Battery module and battery pack including same

Abstract

A battery module according to an embodiment of the present invention includes a battery cell stack formed by stacking a plurality of battery cells, and a barrier layer interposed between adjacent battery cells among the plurality of battery cells, the barrier layer including a body portion parallel to the battery cells and an extension portion bent at one end of the body portion to cover upper ends of the battery cells.

Description

[Technical field]

[0001] [Cross-reference to related applications] This application claims the benefit of priority to Korean Patent Application No. 10-2020-0169334 filed on December 7, 2020, and Korean Patent Application No. 10-2021-0150561 filed on November 4, 2021, and all contents disclosed in the documents of said Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a battery module and a battery pack including the same, and more particularly to a battery module that effectively slows down the rate of heat propagation between battery cells and a battery pack including the same. [Background technology]

[0003] The demand for secondary batteries as an energy source is rapidly increasing due to technological development and increasing demand for mobile devices. In particular, secondary batteries are attracting much attention as an energy source for power devices such as electric bicycles, electric cars, and hybrid electric cars as well as for mobile devices such as mobile phones, digital cameras, laptops, and wearable devices.

[0004] While small mobile devices use one or more battery cells per device, medium to large devices such as automobiles require high output and large capacity, and therefore use medium to large battery modules that electrically connect multiple battery cells.

[0005] Since it is preferable that medium- to large-sized battery modules are manufactured to be as small and lightweight as possible, square batteries, pouch-type batteries, etc., which can be stacked with a high degree of integration and have a small weight relative to their capacity, are mainly used as battery cells for medium- to large-sized battery modules. Meanwhile, the battery module may include a module frame that has an open front and rear and stores the battery cell stack in an internal space to protect the battery cell stack from external impact, heat, or vibration.

[0006] Fig. 1 is a perspective view of a conventional battery module. Fig. 2 is a top view of a battery cell stack included in a conventional battery module. Fig. 3(a) is a plan view of area A of Fig. 2, and Fig. 3(b) is a cross-sectional view taken along the cutting plane BB of Fig. 3(a).

[0007] 1 and 2, a conventional battery module includes a battery cell stack 12 in which a number of battery cells 11 are stacked in one direction, module frames 30, 40 that house the battery cell stack 12, and end plates 15 that cover the front and rear surfaces of the battery cell stack 12. The module frames 30, 40 include a lower frame 30 that covers the bottom and both side surfaces of the battery cell stack 12, and an upper plate 40 that covers the top surface of the battery cell stack 12.

[0008] The battery cell stack 12 also includes fixing members 17 that fix the multiple battery cells 11 to one another, and the fixing members 17 are located at the center and / or ends of the battery cell stack 12. Furthermore, a compression pad 20 is located between a pair of adjacent battery cells in the battery cell stack 12.

[0009] 2 and 3, a compression pad 20 located in a conventional battery cell stack contacts the upper or lower surface of a battery cell 11. The compression pad 20 can absorb an impact that propagates to an adjacent battery cell 11. In addition, when a battery cell 11 ignites, the thickness of the compression pad 20 can slow down the heat propagation speed. However, when a battery cell 11 ignites, a secondary cell ignition may occur due to external heat conduction caused by a flame generated in the battery cell 11 as well as heat conduction between the adjacent battery cells 11.

[0010] As a result, it is difficult for the existing compression pad 20 alone to sufficiently slow down the heat transfer rate, and therefore it is necessary to develop a battery module that effectively slows down the heat transfer rate between battery cells, unlike the conventional battery module. Summary of the Invention [Problem to be solved by the invention]

[0011] An object of the present invention is to provide a battery module that effectively slows down the rate of heat propagation between battery cells, and a battery pack including the same.

[0012] However, the problems to be solved by the embodiments of the present invention are not limited to the above problems, and can be variously expanded within the scope of the technical ideas included in the present invention. [Means for solving the problem]

[0013] A battery module according to one embodiment of the present invention includes a battery cell stack formed by stacking a plurality of battery cells, and a barrier layer interposed between adjacent battery cells among the plurality of battery cells, the barrier layer including a body portion parallel to the battery cells and an extension portion bent at one end of the body portion to cover an upper end of the battery cell.

[0014] The extension portion is made of a flexible material and is capable of covering upper ends of at least two battery cells.

[0015] The barrier layer may include a first barrier layer arranged parallel to the battery cell and a second barrier layer arranged between the first barrier layer and the battery cell, and the second barrier layer may include a body portion arranged parallel to the first barrier layer and an extension portion bent at one end of the body portion to cover an upper end of the battery cell.

[0016] The first barrier layer is located between a first battery cell and a second battery cell adjacent to each other, and the second barrier layer includes a 2-1 barrier layer located between the first barrier layer and the first battery cell and a 2-2 barrier layer located between the first barrier layer and the second battery cell, and a first extension portion of the 2-1 barrier layer and a second extension portion of the 2-2 barrier layer can bend in the same direction.

[0017] The first extension portion and the second extension portion may overlap each other.

[0018] The body portion may include an additional extension portion that covers an end of the battery cell where the electrode lead is located.

[0019] The additional extension of the body portion may have an opening through which the electrode lead passes.

[0020] The barrier layer may be formed of a flame retardant material.

[0021] The first barrier layer may be formed of a sheet of a silicon material, a mica material, or a mixture thereof, and the second barrier layer may be formed of a mica material.

[0022] At least two barrier layers may be included, and at least two battery cells may be located between two adjacent barrier layers among the barrier layers.

[0023] Adjacent barrier layer extensions may curve in different directions.

[0024] A battery pack according to another embodiment of the present invention includes the above-described battery module. Effect of the Invention

[0025] According to an embodiment, the present invention enables a barrier layer formed between a pair of adjacent battery cells in a battery cell stack to function as a flame-retardant member, thereby slowing the rate of heat propagation between adjacent battery cells in the event of a battery cell ignition.

[0026] In addition, by applying the barrier layer not only to the body portion of the battery cell but also extending from the body portion to the top portion and lead portion of the battery cell, the rate at which heat is transmitted from a flame outside the cell to battery cells where no flame is occurring can be delayed.

[0027] The effects of the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims. [Brief description of the drawings]

[0028] [Figure 1] FIG. 1 is a perspective view of a conventional battery module. [Diagram 2] FIG. 2 is a top view of a battery cell stack included in a conventional battery module. [Diagram 3] 3A is a plan view of region A in FIG. 2 as viewed from above, and FIG. 3B is a cross-sectional view taken along the cutting plane BB in FIG. [Figure 4] 1A-1C illustrate a method of forming a battery cell stack according to a comparative example. [Diagram 5] 1A-1C illustrate a method of forming a battery cell stack included in a battery module according to an embodiment of the present invention. [Figure 6] 6 is a perspective view showing one battery cell included in the battery cell stack of FIG. 5. FIG. [Figure 7] 13 is a diagram illustrating a state in which a barrier layer is expanded in a direction in which an electrode lead protrudes in a battery cell included in a battery module according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention may, however, be embodied in various different forms and should not be construed as being limited to the embodiments set forth herein.

[0030] 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.

[0031] In addition, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to those shown. In the drawings, thicknesses are exaggerated to clearly express multiple layers and regions. In the drawings, thicknesses of some layers and regions are exaggerated for convenience of explanation.

[0032] In addition, when a part such as a layer, film, region, or plate is said to be "on" or "above" another part, this includes not only the case where it is "directly on" the other part, but also the case where there is another part in between. Conversely, when a part is said to be "directly on" another part, it means that there is no other part in between. In addition, being "on" or "above" a reference part means being located above or below the reference part, and does not necessarily mean being located "on" or "above" the opposite direction of gravity.

[0033] Also, throughout the specification, when a part "comprises" a certain element, this means that it may further include other elements, but not excluding other elements, unless specifically stated to the contrary.

[0034] Also, throughout the specification, "in a plane" means when the subject part is viewed from above, and "in cross section" means when the subject part is cut vertically and viewed from the side.

[0035] FIG. 4 is a diagram illustrating a method for forming a battery cell stack according to a comparative example.

[0036] Referring to FIG. 4, in stacking the battery cells 11, the compression pads 20 may be interposed between adjacent battery cells 11. After stacking the compression pads 20, stacking of the battery cells 11 may be continued. At this time, the compression pads 20 may have a certain thickness. The compression pads 20 may prevent swelling of the cells and may delay heat propagation to a certain extent when the cells ignite. The battery cells 11 and the compression pads 20 are stacked to form a battery cell stack, and a battery module may be formed by a lead welding process and a module frame process.

[0037] 5 is a diagram illustrating a method of forming a battery cell stack included in a battery module according to an embodiment of the present invention, and FIG 6 is a perspective view illustrating one battery cell included in the battery cell stack of FIG 5.

[0038] 5, the battery cell stack included in the battery module according to the present embodiment is formed by stacking a plurality of battery cells 110, and includes a barrier layer 200 interposed between adjacent battery cells 110 among the plurality of battery cells 110. The barrier layer 200 according to the present embodiment includes body parts 200b11, 200b21 arranged parallel to the battery cells 110, and extension parts 200b12, 200b22 bent at one end of the body parts 200b11, 200b21 to cover the upper end of the battery cell 110. The barrier layer 200 according to the present embodiment includes a first barrier layer 200a arranged parallel to the battery cell 110, and a second barrier layer 200b arranged between the first barrier layer 200a and the battery cell 110.

[0039] The second barrier layer 200b may include body portions 200b11 and 200b21 arranged parallel to the first barrier layer 200a, and extension portions 200b12 and 200b22 bent at one end of the body portions 200b11 and 200b21 to cover upper ends of the battery cells 110. The extension portions 200b12 and 200b22 are made of a flexible material and can cover upper ends of at least two battery cells 110.

[0040] More specifically, the first barrier layer 200a is located between the first battery cell 110a and the second battery cell 110b adjacent to each other, and the second barrier layer 200b may include a 2-1 barrier layer 200b1 located between the first barrier layer 200a and the first battery cell 110a, and a 2-2 barrier layer 200b2 located between the first barrier layer 200a and the second battery cell 110b. At this time, the first extension portion 200b12 of the 2-1 barrier layer 200b1 and the second extension portion 200b22 of the 2-2 barrier layer 200b2 may be curved in the same direction. At this time, the first extension portion 200b12 and the second extension portion 200b22 may overlap each other, and the overlapping portion may be the upper end portion of at least one battery cell 110.

[0041] According to this embodiment, the first extension portion 200b12 and the second extension portion 200b22 overlap each other and cover the upper end of the battery cell 110, thereby blocking the external propagation of a flame between the cells.

[0042] According to the present embodiment, the barrier layer 200 is made of a flame-retardant material. The first barrier layer 200a may be made of a silicon material, a mica material, or a mixture of these materials, and the second barrier layer 200b may be made of a mica material. The first barrier layer 200a may be made of a mica sheet, and the second barrier layer 200b may be made of a mica material that is thin and flexible, with a thickness of about 1 mm or less.

[0043] The battery module according to the present embodiment includes at least two barrier layers 200, and at least two battery cells 110 may be located between two adjacent barrier layers 200.

[0044] In addition, according to the present embodiment, the extension portions of adjacent barrier layers 200 may be curved in different directions. For example, as shown in Fig. 5, the extension portion included in the barrier layer 200 located on the right side of the two central battery cells 110 may be curved in the right direction, and the extension portion included in the barrier layer 200 located on the left side of the two central battery cells 110 may be curved in the left direction.

[0045] The battery cell 110 according to the present embodiment is preferably a pouch-type battery cell. For example, referring to FIG. 6, the battery cell 110 according to the present embodiment has a structure in which two electrode leads 111 and 112 face each other and protrude from one end 114a and the other end 114b of a battery body 113, respectively. The battery cell 110 can be manufactured by bonding both ends 114a and 114b of the battery case 114 and one side 114c connecting them in a state in which an electrode assembly (not shown) is housed in the battery case 114. In other words, the battery cell 110 according to the present embodiment has a total of three sealing parts 114sa, 114sb, and 114sc, and the sealing parts 114sa, 114sb, and 114sc are structured to be sealed by a method such as heat fusion, and the remaining other side is formed of a connecting part 115. The area between both ends 114a, 114b of the battery case 114 can be defined as the longitudinal direction of the battery cell 110, and the area between one side 114c connecting both ends 114a, 114b of the battery case 114 and the connecting portion 115 can be defined as the width direction of the battery cell 110.

[0046] The connecting portion 115 is a region that extends long along one edge of the battery cell 110, and a protrusion 110p of the battery cell 110 may be formed at an end of the connecting portion 115. The protrusion 110p may be formed at at least one of both ends of the connecting portion 115 and may protrude in a direction perpendicular to the extension direction of the connecting portion 115. The protrusion 110p may be located between the connecting portion 115 and one of the sealing portions 114sa, 114sb of both ends 114a, 114b of the battery case 114.

[0047] The battery case 114 is generally formed in a laminate structure of a resin layer / metal foil film layer / resin layer. For example, if the surface of the battery case is formed of an O(oriented)-nylon layer, it tends to slip easily due to external impact when a large number of battery cells are stacked to form a medium- to large-sized battery module. Therefore, in order to prevent this and maintain a stable stacked structure of the battery cells, an adhesive member such as a pressure-sensitive adhesive such as double-sided tape or a chemical adhesive that bonds by a chemical reaction when bonded can be attached to the surface of the battery case to form a battery cell stack. In this embodiment, the battery cell stack 120 can be stacked in the y-axis direction.

[0048] FIG. 7 is a diagram showing a state in which a barrier layer is expanded in a direction in which an electrode lead protrudes in a battery cell included in a battery module according to another embodiment of the present invention.

[0049] Meanwhile, in Fig. 7 and the following description, the reference numerals of the body portion 200b21 and the second extension portion 200b22 of the 2-2 barrier layer 200b2 are used to describe the body portion and extension portion of the second barrier layer 200b, but this is for convenience, and the following description can also be applied to the body portion 200b11 and the first extension portion 200b12 of the 2-1 barrier layer 200b1. Also, in the above description, the reference numeral "200b22" was used to refer to the second extension portion 200b22, but for convenience, the description of Fig. 7 will refer to it as "extension portion."

[0050] Referring to FIG. 7, the barrier layer 200 according to this embodiment includes a second barrier layer 200b covering the body portion 110C of the battery cell 110 of FIG. 6, and the second barrier layer 200b may include a body portion 200b21 arranged parallel to the first barrier layer 200a as described above, and an extension portion 200b22 bent at one end of the body portion 200b21 to cover the upper end portion 110T of the battery cell 110.

[0051] The body portion 110C of the battery cell 110 refers to one surface of the battery cell 110 facing the y-axis direction in which the battery cells 110 are stacked, and the upper end portion 110T of the battery cell 110 may be a portion corresponding to one side portion 114c connecting both ends 114a, 114b of the battery case 114 in Fig. 6. In other words, the upper end portion 110T of the battery cell 110 may refer to the upper end portion based on the width direction of the battery cell 110.

[0052] At this time, the thickness of the body part 200b21 of the second barrier layer 200b may be thicker than the thickness of the extension part 200b22 of the second barrier layer 200b. The body part 200b21 of the second barrier layer 200b is formed relatively thick to improve the flame retardant performance for blocking heat transfer between adjacent battery cells 110, and the extension part 200b22 of the second barrier layer 200b is formed relatively thin to minimize the occurrence of a gap between a module frame accommodating the battery cell stack and the upper end of the battery cell 110. In addition, the extension part 200b22 of the second barrier layer 200b may be formed of a flexible material to closely cover the double-sided folding structure at the upper end of the battery cell 110.

[0053] 7, the barrier layer 200 according to the present embodiment may further include a third barrier layer 200c covering an end of the battery cell 110 around the electrode leads 111, 112 protruding from the battery cell 110. The third barrier layer 200c may have openings 200D through which the electrode leads 111, 112 pass. The third barrier layer 200c may be formed by extending the second barrier layer 200b or the first barrier layer 200a. The third barrier layer 200c may also be referred to as an "additional extension".

[0054] Meanwhile, one or more battery modules according to the embodiments of the present invention may be packaged in a pack case to form a battery pack.

[0055] The battery module and the battery pack including the battery module may be applied to various devices, such as vehicles including electric bicycles, electric cars, and hybrid cars, but the present invention is not limited thereto and may be applied to various devices that can use the battery module and the battery pack including the battery module, which also fall within the scope of the present invention.

[0056] Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements made by those skilled in the art using the basic concept of the present invention defined in the following claims also fall within the scope of the present invention. [Explanation of symbols]

[0057] 110 Battery Cell 111, 112 Electrode lead 120 Battery cell stack 200 Barrier Layer 200a First Barrier Layer 200b Second Barrier Layer 200b1 Barrier layer 200b11 Body part 200b12 First extension 200b2 Barrier layer 200b21 Body part 200b22 Second extension 200c 3rd Barrier Layer

Claims

1. A battery cell stack formed by stacking a plurality of battery cells; and a barrier layer interposed between adjacent battery cells among the plurality of battery cells to delay heat transfer between the plurality of battery cells; the barrier layer includes a body portion parallel to the battery cell and an extension portion bent at one end of the body portion to cover an upper end of the battery cell; the barrier layer includes a first barrier layer disposed parallel to the battery cell, and a second barrier layer disposed between the first barrier layer and the battery cell; The second barrier layer includes a body portion arranged parallel to the first barrier layer, and an extension portion bent at one end of the body portion to cover an upper end of the battery cell.

2. The battery module according to claim 1 , wherein the extension portion is made of a flexible material and covers upper ends of at least two battery cells.

3. the first barrier layer is located between a first battery cell and a second battery cell adjacent to each other, and the second barrier layer includes a 2-1 barrier layer located between the first barrier layer and the first battery cell, and a 2-2 barrier layer located between the first barrier layer and the second battery cell; 3. The battery module according to claim 1, wherein the first extension portion of the 2-1 barrier layer and the second extension portion of the 2-2 barrier layer are curved in the same direction.

4. The battery module according to claim 3 , wherein the first extension portion and the second extension portion overlap each other.

5. The battery module according to claim 1 , wherein the body portion includes an additional extension portion covering an end of the battery cell where an electrode lead is located.

6. The battery module according to claim 5 , wherein the additional extension of the body portion has an opening through which the electrode lead passes.

7. A battery cell stack formed by stacking a plurality of battery cells; and a barrier layer interposed between adjacent battery cells among the plurality of battery cells; the barrier layer includes a body portion parallel to the battery cell and an extension portion bent at one end of the body portion to cover an upper end of the battery cell; the barrier layer includes a first barrier layer disposed parallel to the battery cell, and a second barrier layer disposed between the first barrier layer and the battery cell; the second barrier layer includes a body portion disposed parallel to the first barrier layer, and an extension portion bent at one end of the body portion to cover an upper end of the battery cell; The barrier layer of the battery module is formed of a flame-retardant material.

8. A battery cell stack formed by stacking a plurality of battery cells; and a barrier layer interposed between adjacent battery cells among the plurality of battery cells; the barrier layer includes a body portion parallel to the battery cell and an extension portion bent at one end of the body portion to cover an upper end of the battery cell; the barrier layer includes a first barrier layer disposed parallel to the battery cell, and a second barrier layer disposed between the first barrier layer and the battery cell; the second barrier layer includes a body portion disposed parallel to the first barrier layer, and an extension portion bent at one end of the body portion to cover an upper end of the battery cell; The first barrier layer is made of a silicon material, a mica material, or a mixture thereof, and the second barrier layer is made of a mica material.

9. The battery module according to any one of claims 1 to 8, wherein at least two or more barrier layers are included, and at least two or more battery cells are located between two adjacent ones of the barrier layers.

10. The battery module of claim 9 , wherein adjacent barrier layer extensions curve in different directions.

11. A battery pack comprising a battery module according to any one of claims 1 to 10.

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