Rechargeable batteries and rechargeable battery modules containing them

Abstract

The secondary battery according to the present invention includes an electrode assembly and a battery case in which the electrode assembly is housed and the edge portion is sealed. The battery case can include at least one folding portion that is folded so that a part of the end of the edge portion of the battery case is hidden inside, and at least one exposed portion where the other part of the end of the edge portion of the battery case is exposed outside.

Description

Technical Field

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0085280 filed on July 11, 2022 and Korean Patent Application No. 10-2023-0087159 filed on July 5, 2023, and all the contents disclosed in the documents of the Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a secondary battery and a secondary battery module including the same, and more particularly, to a secondary battery including an electrode assembly and a battery case for housing the electrode assembly, and a secondary battery module including the same.

Background Art

[0003] Recently, secondary batteries have been attracting attention as a power source for electric vehicles (EVs), hybrid electric vehicles (HEVs), etc., which are presented as a method for solving problems such as air pollution in existing gasoline vehicles and diesel vehicles that use fossil fuels.

[0004] One or two to three secondary batteries are used in small mobile devices, while battery modules in which a number of secondary batteries are electrically connected or battery packs in which a plurality of battery modules are electrically connected to each other are used in medium and large-sized devices such as electric vehicles due to the need for high output and large capacity.

[0005] Currently, one of the most spotlighted commercialized secondary batteries is the lithium secondary battery, and the lithium secondary battery can be divided into a can type, a square type, a pouch type, etc. according to the shape of the exterior material. Among these, pouch-type secondary batteries are widely used in medium and large-sized battery modules because of their advantages of high energy density and easy stacking.

[0006] On the other hand, in recent years, as the demand for secondary battery modules installed in vehicles has increased, customer needs for stability have been steadily rising. However, while customers are seeking to increase the energy density of secondary batteries within the limited space of the secondary battery module, this also leads to an increased risk of ignition and explosion of the secondary batteries.

[0007] A pouch-type rechargeable battery may have a structure in which the electrode assembly is housed in a pouch-type battery case, and the edges of the battery case are sealed. However, if the rechargeable battery ignites and its temperature rises, causing the electrolyte to vaporize inside the battery case and generate gas, the gas tends to escape from areas where the battery case is not sealed properly, without a predetermined path.

[0008] In this case, if gas is ejected from a position adjacent to the electrode lead, a critical problem can occur where a spark causes the secondary battery to ignite rapidly. Therefore, the development of technology to solve the aforementioned problem is necessary. [Overview of the project] [Problems that the invention aims to solve]

[0009] The present invention was derived to solve the above-mentioned problems, and the object of the present invention is to provide a secondary battery and a secondary battery module including the same that can minimize the risk of ignition by inducing the gas inside the battery case to dissipate at a specified location when an emergency situation such as the secondary battery igniting occurs. [Means for solving the problem]

[0010] A secondary battery according to an embodiment of the present invention includes an electrode assembly and a battery case in which the electrode assembly is housed and whose edges are sealed, the battery case including at least one folding portion such that a portion of the edge of the battery case is folded inward and at least one exposed portion such that another portion of the edge of the battery case is exposed outward.

[0011] The exposed portion can be configured such that, when the pressure inside the battery case exceeds a predetermined pressure, the seal is released and the gas inside the battery case is discharged.

[0012] The folding section can be folded at least twice in one direction.

[0013] The exposed portion can be folded at least once or more times so that the end of the edge is exposed to the outside.

[0014] The exposed portion can be folded in the opposite direction to the folding portion.

[0015] The exposed portion can be folded in fewer steps than the folding portion.

[0016] The distance between opposing inner surfaces in the exposed portion may be greater than the distance between opposing inner surfaces in the folding portion.

[0017] The secondary battery may further include electrode leads that protrude from one edge of the battery case. The exposed portion may be formed on the other edge of the battery case.

[0018] The folding portion can be formed on another edge of the battery case.

[0019] The exposed portion can be positioned adjacent to the folding portion.

[0020] Multiple exposed portions are formed spaced apart along the longitudinal direction of the battery case, and these exposed portions can be provided between multiple folding portions.

[0021] The secondary battery may further include a membrane portion that is folded such that both ends are connected to the exposed portion and wrap around the end of the exposed portion.

[0022] The membrane portion can be configured to be deployed in a state where both ends are connected to the outer surface of the exposed portion when the pressure inside the battery case increases to a predetermined pressure or more and the exposed portion is unsealed.

[0023] The membrane portion can have a porous material.

[0024] A secondary battery module according to an embodiment of the present invention can include a plurality of secondary batteries arranged in one direction and a housing that houses the plurality of secondary batteries. The secondary battery includes an electrode assembly and a battery case in which the electrode assembly is housed and the edge is sealed. The battery case includes at least one folding portion that is folded such that a part of the end of the edge of the battery case is hidden inside, and at least one exposed portion where the end of another part of the edge of the battery case is exposed outside.

Advantages of the Invention

[0025] The present invention has the effect of minimizing the risk of ignition by providing an exposed portion at the edge of the battery case where the end is exposed outside and guiding the gas generated inside the battery case to diverge at a designated position.

[0026] In addition, the present invention further includes a membrane portion connected to the exposed portion, which has the effect of discharging the gas inside the battery case and preventing external moisture, foreign matter, etc. from penetrating into the battery case.

[0027] In addition, in a secondary battery module including a plurality of secondary batteries, the present invention provides an exposed portion with a terminal exposed to the outside at the edge of the battery case of the secondary battery, and guides the gas to diverge at a designated position, thereby minimizing the risk of ignition. As a result, it is possible to suppress and delay the progress of thermal runaway propagation between the secondary batteries inside the secondary battery module.

Brief Description of the Drawings

[0028] [Figure 1] It is a front view showing the state of the secondary battery before the edge of the battery case is folded for the manufacture of the secondary battery according to the first embodiment of the present invention. [Figure 2] It is a front view of the secondary battery according to the first embodiment of the present invention. [Figure 3] It is a perspective view showing the exposed portion in the secondary battery of FIG. 2 in more detail. [Figure 4] It is a cross-sectional view showing the cross-section in the A-A direction in FIG. 2. [Figure 5] As a cross-sectional view in the B-B direction in FIG. 2, it is a cross-sectional view showing the state before gas is released through the exposed portion. [Figure 6] It is a cross-sectional view showing the state in which gas is released through the exposed portion of FIG. 5. [Figure 7] It is a perspective view showing the state in which gas is released through the exposed portion in the secondary battery of FIG. 2. [Figure 8] It is a front view of the secondary battery according to the second embodiment of the present invention. [Figure 9] It is a perspective view showing the state in which a membrane portion is connected to the exposed portion in the secondary battery according to the third embodiment of the present invention. [Figure 10] It is a cross-sectional view showing the state before gas is released through the exposed portion in the secondary battery of FIG. 9. [Figure 11] It is a cross-sectional view showing the state in which gas is released through the exposed portion of FIG. 10.

Modes for Carrying Out the Invention

[0029] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, so that they can be easily implemented by a person with ordinary skill in the art to which the present invention pertains. However, the present invention can be realized in a variety of different forms and is not limited or restricted by the embodiments described below.

[0030] For the purpose of clearly describing the present invention, detailed descriptions of relevant prior art that are irrelevant to the description or that could obscure the gist of the invention have been omitted. In this specification, when assigning reference numerals to components in the drawings, the same or similar reference numerals are used for components that are the same or similar throughout the specification.

[0031] Furthermore, terms and words used in this specification and in the claims should not be interpreted in a manner limited to their ordinary or dictionary meanings, but rather should be interpreted in a manner consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors may appropriately define the concepts of terms in order to best explain their invention.

[0032] secondary battery An embodiment of the present invention may include an electrode assembly 110 and a battery case 120 in which the electrode assembly 110 is housed and which has a sealed edge. The battery case 120 may include at least one folding portion 121 which is folded so that a portion of the edge of the battery case 120 is hidden inward, and at least one exposed portion 122 which exposes the other portion of the edge of the battery case 120 to the outside.

[0033] The exposed portion 122 can be configured such that, when the pressure inside the battery case 120 exceeds a predetermined pressure, the seal is released and the gas inside the battery case 120 is discharged.

[0034] In the present invention, the electrode assembly 110 can have various structures. For example, the electrode assembly 110 can be formed by sequentially stacking electrodes and separators. More specifically, the electrode assembly 110 can have a structure in which a positive electrode current collector / positive electrode active material layer / separator / negative electrode active material layer / negative electrode current collector are stacked in that order, with the positive electrode active material layer facing one side of the separator and the negative electrode active material layer facing the other side of the separator. However, it goes without saying that the type of electrode assembly 110 is not limited to this, and it may also be composed of a jelly roll type electrode assembly.

[0035] Note that such an electrode assembly 110 is housed inside the battery case 120 and is represented by a dotted line in the drawing.

[0036] Furthermore, the battery case 120 in which the electrode assembly 110 is housed has a sealed edge and can have various structures.

[0037] For example, the battery case 120 can be provided by two sheets, one above and one below the electrode assembly 110. Furthermore, at least one of the two sheets can be partially formed into a concave shape to create an empty space in which the electrode assembly 110 can be housed. This empty space can accommodate the electrode assembly 110 along with an electrolyte solution or the like.

[0038] Such a battery case 120 may have a structure in which the edges are sealed, which may be to prevent the electrode assembly 110 housed inside the battery case 120 from being exposed to external moisture and air and being damaged. In this case, the edges of the battery case 120 may be sealed by methods such as heat sealing. The edges of the battery case 120 may be referred to as a terrace portion or a sealing portion.

[0039] On the other hand, the secondary battery 100 according to the present invention may be provided with the edges of the battery case 120 folded in order to reduce the volume of the secondary battery 100 in order to improve energy density, or to further improve the sealing force of the battery case 120.

[0040] In other words, the secondary battery 100 described above can be folded in the direction of the arrow with the edge of the battery case 120 unfolded, as shown in Figure 1, and thereby can be provided with the edge of the battery case 120 folded, as shown in Figure 2.

[0041] Here, at least one exposed portion 122 and a folding portion 121 can be formed on the edge of the battery case 120 so that if gas is generated inside the battery case 120 due to the ignition of the secondary battery 100 or the like, the gas can be released at a designated location.

[0042] Specifically, as illustrated in Figures 2 and 3, the battery case 120 may include at least one folding portion 121 in which a portion of the edge of the battery case 120 is folded inward, and at least one exposed portion 122 in which the other portion of the edge of the battery case 120 is exposed outward.

[0043] As a result, if a certain amount of gas is generated inside the battery case 120, the gas can be released first from the exposed portion 122, which is relatively easier to release gas from than the folding portion 121. Therefore, in the battery case 120 with the above structure, the user can selectively position the exposed portion 122 on the battery case 120 to release the gas to a specified location, thereby minimizing the risk of fire caused by the secondary battery 100.

[0044] The structures of the folding portion 121 and the exposed portion 122 will be described in more detail below.

[0045] First, the folding section 121 is configured such that a portion of the end of the edge of the battery case 120 is hidden inside, and can have various structures.

[0046] Specifically, the folding portion 121 can be formed by folding a portion of the edge of the battery case 120, as illustrated in Figures 3 and 4. That is, the end of a portion of the edge of the battery case 120 can be the end portion 121a of the folding portion 121. The end portion 121a of the folding portion 121 can be hidden by the opposing inner surfaces of the folding portion 121.

[0047] The folding section 121 has an end 121a from which gas can be released to the outside hidden inside, making it relatively more difficult for gas to be released than the exposed section 122 from which end 122a is exposed to the outside. This can be understood as a configuration that induces the release of gas to the exposed section 122.

[0048] Furthermore, since the end portion 121a of the folding portion 121 is hidden inside, it has a structure that makes it relatively difficult for external moisture and air to penetrate, and can be understood as a configuration that improves the sealing force of the battery case 120.

[0049] The folding portion 121 described above may have any structure as long as the end portion 121a is hidden inside. For example, the folding portion 121 may have a structure that is folded at least twice in one direction so that the end portion 121a is enclosed inside at the edge of the battery case 120.

[0050] Furthermore, even if gas flows into the folding section 121, the opposing inner surfaces of the folding section 121 can be in contact with or adjacent to each other in order to minimize gas movement.

[0051] On the other hand, the present invention may include an exposed portion 122 that releases the seal and allows gas from inside the battery case 120 to be discharged when the internal pressure of the battery case 120 exceeds a predetermined pressure.

[0052] Specifically, the exposed portion 122 can be formed by folding another portion of the edge of the battery case 120, as illustrated in Figures 3 and 5. That is, the end of the other portion of the edge of the battery case 120 can be the end portion 122a of the exposed portion 122. The end portion 122a of the exposed portion 122 can be exposed to the outside.

[0053] As a result, the exposed portion 122 has an end 122a that can release gas to the outside, which is exposed to the outside, making it easier to release gas than the folding portion 121, whose end is hidden inside. The exposed portion 122 can be understood as being configured to operate before the folding portion 121 when gas is generated inside the battery case 120 and to be used as a gas release passage.

[0054] The exposed portion 122 described above may have any structure as long as its end 122a is exposed to the outside. For example, the exposed portion 122 may have a structure that is folded at least once so that its end 122a is exposed to the outside. Here, the exposed portion 122 may be folded in the opposite direction to the folding portion 121. Also, the exposed portion 122 may be folded fewer times than the folding portion 121.

[0055] Furthermore, the distance g2 between opposing inner surfaces in the exposed portion 122 can be greater than the distance g1 between opposing inner surfaces in the folding portion 121. Each distance g1 and g2 can represent an average distance.

[0056] This allows for smoother and more expedited gas discharge through the exposed portion 122 when the pressure resistance of the battery case 120 increases.

[0057] As shown in Figure 5, such exposed portion 122 can maintain a sealed state if no gas is generated inside the battery case 120, or if the gas pressure inside the battery case 120 is below a predetermined pressure.

[0058] Furthermore, as shown in Figure 6, the exposed portion 122 can release the seal and induce gas release when gas is generated inside the battery case 120 and the internal pressure of the battery case 120 exceeds a predetermined pressure, thereby reducing the internal pressure of the battery case 120.

[0059] On the other hand, the exposed portion 122 can be positioned in various locations within the battery case 120.

[0060] However, the secondary battery 100 according to the present invention may further include electrode leads 130 that protrude from at least one end of the battery case 120, in which case it is preferable that the exposed portion 122 is formed at a position that is as far away from the electrode leads 130 as possible.

[0061] This is because the electrode lead 130 is electrically connected to the electrode assembly 110 inside the battery case 120 and to an external electrical device or secondary battery 100, and if the gas released from the exposed portion 122 is discharged to a position close to the electrode lead 130, a spark may occur, potentially leading to a rapid ignition.

[0062] As illustrated in Figures 6 and 7, when the electrode lead 130 protrudes from one edge of the battery case 120, it is preferable that the exposed portion 122 be formed on the other edge of the battery case 120. The folding portion 121 can also be formed on the other edge of the battery case 120.

[0063] More specifically, the electrode lead 130 can be located on the short side of the battery case 120, and the folding portion 121 and exposed portion 122 can be located on the long side of the battery case 120.

[0064] The exposed portion 122 can be located adjacent to the folding portion 121. Preferably, the exposed portion 122 can be located between multiple folding portions 121.

[0065] On the other hand, the exposed portions 122 described above can be provided on the battery case 120 in various numbers and positions, taking into consideration the amount of gas generated inside the battery case 120.

[0066] As an example, one exposed portion 122 may be formed and provided in the center of the edge of the battery case 120, as shown in Figure 7. As another example, multiple exposed portions 122 may be formed and provided spaced apart along the longitudinal direction (X direction in Figure 8), as shown in Figure 8. In this case, the multiple exposed portions 122 can be positioned alternately with the multiple folding portions 121.

[0067] On the other hand, the secondary battery 100 according to the present invention may further include a membrane portion 140 that is folded to enclose the end portion 122a of the exposed portion 122.

[0068] Specifically, as shown in Figures 9 to 11, the membrane portion 140 has a configuration in which both ends are connected to the exposed portion 122 and it is folded to enclose the end 122a of the exposed portion 122, and it can have various structures.

[0069] More specifically, the membrane portion 140 may have a structure that folds to enclose the end of the exposed portion 122 when the pressure inside the battery case 120 is below a predetermined pressure and the exposed portion 122 is in a sealed state, as illustrated in Figure 10.

[0070] Here, the membrane portion 140 can be provided such that, when the exposed portion 122 is sealed, the folded portion of the membrane portion 140 is separated from the end portion 122a of the exposed portion 122 by a predetermined distance, so that both ends of the membrane portion 140 remain connected to the exposed portion 122 even when the seal of the exposed portion 122 is released.

[0071] On the other hand, as illustrated in Figure 11, if the pressure inside the battery case 120 is above a predetermined pressure and the exposed portion 122 is released from its seal, the membrane portion 140 can be deployed with both ends connected to the outer surface of the exposed portion 122.

[0072] Such a membrane portion 140 can be made of a porous material. This has the effect of allowing gas inside the battery case 120 to be released to the outside when the exposed portion 122 is released from its seal, while preventing external moisture and foreign matter from penetrating into the battery case 120.

[0073] Furthermore, the membrane portion 140 can be connected to the exposed portion 122 in various ways. For example, as shown in Figures 10 to 11, the membrane portion 140 can be connected to the exposed portion 122 by interposing an adhesive substance 140a between the inner surface of the membrane portion 140 and the outer surface of the exposed portion 122. The adhesive substance 140a can be used to join the membrane portion 140 and the exposed portion 122 by heat fusion or the like.

[0074] Secondary battery module An embodiment of the present invention may include a secondary battery module comprising a plurality of secondary batteries 100 arranged in one direction, and a housing for housing the plurality of secondary batteries 100. The secondary battery 100 may include an electrode assembly 110 and a battery case 120 in which the electrode assembly 110 is housed and whose edges are sealed. The battery case 120 may include at least one folding portion 121 in which a portion of the edge of the battery case 120 is folded inward, and at least one exposed portion 122 in which the other portion of the edge of the battery case 120 is exposed outward.

[0075] The exposed portion 122 can be configured such that, when the pressure inside the battery case 120 exceeds a predetermined pressure, the seal is released and gas inside the battery case 120 is discharged.

[0076] Here, the secondary battery 100 is configured such that multiple batteries are arranged in one direction within the housing space inside the housing, and various configurations are possible.

[0077] A more detailed explanation of the folding portion 121 and the exposed portion 122 is as described above.

[0078] On the other hand, the housing is configured to accommodate multiple secondary batteries 100, and various configurations are possible.

[0079] For example, the housing can have a housing space formed inside for accommodating the secondary battery 100. The housing can also be equipped with a busbar electrically connected to the electrode leads 130 of the secondary battery 100, and a heat sink for dissipating the heat generated by the secondary battery 100.

[0080] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible by persons with ordinary skill in the art to which the present invention pertains, within the equivalent scope of the technical concept of the present invention and the claims described below. [Explanation of Symbols]

[0081] 100 Secondary battery 110 Electrode assembly 120 Battery Case 121 Folding section 121a End of folding section 122 Exposed part 122a Exposed end 130 electrode leads 140 Membrane section 140a Adhesive substance

Claims

1. Electrode assembly and The electrode assembly is housed in a battery case with a sealed edge, The aforementioned battery case is The battery case comprises at least one folding portion, the end of which is folded inward, The battery case includes at least one exposed portion where the other end of the edge of the battery case is exposed to the outside, A secondary battery in which the exposed portion is folded at least once so that the end of the edge is exposed to the outside.

2. The exposed portion is, The secondary battery according to claim 1, wherein the battery case is configured such that when the internal pressure of the battery case exceeds a predetermined pressure, the seal is released and the gas inside the battery case is discharged.

3. The secondary battery according to claim 1, wherein the folding portion is folded at least twice in one direction.

4. The secondary battery according to claim 1, wherein the exposed portion is folded in the opposite direction to the folding portion.

5. The secondary battery according to claim 1, wherein the exposed portion is folded fewer times than the folding portion.

6. The secondary battery according to claim 1, wherein the distance between opposing inner surfaces in the exposed portion is greater than the distance between opposing inner surfaces in the folding portion.

7. The battery case further includes an electrode lead that protrudes from one edge, The secondary battery according to claim 1, wherein the exposed portion is formed on another edge of the battery case.

8. The secondary battery according to claim 7, wherein the folding portion is formed on another edge of the battery case.

9. The secondary battery according to claim 1, wherein the exposed portion is located adjacent to the folding portion.

10. Multiple exposed portions are formed spaced apart along the longitudinal direction of the battery case. The secondary battery according to claim 1, wherein the exposed portion is provided between a plurality of the folding portions.

11. The secondary battery according to claim 1, further comprising a membrane portion whose both ends are connected to the exposed portion and which is folded so as to enclose the end of the exposed portion.

12. The aforementioned membrane portion is The secondary battery according to claim 11, wherein when the pressure inside the battery case increases to a predetermined pressure or higher and the exposed portion is released from its seal, it is configured to unfold with both ends connected to the outer surface of the exposed portion.

13. The secondary battery according to claim 11, wherein the membrane portion is made of a porous material.

14. A secondary battery in which multiple units are arranged in one direction, The invention includes a housing that accommodates a plurality of the aforementioned secondary batteries, The aforementioned secondary battery is Electrode assembly and The electrode assembly is housed in a battery case with a sealed edge, The aforementioned battery case is The battery case comprises at least one folding portion, the end of which is folded inward, The battery case includes at least one exposed portion where the other end of the edge of the battery case is exposed to the outside, The exposed portion is folded at least once so that the end of the edge is exposed to the outside, in a secondary battery module.

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