Secondary battery

Abstract

The present invention relates to a secondary battery in which a cooling member electrically connected to a cooling terminal cools an electrode assembly within a case, so that the cooling performance can be improved. As an example, the present invention provides a secondary battery comprising: an electrode assembly which includes a first electrode plate, a separator, and a second electrode plate; a case in which the electrode assembly is accommodated; a cap plate which seals the case; a first terminal which is electrically connected to the first electrode plate of the electrode assembly and exposed to the outside through the cap plate; a cooling member which is accommodated in the case and comes into contact with the electrode assembly; and a cooling terminal which is electrically connected to the cooling member and exposed out of the cap plate.

Description

secondary batteries

[0001] Various embodiments of the present invention relate to secondary batteries.

[0002] Secondary batteries, unlike primary batteries, which are non-rechargeable, are rechargeable and dischargeable. Low-capacity secondary batteries, each packaged as a single cell, are used in small, portable electronic devices such as mobile phones and camcorders. Furthermore, large-capacity secondary battery modules, consisting of dozens of battery packs connected together, are widely used as power sources for motors in hybrid and electric vehicles.

[0003] A secondary battery can be configured by placing a separator between a positive electrode plate and a negative electrode plate, stacking or winding an electrode assembly, and an electrolyte in a case, and installing a cap plate in the case. Such an electrode assembly may have a non-conductive tab protruding from the side or top, and a current collecting structure connected to the non-conductive tab.

[0004] Secondary batteries of this type can be installed in a battery module or battery pack, with multiple secondary batteries connected in series, to form a battery module or battery pack. As the energy density of these battery modules or battery packs increases, heat generation increases. Therefore, various methods are required to reduce heat generation or improve heat dissipation to ensure user safety.

[0005] 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.

[0006] The present invention provides a secondary battery capable of improving cooling performance.

[0007] A secondary battery according to an embodiment of the present invention may have an electrode assembly having a first electrode plate, a separator, and a second electrode plate, a case accommodating the electrode assembly, a cap plate sealing the case, a first terminal electrically connected to the first electrode plate of the electrode assembly and exposed to the outside through the cap plate, a cooling member accommodated on the inside of the case and in contact with the electrode assembly, and a cooling terminal electrically connected to the cooling member and exposed to the outside of the cap plate.

[0008] The above cooling member may have a flat plate shape.

[0009] The cooling member may include an inner cooling member interposed between the first electrode plate and the separator or between the second electrode plate and the separator on the inside of the electrode assembly.

[0010] The cooling member may further include an outer cooling member in contact with the outer surface of the electrode assembly.

[0011] The above outer cooling member may include two outer cooling members that are in contact with each other to cover the long sides of the electrode assembly, respectively.

[0012] The inner cooling member may be interposed between the electrode assemblies at regular intervals.

[0013] The above cooling members can each be electrically connected to the cooling terminals through conductors.

[0014] The above cooling member and the above conductor may be coated with an insulating material.

[0015] The above insulating material can cover both the cooling member and the conductor.

[0016] The above insulating material may be silica aerogel or polyimide foam.

[0017] The above cooling member may be a thermoelectric element or a thermoelectric material.

[0018] The size of the cooling member may be smaller than the size of the first electrode plate or the second electrode plate.

[0019] The above electrode assembly may be a laminated electrode assembly in which a first electrode plate, a separator, a second electrode plate, and a separator are sequentially laminated.

[0020] A sealing member may further be included between the cooling terminal and the cap plate.

[0021] The secondary battery of the present invention can improve cooling performance because a cooling member electrically connected to a cooling terminal cools an electrode assembly inside a case.

[0022] Figure 1 is a perspective view illustrating a secondary battery according to the present invention.

[0023] Figure 2 is a cross-sectional view taken along line 2-2' of Figure 1.

[0024] FIG. 3 is a perspective view illustrating an electrode assembly combined with a cooling member in the secondary battery of FIG. 1.

[0025] Figure 4 is an exploded perspective view of the cooling member and electrode assembly of Figure 3.

[0026] FIG. 5 is a perspective view showing the connection between the cooling member and the cooling terminal in the secondary battery of FIG. 1.

[0027] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0028] The embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art. The following embodiments may be modified in various ways, and the scope of the present invention is not limited to the embodiments described below. Rather, these embodiments are provided to more faithfully and completely explain the present disclosure and fully convey the spirit of the present invention to those skilled in the art.

[0029] In addition, in the drawings below, the thickness and size of each layer are exaggerated for convenience and clarity of explanation, and the same reference numerals in the drawings indicate the same elements. As used herein, the term "and / or" includes any one and all combinations of one or more of the listed items. In addition, the meaning of "connected" in this specification means not only when member A and member B are directly connected, but also when member C is interposed between member A and member B, so that member A and member B are indirectly connected.

[0030] The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of the present invention. As used herein, the singular forms "a," "an," and "the" include plural forms unless the context clearly dictates otherwise. Furthermore, when used herein, the words "comprise" and / or "comprising" specify the presence of stated features, numbers, steps, operations, elements, components, and / or groups thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, elements, components, and / or groups thereof.

[0031] Although the terms first, second, etc. are used herein to describe various elements, components, regions, layers, and / or portions, it is to be understood that these elements, components, regions, layers, and / or portions are not limited by these terms. These terms are only used to distinguish one element, component, region, layer, or portion from another. Accordingly, a first element, component, region, layer, or portion described below may refer to a second element, component, region, layer, or portion without departing from the teachings of the present invention.

[0032] Spatial terms such as "beneath," "below," "lower," "above," and "upper" are used to facilitate understanding of one element or feature depicted in the drawings relative to another element or feature. These spatial terms are intended to facilitate understanding of the present invention in various process states or usage states and are not intended to limit the present invention. For example, if an element or feature in a drawing is flipped, an element described as "beneath" or "below" becomes "above" or "above." Therefore, "beneath" is a concept encompassing "top" or "below."

[0033] FIG. 1 is a perspective view illustrating a secondary battery according to the present invention, and FIG. 2 is a cross-sectional view taken along line 2-2' of FIG. 1. FIG. 3 is a perspective view illustrating an electrode assembly coupled to a cooling member in the secondary battery of FIG. 1, FIG. 4 is an exploded perspective view of the cooling member and electrode assembly in FIG. 3, and FIG. 5 is a transparent perspective view illustrating a connection between a cooling member and a cooling terminal in the secondary battery of FIG. 1. Hereinafter, the secondary battery according to the present invention will be described with reference to FIGS. 1 to 5.

[0034] As illustrated in FIGS. 1 to 5, the secondary battery (100) includes an electrode assembly (110), a cooling member (120), a first collector plate (130), a second collector plate (140), a first terminal (150), a second terminal (160), a case (170), and a cap assembly (180). Here, the first terminal (150) may include a first terminal pillar (151) and a first terminal plate (152), and the second terminal (160) may include a second terminal pillar (161) and a second terminal plate (162).

[0035] The electrode assembly (110) is formed by laminating a plurality of laminated bodies of a first electrode plate, a separator, and a second electrode plate formed in a thin plate shape or film shape. Here, the first electrode plate can operate as a first polarity, for example, an anode, and the second electrode plate can operate as a second polarity, for example, a cathode. Of course, the first electrode plate and the second electrode plate may be arranged with different polarities depending on the selection of a person skilled in the art.

[0036] The first electrode plate is formed by applying a first electrode active material such as a transition metal oxide to a first electrode current collector formed of a metal foil such as aluminum, and includes a first electrode non-conductive region (111) where the first active material is not applied. The first electrode non-conductive region (111) provides a path for current flow between the first electrode plate and the outside.

[0037] In addition, the first electrode non-coated portion (111) is formed to overlap at the same position when the first electrode plates are laminated, thereby forming a multi-tab structure. The first electrode non-coated portion (111) is formed to protrude toward one side of the electrode assembly (110), and in some cases, a plurality of the first electrode non-coated portions may be welded together to form a single first collector tab. The first electrode non-coated portions (111) are aligned and protrude toward one side of the electrode assembly (110).

[0038] The second electrode plate is formed by applying a second electrode active material such as graphite or carbon to a first electrode current collector formed of a metal foil such as copper or nickel, and includes a second electrode non-conductive region (112) which is an area where the second active material is not applied.

[0039] In addition, the second electrode non-conductive portion (112) is also formed to overlap at the same position when the second electrode plates are laminated, thereby forming a multi-tab structure. The second electrode non-conductive portion (112) is formed to protrude from the other side of the electrode assembly (110), and in some cases, a plurality of them may be welded together to form a single second collector tab.

[0040] The separator is positioned between the first and second electrode plates to prevent short circuits and enable the movement of lithium ions. The separator may be made of polyethylene, polypropylene, or a composite film of polyethylene and polypropylene. However, the material of the separator does not limit the scope of the present invention.

[0041] In addition, after a plurality of electrode plates (first electrode plate and second electrode plate) are stacked together with the cooling member (120), the electrode assembly (110) can be maintained in a stacked state through a separate insulating tape (113) attached to a portion of the outer surface. At this time, the insulating tape (113) can maintain the shape of the electrode assembly (110) stacked with the cooling member (120). Thereafter, the insulating tape (113) can enable the non-conductive portions (111, 112) of the electrode assembly (110) to be welded to the current collector plates (130, 140) at precise positions, respectively, and can be fixed so that the structure of the electrode assembly (110) combined with the cooling member (120) is maintained even within the final secondary battery structure.

[0042] In addition, the electrode assembly (110) and the cooling member (120) are housed in a case (170) together with an electrolyte. The electrolyte may be composed of a lithium salt such as LiPF6 or LiBF4 in an organic solvent such as EC (ethylene carbonate), PC (propylene carbonate), DEC (diethyl carbonate), EMC (ethyl methyl carbonate), or DMC (dimethyl carbonate). In addition, the electrolyte may be in the form of a liquid, solid, or gel.

[0043] The cooling member (120) may have a substantially flat plate shape and may include an inner cooling member (120a) interposed between a plurality of electrode plates and a separator of the electrode assembly (110), and two outer cooling members (120b) each in contact with a long side surface of the electrode assembly (110). The two outer cooling members (120b) may each be interposed between the electrode assembly (110) and the case (170). In addition, the inner cooling member (120a) may be positioned on the inner side of the electrode assembly (110). The inner cooling member (120a) may be interposed between the electrode plates and the separator in the electrode assembly (110). For example, as illustrated in FIGS. 4 and 5, the cooling member (120) may include two outer cooling members (120b) and two inner cooling members (120a), but the number of cooling members (120) is not limited in the present invention. The inner cooling member (120a) may be arranged at a constant interval between the electrode assemblies (110). That is, the number of electrode assemblies (110) interposed between the two cooling members (120) may be the same, and their thicknesses may be the same. For example, the cooling member (120) may be additionally interposed one by one each time the number of electrode plates stacked in the electrode assembly (110) reaches 10 to 30. Here, when the number of electrode plates interposed between the two cooling members (120) is 20, it may include 10 first electrode plates and 10 second electrode plates that are sequentially stacked. Of course, additional separators may be interposed between the first and second electrode plates. The fewer the number of electrode plates interposed between the two cooling members (120), the better the cooling performance. However, if the number of cooling members (120) increases, the capacity of the electrode assembly (110) per unit volume may decrease.

[0044] In some examples, the cooling member (120) may include at least one of an inner cooling member (120a) and an outer cooling member (120b). The cooling member (120) may be provided with only an inner cooling member (120a) positioned on the inner side of the electrode assembly (110), or may be provided with only an outer cooling member (120b) positioned on the outer side of the electrode assembly (110). Of course, when the cooling member (120) includes both an inner cooling member (120a) and an outer cooling member (120b), the cooling performance may be higher.

[0045] The cooling member (120) can be electrically connected to the cooling terminal (187) exposed to the outside of the cap plate (181) through the conductor (121). Of course, the conductor (121) can be accommodated in the case (120). The conductor (121) can electrically connect between each cooling member (120) and the cooling terminal (187). The number of conductors (121) can be the same as the number of cooling members (120). Each of the plurality of cooling members (120) can be electrically connected to the cooling terminal (187) through the conductor (121).

[0046] The cooling member (120) may be made of a material with high thermal conductivity and may be made of a material that does not react with the electrolyte or the electrode plates of the electrode assembly (110). For example, the cooling member (120) may include a thermoelectric element or a thermoelectric material. Such a cooling member (120) may be electrically connected to a cooling terminal (187) exposed on the upper side of the cap plate (181). When current is applied to the cooling member (120) through the cooling terminal (187), the cooling member (120) may cool the electrode assembly (110) through cooling.

[0047] Here, the cooling member (120) may be coated with an insulating material. Of course, the conductor (121) electrically connecting the cooling member (120) and the cooling terminal (187) may also be coated with an insulating material. The insulating material may be a material having electrical and thermal insulation properties. For example, the insulating material may be silica aerogel or polyimide foam. That is, the insulating material may prevent the cooling member (120) and the conductor (121) located inside the case (180) from coming into contact with and reacting with the first electrode plate, the second electrode plate, and the electrolyte of the electrode assembly (110). The insulating material may also cover the area where the conductor (121) and the cooling member (120) are in contact and bonded. In some examples, the cooling member (120), the conductor (121), and the insulating material may be formed as an integrated body. The conductor (121) may not be coated with an insulating material only in a portion of the area that is to come into contact with the cooling terminal (187). However, after the conductor (121) is joined to the cooling terminal (187) by welding, it may be covered with an insulating tape and / or an insulating material.

[0048] The cooling member (120) may be smaller in size than the first electrode plate or the second electrode plate. The length of the cooling member (120) in the first direction (x), which is the longitudinal direction of the cap plate (181), may be smaller than that of the first electrode plate and the second electrode plate. In addition, the length of the cooling member (120) in the second direction (y), which is the width direction of the cap plate (181), may be smaller than that of the first electrode plate and the second electrode plate. For example, the cooling member (120) may not overlap the first electrode uncoated portion (111) and the second electrode uncoated portion (112) of the electrode assembly (110). That is, the cooling member (120) may not be interposed between the stacked first electrode uncoated portions (111) and the stacked second electrode uncoated portions (112).

[0049] Here, the size may be the size of the surface provided by the first direction (x), which is the surface corresponding to the long side of the electrode assembly (110), and the third direction (z), which is the height direction of the case (170). Such a cooling member (120) can individually cool the secondary batteries (100) through the cooling member (120), even when a plurality of secondary batteries (100) are electrically connected in the form of a module or pack, thereby improving safety.

[0050] The first collector plate (130) is formed of a conductive material such as aluminum, and is electrically connected to the first electrode plate by being coupled to the first electrode non-conductive portion (111) protruding from one end of the electrode assembly (110). The first collector plate (130) can be electrically connected to the first electrode non-conductive portion (111) by welding. The first collector plate (130) can include a first electrode connection portion (131) extending vertically along one side of the electrode assembly (110), and a first terminal connection portion (132) interposed between the electrode assembly (110) and the cap assembly (180) and coupled to the first terminal (150).

[0051] The first electrode connecting portion (131) extends vertically along one side of the electrode assembly (110) and may have a roughly plate shape. The first electrode connecting portion (131) may be joined by welding while in contact with the first electrode non-conducting portion (111) of the electrode assembly (110), so as to have the same first polarity as the first electrode non-conducting portion (111). For convenience of explanation, in the following description, the surface of the first electrode connecting portion (131) facing one side of the electrode assembly (110) will be referred to as the inner surface, and the surface facing one side of the case (170) will be referred to as the outer surface.

[0052] The first terminal connection portion (132) is formed in an approximately '┎' shape, and includes an upper portion interposed between the cap assembly (180) and the electrode assembly (110) in a roughly plate shape, and a side portion that extends downwardly from the outer end of the upper portion and is connected to the first electrode connection portion (131). The first terminal connection portion (132) is connected to the first electrode connection portion (131) by laser welding to form one first current collector plate (130).

[0053] The second collector plate (140) is formed of a conductive material such as nickel, and is electrically connected to the second electrode plate by making contact with the second electrode non-conductive portion (112) protruding from the other end of the electrode assembly (110). The second collector plate (140) includes a second electrode connection portion (141) and a second terminal connection portion (142). Since the shape of the second collector plate (140) is the same as that of the first collector plate (130), a duplicate description will be omitted.

[0054] The first terminal (150) is formed of a conductive material such as aluminum and can be electrically connected to the first collector plate (130). The first terminal (150) includes a first terminal pillar (151) and a first terminal plate (152).

[0055] The first terminal pillar (151) protrudes and extends upwardly by a certain length through the cap plate (181) of the cap assembly (180), and can be electrically connected to the first collector plate (130) at the lower portion of the cap plate (181). In addition, in some examples, the first terminal pillar (151) can protrude and extend upwardly by a certain length of the cap plate (181). The lower portion of the first terminal pillar (151) can be fitted into the hole of the first collector plate (131) and then riveted and / or welded.

[0056] The first terminal plate (152) has a hole, and the upper portion of the first terminal pillar (151) can be joined to the hole and riveted and / or welded. The first terminal plate (152) can be positioned on the upper portion of the cap plate (181). In some examples, the interface between the first terminal pillar (151) exposed upwardly and the first terminal plate (152) can be welded to each other. For example, a laser beam can be provided to the boundary region of the first terminal pillar (151) exposed upwardly and the first terminal plate (152), so that the boundary region can be melted and then cooled to be welded to each other. In some examples, the first terminal pillar (151) and the first terminal plate (152) can be electrically insulated from the cap plate (181).

[0057] The second terminal (160) is formed of a conductive material such as nickel and is electrically connected to the second collector plate (140). The second terminal (160) includes a second terminal pillar (161) and a second terminal plate (162). Since the shape of the second terminal (160) is the same as that of the first terminal (150), a duplicate description will be omitted.

[0058] The case (170) is formed of a conductive metal such as aluminum, aluminum alloy, or nickel-plated steel, and has a roughly hexahedral shape with an opening formed into which the electrode assembly (110), cooling member (120), first collector plate (130), and second collector plate (140) can be inserted and seated. A cap plate (181) can be coupled to the opening of the case (170) to seal the case (170). The inner surface of the case (170) is basically insulated to prevent an electrical short circuit from occurring inside.

[0059] A cap assembly (180) can be coupled to an opening of a case (170). The cap assembly (180) can include a cap plate (181), a seal gasket (182), a plug (183), a safety vent (184), an upper coupling member (185), a lower insulating member (186), and a cooling terminal (187). The cap plate (181) can seal the opening (171) of the case (170). The seal gasket (182) is formed of an insulating material between the cap plate (181) and the first terminal pillar (151) of the first terminal (150), and between the cap plate (181) and the second terminal pillar (161) of the second terminal (160), thereby sealing between the first terminal pillar (151) and the second terminal pillar (151), respectively, and the cap plate (181). This seal gasket (182) prevents external moisture from penetrating into the interior of the secondary battery (100) or prevents the electrolyte contained inside the secondary battery (100) from leaking out to the outside.

[0060] The plug (183) seals the electrolyte injection port of the cap plate (181), and the safety vent (184) is installed in the vent hole of the cap plate (181) and may be provided with a notch so that it can be opened at a set pressure.

[0061] An upper coupling member (185) may be provided between the first terminal plate (152) and the second terminal plate (162) and the cap plate (181) on the upper portion of the cap plate (181). In addition, the upper coupling member (185) is in close contact with the cap plate (181). Furthermore, the upper coupling member (185) may also be in close contact with the seal gasket (182). The upper coupling member (185) may insulate between the first terminal plate (152) and the cap plate (181), and between the second terminal plate (162) and the cap plate (181). In some examples, the upper coupling member (185) formed on the first terminal pillar (151) may electrically connect the first terminal plate (152) and the cap plate (181), and thus, the cap plate (181) may have the same polarity as the first terminal (150). In this case, the case (170) may also have the same polarity as the cap plate (181), and electrical short circuit with the electrode assembly (110) is prevented by the insulation treatment inside.

[0062] The cooling terminal (187) is formed of a conductive material and is electrically connected to a plurality of cooling members (120) through respective conductors (121). The cooling terminal (187) may have a portion exposed to the upper portion of the cap plate (181). The cooling terminal (187) may penetrate the cap plate (181), and a portion may be located inside the case (170). The lower surface of the cooling terminal (187) may be in contact with and electrically connected to the conductor (121). Here, a sealing member (187a) may be further interposed between the cooling terminal (187) and the cap plate (181). The sealing member (187a) may electrically insulate between the cooling terminal (187) and the cap plate (181). The sealing member (187a) may be a seal gasket. Additionally, the upper connecting member (185) can seal between the cooling terminal (187) and the cap plate (181).

[0063] The cooling terminal (187) may be connected to the cooling terminal hole of the cap plate (181) from the upper side to the lower side of the cap plate (181) and then connected by riveting, but the present invention does not limit the method of connecting the cooling terminal (187) to the cap plate (181). The cooling terminal (187) may be an external input / output terminal and may transmit an externally applied current to the cooling member (120).

[0064] The above description is only one embodiment for implementing the secondary battery according to the present invention, and the present invention is not limited to the above-described embodiment, and as claimed in the following claims, it will be understood that the technical spirit of the present invention exists to the extent that various modifications can be implemented by anyone having ordinary skill in the art to which the present invention pertains without departing from the gist of the present invention.

Claims

1. An electrode assembly having a first electrode plate, a separator, and a second electrode plate; A case accommodating the above electrode assembly; A cap plate sealing the above case; A first terminal electrically connected to the first electrode plate of the electrode assembly and exposed to the outside through the cap plate; A cooling member accommodated inside the case and in contact with the electrode assembly; and A secondary battery having a cooling terminal electrically connected to the cooling member and exposed to the outside of the cap plate.

2. In paragraph 1, The above cooling member is a secondary battery having a flat plate shape.

3. In paragraph 1, The above cooling member A secondary battery including an inner cooling member interposed between the first electrode plate and the separator or between the second electrode plate and the separator on the inner side of the electrode assembly.

4. In paragraph 3, A secondary battery wherein the cooling member further includes an outer cooling member in contact with an outer surface of the electrode assembly.

5. In paragraph 4, A secondary battery including two outer cooling members that are in contact with each other so as to cover the long sides of the electrode assembly, respectively.

6. In paragraph 4, A secondary battery in which the inner cooling member is interposed between the electrode assemblies at regular intervals.

7. In paragraph 4, The above cooling member is a secondary battery electrically connected to the cooling terminal through a conductor.

8. In paragraph 7, A secondary battery in which the cooling member and the conductor are coated with an insulating material.

9. In paragraph 8, A secondary battery in which the insulating material covers both the cooling member and the conductor.

10. In paragraph 8, A secondary battery in which the insulating material is silica aerogel or polyimide foam.

11. In paragraph 1, The above cooling member is a secondary battery which is a thermoelectric element or a thermoelectric material.

12. In paragraph 2, A secondary battery wherein the size of the cooling member is smaller than the size of the first electrode plate or the second electrode plate.

13. In paragraph 1, The above electrode assembly is a secondary battery which is a laminated electrode assembly in which a first electrode plate, a separator, a second electrode plate, and a separator are sequentially laminated.

14. In paragraph 1, A secondary battery further comprising a sealing member interposed between the cooling terminal and the cap plate.

15. In paragraph 1, A secondary battery including an outer cooling member each in contact with an outer surface of the electrode assembly.

Images