Battery module and battery pack including the battery module

Abstract

A battery module according to one embodiment of the present disclosure includes: a battery cell stack formed by stacking a plurality of battery cells; and at least one barrier layer interposed between battery cells adjacent to each other among the plurality of battery cells, wherein the barrier layer includes a first region and a second region, and includes mutually different materials in the first region and the second region.

Description

Technical Field

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Korean Patent Application No. 10-2020-0141977 filed on October 29, 2020, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety.

[0003] The present disclosure relates to a battery module and a battery pack including the same, and more particularly, to a battery module that effectively slows down a heat transfer speed between battery cells and a battery pack including the same. Background Art

[0004] As technology develops and demand for mobile devices increases, demand for batteries as energy sources is rapidly increasing. In particular, secondary batteries are attracting attention as energy sources for power-driven devices such as electric bicycles, electric vehicles, and hybrid vehicles, and as energy sources for mobile devices such as mobile phones, digital cameras, laptop computers, and wearable devices.

[0005] For small mobile devices, each device uses one or more battery cells, while medium or large devices such as vehicles require high power and large capacity. Therefore, medium or large battery modules with multiple battery cells electrically connected to each other are used.

[0006] Since the medium or large battery module is preferably manufactured to have the smallest possible size and weight, square batteries, pouch-type batteries, etc., which can be stacked with high integration and have a small weight relative to capacity, are mainly used as battery cells of the medium or large battery module. Meanwhile, in order to protect the battery cell stack from external impact, heat or vibration, the battery module may include a module frame that is opened at the front and rear sides thereof and accommodates the battery cell stack in the internal space.

[0007] Figure 1 is a perspective view of a conventional battery module. Figure 2 is a top view of a battery cell stack included in a conventional battery module. Figure 3 (a) Observed from above Figure 2 Top view of area A, Figure 3 (b) is along Figure 3 (a) is a cross-sectional view taken along section BB.

[0008] Reference Figure 1 and Figure 2, a conventional battery module includes a battery cell stack 12 in which a plurality of battery cells 11 are stacked in one direction, module frames 30 and 40 accommodating the battery cell stack 12, and end plates 15 covering the front and rear surfaces of the battery cell stack 12. The module frames 30 and 40 include a lower frame 30 covering the lower surface and both sides of the battery cell stack 12, and an upper plate 40 covering the upper surface of the battery cell stack 12.

[0009] Furthermore, the battery cell stack 12 includes a fixing member 17 fixing the plurality of battery cells 11 to each other, and the fixing member 17 is located at the center and / or end of the battery cell stack 12. In addition, the compression pad 20 is located between a pair of battery cells adjacent to each other in the battery cell stack 12.

[0010] Reference Figure 2 and Figure 3 , the compression pad 20 located in the conventional battery cell stack is in contact with the upper surface or the lower surface of the battery cell 11. The compression pad 20 can absorb the impact propagating to the adjacent battery cell 11. In addition, when the battery cell 11 catches fire, the heat propagation speed is delayed due to the thickness of the compression pad 20. However, when an expansion phenomenon occurs during the charging / discharging process of the battery cell 11, pressure and / or heat are applied to the compression pad 20. At this time, the compression rate of the conventional compression pad 20 varies depending on the position, which may cause changes in the physical properties of the compression pad 20. In addition, when the battery cell 110 catches fire, a secondary battery fire may occur due to the thermal conductivity between the adjacent battery cells 11 and the external thermal conductivity caused by the flame generated in the battery cell 11.

[0011] Therefore, it is difficult to sufficiently perform the effect of delaying the heat propagation speed using only the conventional compression pad 20. Therefore, unlike conventional cases, it is necessary to develop a battery module that effectively delays the heat propagation speed between battery cells even if a swelling phenomenon occurs. Summary of the invention

[0012] Technical issues

[0013] An object of the present disclosure is to provide a battery module that effectively slows down the speed of heat propagation between battery cells and a battery pack including the battery module.

[0014] However, the technical problems to be solved by the embodiments of the present disclosure are not limited to the above-mentioned problems, and various extensions can be made within the scope of the technical ideas included in the present disclosure.

[0015] Technical Solution

[0016] According to one embodiment of the present disclosure, a battery module is provided, comprising: a battery cell stack formed by stacking a plurality of battery cells; and at least one barrier layer interposed between battery cells adjacent to each other among the plurality of battery cells, wherein the barrier layer comprises a first region and a second region, and comprises mutually different materials in the first region and the second region.

[0017] The first region may be a portion corresponding to the center of the battery cell, and the second region may be a portion corresponding to an edge of the battery cell.

[0018] The barrier layer may include a first material in the first region and a second material in the second region, and the first material may have a higher thermal conductivity than the second material.

[0019] The first material may have a higher compressibility than the second material.

[0020] The barrier layer may include a first region and a second region distinguished based on a surface facing the body part of the battery cell.

[0021] The body portion of the battery cell may correspond to a surface perpendicular to a stacking direction of the battery cells.

[0022] The barrier layer may be formed of a flame retardant member.

[0023] The material formed in the first region may include a silicon material, and the material formed in the second region may include a mica material.

[0024] The battery module includes at least two barrier layers, and at least two battery cells may be located between two adjacent barrier layers among the barrier layers.

[0025] According to another embodiment of the present disclosure, a battery pack is provided. The battery pack includes the above-mentioned battery module.

[0026] Beneficial Effects

[0027] According to an embodiment of the present disclosure, a barrier layer formed between a pair of battery cells adjacent to each other in a battery cell stack may function as a flame retardant member, thereby slowing down a heat propagation speed between adjacent battery cells when the battery cells catch fire.

[0028] Furthermore, the barrier layer is formed such that the material applied to each position is different, thereby reducing the compression rate of the barrier layer when a cell expansion phenomenon occurs and maximizing the performance as a flame retardant member, thereby effectively delaying the heat propagation time between battery cells.

[0029] The effects of the present disclosure are not limited to the above-described effects, and other additional effects not described above will be clearly understood by those skilled in the art from the description of the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a perspective view of a conventional battery module;

[0031] Figure 2 is a top view of a battery cell stack included in a conventional battery module;

[0032] Figure 3 (a) Observed from above Figure 2 Top view of area A, Figure 3 (b) is along Figure 3 (a) is a cross-sectional view taken along section BB;

[0033] Figure 4 is a perspective view showing a battery module according to an embodiment of the present disclosure;

[0034] Figure 5 is along Figure 4 A view of a cross section taken along the cutting line CC of ;

[0035] Figure 6 It is shown Figure 5 A perspective view of a battery cell included in a battery cell stack;

[0036] Figure 7 Observed from the x-axis direction Figure 5 A view of a region P;

[0037] Figure 8 is along Figure 7 A cross-sectional view taken along cutting line DD. DETAILED DESCRIPTION

[0038] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the embodiments. The present disclosure can be modified in various different ways and is not limited to the embodiments set forth herein.

[0039] Parts irrelevant to the description will be omitted to clearly describe the present disclosure, and the same reference numerals refer to the same elements throughout the specification.

[0040] In addition, in the drawings, for the convenience of description, the size and thickness of each element are arbitrarily shown, and the present disclosure is not necessarily limited to the contents shown in the drawings. In the drawings, for the sake of clarity, the thickness of layers, regions, etc. are exaggerated. In the drawings, for the convenience of description, the thickness of some layers and regions is exaggerated.

[0041] In addition, it should be understood that when an element such as a layer, film, region, or plate is referred to as being "on" or "above" another element, it can be directly on the other element, or intervening elements may be present. Conversely, when an element is referred to as being "directly on" another element, it means that there are no other intervening elements. In addition, the terms "on" or "above" refer to being disposed above or below a reference portion, and do not necessarily mean being disposed "on" or "above" a reference portion in an opposite direction of gravity.

[0042] Furthermore, throughout the specification, when a part is referred to as “comprising” a certain component, unless otherwise specified, it means that the part may further include other components and does not exclude the other components.

[0043] Furthermore, throughout the specification, when referred to as a “plane”, it means when the target portion is viewed from the upper side, and when referred to as a “cross section”, it means when the target portion is viewed from the cross section side cut vertically.

[0044] Figure 4 is a perspective view showing a battery module according to an embodiment of the present disclosure. Figure 5 is along Figure 4 A view of a cross section taken along cutting line CC. Figure 6 It is shown Figure 5 A perspective view of a battery cell included in a battery cell stack.

[0045] Reference Figure 4 and Figure 5 , the battery module 100 according to the present embodiment includes: a battery cell stack 120 including a plurality of battery cells 110 ; a module frame 150 for accommodating the battery cell stack 120 ; and end plates 130 respectively located on the front and rear surfaces of the battery cell stack 120 .

[0046] like Figure 4 As shown, the module frame 150 may be in the form of a metal plate having an upper surface, a lower surface, and two side surfaces integrated. That is, in the case where the module frame 150 has a square tube shape, a space capable of accommodating the battery cell stack 10 is formed therein, and the end plate 130 is coupled to both ends of the square tube shape. However, the present disclosure is not limited thereto, and module frames 150 of various shapes may be applied. As a possible modification, a module frame in which an upper cover and a U-shaped frame are combined is also possible, and there is no particular limitation.

[0047] The battery cell stack 120 includes a plurality of battery cells 110 stacked in one direction, and as shown in FIG. Figure 5 As shown, the plurality of battery cells 110 may be stacked in an upright form parallel to the sidewalls 124 of the module frame 150 .

[0048] The battery cell 110 is preferably a pouch-type battery cell. Figure 6 According to the present embodiment, the battery cell 110 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 the battery body 113. The electrode lead included in each battery cell 110 is a positive lead or a negative lead, and the ends of the electrode leads 111 and 112 of each battery cell 110 can be bent in one direction so that the ends of the electrode leads 111 and 112 of other adjacent battery cells 110 can contact each other. The two electrode leads 111 and 112 contacting each other can be fixed to each other by welding, etc., thereby making it possible to make an electrical connection between the battery cells 110 inside the battery cell stack. In addition, the electrode leads aligned at both ends of the battery cell stack can be coupled to a bus bar frame (not shown) to be electrically connected to the bus bar mounted on the bus bar frame. The end plates 130 covering the bus bar frame are respectively disposed on the two opening sides of the module frame 150, and can be coupled to the module frame 150 by a method such as welding.

[0049] The battery cell 110 can be manufactured by bonding the two end portions 114a and 114b of the case 114 and the two side surfaces 114c connecting them in a state where the electrode assembly is accommodated in the battery case 114. In other words, the battery cell 110 according to the present embodiment has a total of three sealing portions 114sa, 114sb, and 114sc, and the sealing portions 114sa, 114sb, and 114sc have a structure sealed by a method such as hot melting, and the remaining other side portion can be formed by the connecting portion 115. The space between the two end portions 114a and 114b of the battery case 114 is defined as the longitudinal direction of the battery cell 110, and the space between one side surface 114c and the connecting portion 115 connecting the two ends 114a and 114b of the battery case 114 is defined as the width direction of the battery cell 110.

[0050] The connection portion 115 is a region extending longer 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 connection portion 115. The protrusion 110p may be formed on at least one of the two ends of the connection portion 115 and may protrude in a direction perpendicular to the direction in which the connection portion 115 extends. The protrusion 110p may be located between one of the sealing portions 114sa and 114sb of the two ends 114a and 114b of the battery case 114 and the connection portion 115.

[0051] The battery housing 114 is generally formed of a laminated structure of a resin layer / metal film layer / resin layer. For example, when a plurality of battery cells are stacked to form a medium or large battery module, the surface of the battery housing formed by the O (oriented) nylon layer is susceptible to sliding due to external impact. Therefore, in order to prevent such sliding and maintain a stable stacking structure of the battery cells, a battery cell stack can be formed by attaching an adhesive member (e.g., a sticky adhesive such as a double-sided tape or a chemical adhesive that is bonded by a chemical reaction when adhered) to the surface of the battery housing. In the present embodiment, the battery cell stack 120 can be stacked along the x-axis direction.

[0052] Return to reference Figure 5 The thermally conductive resin layer 200 may be located between the battery cell stack and the bottom of the module frame 150. The thermally conductive resin layer 200 may transfer heat generated by the battery cell stack 120 to the bottom of the battery module 100 and may also play a role in fixing the battery cell stack 120 to the bottom.

[0053] According to the present embodiment, a plurality of barrier layers 400 may be interposed between adjacent battery cells 110. The barrier layer 400 is formed of a flame retardant member. At this time, the barrier layer 400 is formed of a flame retardant pad, which may be formed of a silicone foam pad or a mica sheet. The battery module 100 includes at least two barrier layers 400, and at least two battery cells 110 may be located between two adjacent barrier layers 400 in the barrier layer 400. Of course, it may also be formed into a structure in which one battery cell 110 is arranged between two adjacent barrier layers 400.

[0054] like Figure 2 As shown, whenever four battery cells 110 are stacked, multiple barrier layers 400 can be inserted layer by layer so that multiple barrier layers 400 can be arranged at equal intervals. The present disclosure is not limited to this, and multiple barrier layers 400 can be arranged at different intervals from each other. There is no special restriction on the arrangement of the barrier layer 400, and its number and thickness can be appropriately adjusted as needed. In this way, the barrier layers 400 can be arranged separately from each other at equal intervals or unequal intervals, thereby increasing the thermal resistance of the battery cells 110 in the battery module 100 when thermal runaway occurs, and preventing or delaying heat transfer between adjacent battery cells. In addition, the barrier layer 400 can also be arranged between the battery cell 110 and the outermost side wall 124 stacked on the battery cell stack 120. The barrier layer 400 can delay or block the transfer of heat from the battery cell to the adjacent battery cell when problems such as thermal runaway occur in the battery module 100, and can also play a role in absorbing the expansion of the battery cell 110 and controlling the expansion.

[0055] When the battery cell 110 expands inside the battery module 100, the barrier layer 400 may change its physical properties, and in particular, the thermal conductivity may vary depending on the position in contact with the battery cell 110. In one example, when the expansion phenomenon of the battery cell 110 occurs, a large volume expansion occurs in the center of the battery cell 110. Therefore, when the thickness of the barrier layer 400 is constant, the thermal conductivity of the portion of the barrier layer 400 corresponding to the position in contact with the center of the battery cell 110 may change, which makes it difficult to fully exert the effect of delaying the heat propagation speed. Therefore, in order to effectively delay the heat propagation speed between the battery cells 110 even when the expansion phenomenon occurs, the barrier layer 400 according to the present embodiment is formed so that the material applied to each position is different. Hereinafter, the barrier layer 400 according to the present embodiment will be described in detail.

[0056] Figure 7 Observed from the x-axis direction Figure 5 A view of an area P. Figure 8 is along Figure 7 A cross-sectional view taken along cutting line DD.

[0057] Reference Figure 5 and Figure 7 The barrier layer 400 according to the present embodiment includes a first region 400a and a second region 400b, and includes mutually different materials in the first region 400a and the second region 400b. The first region 400a is a portion corresponding to the center of the battery cell 110, and the second region 400b may be a portion corresponding to the edge of the battery cell 110.

[0058] The first region 400a of the barrier layer 400 includes a first material and the second region 400b of the barrier layer 400 includes a second material. The first material may have a higher thermal conductivity than the second material, and the first material may have a higher compressibility than the second material. The barrier layer 400 may include a first region 400a and a second region 400b distinguished based on a surface facing the main body 110B of the battery cell 110.

[0059] The main body 110B of the battery cell 110 may correspond to a surface perpendicular to the stacking direction of the battery cell 110. The material formed in the first region 400a includes a silicon material, and the material formed in the second region 400b may include a mica material. Therefore, in the first region 400a, the degradation of thermal conductivity due to compression of a material (such as silicon) having good compressible physical properties can be prevented. In the second region 400b, although the compression rate is relatively reduced, the thermal conductivity can be reduced by a material having excellent flame retardant properties. In this regard, in the second region 400b corresponding to the outside, the expansion phenomenon of the battery cell 110 is relatively small compared to the first region 400a corresponding to the central part of the monomer during the expansion of the monomer, so it is preferred to use a member having a lower thermal conductivity than a material having a good compressibility. Therefore, materials with different compression rates are applied to each region of the barrier layer 400 to maximize the performance of the flame retardant member, and even if the monomer expansion phenomenon occurs, the heat transfer time between the battery cells can be effectively delayed.

[0060] The body portion 110B of the battery cell 110 may refer to one surface of the battery cell 110 facing an x-axis direction, which is a direction in which the battery cells 110 are stacked.

[0061] Reference Figure 8 When the battery cell 110 expands, the central portion of the main body 110B of the battery cell 110 expands significantly, and the first region 400a of the barrier layer 400 corresponding to the central portion of the battery cell 110 can be compressed more than the second region 400b. At this time, the physical properties of the barrier layer 400 change. Therefore, the performance of the flame retardant member can be maximized, thereby effectively delaying the heat propagation time between the battery cells 110.

[0062] On the other hand, one or more battery modules according to the present embodiment may be packaged in a battery pack case to form a battery pack.

[0063] The battery module and the battery pack including the battery module can be applied to various devices. Such devices can be applied to vehicle equipment such as electric bicycles, electric vehicles or hybrid vehicles, but the present disclosure is not limited thereto and can be applied to various devices that can use the battery module and the battery pack including the battery module within the scope of the present disclosure.

[0064] Although the present invention has been shown and described above with reference to the preferred embodiments, the scope of the present disclosure is not limited thereto, and those skilled in the art may make many other modifications and improvements to the present disclosure using the basic principles of the present invention described in the appended claims, which also fall within the spirit and scope of the present disclosure.

[0065] [Description of Reference Numerals]

[0066] 110: Battery Cell

[0067] 110B: Main body

[0068] 400: Barrier layer

[0069] 400a and 400b: first area and second area

Claims

1. A battery module, comprising: A battery cell stack formed by stacking a plurality of battery cells; as well as at least one barrier layer interposed between battery cells adjacent to each other among the plurality of battery cells, Wherein, the barrier layer includes a first region and a second region, The first region is a portion corresponding to the center of the battery cell, and the second region is a portion corresponding to the edge of the battery cell. wherein the first region of the barrier layer includes a first material and the second region of the barrier layer includes a second material, the first material having a higher thermal conductivity than the second material, wherein the first material has a higher compressibility than the second material, wherein the barrier layer is formed of a flame retardant member, Wherein, the first material comprises silicon material, the second material comprises mica material, and Wherein, the barrier layer is in complete contact with adjacent battery cells.

2. The battery module according to claim 1, wherein: The barrier layer includes the first region and the second region distinguished based on a surface facing a main body portion of the battery cell.

3. The battery module according to claim 2, wherein: The body portion of the battery cell corresponds to a surface perpendicular to a stacking direction of the battery cells.

4. The battery module according to claim 1, wherein: The battery module includes at least two barrier layers, and at least two of the battery cells are located between two adjacent barrier layers among the barrier layers. 5 . A battery pack comprising the battery module according to claim 1 .

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