Secondary battery

Abstract

Provided is a secondary battery in which cooling performance is improved because a cooling member electrically connected to a cooling terminal cools an electrode assembly inside a case. The secondary battery includes: an electrode assembly including a first electrode plate, a separator, and a second electrode plate; a case configured to accommodate the electrode assembly; a cover plate configured to seal the housing; a first terminal electrically connected to a first electrode plate of the electrode assembly and exposed outside the cap plate; a cooling member accommodated inside 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.

Description

Technical Field

[0001] The embodiment relates to a secondary battery. Background Art

[0002] Unlike non-rechargeable primary batteries, secondary batteries are rechargeable and dischargeable batteries. Low-capacity secondary batteries are used in small portable electronic devices such as mobile phones and cameras, in which a single battery cell is encapsulated in a battery pack. In addition, high-capacity secondary battery modules are widely used as power sources for driving engines in hybrid vehicles, electric vehicles, etc., and the high-capacity secondary battery modules are provided in the form of battery pack units, in which dozens of battery packs are connected.

[0003] A secondary battery can be manufactured by embedding a stacked or wound electrode assembly and an electrolyte in a case with a separator between a positive electrode plate and a negative electrode plate, and then mounting a cover plate on the case. The electrode assembly may have an uncoated portion tab protruding toward a side or an upper portion, and a current collecting structure may be connected to the uncoated portion tab.

[0004] In such a secondary battery, a plurality of secondary batteries are connected in series with each other in the form of a battery module or a battery pack, and then mounted on a vehicle or an energy storage device. As the energy density of the battery module or the battery pack increases, heat generation increases, and thus, various methods are needed to reduce heat generation or improve heat dissipation for users.

[0005] The above information disclosed in the technology used as the background of the present disclosure is only for enhancing the understanding of the background of the present disclosure, and thus, may include information that does not constitute related art. Summary of the Invention

[0006] Aspects of some embodiments of the present disclosure provide a secondary battery capable of improving cooling performance.

[0007] According to some embodiments, a secondary battery includes: an electrode assembly including a first electrode plate, a separator, and a second electrode plate; a case configured to accommodate the electrode assembly; a cover plate configured to seal the case; a first terminal electrically connected to the first electrode plate of the electrode assembly and exposed outside the cover plate; a cooling member accommodated inside the case and in contact with the electrode assembly; and a cooling terminal electrically connected to the cooling member and exposed outside the cover plate.

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

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

[0010] The cooling member may further include an external cooling member that contacts an outer surface of the electrode assembly.

[0011] The external cooling member may include two external cooling members that respectively contact two long side surfaces of the electrode assembly to cover the two long side surfaces of the electrode assembly.

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

[0013] The cooling member may be electrically connected to the cooling terminal through a wire.

[0014] Each of the cooling member and the wire may be coated with an insulating material.

[0015] The insulating material may be configured to cover the entire cooling member and the wire.

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

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

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

[0019] The electrode assembly may include a stacked electrode assembly in which a first electrode plate, a separator, a second electrode plate, and a separator are sequentially stacked.

[0020] The secondary battery may further include a sealing member interposed between the cooling terminal and the cover plate.

[0021] Since the cooling member electrically connected to the cooling terminal cools the electrode assembly inside the housing, the secondary battery of the present invention can improve the cooling performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A perspective view of a secondary battery according to an embodiment is illustrated;

[0023] Figure 2 A cross-sectional view taken along line 2-2' is illustrated; Figure 1 of;

[0024] Figure 3 Illustrated Figure 1 is a perspective view of an electrode of the secondary battery coupled to the cooling member;

[0025] Figure 4 Illustrated Figure 3 is an exploded perspective view of a state in which the cooling member and the electrode assembly are disassembled; and

[0026] Figure 5 Illustrated Figure 1Transmission perspective view of the connection between a cooling member and a cooling terminal in a secondary battery. Detailed Description of the Embodiments

[0027] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings.

[0028] However, the embodiments of the present disclosure may be implemented in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that those skilled in the art will thoroughly understand the present disclosure. On the contrary, these embodiments are provided so that the present disclosure is thorough and complete, and these embodiments will fully convey the scope of the present disclosure to those skilled in the art.

[0029] In addition, in the following drawings, for convenience and clarity of description, the thickness or size of each layer is exaggerated, and the same reference numerals in the drawings denote the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the related listed items. In this specification, it will also be understood that if member A is referred to as being connected to member B, member A may be directly connected to member B, or indirectly connected to member B in the case where there is a member between member A and member B.

[0030] The terms used in this specification are only for the purpose of describing the present disclosure and should not be construed as limiting the meaning or scope of the present disclosure. As used in this specification, unless specifically stated in the context, the singular form may include the plural form. In addition, the expressions "comprising" and / or "including" used in this specification do not limit the shapes, quantities, processes, operations, members, elements, and / or groups mentioned, nor do they exclude the existence or addition of one or more other different shapes, quantities, processes, operations, members, elements, and / or groups. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0031] As used herein, terms such as "first", "second", etc. are used to describe various members, components, regions, layers, and / or parts. However, it is obvious that the members, components, regions, layers, and / or parts should not be limited by these terms. These terms do not imply a specific order, up and down, or priority, and are only used to distinguish one member, component, region, layer, or part from another member, component, region, layer, or part. Therefore, without departing from the teachings of the present disclosure, the first member, component, region, layer, or part to be described may also refer to the second member, component, region, layer, or part.

[0032] For ease of description, in this document, spatial relative terms such as "below", "beneath", "under", "above", and "on" are used to describe the relationship of one element or feature (or multiple other elements or features) shown in the drawings with another element or feature. These spatially relative terms are intended to facilitate the understanding of the present invention according to various process states or usage states of the present invention, and thus the present disclosure is not limited thereto. For example, if the element or feature shown in the drawing is flipped, the element or feature described as "below" or "beneath" can become "above" or "on". Therefore, the term "beneath" can encompass the terms "above" or "below".

[0033] Figure 1 A perspective view of a secondary battery according to an embodiment is shown, and Figure 2 a cross-sectional view taken along Figure 1 line 2-2'- is shown. Figure 3 A perspective view of an electrode connected to a cooling member in a secondary battery is shown Figure 1 as shown. Figure 4 A perspective exploded view of a state in which Figure 3 the cooling member and the electrode assembly are disassembled is shown, and Figure 5 a transmissive perspective view of the connection between the cooling member and the cooling terminal in a secondary battery is shown Figure 1 as shown. Hereinafter, a secondary battery according to an embodiment will be described with reference to Figures 1 to 5 the drawings.

[0034] As Figures 1 to 5 shown, the secondary battery 100 may include an electrode assembly 110, a cooling member 120, a first current collector 130, a second current collector plate 140, a first terminal 150, a second terminal 160, a case 170, and a cover assembly 180. In some embodiments, the first terminal 150 may include a first terminal post 151 and a first terminal plate 152, and the second terminal 160 may include a second terminal post 161 and a second terminal plate 162.

[0035] The electrode assembly 110 may be provided by stacking multiple stacks of a first electrode plate, a separator, and a second electrode plate, each of the first electrode plate, the separator, and the second electrode plate being provided in a thin plate or film shape. In some embodiments, the first electrode plate may operate with a first polarity, for example, as a positive electrode, and the second electrode plate may operate with a second polarity, for example, as a negative electrode. In some embodiments, depending on the choice of those skilled in the art, the first electrode plate and the second electrode plate may be provided with different polarities.

[0036] The first electrode plate is formed by applying a first electrode active material such as a transition metal oxide on a first electrode current collector formed of a metal foil such as aluminum foil, and includes a first electrode uncoated portion 111 on which the first electrode active metal is not applied. The first electrode uncoated portion 111 can provide a path for current between the first electrode plate and the outside.

[0037] In some embodiments, when stacking the first electrode plates, the first electrode uncoated portions 111 can be arranged to overlap at the same position to provide a multi-tab structure. The first electrode uncoated portions 111 can be provided to protrude to one side of the electrode assembly 110. In some embodiments, a plurality of the first electrode uncoated portions 111 can be welded to each other to provide one first current collector tab. The first electrode uncoated portions 111 can be aligned to protrude to 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 on a first electrode current collector formed of a metal foil such as nickel or copper foil, and includes a second electrode uncoated portion 112 on which the second electrode active metal is not applied.

[0039] In some embodiments, when stacking the second electrode plates, the second electrode uncoated portions 112 can also be arranged to overlap at the same position to provide a multi-tab structure. The second electrode uncoated portions 112 can be provided to protrude to the other side of the electrode assembly 110. In some embodiments, a plurality of the first electrode uncoated portions 111 can be welded to each other to provide one second current collector tab.

[0040] A separator is disposed between the first electrode plate and the second electrode plate to prevent short circuit and enable the movement of lithium ions. The separator can be made of polyethylene, polypropylene, or a composite film of polyethylene and polypropylene. The material of the separator does not limit the scope of the present disclosure.

[0041] In some embodiments, after stacking a plurality of electrode plates (the first electrode plate and the second electrode plate) together with the cooling member 120, the electrode assembly 110 can be held in a stacked state by a separate insulating tape 113 attached to a partial area of its outer surface. In some embodiments, the insulating tape 113 can hold the shape of the cooling member 120 stacked with the electrode assembly 110. Thereafter, the insulating tape 113 can allow the uncoated portions 111 and 112 of the electrode assembly 110 to be welded to the current collectors 130 and 140 at precise positions respectively, and can be fixed such that the structure of the electrode assembly 110 coupled to the cooling member 120 is held within the final secondary battery structure.

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

[0043] The cooling member 120 may have a substantially flat plate shape and include an internal cooling member 120a and two external cooling members 120b. The internal cooling member 120a is disposed between a plurality of electrode plates of the electrode assembly 110 and the separator, and each of the two external cooling members 120b contacts a long side surface of the electrode assembly 110. Each of the two external cooling members 120b may be disposed between the electrode assembly 110 and the housing 170. In some embodiments, the internal cooling member 120a may be disposed inside the electrode assembly 110. The internal cooling member 120a may be disposed between the electrode plates and the separator in the electrode assembly 110. For example, as Figure 4 and Figure 5 shown, the cooling member 120 may include two external cooling members 120b and two internal cooling members 120a, but in the present disclosure, the number of the cooling members 120 may not be limited thereto. The internal cooling members 120a may be disposed at regular intervals between the electrode assemblies 110. In some embodiments, the number of the electrode assemblies 110 disposed between two cooling members 120 may be the same, and their thicknesses may be the same. For example, the cooling member 120 may be additionally inserted one by one for every 10 to 30 electrode plates stacked in the electrode assembly 110. In some embodiments, if twenty electrode plates are disposed between two cooling members 120, the cooling member 120 may include ten first electrode plates and ten second electrode plates stacked in sequence. In some embodiments, the separator may be further disposed between the first electrode plate and the second electrode plate. As the number of the electrode plates disposed between two cooling members 120 decreases, the cooling performance may be improved. However, if the number of the cooling members 120 increases, the capacity of the electrode assembly 110 of the same volume will decrease.

[0044] In some embodiments, the cooling member 120 may include at least one of the internal cooling member 120a or the external cooling member 120b. The cooling member 120 may include only the internal cooling member 120a disposed inside the electrode assembly 110, or may include only the external cooling member 120b disposed outside the electrode assembly 110. In some embodiments, if the cooling member 120 includes both the internal cooling member 120a and the external cooling member 120b, the cooling performance may be improved.

[0045] The cooling member 120 can be electrically connected to a cooling terminal 187 that is exposed to the outside of the cover plate 181 through a wire 121. In some embodiments, the wire 21 can be accommodated in the housing 120. The wire 121 can electrically connect each cooling member 120 to each cooling terminal 187. The number of wires 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 wire 121.

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

[0047] In some embodiments, the cooling member 120 can be coated with an insulating material. In some embodiments, the wire 121 that electrically connects the cooling member 120 to the cooling terminal 187 can also be coated with an insulating material. The insulating material can be a material with electrical insulation properties and thermal insulation properties. For example, the insulating material can be silica aerogel or polyimide foam. In some embodiments, the insulating material can prevent the cooling member 120 and the wire 121 disposed inside the housing 180 from contacting and reacting with the first electrode plate, the second electrode plate, and the electrolyte of the electrode assembly 110. The insulating material can also cover the area where the wire 121 and the cooling member 120 contact and are connected to each other. In some embodiments, the cooling member 120, the wire 121, and the insulating material can be integrated with each other. The wire 121 can be uncoated with the insulating material only at a part that contacts the cooling terminal 187 in this area. However, after the wire 121 is connected to the cooling terminal 187 by welding, the wire 121 can be covered with an insulating tape and / or an insulating material.

[0048] The cooling member 120 can have a size smaller than that of 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 cover plate 181, can be less than the length of each of the first electrode plate and the second electrode plate. In some embodiments, the length of the cooling member 120 in the second direction y, which is the width direction of the cover plate 181, can be less than the length of each of the first electrode plate and the second electrode plate. For example, the cooling member 120 can not overlap with the first electrode uncoated portion 111 and the second electrode uncoated portion 112 of the electrode assembly 110. That is, the cooling member 120 can not be interposed between the stacked first electrode uncoated portions 111 and between the stacked second electrode uncoated portions 112.

[0049] In some embodiments, the dimension may be the dimension of the surface provided by the first direction x and the third direction z, and the surface corresponds to the long side surface of the electrode assembly 110. The third direction z is the height direction of the housing 170. As described above, even if a plurality of secondary batteries 100 are electrically connected to each other in the form of a module or a group, the cooling member 120 can improve safety by cooling the secondary batteries 100 individually via the cooling member 120.

[0050] The first current collector plate 130 may be made of a conductive material such as aluminum and may be electrically connected to the first uncoated electrode portion 111 so as to be electrically connected to the first electrode plate. The first uncoated electrode portion 111 protrudes from one end of the electrode assembly 110. The first current collector plate 130 may be electrically connected to the first uncoated electrode portion 111 by welding. The first current collector plate 130 may be interposed between the first electrode connection portion 131 extending vertically along one side of the electrode assembly 110 and the first terminal connection portion 132. The first terminal connection portion 132 is interposed between the electrode assembly 110 and the cover assembly 180 and is connected to the first terminal 150.

[0051] The first electrode connection portion 131 extends vertically along one side of the electrode assembly 110 and may have a substantially plate shape. The first electrode connection portion 131 may be connected by welding in a state of being in contact with the first uncoated electrode portion 111 of the electrode assembly 110 and may have the same first polarity as the first uncoated electrode portion 111. Hereinafter, for the sake of convenience of description, the surface of the first electrode connection portion 131 facing one surface of the electrode assembly 110 will be referred to as the inner surface, and the surface facing one surface of the housing 170 will be referred to as the outer surface.

[0052] The first terminal connection portion 132 may include an upper portion and a side portion. The upper portion has a shape similar to a "┎" shape and is interposed between the cover assembly 180 and the electrode assembly 110 in a substantially plate shape. The side portion is bent downward from the outer end of the upper portion to extend and is connected to the first electrode connection portion 131. The first terminal connection portion 132 may be connected to the first electrode connection portion 131 by laser welding to form one first current collector plate 130.

[0053] The second current collector plate 140 may be made of a conductive material such as nickel and is in contact with the second uncoated electrode portion 112 so as to be electrically connected to the second electrode plate. The second uncoated electrode portion 112 protrudes to the other end of the electrode assembly 110. The second current collector plate 140 may include a second electrode connection portion 141 and a second terminal connection portion 142. Since the shape of the second current collector plate 140 is the same as the shape of the first current collector plate 130, repeated descriptions will be omitted.

[0054] The first terminal 150 can be made of a conductive material such as aluminum and is electrically connected to the first current collector plate 130. The first terminal 150 can include a first terminal post 151 and a first terminal plate 152.

[0055] The first terminal post 151 can protrude through the cover plate 181 of the cover assembly 180 and extend upward for a certain length, and can be electrically connected to the first current collector 130 at the lower part of the cover plate 181. In some embodiments, the first terminal post 151 can protrude and extend to the upper part of the cover plate 181 for a certain length. The lower part of the first terminal post 151 can be inserted into the hole of the first current collector plate 131 and then riveted and / or welded.

[0056] The first terminal plate 152 has a hole, and the upper part of the first terminal post 151 can be coupled to the hole and riveted and / or welded. The first terminal plate 152 can be disposed on the upper part of the cover plate 181. In some embodiments, the interface between the upwardly exposed first terminal post 151 and the first terminal plate 152 can be welded to each other. For example, a laser beam can be directed to the boundary region between the upwardly exposed first terminal post 151 and the first terminal plate 152, and thus, the boundary region can be melted together and then cooled to be welded. In some embodiments, the first terminal post 151 and the first terminal plate 152 can be electrically insulated from the cover plate 181.

[0057] The second terminal 160 can be made of a conductive material such as nickel and is electrically connected to the second current collector plate 140. The second terminal 160 can include a second terminal post 161 and a second terminal plate 162. Since the shape of the second current collector plate 160 is the same as the shape of the first current collector plate 150, the repeated description will be omitted.

[0058] The housing 170 is made of a conductive metal such as aluminum, aluminum alloy or nickel-plated steel and has an approximate hexahedral shape provided with an opening through which the electrode assembly 110, the cooling member 120, the first current collector plate 130 and the second current collector plate 140 are inserted and disposed. The cover plate 181 can be coupled to the opening of the housing 170 to seal the housing 170. The inner surface of the housing 170 can be substantially insulated to prevent an electrical short circuit from occurring therein.

[0059] The cover assembly 180 may be coupled to an opening of the housing 170. The cover assembly 180 may include a cover plate 181, a sealing 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 cover plate 181 may seal the opening 171 of the housing 170. The sealing gasket 182 may be made of an insulating material, disposed between the cover plate 181 and the first terminal post 151 of the first terminal 150 and between the cover plate 181 and the second terminal post 151 of the second terminal 160, and seal the gaps between each of the first terminal post 151 and the second terminal post 161 and the cover plate 181. The sealing gasket 182 prevents moisture from entering the secondary battery 100 or prevents the electrolyte from leaking out of the secondary battery 100.

[0060] The plug 183 may seal the electrolyte injection port of the cover plate 181, and the safety vent 184 may be installed in the vent hole of the cover plate 181 and provided with a notch that can be opened under a set pressure.

[0061] The upper coupling member 185 may be provided between each of the first terminal plate 152 and the second terminal plate 162 and the cover plate 181 at the upper part of the cover plate 181. In some embodiments, the upper coupling member 185 may be in close contact with the cover plate 181. In some embodiments, the upper coupling member 185 may be tightly adhered to the sealing gasket 182. The upper coupling member 185 may insulate the first terminal plate 152 and the cover plate 181 from each other, and insulate the second terminal plate 162 and the cover plate 181 from each other. In some embodiments, the upper coupling member 185 disposed on the first terminal post 151 may electrically connect the first terminal plate 152 to the cover plate 181, and thus, the cover plate 181 may have the same polarity as the first terminal 150. In some embodiments, the housing 170 may also have the same polarity as the cover plate 181, and may prevent an electrical short circuit with the electrode assembly 110 through internal insulation.

[0062] The cooling terminal 187 may be made of a conductive material and electrically connected to a plurality of cooling members 120 through wires 121 respectively. A part of the cooling terminal 187 may be exposed on the upper side of the cover plate 181. The cooling terminal 187 may pass through the cover plate 181, and a part of the cooling terminal 187 may be disposed inside the housing 170. The bottom surface of the cooling terminal 187 may contact and be electrically connected to the wire 121. In some embodiments, a sealing member 187a may be further interposed between the cooling terminal 187 and the cover plate 181. The sealing member 187a may electrically insulate the cooling terminal 187 from the cover plate 181. The sealing member 187a may be a sealing gasket. In some embodiments, the upper coupling member 185 may seal the gap between the cooling terminal 187 and the cover plate 181.

[0063] The cooling terminal 187 may be connected downward from the upper side of the cover plate 181 to the cooling terminal hole of the cover plate 181 and then connected by riveting. However, in the present disclosure, the method of connecting the cooling terminal 187 to the cover plate 181 may not be limited. The cooling terminal 187 may be an external input / output terminal and may transmit the current applied from the outside to the cooling member 120.

[0064] The above-described embodiments are merely embodiments of the secondary battery, and thus, the present disclosure is not limited to the foregoing embodiments, and those of ordinary skill in the art will understand that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure defined by the appended claims.

Claims

1. A secondary battery, comprising: An electrode assembly, including a first electrode plate, a separator, and a second electrode plate; A housing configured to accommodate the electrode assembly; A cover plate configured to seal the housing; A first terminal electrically connected to the first electrode plate of the electrode assembly and exposed outside the cover plate; A cooling member accommodated inside the housing and in contact with the electrode assembly; and A cooling terminal electrically connected to the cooling member and exposed outside the cover plate.

2. The secondary battery according to claim 1, wherein, The cooling member has a flat plate shape.

3. The secondary battery according to claim 1, wherein, The cooling member includes an internal cooling member that is disposed between the first electrode plate and the separator or between the second electrode plate and the separator inside the electrode assembly.

4. The secondary battery according to claim 3, wherein, The cooling member further includes an external cooling member that is in contact with the outer surface of the electrode assembly.

5. The secondary battery according to claim 4, wherein, The external cooling member includes two external cooling members that are respectively in contact with two long sides of the electrode assembly to cover the two long sides of the electrode assembly.

6. The secondary battery according to claim 4, wherein, The internal cooling members are spaced at regular intervals between the electrode assemblies.

7. The secondary battery according to claim 4, wherein, The cooling member is electrically connected to the cooling terminal through a wire.

8. The secondary battery according to claim 7, wherein, Each of the cooling member and the wire is coated with an insulating material.

9. The secondary battery according to claim 8, wherein The insulating material is configured to cover the entire cooling member and the wire.

10. The secondary battery according to claim 8, wherein, The insulating material includes silica aerogel or polyimide foam.

11. The secondary battery according to claim 1, wherein, The cooling member is made of a thermoelectric element or a thermoelectric material.

12. The secondary battery according to claim 2, wherein, The cooling member has a size smaller than that of the first electrode plate or the second electrode plate.

13. The secondary battery according to claim 1, wherein, The electrode assembly includes a stacked electrode assembly in which the first electrode plate, the separator, the second electrode plate, and the separator are sequentially stacked.

14. The secondary battery according to claim 1, further comprising: A sealing member disposed between the cooling terminal and the cover plate.

15. The secondary battery according to claim 1, wherein, The cooling member includes an external cooling member that is in contact with the outer surface of the electrode assembly.

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