Battery module, battery pack including same, and automobile

Abstract

A battery module according to an embodiment of the present invention includes a battery cell stack in which a plurality of battery cells are stacked, a cover in which the battery cell stack is housed, and a buffer member in contact with the battery cell stack, the buffer member being configured to allow fluid to move therein.

Description

[Technical field]

[0001] The present invention relates to a battery module, a battery pack including the same, and an automobile, and more particularly to a battery module that allows uniform pressure to act on an entire battery cell when swelling occurs in the battery cell, a battery pack including the same, and an automobile.

[0002] This application claims priority to Korean Patent Application No. 10-2020-0136072, filed on October 20, 2020, and the entire contents disclosed in the specification and drawings of the corresponding application are incorporated herein by reference. [Background technology]

[0003] As technological development and demand for mobile devices increases, the demand for secondary batteries as an energy source is rapidly increasing. Traditionally, nickel-cadmium batteries or hydrogen-ion batteries have been used as secondary batteries, but recently lithium secondary batteries have come into widespread use because they have almost no memory effect compared to nickel-based secondary batteries and can be charged and discharged freely, have a very low self-discharge rate, and have a high energy density.

[0004] Such lithium secondary batteries mainly use lithium-based oxides and carbon materials as positive and negative active materials, respectively, and include an electrode assembly in which positive and negative electrode plates coated with the positive and negative active materials are arranged with a separator sandwiched therebetween, and an exterior material, i.e., a battery case, that seals and houses the electrode assembly together with an electrolyte.

[0005] Lithium secondary batteries are composed of a positive electrode, a negative electrode, and a separator and electrolyte interposed between them, and are classified as lithium ion batteries (LIBs) and polymer lithium ion batteries (PLIBs) depending on the positive and negative active materials used. Typically, electrodes of these lithium secondary batteries are formed by applying a positive or negative active material to a current collector such as an aluminum or copper sheet, mesh, film, or foil, and then drying it. Various types of secondary batteries include a battery module in which a cover is provided to protect the battery cells, a plurality of battery cells are stacked and placed in the cover, and a battery pack including a plurality of battery modules.

[0006] The battery cells may be electrically connected to each other by bus bars, which are conductive materials. Typically, the positive electrode lead is made of an aluminum material, the negative electrode lead is made of a copper material, and the bus bars are also made of a copper material.

[0007] Meanwhile, a swelling phenomenon may occur in the battery cell, in which gas is generated inside the battery cell and the battery cell swells up. Referring to Patent Document 1, which is a prior art document, a swelling absorbing pad 121 is disposed inside the module case 200 to absorb the volume expansion caused by the swelling of the battery cell.

[0008] However, in the case of the conventional technology, when swelling occurs in a part of a battery cell rather than the entire battery cell, the swelling absorbing pad 121 is pressed only on the part where the swelling occurs. This causes a problem that the pressure is not uniform between the part of the battery cell where the swelling occurs and the part of the battery cell where the swelling does not occur, and stress is locally concentrated in the part of the battery cell where the swelling occurs, causing partial deterioration of the battery cell. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Korean Patent Publication No. 10-2020-0106378 Summary of the Invention [Problem to be solved by the invention]

[0010] An object of the present invention is to provide a battery module that prevents stress from concentrating on one part of a battery cell even when swelling occurs in the battery cell, thereby allowing uniform pressure to act on the entire battery cell, and a battery pack and a vehicle including the same. [Means for solving the problem]

[0011] According to one aspect of the present invention, there may be provided a battery module including a battery cell stack in which a plurality of battery cells are stacked, a cover in which the battery cell stack is housed, and a buffer member in contact with the battery cell stack, the buffer member being configured to allow fluid therein to move.

[0012] The cushioning member may also include a first sheet, a second sheet coupled to the first sheet, a plurality of fluid buffer layers formed between the first sheet and the second sheet and filled with a fluid, and a channel connecting the plurality of fluid buffer layers to each other so that the fluid can move between the plurality of fluid buffer layers.

[0013] The first sheet and the second sheet may be formed of a heat-sealable film sheet.

[0014] Also, the channel may be provided in a plurality of channels, and the plurality of channels may be provided to be connected to four sides of the fluid buffer layer.

[0015] A first channel among the plurality of channels may be configured to connect the plurality of fluid buffer layers to each other, and a second channel among the plurality of channels may be configured to connect any one of the plurality of fluid buffer layers to the first channel.

[0016] In addition, the plurality of fluid buffer layers may be all connected to each other through the first channel and the second channel, and when the battery cell swells due to a swelling phenomenon of the battery cell, fluid present in any one of the plurality of fluid buffer layers may move to another fluid buffer layer through at least one of the first channel and the second channel due to pressure transmitted from the battery cell.

[0017] And, the first channel and the second channel may be vertically connected.

[0018] The fluid buffer layer may be formed in a symmetrical or asymmetrical shape with respect to a joint portion between the first sheet and the second sheet.

[0019] According to another aspect of the present invention, a battery pack including the above-described battery module is provided, and a vehicle including the battery module is also provided. Effect of the Invention

[0020] According to an embodiment of the present invention, even if swelling occurs in a battery cell, a buffer member having a fluid movable therein prevents stress from concentrating in one part of the battery cell, thereby allowing a uniform pressure to act on the entire battery cell. [Brief description of the drawings]

[0021] [Figure 1] 1 is a schematic cross-sectional view of a battery module according to an embodiment of the present invention; [Diagram 2] 2 is a schematic perspective view of a buffer member in a battery module according to an embodiment of the present invention; FIG. [Diagram 3] 3 is an enlarged view of a portion of the cushioning member of FIG. 2. [Figure 4] 1 is a schematic diagram illustrating that a first sheet and a second sheet of a fluid buffer layer are formed symmetrically in a battery module according to an embodiment of the present invention. [Diagram 5] FIG. 5 is a schematic diagram illustrating another embodiment of the fluid buffer layer of FIG. 4, in which the first and second sheets are formed in asymmetric shapes. [Figure 6] FIG. 5 is a schematic diagram illustrating a case where swelling occurs at one end of the battery cell in FIG. 4. [Figure 7] FIG. 5 is a diagram illustrating a case where swelling occurs in the center of the battery cell in FIG. 4. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Prior to this, the terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted as being in accordance with the meaning and concept of the technical idea of ​​the present invention, in accordance with the principle that the inventor himself can appropriately define the concept of the term in order to best describe the invention. Therefore, it should be understood that the embodiment described in this specification and the configuration shown in the drawings are only one most preferred embodiment of the present invention, and do not represent the entire technical idea of ​​the present invention, and therefore there may be various equivalents and modifications that can be substituted for them at the time of this application.

[0023] The size of each component or a specific part of the component in the drawings may be exaggerated, omitted, or illustrated in a schematic manner for convenience and clarity of description. Therefore, the size of each component does not completely reflect the actual size. If a detailed description of a known function or configuration related to the present invention is determined to unnecessarily blur the gist of the present invention, the description will be omitted.

[0024] The terms "couple" and "connect" as used in this specification include not only cases where one member is directly coupled or connected to another member, but also cases where one member is indirectly coupled or connected to another member via a connecting member.

[0025] FIG. 1 is a schematic cross-sectional view of a battery module according to one embodiment of the present invention, FIG. 2 is a schematic perspective view of a buffer member in a battery module according to one embodiment of the present invention, FIG. 3 is an enlarged view of a portion of the buffer member of FIG. 2, FIG. 4 is a schematic diagram showing that a first sheet and a second sheet of a fluid buffer layer are formed symmetrically in a battery module according to one embodiment of the present invention, FIG. 5 is a schematic diagram showing that a first sheet and a second sheet of a fluid buffer layer are formed asymmetrically in another embodiment of FIG. 4, FIG. 6 is a schematic diagram showing a case where swelling occurs at one side end of a battery cell in FIG. 4, and FIG. 7 is a schematic diagram showing a case where swelling occurs at the center of a battery cell in FIG. 4.

[0026] Referring to the drawings, a battery module 10 according to an embodiment of the present invention includes a battery cell stack 100, a cover 200, and a cushioning member 300.

[0027] 1, a plurality of battery cells 110 each having an electrode lead are stacked to form a battery cell stack 100. The electrode lead of the battery cell 110 is a type of terminal exposed to the outside and connected to an external device, and may be made of a conductive material.

[0028] The electrode leads may include a positive electrode lead and a negative electrode lead. The positive electrode lead and the negative electrode lead may be disposed in opposite directions relative to the longitudinal direction of the battery cell 110, or the positive electrode lead and the negative electrode lead may be located in the same direction relative to the longitudinal direction of the battery cell 110.

[0029] The positive electrode lead and the negative electrode lead may be made of various materials. For example, the positive electrode lead may be made of an aluminum material, and the negative electrode lead may be made of a copper material.

[0030] The electrode lead may be electrically coupled to the bus bar. The battery cell 110 may have a structure in which a plurality of unit cells arranged in the order of a positive electrode plate / separator / negative electrode, or a bi-cell arranged in the order of a positive electrode plate / separator / negative electrode plate / separator / positive electrode plate / separator / negative electrode, are stacked according to the battery capacity.

[0031] The battery cell stack 100 may be configured such that a plurality of battery cells 110 are stacked on one another. Here, the battery cells 110 may have a variety of structures, and the plurality of battery cells 110 may be stacked in a variety of ways.

[0032] The battery cell stack 100 may include a plurality of cartridges (not shown) that house the respective battery cells 110. Each cartridge (not shown) may be manufactured by plastic injection molding, and a plurality of cartridges (not shown) each having a housing portion that houses the battery cells 110 may be stacked.

[0033] A cartridge assembly in which multiple cartridges (not shown) are stacked may be provided with a connector element or a terminal element. The connector element may include various types of electrical connection parts or connection members for connection to, for example, a BMS (Battery Management System, not shown) that can provide data related to the voltage or temperature of the battery cells 110.

[0034] The terminal elements include a positive terminal and a negative terminal as main terminals connected to the battery cell 110, and the terminal elements may be provided with terminal bolts to be electrically connected to the outside. Meanwhile, the battery cell 110 may have various shapes.

[0035] 1 , the cover 200 houses the battery cell stack 100 or a cartridge assembly housing the battery cell stack 100. For example, the cover 200 may be provided to surround the battery cell stack 100.

[0036] The cover 200 encloses the entire battery cell stack 100 or the multiple cartridge assemblies, thereby protecting the battery cell stack 100 or the cartridge assemblies from external vibrations and shocks.

[0037] The cover 200 may be formed in a shape that corresponds to the shape of the battery cell stack 100 or the cartridge assembly. For example, if the battery cell stack 100 or the cartridge assembly is provided in a hexahedral shape, the cover 200 may also be provided in a corresponding hexahedral shape.

[0038] The cover 200 may be manufactured, for example, by bending a metal plate or by plastic injection, and may be manufactured as a single unit or a separate unit.

[0039] A through-hole (not shown) through which the connector element or terminal element can be exposed to the outside may be formed in the cover 200. That is, the connector element or terminal element can be electrically connected to a predetermined external part or member, and the through-hole may be formed in the cover 200 so that such electrical connection is not interfered with by the cover 200.

[0040] The cover 200 may be integrally formed or may be configured to include, but is not limited to, an upper cover 200, a lower cover 200, and a side cover 200.

[0041] The buffer member 300 is in contact with the battery cell stack 100 and is provided so that the fluid 400 (see FIG. 4) inside the buffer member 300 can move.

[0042] 2 to 4, the cushioning member 300 may include a first sheet 310, a second sheet 320, a fluid cushioning layer 330, and a channel 340.

[0043] The first sheet 310 and the second sheet 320 may be, for example, a heat-sealable film sheet, and may be joined to each other up and down as shown in FIG.

[0044] A plurality of fluid buffer layers 330 are formed, and when the first sheet 310 and the second sheet 320 are joined together, the fluid buffer layers 330 are formed between the first sheet 310 and the second sheet 320. Referring to FIG. 3, the fluid buffer layers 330 may be bulging upward and downward.

[0045] The fluid buffer layer 330 is filled with a fluid 400 (see FIG. 4), and the fluid 400, for example, air, is filled into the fluid buffer layer 330 to buffer the battery cell 110 when swelling of the battery cell 110 occurs.

[0046] The channels 340 are provided to connect the plurality of fluid buffer layers 330 to each other. When the plurality of fluid buffer layers 330 are connected to each other by the channels 340, if swelling occurs in the battery cell 110 and the battery cell 110 pressurizes some of the plurality of fluid buffer layers 330, the fluid 400 present in the fluid buffer layer 330 pressurized by the battery cell 110 moves to the other fluid buffer layers 330 that are not pressurized.

[0047] That is, the channels 340 connect the multiple fluid buffer layers 330 to each other so that the fluid 400 can move between the multiple fluid buffer layers 330 .

[0048] For example, referring to FIG. 6, if swelling occurs on the left side of the battery cell 110 with reference to FIG. 6, the fluid buffer layer 330 in contact with the battery cell 110 on the left side is pressurized by the battery cell 110, and the fluid 400 moves from the fluid buffer layer 330 on the left side to the fluid buffer layer 330 on the right side that is not pressurized.

[0049] 7, when swelling occurs at the center of the battery cell 110, the fluid buffer layer 330 in contact with the battery cell 110 at the center is pressurized by the battery cell 110, and the fluid 400 moves from the central fluid buffer layer 330 to the fluid buffer layers 330 on the left and right sides that are not pressurized.

[0050] Referring to FIG. 2, multiple fluid buffer layers 330 are arranged vertically and horizontally between a rectangular first sheet 310 and a rectangular second sheet 320. Even if pressure is applied to a certain part of the fluid buffer layer 330, the fluid 400 may move to various fluid buffer layers 330 in vertical and horizontal positions that are not pressurized.

[0051] This is similar to the way an air mattress works, where when one part is pressurized, air moves to other parts to provide cushioning.

[0052] For ease of explanation, Figures 6 and 7 exaggerate the change in size of the fluid buffer layer 330 due to the movement of the fluid 400. However, even if a portion of the battery cell 110 expands and the fluid buffer layer 330 in that portion is pressurized, and the fluid 400 present in that fluid buffer layer 330 moves to other fluid buffer layers 330, the actual change in size of the fluid buffer layer 330 is not as excessive as in Figures 6 and 7.

[0053] The reason is that, as shown in FIG. 2, the multiple fluid buffer layers 330 are arranged in the vertical and horizontal directions. Therefore, even if any one of the fluid buffer layers 330 is pressurized or several of the fluid buffer layers 330 in the same portion are pressurized together, the fluid 400 present in the pressurized fluid buffer layer 330 is dispersed to the multiple fluid buffer layers 330 in the vertical and horizontal directions via the multiple channels 340, i.e., the first channel 341 and the second channel 342, so that the actual change in shape of the fluid buffer layer 330 is minimal.

[0054] On the other hand, assuming that swelling occurs in a battery cell 110 and the initial absolute size of the fluid buffer layer 330 pressurized by the battery cell 110 in that portion is, for example, "5", after the fluid 400 in the pressurized fluid buffer layer 330 moves to other fluid buffer layers 330 in portions where swelling is not occurring, the absolute size of the initially pressurized fluid buffer layer 330 may decrease to "3".

[0055] Then, assuming that the initial absolute size of the fluid buffer layer 330 in the portion of the battery cell 110 where swelling is not occurring is pressurized by the battery cell 110 is, for example, "1," the absolute size of the fluid buffer layer 330 in the portion of the battery cell 110 where swelling is not occurring after the fluid 400 moves from the pressurized fluid buffer layer 330 due to swelling in the battery cell 110 to the fluid buffer layer 330 in the portion of the battery cell 110 where swelling is not occurring may increase to 3.

[0056] That is, in the battery module 10 according to an embodiment of the present invention, when swelling of the battery cell 110 occurs, the fluid 400 disperses from the fluid buffer layer 330 pressurized by the battery cell 110 through the multiple channels 340 to the multiple other fluid buffer layers 330 that are not pressurized, and moves in various directions, so that the pressure acting on the entire part of the battery cell 110 where swelling has occurred and the part where swelling has not occurred are the same.

[0057] This prevents stress from concentrating on a certain portion of the battery cell 110, thereby preventing partial deterioration of the battery cell 110.

[0058] 2 and 3, a plurality of channels 340 may be provided, and the plurality of channels 340 may be connected to all four sides of the fluid buffer layer 330.

[0059] For example, a first channel 341 of the multiple channels 340 may be configured to connect the multiple fluid buffer layers 330 to each other, and a second channel 342 of the multiple channels 340 may be configured to connect the first channel 341 to any one of the multiple fluid buffer layers 330.

[0060] Here, the first channel 341 and the second channel 342 may be vertically connected to each other. In this manner, the plurality of fluid buffer layers 330 may all be in communication with each other via the first channel 341 and the second channel 342.

[0061] Thus, the fluid 400 present in the fluid buffer layer 330 added when the battery cell 110 swells can be dispersed and moved to the other fluid buffer layers 330 .

[0062] That is, when the battery cell 110 swells due to the swelling phenomenon of the battery cell 110, the fluid 400 present in any one of the multiple fluid buffer layers 330 moves to another fluid buffer layer 330 through the first channel 341 or the second channel 342 due to the pressure transmitted from the battery cell 110.

[0063] Meanwhile, the fluid buffer layer 330 may be formed symmetrically with respect to the joint between the first sheet 310 and the second sheet 320 as shown in FIG. 4 or asymmetrically with respect to the joint between the first sheet 310 and the second sheet 320 as shown in FIG.

[0064] Hereinafter, the operation and effects of the battery module 10 according to the embodiment of the present invention will be described with reference to the drawings.

[0065] The cover 200 of the battery module 10 according to an embodiment of the present invention includes a buffer member 300. The buffer member 300 is provided such that a plurality of fluid buffer layers 330 are connected to each other in the vertical and horizontal directions via channels 340. When any one of the fluid buffer layers 330 is pressurized due to swelling of the battery cell 110, the fluid 400 present in the fluid buffer layer 330 disperses and moves to other fluid buffer layers 330 that are not pressurized, so that a uniform pressure acts on the entire battery cell 110.

[0066] This prevents stress from concentrating on a certain portion of the battery cell 110, thereby preventing partial degradation of the battery cell 110.

[0067] Meanwhile, a battery pack (not shown) according to an embodiment of the present invention may include one or more battery modules 10 according to an embodiment of the present invention as described above. Also, the battery pack (not shown) may further include, in addition to the battery module 10, a case for accommodating the battery module 10, and various devices for controlling charging and discharging of the battery module 10, such as a BMS, a current sensor, a fuse, etc.

[0068] Meanwhile, an automobile (not shown) according to an embodiment of the present invention may include the above-described battery module 10 or a battery pack (not shown), and the battery pack (not shown) may include the battery module 10. The battery module 10 according to an embodiment of the present invention may be applied to the automobile (not shown), for example, a certain automobile (not shown) that is configured to use electricity, such as an electric automobile or a hybrid automobile.

[0069] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and various modifications and variations can be made by those having ordinary skill in the art to which the present invention pertains within the technical spirit of the present invention and the equivalent scope of the claims. [Industrial Applicability]

[0070] The present invention relates to a battery module, a battery pack including the same, and an automobile, and is particularly applicable to the secondary battery-related industry. [Explanation of symbols]

[0071] 10 Battery Module 100 Battery cell stack 110 Battery Cell 121 Swelling Absorbent Pad 200 Cover 300 Cushioning material 310 Sheet 1 320 2nd Sheet 330 Fluid buffer layer 340 Channels 341 Channel 1 342 Channel 2 400 fluid

Claims

1. a battery cell stack in which a plurality of battery cells are stacked; a cover in which the battery cell stack is housed; a buffer member in contact with the battery cell stack; The buffer member is provided so that the fluid therein can move, The buffer member is a plurality of fluid buffer layers filled with a fluid; a channel connecting the plurality of fluid buffer layers to each other so that the fluid can move between the plurality of fluid buffer layers; A plurality of the channels are provided, and the plurality of the channels are connected to four sides of the fluid buffer layer; The plurality of fluid buffer layers include: A fluid buffer layer array, which is composed of a plurality of fluid buffer layers arranged along a first direction, is arranged along a second direction perpendicular to the first direction, and two fluid buffer layer arrays adjacent to each other in the second direction are arranged such that, in the first direction, each fluid buffer layer in one fluid buffer layer array is positioned at the center of two fluid buffer layers in the other fluid buffer layer array; a first channel among the plurality of channels connecting the plurality of fluid buffer layers to each other in the first direction; A second channel of the plurality of channels connects the first channel to any one of the plurality of fluid buffer layers in the second direction. A battery module comprising:

2. The plurality of fluid buffer layers include: A first sheet; A second sheet is formed between the first sheet and the second sheet. The first sheet and the second sheet are provided as heat-adhesive film sheets. The battery module according to claim 1 .

3. the plurality of fluid buffer layers are all in communication with each other through the first channel and the second channel; When the battery cell swells due to a swelling phenomenon of the battery cell, a fluid present in any one of the plurality of fluid buffer layers moves to another fluid buffer layer through at least one of the first channel and the second channel due to a pressure transmitted from the battery cell. The battery module according to claim 1 .

4. The first channel and the second channel are vertically connected. The battery module according to claim 1 or 3.

5. a battery cell stack in which a plurality of battery cells are stacked; a cover in which the battery cell stack is housed; a buffer member in contact with the battery cell stack; The buffer member is provided so that the fluid therein can move, The buffer member is A first sheet; a second sheet attached to the first sheet; a plurality of fluid buffer layers formed between the first sheet and the second sheet and filled with a fluid; a channel connecting the plurality of fluid buffer layers to each other so that the fluid can move between the plurality of fluid buffer layers; The fluid buffer layer is formed in a symmetrical or asymmetrical shape with respect to a joint portion between the first sheet and the second sheet, The plurality of fluid buffer layers include: a fluid buffer layer array including a plurality of fluid buffer layers arranged along a first direction, the fluid buffer layer array being arranged along a second direction perpendicular to the first direction, and two fluid buffer layer arrays adjacent to each other in the second direction being arranged such that, in the first direction, each fluid buffer layer in one fluid buffer layer array is positioned at the center of two fluid buffer layers in the other fluid buffer layer array; a first channel among the plurality of channels connecting the plurality of fluid buffer layers to each other in the first direction; A second channel of the plurality of channels connects the first channel to any one of the plurality of fluid buffer layers in the second direction. A battery module comprising:

6. A battery pack comprising the battery module according to any one of claims 1 to 5.

7. A motor vehicle comprising a battery module according to any one of claims 1 to 5.

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