Battery cell and battery module comprising same

Abstract

In order to improve stability by guiding an exhaust direction, the present invention provides a battery cell and a battery module comprising the same, the battery cell comprising: an electrode assembly; a case accommodating the electrode assembly; an electrode terminal electrically connected to the electrode assembly; and a sealing portion formed by joining edges of the case, the sealing portion including a first sealing portion in which the electrode terminal is inserted and a second sealing portion in which the electrode terminal is not inserted, a folded portion being formed in at least a portion of the second sealing portion, and including a nip member coupled to the folded portion.

Description

Technical Field

[0001] The invention relates to a battery cell and a battery module comprising the battery cell. Background Art

[0002] With the development of electronics, communications and aerospace industries, the demand for secondary batteries as energy sources has increased dramatically. In particular, as the importance of global environmental protection policies has been emphasized, the electric vehicle market is growing rapidly, and research and development of secondary batteries is being actively carried out both at home and abroad.

[0003] Among various secondary batteries, the research and development of lithium secondary batteries with high discharge voltage and energy density is the most active. This lithium secondary battery is manufactured by housing an electrode assembly including a negative electrode, a positive electrode and a separator in a bag-type shell with high flexibility, and then heat-welding the edges of the shell. However, when a lithium secondary battery is used for a long time or exposed to a high temperature environment, gas may be generated inside the shell, resulting in venting. At this time, the direction of gas discharge is not constant, so combustibles such as high-temperature electrolyte and gas may be transferred to adjacent secondary batteries, causing fires. In addition, when secondary batteries are used in electric vehicles, the exhaust direction is not constant, causing the flame to spread toward the driver in the event of a fire.

[0004] Therefore, in order to improve the stability of the secondary battery, it is very important to guide the direction of gas exhaust. Figure 1 and Figure 2 A conventional battery housing having a folded portion is schematically shown. Figure 1 and Figure 2 The battery cell 1 includes a housing 2 for accommodating an electrode assembly and a folded portion 3 formed at the edge of the housing 2. The folded portion 3 is a structure for enhancing the stability of the housing 2 and guiding the exhaust direction. However, even if the folded portion is formed at the edge of the housing, the folded portion is easily loosened due to the increase in the internal pressure of the battery cell ( Figure 2 (a)), and by loosening the folded portion, the seal of the housing is released ( Figure 2 (b)), making it impossible to guide the direction of gas discharge.

[0005] Figure 3 and Figure 4 A conventional battery case formed with an adhesive tape is schematically shown. Figure 3 and Figure 4 The battery cell 4 includes a case 5 for accommodating the electrode assembly and a tape 6 formed on the edge of the case 5. The tape 6 is a structure for enhancing the stability of the case 5 and guiding the exhaust direction. However, even if the tape is formed on the edge of the case, the sealing part is easily broken due to the increase in the internal pressure of the battery cell ( Figure 4(a)), and the seal of the housing is released by the broken seal portion ( Figure 4 (b)), making it impossible to guide the direction of gas discharge.

[0006] In addition, in order to further enhance the stability of the shell and guide the exhaust direction, a method of forming a clamping component in the sealing portion and the main body of the battery cell has been explored. However, since the clamping component applies pressure to the main body of the battery cell including the electrode assembly, problems such as electrode detachment, lithium ion precipitation (lithium plating) or shell rupture may occur, resulting in increased internal resistance of the battery cell and fire.

[0007] Therefore, there is a need for a technology that can improve the stability of a battery cell by guiding the direction in which exhaust gas occurs without applying pressure to the main body of the battery cell. Summary of the invention

[0008] 1. Technical issues to be resolved

[0009] The present invention provides a battery cell and a battery module including the battery cell, which can improve stability by guiding a venting direction.

[0010] (II) Technical solution

[0011] The battery cell according to the present invention includes: an electrode assembly; a shell that accommodates the electrode assembly; an electrode terminal that is electrically connected to the electrode assembly; and a sealing portion that is formed by joining the edges of the shell, the sealing portion including a first sealing portion in which the electrode terminal is inserted and a second sealing portion in which the electrode terminal is not inserted, a folding portion is formed in at least a portion of the second sealing portion, and includes a clamping part coupled to the folding portion.

[0012] In one embodiment of the present invention, the folded portion may be formed to extend along the length direction of the battery cell.

[0013] In one embodiment of the present invention, the clamping member may be coupled to the entire folding portion.

[0014] In one embodiment of the present invention, the clamping member may be detachably coupled to the folding portion.

[0015] In one embodiment of the present invention, the clamping member can accommodate the folded portion.

[0016] In one embodiment of the present invention, the clamping component may be in the form of an integrated clamp.

[0017] In one embodiment of the present invention, the clamping member can pressurize the folded portion by elastic force.

[0018] In one embodiment of the present invention, based on the height direction of the battery core, the width of the upper portion of the clamping member may be wider than that of the lower portion, and an inclined surface may be formed in a direction from the upper portion to the lower portion.

[0019] In one embodiment of the present invention, the clamping member may include a wing portion extending from the lower portion, and the folded portion may be pressurized by the inclined surface and the wing portion.

[0020] In one embodiment of the present invention, the clamping component may be in the form of a separate clamp.

[0021] In one embodiment of the present invention, the split clamp form may include an upper component and a lower component, and the folded portion may be clamped between the upper component and the lower component.

[0022] In one embodiment of the present invention, the upper member may surround the folded portion, and the lower member may be inserted into a hollow formed in the folded portion.

[0023] In one embodiment of the present invention, the clamping member may comprise insulating material.

[0024] The battery module according to the present invention may include the battery cell.

[0025] (III) Beneficial effects

[0026] The present invention includes a folded portion and a clamping member coupled to the folded portion in the sealing portion of the battery cell, thereby improving the durability of the folded portion and guiding the exhaust gas to occur in the direction of the electrode terminal. Thus, when a fire occurs in a part of the battery cell, the risk of the fire spreading to the adjacent battery cell or the flame spreading toward the vehicle driver can be reduced.

[0027] In addition, the clamping member coupled to the folding portion in the present invention is a detachable structure, and the form of the folding portion does not need to be specific, so it is easy to change the production conditions of the battery cell and can be applied to the manufactured battery cell.

[0028] In addition, in the present invention, the clamping member is not coupled to the main body of the battery cell, and thus does not cause the problem of increased internal resistance and reduced stability due to pressurization of the main body of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 and Figure 2 A conventional battery case formed with a folded portion is schematically shown.

[0030] Figure 3 and Figure 4 A conventional battery case formed with an adhesive tape is schematically shown.

[0031] Figure 5 (a) and (b) schematically show a plan view and a side view of a battery cell according to an embodiment of the present invention.

[0032] Figure 6 A clamping component in the form of an integrated clamp according to an embodiment of the present invention is schematically shown.

[0033] Figure 7 A clamping component in the form of a separate clamp according to another embodiment of the present invention is schematically shown.

[0034] Figure 8 (a) to (c) schematically show the lower component and the upper component of the split clamp form inserted into the hollow.

[0035] Fig. 9 (a) and (b) schematically show three-dimensional views of an integrated clamp form and a separate clamp form. Best Mode for Carrying Out the Invention

[0036] The structural or functional descriptions of the embodiments disclosed in this specification or application are merely exemplified for the purpose of illustrating the embodiments of the technical ideas according to the present invention. The embodiments of the technical ideas according to the present invention can be implemented in various forms other than the embodiments disclosed in this specification or application, and the technical ideas of the present invention should not be interpreted as being limited to the embodiments described in this specification or application.

[0037] Hereinafter, a battery cell and a battery module including the battery cell according to the present invention will be described in detail.

[0038] The battery cell according to the present invention includes: an electrode assembly; a shell that accommodates the electrode assembly; an electrode terminal that is electrically connected to the electrode assembly; and a sealing portion that is formed by joining the edges of the shell, wherein the sealing portion includes a first sealing portion in which the electrode terminal is inserted and a second sealing portion in which the electrode terminal is not inserted, a folding portion is formed in at least a portion of the second sealing portion, and includes a clamping (holding) component coupled to the folding portion.

[0039] Figure 5 (a) and (b) schematically show a plan view and a side view of a battery cell according to an embodiment of the present invention.

[0040] Reference Figure 5, the battery cell 100 according to the present invention includes an electrode assembly 10. The electrode assembly 10 may include a structure of a positive electrode, a negative electrode, and a separator stacked between the positive electrode and the negative electrode. The positive electrode may include a positive electrode active material, and the negative electrode may include a negative electrode active material in which lithium (Li) ions generated by the positive electrode active material can be embedded and deintercalated. In addition, the positive electrode active material and the negative electrode active material of the positive electrode and the negative electrode may each further contain a binder and a conductive material to improve mechanical stability and conductivity. The separator may be configured to prevent electrical short circuits between the positive electrode and the negative electrode and allow ion flow. The type of the separator is not particularly limited and may include a porous polymer film. The electrode assembly may be manufactured by alternately stacking a plurality of positive electrodes and negative electrodes and inserting a separator between the positive electrode and the negative electrode and by stacking or zigzag stacking.

[0041] The battery cell 100 according to an embodiment of the present invention may further include an electrolyte. The electrolyte may be a non-aqueous electrolyte. The electrolyte may include a lithium salt and an organic solvent. For example, the organic solvent may include one or more selected from propylene carbonate (PC), ethylene carbonate (EC), diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), methyl propyl carbonate (MPC), dipropyl carbonate (DPC), vinylene carbonate (VC), dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, sulfolane, gamma-butyrolactone, propylenesulfide and tetrahydrofuran.

[0042] The battery cell 100 according to the present invention includes a shell 20 for accommodating an electrode assembly 10. The shell 20 may be a bag made of a flexible material. The shell 20 may include: a lower sheet formed with a cup portion for accommodating the electrode assembly 10; and an upper sheet covering the lower sheet. The cup portion may prevent the electrode assembly 10 from falling off to the outside of the shell 20. The lower sheet and the upper sheet may protect the electrode assembly 10 from the external environment. The lower sheet and the upper sheet may contain a waterproof resin, for example, a film form in which a polyolefin-based resin, a metal, a nylon resin, and a polyester terephthalate resin are stacked.

[0043] The battery cell 100 according to the present invention includes: an electrode terminal 30 electrically connected to the electrode assembly 10; and a sealing portion 21 formed by joining the edge of the shell 20. The electrode terminal 30 may be a positive terminal electrically connected to a plurality of positive electrodes included in the electrode assembly 10, or may be a negative terminal electrically connected to a plurality of negative electrodes included in the electrode assembly 10. Figure 5 In (a), the electrode terminals are shown as being formed on different sides, respectively, but are not limited thereto and may be formed on the same side. The sealing portion 21 may be formed by joining the edges of the inner surfaces of the lower sheet and the upper sheet to prevent the electrode assembly 10 from falling off from the case 20. The forming method of the sealing portion 21 is not particularly limited and may be formed by thermally fusing the polyolefin-based resin formed on the inner surfaces of the lower sheet and the upper sheet.

[0044] The sealing portion 21 includes a first sealing portion 21-1 in which the electrode terminal 30 is inserted and a second sealing portion 21-2 in which the electrode terminal 30 is not inserted, and a folding portion 40 is formed in at least a portion of the second sealing portion 21-2. The folding portion 40 can prevent the second sealing portion 21-2 from being broken by the gas generated inside the housing 20. The folding portion 40 can be formed by folding the second sealing portion 21-2 by 90 degrees, 180 degrees, 270 degrees, or 360 degrees. In addition, the folding portion 40 can be formed by extending along the length direction L of the battery cell 100.

[0045] The battery cell 100 according to the present invention includes a clamping part 50 coupled to the folding portion 40, and the clamping part 50 may be coupled to the entire folding portion 40. The clamping part 50 may contain the folding portion 40 to prevent the folding portion 40 from being exposed to the outside. The clamping part 50 coupled to the folding portion 40 may prevent the folding portion 40 from being unfolded due to the gas pressure generated inside the housing 20, so that venting occurs in the direction of the first sealing portion 21-1 in which the electrode terminal 30 is inserted instead of venting in the direction of the second sealing portion 21-2. Since the venting is guided in a specific direction, the risk of the fire spreading to the adjacent battery cells or the flame spreading toward the vehicle driver when a fire occurs in a part of the battery cell can be reduced.

[0046] Figure 6 and Fig. 9 (a) schematically shows a clamping component in the form of an integrated clamp according to an embodiment of the present invention.

[0047] Reference Figure 6 and Fig. 9(a), the clamping part 50 can be in the form of an integrated clamp and can be detachably coupled to the folding portion 40. The clamping part 50 is not a structure that is integrally coupled to the folding portion 40, but can be detached as needed, so the form of the folding portion 40 does not need to be specific. Therefore, it is easy to change the production conditions of the battery cell, and it can be applied to manufactured battery cells. In addition, the clamping part 50 is not coupled to the main body of the battery cell 100, but is only partially coupled to the folding portion 40, so it does not cause problems such as increased internal resistance and reduced stability due to the pressurization of the main body of the battery cell 100 (the area that accommodates the electrode assembly).

[0048] The clamping member 50 may pressurize the folding portion 40 by elastic force. Specifically, based on the height direction h of the battery cell 100, the width X of the upper portion of the clamping member 50 is wider than the width Y of the lower portion, and an inclined surface 50-1 may be formed in the direction from the upper portion to the lower portion. In addition, the clamping member 50 may include a wing portion 50-2 extending from the lower portion, and the folding portion 40 may be pressurized by the inclined surface 50-1 and the wing portion 50-2.

[0049] Figure 7 and Fig. 9 (b) schematically shows a clamping component in the form of a separate clamp according to another embodiment of the present invention, Figure 8 (a) to (c) schematically show the lower component and the upper component of the split clamp form inserted into the hollow.

[0050] Reference Figure 7 , Figure 8 and Fig. 9 (b), the clamping member 60 may be in a separate clamp form and may be detachably coupled to the folding portion 40. Specifically, the separate clamp form may include an upper member 60-1 and a lower member 60-2, and the folding portion 40 may be clamped between the upper member 60-1 and the lower member 60-2. In addition, the upper member 60-1 surrounds the folding portion 40, and the lower member 60-2 may be inserted into the hollow 40-1 formed in the folding portion 40. For example, the step ( Figure 8 (a)), the step of inserting the lower part 60-2 in the form of a separate clamp into the hollow 40-1 ( Figure 8 (b)) and a step of attaching the upper member 60-1 in the form of a separate clamp to the folding portion 40 to clamp the folding portion 40 between the upper member 60-1 and the lower member 60-2 ( Figure 8(c)) to couple the separate clamp-shaped clamping member 60 to the folding portion 40. The separate clamp-shaped clamping member 60 can be more firmly coupled to the folding portion 40, thereby more effectively preventing the folding portion 40 from unfolding due to the gas pressure generated inside the housing 20.

[0051] The clamping members 50 and 60 may be formed of a rigid material that is not easily deformed by external force. Preferably, the clamping members 50 and 60 may include an insulating material. Since the insulating property of the folded portion 40 is ensured by the clamping members 50 and 60 including the insulating material, the battery cell 100 may have excellent insulating properties.

[0052] The battery module according to the present invention includes the battery cell of the present invention as a unit battery cell. The battery module may include a battery cell stack having a plurality of battery cells stacked therein and a heat sink. The heat sink may be a cooling plate, and the battery cell stack may be cooled by the heat sink. The heat sink may be disposed at the upper portion, the lower portion, the side portion, etc. of the battery cell stack. The battery cell stack may be formed by stacking batteries in a horizontal direction or a vertical direction. The battery cell according to the present invention includes a structure in which exhaust occurs in the direction of the electrode terminal. Therefore, even if exhaust occurs in the battery cell, gas may be generated in a controllable direction within the battery module, thereby reducing the risk of fire spreading to adjacent batteries or flames spreading toward the driver of the vehicle when a fire occurs in some batteries.

[0053] Description of reference numerals:

[0054] 10: Electrode assembly

[0055] 20: Shell

[0056] 21: Sealing part

[0057] 21-1: First sealing part

[0058] 21-2: Second sealing part

[0059] 30: Electrode terminal

[0060] 40: Folding part

[0061] 50, 60: Clamping parts

[0062] 100: Battery Cell

Claims

1. A battery cell, comprising: Electrode assembly; A shell, accommodating the electrode assembly; an electrode terminal, electrically connected to the electrode assembly; as well as a sealing portion formed by joining the edges of the housing, The sealing portion includes a first sealing portion in which the electrode terminal is inserted and a second sealing portion in which the electrode terminal is not inserted, a folded portion is formed in at least a portion of the second sealing portion, and a clamping member coupled to the folded portion.

2. The battery cell according to claim 1, wherein: The folded portion is formed and extended along the length direction of the battery core.

3. The battery cell according to claim 1, wherein: The clamping member is coupled to the entire folded portion.

4. The battery cell according to claim 1, wherein: The clamping member is detachably coupled to the folding portion.

5. The battery cell according to claim 1, wherein: The clamping member accommodates the folded portion.

6. The battery cell according to claim 1, wherein: The clamping component is in the form of an integrated clamp.

7. The battery cell according to claim 1, wherein: The clamping member presses the folded portion by elastic force.

8. The battery cell according to claim 1, wherein: With the height direction of the battery cell as a reference, the width of the upper portion of the clamping member is wider than that of the lower portion, and an inclined surface is formed in a direction from the upper portion to the lower portion.

9. The battery cell according to claim 8, wherein: The clamping member includes a wing portion extending from the lower portion, and the folded portion is pressed by the inclined surface and the wing portion.

10. The battery cell according to claim 1, wherein: The clamping component is in the form of a separate clamp.

11. The battery cell according to claim 10, wherein: The split clamp comprises an upper part and a lower part, The folded portion is sandwiched between the upper member and the lower member.

12. The battery cell according to claim 11, wherein: The upper member surrounds the folded portion, and the lower member is inserted into a hollow formed in the folded portion.

13. The battery cell according to claim 1, wherein: The clamping member comprises an insulating material.

14. A battery module comprising the battery cell according to claim 1 as a unit battery cell.

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