to the concave surface, is suppressed, thereby improving the safety of the prismatic secondary battery.

[0025] Furthermore, since the electrode assembly included in the prismatic secondary battery of the present invention has a wedge-shaped insertion end, the risk of the electrode assembly being damaged by a concave surface when the electrode assembly is inserted into the case is greatly reduced. Therefore, this electrode assembly structure also improves the safety of the prismatic secondary battery.

[0026] In addition, by utilizing the concave spaces formed on the front and / or rear surfaces of the prismatic secondary battery and disposing a heat sink therein, the prismatic secondary battery can be cooled smoothly. Therefore, the present invention can achieve effective cooling without providing an additional cooling space.

[0027] However, the technical effects that can be obtained by the present invention are not limited to the effects described above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0028] 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 concept of the present invention, and therefore the present invention should not be interpreted as being limited solely to the matters depicted in such drawings. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is an exploded perspective view of a prismatic secondary battery according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view taken along the line "AA" in FIG. [Figure 3] 10 is a view illustrating another embodiment in which a concave surface is formed along the width direction of the case. [Figure 4] 10 is a view illustrating an embodiment in which a concave surface is formed along the width direction of the case. [Figure 5] 10 is a view illustrating an embodiment in which a concave surface is formed along the width direction of the case. [Figure 6] 1 is a diagram illustrating an embodiment of a concave surface formed of stepped surfaces; [Figure 7] 10 is a diagram illustrating an embodiment of a concave surface formed in a central portion of a case. [Figure 8] 1 illustrates an embodiment including a heat sink. DETAILED DESCRIPTION OF THE INVENTION

[0030] Because the present invention can be modified in various ways and can have various embodiments, specific embodiments will be described in detail below.

[0031] However, this is not intended to limit the invention to any particular embodiment, but should be understood to include all modifications, equivalents, or alternatives falling within the spirit and scope of the invention.

[0032] In the present invention, the terms "comprise" and "have" are intended to specify the presence of features, numbers, steps, operations, components, parts or combinations thereof described in the specification, and should be understood as not precluding the presence or possibility of addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0033] Furthermore, in the present invention, when a layer, film, region, plate, or other portion is described as being "on" another portion, this includes not only the case where it is "directly on" the other portion, but also the case where there is another portion therebetween. Conversely, when a layer, film, region, plate, or other portion is described as being "under" the other portion, this includes not only the case where it is "directly under" the other portion, but also the case where there is another portion therebetween. Furthermore, in this application, being "located on" can include not only the case where it is located at the top, but also the case where it is located at the bottom.

[0034] The present invention relates to a prismatic secondary battery including a hexahedral metal case and one or more electrode assemblies housed in the case and inserted through an opening formed on the top surface of the case.

[0035] In one example, the prismatic secondary battery of the present invention is characterized in that a concave surface is formed on at least one of the front and rear surfaces of the case, the electrode assembly is supported in contact with the concave surface, and an insertion end of the electrode assembly is wedge-shaped.

[0036] With the above-described configuration, in the prismatic secondary battery of the present invention, the electrode assembly is supported in contact with the concave surface formed in the case, thereby preventing various problems such as damage to the electrode tabs caused by the electrode assembly moving within the case.

[0037] Furthermore, even if swelling occurs in the electrode assembly, the case is prevented from deforming due to the improved structural rigidity of the concave surface, thereby improving the safety of the prismatic secondary battery.

[0038] Furthermore, since the electrode assembly included in the prismatic secondary battery of the present invention has a wedge-shaped insertion end, the risk of the electrode assembly being damaged by a concave surface when the electrode assembly is inserted into the case is greatly reduced. Therefore, this electrode assembly structure also improves the safety of the prismatic secondary battery.

[0039] Hereinafter, specific embodiments of the prismatic secondary battery of the present invention will be described in detail with reference to the accompanying drawings. For reference, the directions of front, back, up, down, left, and right used in the following description to designate relative positions are intended to facilitate understanding of the invention, and unless otherwise specified, are based on the directions shown in the drawings.

[0040] (First embodiment) FIG. 1 is an exploded perspective view of a prismatic secondary battery 10 according to the present invention, and FIG. 2 is a cross-sectional view taken along the line "AA" in FIG.

[0041] The prismatic secondary battery 10 of the present invention includes a hexahedral metal case 100 and one or more electrode assemblies 200 inserted through an opening formed on the top surface of the case 100 and housed therein.

[0042] Here, in the structure of the prismatic secondary battery 10 of the present invention, the case 100 and the electrode assembly 200 have a concave surface 110 formed on at least one of the front and rear surfaces of the case 100, so that the electrode assembly 200 is supported by contacting the concave surface 110. In addition, the electrode assembly 200 has a wedge-shaped insertion end 210.

[0043] While the accompanying drawings show an embodiment in which concave surfaces 110 are formed on both the front and rear surfaces of the case 100, the concave surface 110 may be formed on only one of the front and rear surfaces, although this is not shown in the drawings, as long as the concave surface 110 can contact and support the electrode assembly 200. The insertion end 210 of the electrode assembly 200 refers to one end that forms the leading edge when the electrode assembly 200 is inserted into the open top surface of the case 100. In other words, the insertion end 210 is the end of the electrode assembly 200 that first enters the interior space of the case 100.

[0044] Since the wedge-shaped insertion end 210 can reduce the capacity of the electrode assembly 200, it is preferable that the insertion end 210 be formed with a suitable length so that it does not come into contact with the concave surface 110 when the electrode assembly 200 is fully housed within the case 100.

[0045] In the prismatic secondary battery 10 of the present invention, a recess is formed on the front and / or rear surface of the case 100, so that the electrode assembly 200 is supported in contact with the recess 110, thereby preventing various problems such as damage to the electrode tabs caused by the movement of the electrode assembly 200 within the case 100.

[0046] Furthermore, even if a swelling phenomenon occurs in which the electrode assembly 200 expands, the case 100, whose structural rigidity is improved by the concave surface 110, is prevented from deforming, thereby improving the safety of the prismatic secondary battery 10.

[0047] Furthermore, because the insertion end 210 of the electrode assembly 200 is wedge-shaped, the risk of damage to the electrode assembly 200 due to the concave surface 110 when the electrode assembly 200 is inserted into the case 100, for example, the risk of the separator that provides insulation for the electrode assembly 200 being torn, is greatly reduced. As a result, the electrode assembly 200 having the wedge-shaped insertion end 210 also greatly improves the safety of the prismatic secondary battery 10.

[0048] In one embodiment of the present invention, the concave surface 110 is formed along one of the width direction W or height direction H of the case 100. The concave surface 110 is formed continuously from one end to the other end in either the width direction W or height direction H. In other words, the concave surface 110 is formed long along the width direction W or height direction H across the entire central portion of the front and / or rear surface of the case 100.

[0049] 1 to 3 show an example of an embodiment in which the concave surface 110 is formed along the width direction W of the case 100, and Figs. 4 and 5 show an example of an embodiment in which the concave surface 110 is formed along the width direction W of the case 100. Here, in the accompanying drawings, in order to clearly understand the cross-sectional shape of the concave surface 110, Figs. 2 and 3 show a cross section along the height direction H, and Figs. 4 and 5 show a cross section along the width direction W.

[0050] As shown, the concave surface 110 may be curved or flat. A curved concave surface 110 is advantageous in that it provides elastic support for the electrode assembly 200, while a flat concave surface 110 is advantageous in that it provides a larger contact area for the electrode assembly 200.

[0051] 1 to 5, the concave surface 110 is connected to both ends in the height direction H or width direction W, which intersect with the direction in which the concave surface 110 extends, by curved or flat surfaces. In other words, the concave surface 110 is gently connected to the peripheral corners by curved or flat surfaces. Such a gentle shape of the concave surface 110 is advantageous for the firing process of the case 100.

[0052] Meanwhile, the concave surface 110 provided on the prismatic secondary battery 10 of the present invention may have other modified forms, and such modified embodiments are shown in FIGS.

[0053] 6 shows an embodiment of a concave surface 110 formed of a stepped surface 112. As an example, the concave surface 110, which is the stepped surface 112, is formed in the width direction W of the case 100, and the concave stepped surface 112, which includes a bent stepped surface, contacts and supports the outer surface of the electrode assembly 200.

[0054] Figure 7 shows a modified embodiment in which a concave surface 110 is formed in a central portion of at least one of the front and rear surfaces of case 100. That is, concave surface 110 in Figure 7 is not formed continuously from one end to the other in either the width direction W or the height direction H of case 100, but rather only forms a central concave portion.

[0055] Here, in order for the concave surface 110 formed in the center to be able to flexibly support the electrode assembly 200, it is preferable that the concave surface 110 has a structure in which the corners of the case 100 are connected by continuous inclined surfaces. In other words, the surface profile of the concave surface 110 in Fig. 7 has a shape similar to that of a truncated quadrangular pyramid.

[0056] As described above, in the prismatic secondary battery 10 of the present invention, the electrode assembly 200 is supported in contact with the concave surface 110 formed in the case 100, thereby suppressing internal flow, and the insertion end 210 of the electrode assembly 200 is wedge-shaped, thereby reducing the risk of damage when the electrode assembly 200 is inserted into the case 100.

[0057] (Second embodiment) FIG. 8 is a diagram illustrating a second embodiment of the prismatic secondary battery 10 of the present invention, and the illustrated prismatic secondary battery 10 further includes a heat sink 300 disposed in the external space formed by the concave surface 110.

[0058] The heat absorber 300 is a component that absorbs heat generated in the prismatic secondary battery 10 to ensure stable operation, and in particular, it plays a role in delaying fires and explosions by effectively absorbing heat in overheating situations such as thermal runaway. The heat absorber 300 also functions as a heat insulator, suppressing heat transfer between adjacent batteries.

[0059] As described above, the second embodiment of the present invention utilizes the space of the concave surface 110 formed on the front and / or rear surface of the prismatic secondary battery 10 and places a heat sink therein, thereby enabling smooth cooling of the prismatic secondary battery, and therefore achieving effective cooling without providing an additional cooling space.

[0060] In the illustrated second embodiment, the outer covering 310 of the heat absorber 300 is a pouch, and the pouch as the outer covering 310 seals an absorbent material 320 impregnated with a liquid that absorbs external heat and vaporizes.

[0061] Here, the absorbent material 320 impregnated with the heat-absorbing liquid may be a highly absorbent matrix, such as a super absorbent polymer (SAP) or a super absorbent fiber (SAF). The highly absorbent matrix is ​​porous or fibrous and can absorb a large amount of liquid by exhibiting capillary action, and the highly absorbent fiber can be made into a fiber form such as a nonwoven fabric by processing a highly absorbent resin.

[0062] In the present invention, the specific types of superabsorbent resin and the superabsorbent fiber produced therefrom are not particularly limited, and any resin having excellent fluid, particularly water, absorption capacity can be used without limitation. Examples of superabsorbent resins include polyacrylic acid, polyacrylates, polyacrylate graft polymers, starch, crosslinked carboxymethyl cellulose, acrylic acid copolymers, hydrolyzed starch-acrylonitrile graft copolymers, starch-acrylic acid graft copolymers, saponified vinyl acetate-acrylic acid ester copolymers, hydrolyzed acrylonitrile copolymers, hydrolyzed acrylamide copolymers, ethylene-maleic anhydride copolymers, isobutylene-maleic anhydride copolymers, polyvinyl sulfonic acid, polyvinyl phosphonic acid, polyvinyl phosphoric acid, polyvinyl sulfuric acid, sulfonated polyvinyl acrylate, polyvinyl acrylate copolymers ... hydrolyzed acrylamide copolymers, ethylene-maleic anhydride copolymers, isobutylene-maleic anhydride copolymers, polyvinyl sulfonic acid, polyvinyl phosphonic acid, polyvinyl phosphoric acid, polyvinyl sulfuric acid, sulfonated polyvinyl acrylate copolymers, acrylic acid copolymers, hydrolyzed starch-acrylonitrile graft copolymers, hydrolyzed starch-acrylic acid graft copolymers, Examples of the polyacrylate include one or more selected from the group consisting of styrene, polyvinylamine, polydialkylaminoalkyl(meth)acrylamide, polyethyleneimine, polyallylamine, polyallylguanidine, polydimethyldiallylammonium hydroxide, quaternized polystyrene derivatives, guanidine-modified polystyrene, quaternized poly(meth)acrylamide, polyvinylguanidine, and mixtures thereof, and preferably one or more selected from the group consisting of crosslinked polyacrylates, crosslinked polyacrylic acids, and crosslinked acrylic acid copolymers, although the present invention is not limited thereto.

[0063] In the present invention, the type of acrylic acid copolymer used as the superabsorbent resin is not particularly limited, but it may be a copolymer containing an acrylic acid monomer and one or more comonomers selected from the group consisting of maleic acid, itaconic acid, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, 2-(meth)acryloylethanesulfonic acid, 2-hydroxyethyl (meth)acrylate, and styrenesulfonic acid.

[0064] In the present invention, the superabsorbent resin can have a water absorption capacity of 10 g / g to 500 g / g, preferably 50 g / g to 200 g / g, but is not limited thereto. That is, 1 g of the superabsorbent resin can absorb 10 g to 500 g, preferably 50 g to 200 g of water.

[0065] In the present invention, the greater the water absorption capacity of the superabsorbent resin, the longer the cooling effect can last. However, if the water absorption capacity exceeds 500 g / g, the fluidity of the superabsorbent resin increases and it becomes difficult to maintain its shape, making it impossible to provide effective cooling. If the water absorption capacity is less than 10 g / g, the cooling effect will last too long and may be inefficient.

[0066] In one embodiment of the present invention, the liquid impregnated in the absorbent material 320 may be water. Water has the highest specific heat and latent heat among readily available liquids. Therefore, the water contained in the absorbent material 320 absorbs a large amount of heat during the process of its temperature rising to its boiling point and changing into a gas phase, making it suitable for use as the liquid contained in the heat absorber 300 of the present invention.

[0067] The present invention has been described in more detail above with reference to the drawings and embodiments, etc. However, the configurations described in the drawings or embodiments in this specification are merely one embodiment of the present invention and do not represent all of the technical ideas of the present invention, so it should be understood that there may be various equivalents and modifications that can replace them at the time of filing this application. [Explanation of symbols]

[0068] 10: Prismatic secondary battery 100: Case 110: Concave 112: Step surface 200: Electrode assembly 210: Insertion end 300: Heat absorber 310: Outer packaging (pouch) 320: Absorbent material W: Width direction H: Height T: Thickness direction

Claims

1. A prismatic secondary battery comprising: a hexahedral metal case; and one or more electrode assemblies housed in the case by being inserted through an opening formed on an upper surface of the case, a concave surface is formed on at least one of the front and rear surfaces of the case; the electrode assembly is supported in contact with the concave surface; the concave surface forms a plane in surface contact with the electrode assembly at a center of at least one of the front and rear surfaces of the case; The electrode assembly has an insertion end that is wedge-shaped, and the insertion end of the electrode assembly does not contact the concave surface; The device further includes a pouch-shaped heat sink disposed in the space formed by the concave surface, The pouch is a prismatic secondary battery that seals an absorbent material impregnated with a liquid that absorbs external heat and vaporizes.

2. The concave surface is The prismatic secondary battery according to claim 1 , wherein the prismatic secondary battery is formed along one of a width direction and a height direction.

3. The concave surface is The prismatic secondary battery according to claim 2 , wherein the case is formed continuously from one end to the other end in either a width direction or a height direction.

4. The concave surface is 4. The prismatic secondary battery according to claim 1, wherein both ends of the concave surface in a height direction or width direction intersecting with the extending direction are connected by a curved surface or a flat surface.

5. The concave surface is The prismatic secondary battery according to any one of claims 1 to 3, wherein a stepped surface is formed.

6. The concave surface is The prismatic secondary battery according to any one of claims 1 to 3, wherein the protective layer is formed in a central portion of at least one of the front and rear surfaces of the case.

7. The concave surface is The prismatic secondary battery according to claim 6 , wherein the case is connected to a corner thereof by a continuous inclined surface.

8. A prismatic secondary battery comprising: a hexahedral metal case; and one or more electrode assemblies housed in the case by being inserted through an opening formed on an upper surface of the case, a concave surface is formed on at least one of the front and rear surfaces of the case; the electrode assembly is supported in contact with the concave surface; The electrode assembly is a prismatic secondary battery having a wedge-shaped insertion end, The heating element further includes a heat sink disposed in a space formed by the concave surface, the packaging material of the heat absorber is a pouch, The pouch is a prismatic secondary battery that seals an absorbent material impregnated with a liquid that absorbs external heat and vaporizes.

9. The absorbent material is The prismatic secondary battery according to claim 8 , which is a highly absorbent matrix.

10. The prismatic secondary battery according to claim 9 , wherein the highly absorbent matrix comprises a highly absorbent polymer or a highly absorbent fiber.

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