Battery module and manufacturing method thereof

Abstract

The battery module according to the present invention relates to a battery module having a structure in which an electrode assembly is mounted in a pouch, and in which a plurality of battery cells, each having an electrode lead extending from the electrode assembly protruding from a portion of a seal portion formed along the edge of the pouch, are bound together with their flat surfaces abutting against each other, and includes a fixing part disposed between the seal portions of adjacent battery cells and supporting the seal portion so as to maintain its original shape, the fixing part being positioned so as to be coupled to an area of ​​the seal portion of the pouch from which the electrode lead protrudes.A manufacturing method for the battery module includes a battery cell stacking step of stacking a plurality of battery cells, each having an electrode assembly mounted in a pouch, and each having an electrode lead extending from the electrode assembly protruding from a portion of a seal portion formed along the edge of the pouch, and a fixing part injection step of injecting a foam fixing part between the seal portions of adjacent battery cells, the fixing part injected between the seal portions of the battery cells solidifies to support the seal portion so as to maintain its original shape.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0069815 filed on June 8, 2022 and Korean Patent Application No. 10-2023-0060509 filed on May 10, 2023, and all contents disclosed in the documents of said Korean patent applications are incorporated by reference into this specification.

[0002] The present invention relates to a battery module formed by bundling (joining) a number of pouch-type battery cells so that their flat surfaces abut against each other, and to a manufacturing method thereof, and more particularly to a battery module that can prevent or delay tearing of the seal in the portion where the electrode lead protrudes, and to a manufacturing method thereof. [Background technology]

[0003] Demand for highly efficient secondary batteries is rapidly increasing in the fields of mobile devices and electric vehicles, etc. Among these secondary batteries, lithium secondary batteries, which have high energy density, can maintain a relatively high voltage, and have a low self-discharge rate, have been commercialized and are widely used, and research and development to improve their performance is being actively conducted.

[0004] A secondary battery has a structure in which an electrode assembly and an electrolyte are contained in a case such as a can or a pouch. Among them, the pouch-type secondary battery is equipped with a stacked electrode assembly, and the stacked electrode assembly has a structure in which a positive electrode, a separator, and a negative electrode are repeatedly stacked, and in this case, the positive electrode tabs extending from each positive electrode are joined together and connected to a positive electrode lead, and the negative electrode tabs extending from each negative electrode are joined together and connected to a negative electrode lead. The ends of the positive electrode lead and the negative electrode lead protrude from the pouch so as to be electrically connected to the outside. The positive electrode lead and the negative electrode lead may be configured to protrude from the same side of the pouch, but generally, when the positive electrode lead protrudes from one side, the negative electrode lead protrudes from the other side opposite thereto.

[0005] In order to increase output and electrical storage capacity, secondary batteries installed in vehicles, ESSs (Energy Storage Systems), etc. are combined together to form a module, and a plurality of modules are combined together to form a pack. That is, a plurality of secondary batteries (battery cells) are assembled together to be manufactured as a battery module, and a plurality of battery modules are assembled together to be manufactured as a battery pack.

[0006] On the other hand, when a pouch-type secondary battery is provided as a battery cell included in a battery module, the pouch-type secondary batteries are stacked with their flat surfaces abutting each other and bound together via a tape or cable, or by applying an adhesive to the abutting surfaces.

[0007] Referring to FIG. 1 , which shows the bus bar plates connected to the electrode leads (positive electrode lead, negative electrode lead) in a bundled battery cell and the bus bar plates separated, each battery cell 10 has a structure in which an electrode assembly is mounted in a pouch, and one of the electrode leads 12 extending from the electrode assembly (either the positive electrode lead or the negative electrode lead) protrudes from one side of the pouch, and the other (the other of the positive electrode lead or the negative electrode lead) (not shown) protrudes from the opposite side of the pouch.

[0008] The electrode lead 12 protrudes from the seal portion 11 at the edge of the pouch, and at this time, it is mounted on the pouch with insulating tape 13 attached to it to ensure electrical insulation, and the end of the insulating tape 13 protrudes from the seal portion 11 of the pouch so that a predetermined length is exposed.

[0009] Meanwhile, when the battery cell generates heat during charging and discharging (or when heat is generated for other reasons), the electrolyte contained therein vaporizes, causing the pressure inside the pouch to increase.

[0010] When the amount of vaporization increases and the pressure inside the pouch exceeds a critical point, venting occurs at the sealed portion 11 (the gas generated inside the pouch is ejected to the outside).

[0011] In particular, the portion where the electrode lead protrudes from the sealed portion 11 (the side along the edge of the pouch on which the electrode lead is located) has a relatively weaker bonding strength than other portions, making such venting more likely to occur, and there was a problem that the insulating tape 13 increases the size of the expansion from the sealed portion 11, further increasing the possibility of venting.

[0012] That is, of the sealed portion 11 of the pouch, the region 11a of the sealed portion where the electrode lead 12 is located was more likely to be vented than the region 11b of the sealed portion where the electrode lead 12 is located. Furthermore, based on the electrode lead 12, the "region (B) surrounded by the insulating tape 13 and located on the inside of the sealed portion 11a" had a lower sealing strength than the "exposed region (A)" and the "region (C) located on the inside of the sealed portion 11a." In particular, although a space (G) of a specified size is formed between each of the adjacent battery cells 10, there was a problem in that this region was not separately supported.

[0013] Furthermore, if a bend occurs toward the portion (A) from which the electrode lead 12 protrudes, the bus bar plate 30 through which electricity flows is directly affected, which may result in a short circuit at the terminal portions 31, 32 connected to the electrode lead 12. Summary of the Invention [Problem to be solved by the invention]

[0014] Therefore, the main object of the present invention is to provide a battery module and a manufacturing method thereof that can reduce the possibility of venting, and even if venting does occur, can delay the time of venting as much as possible, and can avoid the direction in which the electrode lead 12 protrudes, so as to solve the above problems. [Means for solving the problem]

[0015] In order to achieve the above object, the battery module according to the present invention is a battery module comprising a plurality of battery cells each having a structure in which an electrode assembly is mounted in a pouch, an electrode lead extending from the electrode assembly protruding from a part of a seal part formed along the edge of the pouch, and a plurality of battery cells bound to each other such that flat surfaces of the battery cells abut against each other, the battery module is characterized in that the battery module includes a fixing part disposed in a space (G) between the seal parts of adjacent battery cells and supporting the seal part so as to maintain its original shape, the fixing part being positioned so as to be coupled to a region of the seal part of the pouch from which the electrode lead protrudes. In this case, being positioned so as to be coupled to a region of the seal part of the pouch from which the electrode lead protrudes does not mean that the fixing part is positioned at the part from which the electrode lead protrudes, but means a region of the seal part that is located near the direction in which the electrode lead protrudes, i.e., the region 11a of the seal part including the side of the pouch on which the electrode lead is formed.

[0016] The fixing portion is injected in the form of a foam between the seal portions of the adjacent battery cells while the battery cells are bundled together, and then solidifies (cures). The fixing part may be made of polyurethane expanded in a foam state or may be made to contain at least a portion of the polyurethane.

[0017] The electrode lead protrudes from the seal portion while being coupled with the insulating tape, the insulating tape protrudes to a length shorter than the electrode lead, and the fixing portion is foamed so as not to cover the insulating tape. The fixing portion is manufactured to have electrical insulating properties.

[0018] Furthermore, the present invention further provides a method for manufacturing a battery module having the above-mentioned configuration. A manufacturing method provided by the present invention is a method for manufacturing a battery module, and includes a battery cell stacking step of stacking a plurality of battery cells having a structure in which an electrode assembly is mounted in a pouch, and electrode leads extending from the electrode assembly protrude from a part of a seal part formed along an edge of the pouch, and a fixing part injection step of injecting a foam fixing part between the seal parts of adjacent battery cells, and the fixing part injected between the seal parts of adjacent battery cells is solidified (cured) to support the seal part so as to maintain its original shape.

[0019] After the step of injecting the fixing portion, the method further includes a step of leaving the fixing portion for a predetermined time so that the fixing portion solidifies from a foam state to a solid state. The electrode lead protrudes from the seal portion while being coupled with the insulating tape, the insulating tape protrudes a length shorter than the electrode lead, and in the ejection step of the fixing portion, the fixing portion is ejected so as not to cover the insulating tape.

[0020] In the fixing portion injection step, the same amount of fixing portion is injected between the seal portions of adjacent battery cells. The fixing portion has electrical insulation properties after solidification. Effect of the Invention

[0021] In the present invention having the above-mentioned configuration, the fixing part injected in foam form fills the space (G) formed between the sealing parts of adjacent battery cells and hardens on the spot, thereby reducing the possibility of venting occurring even if swelling of the battery cell occurs, and even if venting does occur, the time of venting can be delayed as much as possible. Even if venting does occur, it is possible to prevent venting from occurring in the region of the seal portion from which the electrode lead protrudes.

[0022] Since the fixing portion is sprayed in a foam state, the thickness and the forming position of the fixing portion can be easily adjusted by adjusting the spray amount and the spray position. The fixing portion is manufactured to have electrical insulation properties, which can further reduce the possibility of short circuits occurring. [Brief description of the drawings]

[0023] [Figure 1] 11A and 11B are diagrams illustrating a state in which a bus bar plate is connected to an electrode lead in a state in which the battery cells are bundled together, and a state in which the bus bar plate is separated. [Diagram 2] FIG. 13 is a diagram showing a state in which, of multiple regions 11a, 11b of the seal portion, the fixing portion according to the present invention is positioned in region 11a of the seal portion from which an electrode lead protrudes. [Diagram 3] FIG. 13 is a diagram showing foam being injected between the seals of adjacent battery cells. [Figure 4] This shows the foam after injection (left side) and after it has solidified (right side). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the accompanying drawings, in order to enable those skilled in the art to easily carry out the present invention. However, the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[0025] In order to clearly describe the present invention, parts that are not relevant to the description will be omitted, and the same reference numerals will be used throughout the specification to refer to the same or similar components.

[0026] Furthermore, the terms and words used in this specification and the claims should not be interpreted in a limited manner to their ordinary or dictionary meanings, but should be interpreted in a manner that is consistent with the technical ideas of the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best describe their invention.

[0027] The present invention relates to a battery module and a manufacturing method thereof that can reduce the possibility of venting, and if venting does occur, can delay the time of venting as much as possible, and can cause venting to occur in a manner that avoids the area 11a of the seal portion 11 from which the electrode lead 12 protrudes. Hereinafter, embodiments provided by the present invention will be described in more detail with reference to the accompanying drawings.

[0028] First embodiment The present invention provides, as a first embodiment, a method for manufacturing a battery module that can reduce the likelihood of venting or delay venting.

[0029] FIG. 2 is a diagram showing how the fixing portion 20 of the present invention is positioned in region 11a of the seal portion from which the electrode lead protrudes, among the multiple regions 11a, 11b of the seal portion 11. FIG. 3 is a diagram showing how foam is injected into the space between the seal portions of adjacent battery cells. FIG. 4 is a diagram showing the foam after injection (view on the left) and in a solidified state (view on the right).

[0030] Referring to the drawings, the manufacturing method of the battery module provided in the present embodiment includes a step of stacking the battery cells and a step of injecting the fixing parts. The battery cell stacking step includes stacking a plurality of battery cells 10, and each battery cell 10 is bound to each other by tape, cable, adhesive, etc. In this embodiment, each battery cell is provided as a pouch-type secondary battery.

[0031] That is, each battery cell 10 has a structure in which an electrode assembly and an electrolyte are mounted within a pouch, and an electrode lead 12 extending from the electrode assembly protrudes from a partial area 11a of a seal portion 11 formed along the edge of the pouch.

[0032] At this time, the electrode lead 12 is placed in the pouch with the insulating tape 13 attached, and the pouch is sealed with one end of the electrode lead 12 protruding to form the sealed portion 11, but at this time, the sealing is performed so that a portion of the insulating tape 13 is exposed at the sealed portion 11.

[0033] Then, after the battery cells 10 are aligned so that the electrode leads 12 protrude uniformly, they are stacked so as to be in surface contact with each other, and are bound together so as to prevent movement. Therefore, each battery cell 10 is bound in a stacked state with flat surfaces abutting each other, and the terrace portions (the upper end portions of the sealed portions in the areas where the electrode leads protrude with reference to Figure 2) of each battery cell 10 are aligned.

[0034] Then, a fixing part injection step is performed in which foam fixing parts 20 are injected between the seal parts 11a of adjacent battery cells 10 so as not to go beyond the terrace parts (below the terrace parts with reference to FIG. 2).

[0035] At this time, even if a part of the foam that forms the fixing portion 20 on the insulating tape 13 is sprayed onto the terrace portion, the spraying is performed so that the foam that will solidify as the fixing portion 20 on the electrode lead 12 is not applied onto the insulating tape 13.

[0036] Since the foam has electrical insulation properties even when solidified, there is little or no risk of causing a short circuit. However, since the solidified fixing portion 20 on the electrode lead may reduce the flexibility of the electrode lead (when the battery pack is subjected to vibration) and may increase electrical resistance while current flows, it is preferable that the foam be sprayed while avoiding the electrode lead 12. That is, as shown in FIG. 3, the foam forming the fixing portion 20 is applied in a state where the application device 40 is inserted between the adjacent electrode leads 12 to a certain depth.

[0037] The foam, as the dictionary definition of a cellular foam, is applied in a liquid state containing gas particles surrounded by a thin film, and after some of the foam is liquefied and evaporated in the gas and liquid state as shown in Figure 4, it solidifies in a state where its volume has decreased by a specified amount, thereby fixing the space between adjacent seal portions 11a. As a result, each seal portion 11, more precisely, between the regions 11a from which the electrode leads 12 protrude, is supported so as to maintain its original shape.

[0038] This embodiment may further include a step of leaving the foam for a predetermined time after application so that the foam solidifies into a solid state to form the fixing part 20. In this case, the leaving time may be determined depending on the temperature when the foam is applied and the components and concentration of the foam.

[0039] Therefore, it is preferable that the electrode lead 12 is combined with the insulating tape 13 and protrudes from the sealing portion 11, and the insulating tape 13 protrudes a length shorter than the electrode lead 12, and when the fixing portion 20 is sprayed in foam form, it is sprayed so as not to cover the insulating tape 13.

[0040] 4, in the fixing part injection step, the same amount of fixing part 20 may be injected between the seal parts 11 of adjacent battery cells 10. However, if a specific position of the battery module needs to more strongly support a load and impact, the injection amount of fixing part 20 may be adjusted according to design. For example, a larger amount of fixing part 20 may be injected between the outermost battery cell 10 and the adjacent battery cell 10 than in other parts, so that the corresponding part has greater robustness than the other parts and can more efficiently cushion external impact.

[0041] Furthermore, the fixing portion 20 is preferably provided as polyurethane foamed in a foamed state, and has electrical insulation properties after solidification.

[0042] Second embodiment The present invention provides, as a second embodiment, a battery module that can be manufactured by the manufacturing method provided in the first embodiment.

[0043] As described above, the battery module provided by this embodiment has a structure in which an electrode assembly is mounted in a pouch, and a plurality of battery cells, each having electrode leads 12 extending from the electrode assembly and protruding from a partial region 11a of a seal portion 11 formed along the edge of the pouch, are bound together so that their flat surfaces abut against each other.

[0044] The battery cell further includes a fixing portion 20, which is disposed between the seal portions 11a of adjacent battery cells and supports the seal portions 11a so as to maintain their original shape.

[0045] The fixing part 20 is positioned so as to be coupled to the region 11a from which the electrode lead protrudes in the sealed part 11 of the pouch. In this regard, being positioned so as to be coupled to the region 11a from which the electrode lead 12 protrudes does not mean that the fixing part 20 is positioned at the portion from which the electrode lead 12 protrudes, but means the region 11a including the portion from which the electrode lead 12 protrudes, among the multiple regions 11a, 11b of the sealed part 11.

[0046] The fixing part 20 is solidified after being injected in the form of a foam between the seal parts 11 of the adjacent battery cells 10 in a state where the plurality of battery cells 10 are bundled together. The fixing part 20 may be made of polyurethane expanded into a foam state or may be made to contain the polyurethane.

[0047] Specifically, the fixing part 20 may include polyurethane and an additive added to the polyurethane. Here, the additive may be a substance that serves to further increase the hardness of the polyurethane. As such an additive, at least one of calcium carbonate and silica may be used.

[0048] The electrode lead 12 protrudes from the seal portion 11a in a state where it is connected to the insulating tape 13, the insulating tape 13 protrudes to a length shorter than the electrode lead 12, and the fixing portion 20 is foamed so as not to cover the insulating tape 13. The fixing portion 20 is manufactured to have electrical insulation properties.

[0049] In the present invention having the above-mentioned configuration, the fixing portion 20 sprayed in foam form solidifies between the seal portions 11a of adjacent battery cells 10, thereby reducing the possibility of venting occurring even if swelling of the battery cell occurs, and even if venting does occur, it is possible to delay the time of venting as much as possible. Furthermore, even if venting does occur, it is possible to prevent venting from occurring in the portion where the electrode lead 12 protrudes.

[0050] Since the fixing part 20 is sprayed in a foam state, the thickness and the forming position of the fixing part can be easily adjusted by adjusting the spray amount and the spray position. The fixing portion 20 is manufactured to have electrical insulation properties, which can further reduce the possibility of short circuit occurrence.

[0051] Although the present invention has been described above using limited embodiments and drawings, the present invention is not limited thereto, and various implementations are possible within the scope equivalent to the technical concept of the present invention and the claims described below by a person having ordinary knowledge in the technical field to which the present invention pertains. [Explanation of symbols]

[0052] 10: Battery cell 11: Seal part 11a: Region including the portion where the electrode lead protrudes from the seal portion 11b: Remaining area excluding the area including the portion where the electrode lead protrudes from the seal portion 12: Electrode lead 13: Insulating tape 20: Fixed part 30: Busbar plate 40: Coating device G: Space

Claims

1. A battery module, A battery module comprising a plurality of battery cells each having a structure in which an electrode assembly is mounted within a pouch, an electrode lead extending from the electrode assembly protruding from a part of a seal portion formed along an edge of the pouch, and the battery cells being bound to each other such that flat surfaces of the battery cells abut against each other, a fixing portion disposed between the sealing portions of adjacent battery cells and supporting the sealing portions so as to maintain their original shapes; The fixing portion is positioned to be coupled to a region of the sealed portion of the pouch from which the electrode lead protrudes.

2. The battery module of claim 1 , wherein the fixing portion is formed by being injected in a foam state between the seal portions of the adjacent battery cells while the plurality of battery cells are bound together, and then being solidified.

3. The battery module of claim 1 , wherein the fixing portion comprises polyurethane expanded into a foam state.

4. The battery module according to claim 3 , wherein the fixing portion contains at least one of calcium carbonate and silica as an additive for increasing hardness of the polyurethane.

5. 3. The battery module according to claim 2, wherein the electrode lead protrudes from the seal portion while being coupled with an insulating tape, the insulating tape protrudes by a length shorter than that of the electrode lead, and the fixing portion is positioned so as not to cover the insulating tape.

6. The battery module according to any one of claims 1 to 4, wherein the fixing portion has electrical insulation properties.

7. A method for manufacturing a battery module, comprising: a battery cell stacking step of stacking a plurality of battery cells, each of the plurality of battery cells having a structure in which an electrode assembly is mounted in a pouch, and an electrode lead extending from the electrode assembly protrudes from a part of a seal portion formed along an edge of the pouch; A fixing part injection step of injecting a foam fixing part between the seal parts of adjacent battery cells; Including, A method for manufacturing a battery module, wherein a fixing portion injected between the seal portions of adjacent battery cells solidifies and supports the seal portions so that the seal portions maintain their original shape.

8. The method for manufacturing a battery module according to claim 7 , further comprising, after the step of injecting the fixing portion, a step of leaving the fixing portion for a predetermined time so that the fixing portion solidifies from a foam state to a solid state.

9. the electrode lead protrudes from the seal portion while being coupled with the insulating tape, the insulating tape protruding by a length shorter than that of the electrode lead, The method for manufacturing a battery module according to claim 7 , wherein in the fixing portion ejecting step, the fixing portion is ejected so as not to cover the insulating tape.

10. The method for manufacturing a battery module according to any one of claims 7 to 9, wherein in the fixing portion injection step, the same amount of fixing portion is injected between each of the seal portions of adjacent battery cells.

11. The method for manufacturing a battery module according to any one of claims 7 to 9, wherein the fixing portion has electrical insulation properties after solidification.

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