Battery module and manufacturing method thereof

Abstract

The battery module according to the present invention has a plurality of battery cells fastened to each other such that flat surfaces of adjacent battery cells are in contact with each other, each battery cell having a structure in which an electrode assembly is mounted in a pouch, and having an electrode lead extending from the electrode assembly, the electrode lead protrudes from a portion of a sealing portion formed along a periphery of the pouch. The present invention includes a fixing portion disposed between sealing portions of adjacent battery cells to support the sealing portions so as to maintain an original shape, in which the fixing portion is positioned as a region from which an electrode lead coupled to a pouch sealing portion protrudes. A method for manufacturing a battery module according to the present invention comprises: a battery cell stacking step of stacking a plurality of battery cells each having a structure in which an electrode assembly is mounted in a pouch and having an electrode lead extending from the electrode assembly, the electrode lead protruding from a part of a sealing part formed along a periphery of the pouch; and a fixing part spraying step of spraying a foamed fixing part between the sealing parts of the adjacent battery cells, in which the fixing part sprayed between the sealing parts of the adjacent battery cells is cured to support the sealing parts so as to maintain the original shape.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to 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, which are hereby incorporated by reference in their entirety. Technical Field

[0004] The present invention relates to a battery module and a method for manufacturing the same, which are formed by combining (connecting) flat surfaces of a plurality of pouch-type battery cells in a contact configuration with each other, and more particularly, to a battery module and a method for manufacturing the same, which prevent or delay rupture of a seal at a portion from which an electrode lead protrudes. Background Art

[0005] The demand for high-efficiency secondary batteries is rapidly increasing in the field of mobile devices and electric vehicles. Among such secondary batteries, lithium secondary batteries with high energy density, relatively high voltage, and low self-discharge rate are widely used commercially, and research and development for improving characteristics are being actively carried out.

[0006] The secondary battery has a structure in which an electrode assembly and an electrolyte are embedded in a case such as a can or a pouch.

[0007] Among them, the pouch-type secondary battery is equipped with a stacked electrode assembly, and the stacked electrode assembly has a structure in which the positive electrode, the separator and the negative electrode are repeatedly stacked. Here, the positive electrode connector extending from the positive electrode is gathered into one and joined to the positive electrode lead, and the negative electrode connector extending from the negative electrode is gathered into one and joined to the negative electrode lead. In addition, the ends of the positive electrode lead and the negative electrode lead protrude from the bag to be electrically connected to the outside. The positive electrode lead and the negative electrode lead can be configured to protrude from the same side of the bag, but generally, when the positive electrode lead protrudes from one side, the negative electrode lead protrudes from the other side of the bag.

[0008] In addition, secondary batteries installed in vehicles, energy storage systems (ESS), etc. are connected to increase output and power storage to form a module, and then a plurality of modules are connected to form a battery pack. That is, a plurality of secondary batteries (battery cells) are gathered to make a battery module, and a plurality of battery modules are gathered to make a battery pack.

[0009] When the pouch type secondary batteries are provided as battery cells included in a battery module, the pouch type secondary batteries are stacked so that flat surfaces contact each other and are provided in a state where an adhesive is applied to the contact surfaces through a tape or a wire so as to be bonded to each other.

[0010] Reference Figure 1 , which shows a configuration in which a busbar and electrode leads (positive lead and negative lead) are connected to each other, and a configuration in which the busbar is separated, each of the battery cells 10 has a structure in which an electrode assembly is installed in a bag, one of the electrode leads 12 extending from the electrode assembly (one of the positive lead and the negative lead) protrudes from one side of the bag, and the other (the other of the positive lead and the negative lead) protrudes from the opposite side of the bag.

[0011] The electrode lead 12 protrudes from the sealing portion 11 at the edge of the bag and is installed in the bag in a state where an insulating tape 13 is attached to ensure electrical insulation, and an end of the insulating tape 13 protrudes from the sealing portion 11 of the bag to be exposed by a predetermined length.

[0012] When heat is generated during charging and discharging of the battery cell (or when heat is generated for other reasons), the built-in electrolyte evaporates, and thus the pressure inside the pouch increases.

[0013] Furthermore, when the amount of evaporation increases and the pressure inside the bag exceeds a critical point, degassing occurs in the sealing portion 11 (gas generated inside the bag is ejected to the outside).

[0014] Specifically, the portion of the sealing portion 11 from which the electrode lead protrudes (the side formed along the edge of the bag where the electrode lead is provided) has a relatively weak connecting force compared to other positions, and therefore, there is a high possibility of degassing, and the size of the expanded sealing portion 11 is increased to further increase the possibility of degassing.

[0015] That is, in the sealing portion 11 of the bag, the region 11a of the sealing portion on which the electrode lead 12 is disposed has a higher possibility of degassing than the region 11b of the sealing portion on which the electrode lead 12 is disposed. In addition, based on the electrode lead 12, the "portion B disposed inside the sealing portion 11a by being surrounded by the insulating tape 13" may be a portion where the sealing force is reduced compared to the "exposed portion A" and the "portion C disposed inside the sealing portion 11a". Specifically, a space (G) having a predetermined size is formed between adjacent battery cells 10, but there is a problem that the portion is not supported separately.

[0016] Furthermore, when degassing occurs toward the protruding portion A of the electrode lead 12 , since the busbar 30 through which electricity flows is directly affected, there is a possibility that a short circuit occurs between the terminal portions 31 and 32 connected to the electrode lead 12 . Summary of the invention

[0017] Technical issues

[0018] Therefore, in order to solve the above problems, an object of the present invention is to provide a battery module and a method for manufacturing the same, in which, even if degassing occurs, the time when degassing occurs is delayed as much as possible to avoid the direction in which the electrode lead 12 protrudes.

[0019] Technical Solution

[0020] According to a battery module for achieving the above-mentioned purpose according to the present invention, in which a plurality of battery cells are connected to each other so that the flat surfaces of the battery cells contact each other, each of the plurality of battery cells has a structure in which an electrode assembly is installed in a bag and an electrode lead extending from the electrode assembly protrudes from a portion of a sealing portion provided along an edge of the bag, the battery module comprises: a fixing portion, the fixing portion being provided in a space G between the sealing portions of adjacent battery cells to support the sealing portion so that the sealing portion maintains its original shape, wherein the fixing portion is provided to be coupled to an area of ​​the sealing portion of the bag from which the electrode lead protrudes. Here, the meaning that the electrode lead is provided to be coupled to the protruding area does not mean that the fixing portion is provided at a portion where the electrode lead 12 protrudes, but refers to an area near the electrode lead being provided on each area 11a and 11b of the sealing portion in a protruding direction, that is, provided on an area 11a of the sealing portion including a side of the bag on which the electrode lead is provided.

[0021] In a state where a plurality of battery cells are connected to each other, the fixing portion may be solidified (cured) after being sprayed in the form of foam between the sealing portions of adjacent battery cells.

[0022] The fixing part may be made of polyurethane foamed in a foamed form, or may be made to include a portion of polyurethane.

[0023] The electrode lead may protrude from the sealing portion in a state of being coupled to the insulating tape, wherein the insulating tape may protrude with a shorter length than the electrode lead, and the fixing portion may be arranged not to cover the insulating tape.

[0024] The fixing portion may have electrical insulating properties.

[0025] In addition, the present invention also provides a method for manufacturing a battery module to manufacture the battery module having the above configuration.

[0026] The method for manufacturing a battery module provided by the present invention includes: a battery cell stacking process of stacking a plurality of battery cells, each of the plurality of battery cells having a structure in which an electrode assembly is installed in a bag and an electrode lead extending from the electrode assembly protrudes from a portion of a sealing portion provided along an edge of the bag; and a fixing portion spraying process of spraying a fixing portion between the sealing portions of adjacent battery cells in the form of foam, wherein the fixing portion sprayed between the sealing portions of adjacent battery cells is cured to support the sealing portion so that the sealing portion maintains its original shape. In addition, the fixing portion sprayed between the sealing portions of adjacent battery cells can be cured (solidified) to support the sealing portion so that the sealing portion maintains its original shape.

[0027] After the fixing part spraying process, the method may further include a holding process of holding the fixing part for a predetermined time to cure the fixing part from a foam form to a solid state.

[0028] The electrode lead may protrude from the sealing part in a state of being coupled to the insulating tape, wherein the insulating tape may protrude with a shorter length than the electrode lead, and in the fixing part spraying process, the fixing part may be disposed not to cover the insulating tape.

[0029] In the fixing portion spraying process, the same amount of the fixing portion may be sprayed between the sealing portions of adjacent battery cells.

[0030] The fixing portion may have electrical insulating properties after curing.

[0031] Beneficial effects

[0032] In the present invention having the above-mentioned configuration, the fixing portion sprayed in the form of foam is filled into the space G formed between the sealing portions of adjacent battery cells and solidified at that position, and even if expansion of the battery cell occurs, the possibility of exhaust can be reduced, and even if exhaust occurs, the time point of exhaust occurrence can be delayed as much as possible.

[0033] Furthermore, even if outgassing occurs, it is possible to avoid outgassing occurring in a region of the sealing portion from which the electrode lead protrudes.

[0034] Since the fixing portion is sprayed in the form of foam, the thickness and the formation position of the fixing portion can be easily adjusted by adjusting the spraying amount and the spraying position.

[0035] Since the fixing portion is manufactured to have electrical insulation, the possibility of short circuit can be further reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 1 and 2 are diagrams showing a configuration in which a busbar plate is connected to an electrode lead in a state in which battery cells are joined to each other and a configuration in which the busbar plate is separated.

[0037] Figure 2 1 is a diagram showing a configuration in which a fixing portion according to the present invention is provided on the region 11 a of the sealing portion from which the electrode lead protrudes, on each of the regions 11 a and 11 b of the sealing portion.

[0038] Figure 3 is a diagram showing a configuration in which foam is sprayed between seal portions of battery cells adjacent to each other.

[0039] Figure 4 It is a figure which shows the state after spraying foam (left view) and solidifying foam (right view). DETAILED DESCRIPTION

[0040] Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings in a manner that a person skilled in the art can easily perform the technical concept of the present invention. However, the present invention can be embodied in different forms and should not be construed as being limited to the embodiments set forth herein.

[0041] In order to clearly describe the present invention, parts irrelevant to the description are omitted, and the same reference numerals are assigned to the same or similar components throughout the specification.

[0042] Furthermore, the terms or words used in the specification and claims should not be restrictively interpreted as ordinary meanings or dictionary-based meanings, but should be interpreted as meanings and concepts consistent with the scope of the present invention on the basis that the inventor can appropriately define the concepts of the terms in order to best describe and interpret his or her invention.

[0043] The present invention relates to a battery module and a method for manufacturing the same, which can reduce the possibility of gas exhaust, delay the time point of gas exhaust as much as possible even if gas exhaust occurs, and avoid the region 11a from which the electrode lead 12 of the sealing part 11 protrudes. Hereinafter, embodiments provided by the present invention will be described in more detail with reference to the accompanying drawings.

[0044] First embodiment

[0045] The present invention provides, as a first embodiment, a method for manufacturing a battery module capable of reducing the possibility of outgassing or delaying outgassing.

[0046] Figure 2 is a diagram showing a configuration in which a fixing portion according to the present invention is provided on each of regions 11a and 11b of a sealing portion on a region 11a of the sealing portion from which an electrode lead protrudes, Figure 3 is a diagram showing a configuration in which foam is sprayed between sealing portions of battery cells adjacent to each other, and Figure 4 It is a figure which shows the state after spraying foam (left view) and solidifying foam (right view).

[0047] Referring to the accompanying drawings, the manufacturing method of the battery module provided in this embodiment includes a battery cell stacking process and a fixing part spraying process.

[0048] The battery cell stacking process is performed by stacking a plurality of battery cells 10 , and each of the battery cells 10 is connected to each other by a tape, a cable, an adhesive, etc. In this embodiment, each battery cell is provided as a pouch-type secondary battery.

[0049] That is, each of the battery cells 10 has a structure in which an electrode assembly and an electrolyte are installed in a pouch, and an electrode lead 12 extending from the electrode assembly protrudes from a portion of a region 11 a of a sealing portion 11 along an edge of the pouch.

[0050] Here, the electrode lead 12 is installed in the bag in a state where the insulating tape 13 is attached to the electrode lead 12, and the sealing of the bag is performed in a state where an end portion of one side of the electrode lead 12 protrudes to form the sealing portion 11. Here, the sealing is performed so that a portion of the insulating tape 13 is exposed in the sealing portion 11.

[0051] In addition, the battery cells 10 are aligned so that the electrode leads 12 constantly protrude and are then stacked to be in surface contact with each other and connected to prevent movement.

[0052] Therefore, each of the battery cells 10 is connected in a state where a plurality of flat surfaces are stacked in contact with each other, and the step portions (see Figure 2 , the upper ends of the corresponding sealing portions on the sealing portions on the areas from which the electrode leads protrude) are aligned.

[0053] Then, between the sealing portions 11a of the adjacent battery cells 10 (based on Figure 2 The foam-like fixing portion 20 is sprayed under the step portion so as not to cross the fixing portion spraying process of the step portion.

[0054] Here, even if a portion of the foam forming the fixing portion 20 is sprayed onto the insulating tape 13 on the step portion, the foam solidified into the fixing portion 20 is not sprayed onto the electrode lead 12 so as not to be applied to the electrode lead 12 on the insulating tape 13 .

[0055] Even if the foam is cured, there is little or no risk of causing a short circuit because the foam has electrical insulation properties. However, since there is a possibility of deteriorating the flexibility of the electrode lead and increasing the resistance when current flows through the fixing portion 20 cured on the electrode lead (when vibration is applied to the battery pack), it is preferable to avoid spraying the foam onto the electrode lead 12.

[0056] That is to say, Figure 3As shown, the foam forming the fixing portion 20 is applied in a state where the coating device 40 enters between the adjacent electrode leads 12 at a predetermined depth.

[0057] As in the dictionary meaning of foam with bubbles, the foam is applied as a liquid in a state of containing gas particles surrounded by a thin film, and as Figure 4 As shown, after a part of the foam is liquefied and evaporated in a gaseous state and a liquid state, the foam is solidified in a state where the volume of the foam is reduced by a predetermined volume to fix the adjacent sealing portions 11 a to each other.

[0058] Therefore, each of the sealing portions 11 , more specifically, the region 11 a of the sealing portion from which the electrode lead 12 protrudes, is supported to be maintained in its original shape.

[0059] In the present embodiment, after applying the foam, a process of maintaining the foam for a predetermined time to solidify and thereby form the fixing portion 20 may be further performed. Here, the maintaining time may be determined according to the temperature, composition, and concentration of the foam when applying the foam.

[0060] Therefore, electrode lead 12 is coupled to insulating tape 13 to protrude from sealing portion 11. Here, in a state where insulating tape 13 protrudes with a shorter length than electrode lead 12, when top 20 is sprayed in the form of foam, it is preferred that the spray does not cover insulating tape 13.

[0061] like Figure 4 As shown, the same amount of the fixing portion 20 can be sprayed between the sealing portions 11 of the adjacent battery cells 10 during the fixing portion spraying process. However, if it is necessary to more firmly support the load and impact at a specific position in the battery module, the spraying amount of the fixing portion 20 can be adjusted according to the design. For example, a larger amount of the fixing portion 20 can be sprayed between the outermost battery cell 10 and the adjacent battery cell 10 compared to other places, and therefore, the corresponding portion can have greater firmness than other positions to more effectively buffer external impacts.

[0062] Furthermore, the fixing portion 20 is preferably provided as polyurethane which is foamed in a foam form and has electrical insulation after being cured.

[0063] Second embodiment

[0064] In the present invention, a battery module that can be manufactured by the manufacturing method provided in the first embodiment is provided as a second embodiment.

[0065] As described above, in the battery module provided in the present embodiment, a plurality of battery cells are connected to each other so that flat surfaces of the battery cells are in contact with each other, and each of the battery cells has a structure in which an electrode assembly is mounted in a bag and an electrode lead 12 extending from the electrode assembly protrudes from a sealing portion 11 (a partial area 11a of the sealing portion 11) provided along an edge of the bag.

[0066] In addition, the fixing portion 20 is provided and disposed between the sealing portions 11 a of the adjacent battery cells to support the sealing portions 11 a so that the sealing portions 11 a maintain their original shape.

[0067] The fixing part 20 is arranged to be connected to the region 11a of the sealing part 11 of the bag from which the electrode lead protrudes. Here, the meaning that the electrode lead 12 is arranged to be connected to the protruding region 11a does not mean that the fixing part 20 is arranged at the point where the electrode lead 12 protrudes, but means that it is arranged on the region 11a from which the electrode lead 12 protrudes, which includes a part of each region 11a and 11b of the sealing part 11.

[0068] In a state where a plurality of battery cells 10 are connected to each other, the fixing part 20 is sprayed in a foamed form between the sealing parts 11 of adjacent battery cells 10 and then cured. The fixing part 20 may be made of polyurethane foamed in a foamed state or may be made to include polyurethane.

[0069] Specifically, the fixing part 20 may include polyurethane and an additive added to the polyurethane. Here, the additive may be a material for further increasing the hardness of the polyurethane. At least one or more of calcium carbonate or silicon dioxide may be used as the additive.

[0070] The electrode lead 12 protrudes from the sealing portion 11a in a state of being coupled to the insulating tape 13. Here, the insulating tape 13 protrudes with a shorter length than the electrode lead 12, and the fixing portion 20 is foamed not to cover the insulating tape 13. The fixing portion 20 is manufactured to have electrical insulating properties.

[0071] In the present invention having the above configuration, the fixing portion 20 sprayed in the form of foam can be cured between the sealing portions 11a of the adjacent battery cells 10, so that even if the battery cells expand, the possibility of gas discharge is reduced, and even if gas discharge occurs, the time point of gas discharge occurrence can be delayed as much as possible. In addition, even if gas discharge occurs, gas discharge can be avoided at the protruding portion of the electrode lead 12.

[0072] Since the fixing portion 20 is sprayed in the form of foam, the thickness and the formation position of the fixing portion can be easily adjusted by adjusting the spraying amount and the spraying position.

[0073] Since the fixing portion 20 is manufactured to have electrical insulation, the possibility of a short circuit occurring can be further reduced.

[0074] While embodiments of the present invention have been described with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

[0075] [Description of symbol]

[0076] 10: Battery Cell

[0077] 11: Sealing part

[0078] 11a: Region including the portion of the sealing portion from which the electrode lead protrudes

[0079] 11b: Remaining area except for the area including the portion of the sealing portion from which the electrode lead protrudes

[0080] 12: Electrode lead

[0081] 13: Insulation tape

[0082] 20: Fixed part

[0083] 30: Manifold

[0084] 40: Coating device

[0085] G: Space

Claims

1. A battery module in which a plurality of battery cells are connected to each other so that flat surfaces of the battery cells contact each other, each of the plurality of battery cells having a structure in which an electrode assembly is installed in a pouch and an electrode lead extending from the electrode assembly protrudes from a portion of a sealing portion provided along an edge of the pouch, the battery module comprising: a fixing portion disposed between the sealing portions of adjacent battery cells to support the sealing portions so that the sealing portions maintain their original shape, The fixing portion is configured to be coupled to a region of the sealing portion of the bag from which the electrode lead protrudes.

2. The battery module according to claim 1, wherein: In a state where the plurality of battery cells are connected to each other, the fixing portion is cured after being sprayed between the sealing portions of the adjacent battery cells in a foam form.

3. The battery module according to claim 1, wherein: The fixing part includes polyurethane foamed in a foamed state.

4. The battery module according to claim 3, wherein: The fixing part includes at least one or more of calcium carbonate and silicon dioxide as an additive for increasing the hardness of the polyurethane.

5. The battery module according to claim 2, wherein: The electrode lead protrudes from the sealing portion in a state of being coupled to the insulating tape, The insulating tape protrudes with a shorter length than the electrode lead, and the fixing portion is arranged 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, the method comprising: a battery cell lamination process of laminating 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 portion of a sealing portion provided along an edge of the pouch; as well as A fixing part spraying process in which a fixing part is sprayed between the sealing parts of adjacent battery cells in the form of foam, The fixing portion sprayed between the sealing portions of adjacent battery cells is cured to support the sealing portion, so that the sealing portion maintains its original shape. 8 . The method according to claim 7 , further comprising, after the fixing part spraying process, a holding process of holding the fixing part for a predetermined time to cure the fixing part from the foam form to a solid state.

9. The method according to claim 7, wherein: The electrode lead protrudes from the sealing portion in a state of being coupled to the insulating tape, wherein the insulating tape protrudes with a shorter length than the electrode lead, and In the fixing portion spraying process, the fixing portion is arranged not to cover the insulating tape.

10. The method according to any one of claims 7 to 9, wherein: In the fixing portion spraying process, the same amount of the fixing portion is sprayed between the sealing portions of adjacent battery cells.

11. The method according to any one of claims 7 to 9, wherein: The fixing portion has electrical insulation properties after being cured.

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