Battery module and method for manufacturing the same

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 the contents disclosed in the documents of the Korean patent applications are incorporated herein by reference in their entirety.

[0002] The present invention relates to a battery module configured by binding (coupling) a plurality of pouch-type battery cells such that flat surfaces thereof abut against each other, and a method of manufacturing the same. More specifically, the present invention relates to a battery module and a method of manufacturing the same that can prevent or delay breakage of a seal portion at a portion where an electrode lead protrudes.

Background Art

[0003] The demand for high-efficiency secondary batteries has been rapidly increasing in fields such as portable devices and electric vehicles. Among such secondary batteries, lithium secondary batteries having a high energy density, capable of maintaining a relatively high voltage, and having a low self-discharge rate have been commercialized and widely used, and research and development for performance improvement have been actively conducted.

[0004] A secondary battery has a structure in which an electrode assembly and an electrolyte are built in a case such as a can or a pouch. Among them, a pouch-type secondary battery is equipped with a laminated electrode assembly, and the laminated electrode assembly has a structure in which a positive electrode, a separator, and a negative electrode are repeatedly laminated. At this time, positive electrode tabs extending from each positive electrode are gathered together and joined to a positive electrode lead, and negative electrode tabs extending from each negative electrode are gathered together and joined to a negative electrode lead. Then, 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 is configured to protrude from the other side opposite thereto.

[0005] Furthermore, secondary batteries installed in vehicles, ESS (Energy Storage Systems), etc., are combined into modules to increase output and electrical storage capacity, and multiple modules are combined to form a pack. In other words, multiple secondary batteries (battery cells) are assembled to manufacture a battery module, and multiple battery modules are assembled to manufacture a battery pack.

[0006] On the other hand, when pouch-type secondary batteries are provided as battery cells included in a battery module, the pouch-type secondary batteries are provided stacked so that their flat surfaces are in contact with each other, and are bundled together via tape or cables or by applying adhesive to the contact surfaces.

[0007] Referring to Figure 1, which shows the battery cells bundled together with the busbar plate connected to the electrode leads (positive lead, negative lead) and the busbar plate separated, each battery cell 10 has a structure in which an electrode assembly is mounted inside a pouch, and one of the electrode leads 12 extending from the electrode assembly (either the positive lead or the negative lead) protrudes from one side of the pouch, while the other (the other of the positive lead or the negative 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. In order to ensure electrical insulation, the electrode lead 12 is mounted on the pouch with an insulating tape 13 attached, and protrudes from the seal portion 11 of the pouch such that the end of the insulating tape 13 is exposed for a predetermined length.

[0009] On the other hand, when heat is generated in the battery cell during charging and discharging (or when heat is generated for other reasons), the built-in electrolyte vaporizes, which increases the pressure inside the pouch.

[0010] Then, when the amount of vaporization increases and the pressure inside the pouch exceeds a critical point, venting occurs at the seal section 11 (where the gas generated inside the pouch is ejected to the outside).

[0011] In particular, the portion where the electrode lead protrudes from the seal portion 11 (the edge along the edge of the pouch where the electrode lead is located) has a relatively weaker bonding force compared to other parts, making it more likely for such venting to occur. Furthermore, the insulating tape 13 increases the size of the venting that spreads from the seal portion 11, further increasing the possibility of venting.

[0012] In other words, within the sealing portion 11 of the pouch, the region 11a where the electrode lead 12 is located was more likely to vent than the region 11b where the electrode lead 12 is located. Furthermore, with respect to the electrode lead 12, the sealing force was reduced in the "part (B) located inside the sealing portion 11a, surrounded by the insulating tape 13" compared to the "exposed portion (A)" and the "part (C) located inside the sealing portion 11a". In particular, although a space (G) of a predetermined size is formed between adjacent battery cells 10, there was a problem in that this part was not supported separately.

[0013] Furthermore, if venting occurs towards the protruding portion (A) of the electrode lead 12, the busbar plate 30 through which electricity flows is directly affected, which could potentially cause a short circuit at the terminal portions 31 and 32 connected to the electrode lead 12. [Overview of the project] [Problems that the invention aims to solve]

[0014] Therefore, the main objective of the present invention is to provide a battery module and a method for manufacturing the same that can solve the above-mentioned problems by reducing the likelihood of venting, delaying the timing of venting as much as possible even if it does occur, and avoiding a direction in which the electrode lead 12 protrudes. [Means for solving the problem]

[0015] The battery module according to the present invention for achieving the above objective is a plurality of battery cells, each having a structure in which an electrode assembly is mounted inside a pouch, wherein electrode leads extending from the electrode assembly protrude from a part of a seal portion formed along the edge of the pouch, and the plurality of battery cells are bound together such that the flat surfaces of the battery cells abut each other, and the battery module includes a fixing portion that is disposed in the space (G) between the seal portions of adjacent battery cells and supports the seal portion so as to maintain its original shape, wherein the fixing portion is positioned to be coupled to the region of the seal portion of the pouch in which the electrode leads protrude. In this case, "positioned to be coupled to the region of the seal portion in which the electrode leads protrude" does not mean that the fixing portion is located on the part in which the electrode leads protrude, but rather means the region of the seal portion 11a that is located near the direction in which the electrode leads protrude from among the plurality of regions 11a, 11b of the seal portion, i.e., the region of the seal portion 11a that includes the edge in the pouch in which the electrode leads are formed.

[0016] The aforementioned fixing part is sprayed in a foam-like form between the sealing portions of adjacent battery cells while multiple battery cells are bundled together, and then solidifies (hardens). The fixing portion may be manufactured from foamed polyurethane, or may be manufactured to contain at least some of the polyurethane.

[0017] The electrode lead protrudes from the sealing portion while connected to 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 aforementioned fixing part is manufactured to have electrical insulating properties.

[0018] Furthermore, the present invention further provides a method for manufacturing a battery module having the above-described configuration. The manufacturing method provided by the present invention is a method for manufacturing a battery module, comprising: 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 protruding from a portion of a seal formed along the edge of the pouch; and a fixing part spraying step of spraying a foam-like fixing part between the seal portions of adjacent battery cells. The fixing part sprayed between the seal portions of adjacent battery cells solidifies (hardens) to support the seal portions so that they maintain their original shape.

[0019] The process further includes a setting step in which the fixing part is left for a predetermined time after the spraying step, allowing the fixing part to solidify from a foamy state to a solid state. The electrode leads protrude from the sealing portion while connected to the insulating tape, the insulating tape protrudes to a length shorter than the electrode leads, and during the spraying step of the fixing portion, the fixing portion is sprayed in such a way that it does not cover the insulating tape.

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

[0021] The present invention, having the above configuration, has a foam-like fixed portion that fills the space (G) formed between the seal portions of adjacent battery cells and solidifies in place, thereby reducing the likelihood of venting even if swelllin occurs in the battery cells, and delaying the timing of venting as much as possible if it does occur. Furthermore, even if venting occurs, it is possible to avoid venting in the area of ​​the seal where the electrode lead protrudes.

[0022] Since the fixing part is sprayed in a foam form, the thickness and position of the fixing part can be easily adjusted by adjusting the spray volume and spray position. The fixing part is manufactured to have electrical insulation, and the possibility of short - circuit occurrence can be further reduced.

Brief Description of the Drawings

[0023] [Figure 1] It is a figure showing a state where a bus bar plate is connected to an electrode lead and a state where the bus bar plate is separated in a state where battery cells are bundled. [Figure 2] It is a figure showing a state where the fixing part according to the present invention is located in the region 11a of the seal part where the electrode lead protrudes among the plurality of regions 11a, 11b of the seal part. [Figure 3] It is a figure showing a state where foam is injected between seal parts of adjacent battery cells. [Figure 4] It is a figure showing a state after injection of foam (left side state) and a solidified state (right side state).

Embodiments for Carrying out the Invention

[0024] Hereinafter, based on the accompanying drawings, the present invention will be described in detail so that a person having ordinary knowledge in the technical field to which the present invention belongs can easily implement it. However, the present invention may be realized in various different forms and is not limited to the embodiments described here.

[0025] In order to clearly explain the present invention, parts not related to the explanation are omitted, and throughout the specification, the same reference numerals are given to the same or similar components.

[0026] Also, terms and words used in this specification and the claims should not be construed as being limited to their ordinary or dictionary meanings. The inventors should interpret them in accordance with the meaning and concept that conform to the technical idea of the present invention, in accordance with the principle that they can appropriately define the concept of the terms in order to explain their invention in the best way.

[0027] The present invention relates to a battery module and a method for manufacturing the same that can reduce the likelihood of venting, delay the timing of venting as much as possible even if it does occur, and avoid venting in the area 11a of the seal portion 11 in which the electrode lead 12 protrudes. Embodiments provided by the present invention will be described in more detail below with reference to the accompanying drawings.

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

[0029] Figure 2 shows how the fixing part 20 according to the present invention is located in the region 11a of the seal portion 11 where the electrode lead protrudes, among the multiple regions 11a and 11b of the seal portion 11. Figure 3 shows how foam is injected into the space between the seal portions of adjacent battery cells. Figure 4 shows the foam after injection (left side) and in its solidified state (right side).

[0030] Referring to the drawings, the method for manufacturing a battery module provided by this embodiment comprises a battery cell stacking step and a fixing portion injection step. The aforementioned battery cell stacking step involves stacking multiple battery cells 10, with each battery cell 10 being bound together by tape, cables, adhesive, etc. In this embodiment, each battery cell is provided as a pouch-type rechargeable battery.

[0031] In other words, each battery cell 10 has a structure in which an electrode assembly and electrolyte are mounted inside a pouch, and the electrode leads 12 extending from the electrode assembly protrude from a portion 11a of the seal portion 11 formed along the edge of the pouch.

[0032] In this case, the electrode lead 12 is mounted 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 a sealed portion 11. However, the sealing is performed such that a portion of the insulating tape 13 is exposed in the sealed portion 11.

[0033] Then, each battery cell 10 is aligned so that the electrode leads 12 protrude at a constant rate, stacked so that they make surface contact, and then bound together so that movement is blocked. Therefore, each battery cell 10 is bundled together in a stacked state with its flat surfaces in contact with each other, and in each battery cell 10, the terrace portion (the upper end of the sealing portion in the area where the electrode leads protrude, based on Figure 2) is aligned.

[0034] Then, a fixing part injection step is performed in which a foam-like fixing part 20 is injected between the sealing parts 11a of adjacent battery cells 10, so as not to exceed the terrace part (below the terrace part with reference to Figure 2).

[0035] In this process, even if a portion of the foam that forms the fixing portion 20 on the insulating tape 13 is sprayed onto the terrace portion, the spraying is performed in such a way that the foam that solidifies as the fixing portion 20 on the electrode lead 12 is not applied to the insulating tape 13.

[0036] Although the foam retains electrical insulating properties even after solidification, thus posing little to no risk of short circuits, (when vibration is applied to the battery pack) the solidified fixing portion 20 on the electrode leads may reduce the flexibility of the electrode leads and potentially increase electrical resistance while current flows. Therefore, it is preferable that the foam be sprayed while avoiding the electrode leads 12. In other words, as shown in Figure 3, the foam forming the fixed portion 20 is applied with the coating device 40 inserted to a certain depth between adjacent electrode leads 12.

[0037] The foam, as in the dictionary definition of a foam containing air bubbles, is applied in a state in which gas particles surrounded by a thin film are contained within a liquid. As shown in Figure 4, after some of it liquefies and evaporates in both the gaseous and liquid states, it solidifies with a predetermined volume reduction, fixing the space between adjacent seal portions 11a. As a result, the area between each seal portion 11, or more precisely, the region 11a where the electrode lead 12 protrudes, is supported in a way that maintains its original shape.

[0038] This embodiment may further include a settling step in which the foam is left for a predetermined time after application to solidify into a solid state and form a fixed portion 20. In this case, the settling time can be determined according to the temperature at the time of application of the foam, the components and concentration of the foam, etc.

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

[0040] As shown in Figure 4, in the injection step of the fixing part, the same amount of fixing part 20 can be injected between each of the seal portions 11 of adjacent battery cells 10. However, if it is necessary to support loads and impacts more strongly at a particular location in the battery module, the amount of fixing part 20 injected can be adjusted according to the design. For example, a larger amount of fixing part 20 can be injected between the outermost battery cell 10 and the adjacent battery cell 10 than in other parts, so that part has greater robustness than other parts and can more efficiently absorb external impacts.

[0041] Furthermore, the fixing portion 20 is preferably provided as foamed polyurethane, and has electrical insulating 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 inside a pouch, and a plurality of battery cells are bundled together such that their flat surfaces come into contact with each other, with electrode leads 12 extending from the electrode assembly protruding from a portion 11a of a seal portion 11 formed along the edge of the pouch.

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

[0045] The fixing portion 20 is positioned to connect to the region 11a in the seal portion 11 of the pouch where the electrode lead protrudes. In this case, "positioned to connect to the region 11a where the electrode lead 12 protrudes" does not mean that the fixing portion 20 is located on the portion where the electrode lead 12 protrudes, but rather that it refers to the region 11a of the multiple regions 11a, 11b of the seal portion 11 that includes the portion where the electrode lead 12 protrudes.

[0046] The fixing portion 20 is sprayed in a foam-like form between the sealing portions 11 of adjacent battery cells 10 while the multiple battery cells 10 are bundled together, and then solidifies. The fixing portion 20 can be manufactured from foamed polyurethane, or can be manufactured to contain the polyurethane.

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

[0048] The electrode lead 12 protrudes from the sealing portion 11a while 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 insulating properties.

[0049] The present invention, having the above configuration, reduces the likelihood of venting even if swelllin occurs in the battery cells, and delays the timing of venting as much as possible, by solidifying the foam-like sprayed fixing portion 20 between the sealing portions 11a of adjacent battery cells 10. Furthermore, even if venting occurs, it can be prevented from occurring at the portion where the electrode lead 12 protrudes.

[0050] Since the fixing part 20 is sprayed in a foam-like manner, the thickness and position of the fixing part can be easily adjusted by adjusting the spray volume and spray position. The fixing portion 20 is manufactured to have electrical insulating properties, which can further reduce the possibility of short circuits.

[0051] 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 a scope equivalent to the technical concept of the present invention and the claims described later. [Explanation of Symbols]

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

Claims

1. It is a battery module, A battery module comprising a plurality of battery cells, each having a structure in which an electrode assembly is mounted inside a pouch, wherein electrode leads extending from the electrode assembly protrude from a portion of a seal formed along the edge of the pouch, and the battery cells are bound together such that the flat surfaces of the battery cells are in contact with each other, It is positioned between the sealing portions of adjacent battery cells and includes a fixing portion that supports the sealing portion, A battery module in which the fixed portion is positioned so as not to be in contact with the electrode leads, and the fixed portion and the seal portion are connected by a seal portion of the pouch that includes the side on which the electrode leads are formed.

2. The battery module according to claim 1, wherein the fixing portion is sprayed in a foam-like form between the sealing portions of adjacent battery cells while the multiple battery cells are bundled together, and then solidified.

3. The battery module according to claim 1, wherein the fixing portion includes foamed polyurethane.

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 the hardness of the polyurethane.

5. The battery module according to claim 2, wherein the electrode leads protrude from the sealing portion while coupled with the insulating tape, the insulating tape protrudes with a length shorter than the electrode leads, 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 fixed portion has electrical insulating properties.

7. A method for manufacturing a battery module, A battery cell stacking step in which multiple battery cells are stacked, wherein each of the multiple battery cells has a structure in which an electrode assembly is mounted in a pouch, and electrode leads extending from the electrode assembly protrude from a portion of a seal formed along the edge of the pouch, A fixing part injection step in which a foam-like fixing part is injected between the sealing parts of adjacent battery cells, including the side on which the electrode leads are formed, Includes, A method for manufacturing a battery module, wherein a fixing agent sprayed between the sealing portions of adjacent battery cells, including the side on which the electrode leads are formed, solidifies to support the sealing portions.

8. The method for manufacturing a battery module according to claim 7, further comprising a setting step in which, after the spraying step of the fixing part, the fixing part is left for a predetermined time to solidify from a foamy state to a solid state.

9. The electrode lead protrudes from the sealing portion while connected to the insulating tape, and the insulating tape protrudes with a length shorter than that of the electrode lead. The method for manufacturing a battery module according to claim 7, wherein in the spraying step of the fixing part, the fixing part is sprayed in such a way that it does not cover the insulating tape.

10. A method for manufacturing a battery module according to any one of claims 7 to 9, wherein in the spraying step of the fixing portion, the same amount of fixing portion is sprayed 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 insulating properties after solidification.

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