Battery module

Abstract

The present application provides a battery module including a pad having a property of swelling at a predetermined temperature or higher, thereby blocking high-temperature and high-pressure gas discharged from a battery cell where an event occurs along a moving path, and thus, preventing the gas from spreading to other battery cells.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application No. 10-2020-0101615, filed on August 13, 2020 with the Korean Intellectual Property Office (KIPO), the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a battery module that can use a pad containing a material that expands in volume at a predetermined temperature or higher to delay or suppress events in the battery cell. Background Technology

[0004] Recently, electric vehicles (EVs) that use rechargeable batteries as their power source or hybrid vehicles (HEVs) that use batteries and another power source have been commercialized as environmentally friendly vehicles. For battery modules used in these electric and hybrid vehicles, pouch-type battery cells, which house individual battery cells within a pouch, are now commonly used. Here, multiple battery cells are stacked and housed within a single battery module, and the number of battery cells is determined based on the required power level.

[0005] Here, since multiple battery cells are stacked in a battery module, an event such as local damage, fire or leakage in one battery cell can affect other battery cells, and if such an event is not contained quickly, the event may spread to the entire module, so the entire battery module may be discarded, or in severe cases, there may be a risk of explosion.

[0006] Simultaneously, pads can be placed between battery cells to absorb thickness variations caused by tolerances during manufacturing or expansion during use. In related technologies, pads are only used to absorb tolerances caused by thickness variations by isolating battery cells, without delaying or suppressing events like those described above that occur within the battery cells.

[0007] [Related Technical Documents]

[0008] [Patent Literature]

[0009] Korean Patent Publication No. 10-2018-0036863 Summary of the Invention

[0010] Exemplary embodiments of the present invention aim to provide a battery module in which high-temperature, high-pressure gases emitted from a battery cell that has experienced an event such as partial damage are prevented from diffusing into other battery cells.

[0011] Exemplary embodiments of the present invention are directed to a battery module in which a battery cell in which an event such as a local damage is isolated from another battery cell to delay the event.

[0012] In one general aspect, a battery module includes a plurality of stacked battery cells, a side pad disposed between stacked surfaces of the plurality of battery cells, and a housing accommodating the plurality of battery cells and the side pad, wherein the side pad includes a material that is flame retardant and volumetrically expands at a predetermined temperature or higher.

[0013] The side pad can volumetrically expand at the predetermined temperature or higher to be in close contact with upper and lower inner walls of the housing to block a path of gas emitted from a battery cell in which an event occurs among the plurality of battery cells to a battery cell in which no event occurs among the plurality of battery cells.

[0014] The material can include a mineral that volumetrically expands as internal moisture thereof evaporates at the predetermined temperature or higher.

[0015] The mineral can be vermiculite.

[0016] The side pad can further include a high-temperature curable material.

[0017] The high-temperature curable material can include ceramic.

[0018] The high-temperature curable material can include 80 to 90 weight percent of mica and 10 to 20 weight percent of silicone.

[0019] The side pad can volumetrically expand at the predetermined temperature or higher to be in close contact with upper and lower inner walls of the housing, and then cure to form a barrier wall that isolates a battery cell in which an event occurs among the plurality of battery cells from a battery cell in which no event occurs among the plurality of battery cells.

[0020] In another general aspect, a battery module includes a plurality of stacked battery cells, a housing accommodating the plurality of battery cells, and an upper pad disposed between the plurality of battery cells and an upper inner wall of the housing, wherein the upper pad includes a material that is flame retardant and volumetrically expands at a predetermined temperature or higher.

[0021] The battery module can further include a side pad disposed between stack surfaces of the plurality of battery cells, wherein a vertical length of the side pad is longer than a vertical length of the battery cell.

[0022] The upper pad can expand in volume at a predetermined temperature or higher, thereby making close contact with the upper inner wall of the housing and the upper surface of the side pads to block the path of gas discharged from the battery cell where an event has occurred to the battery cell where no event has occurred.

[0023] The material may include minerals that expand in volume as their internal moisture evaporates at a predetermined temperature or higher.

[0024] The mineral could be vermiculite.

[0025] The top pad may also include a high-temperature curable material.

[0026] High-temperature curable materials can include ceramics.

[0027] The battery module may also include side pads disposed between the stacked surfaces of multiple battery cells, wherein the side pads comprise a flame-retardant material that expands in volume at a predetermined temperature or higher.

[0028] Side pads may also include high-temperature curable materials.

[0029] Other features and aspects will become apparent from the following detailed description, drawings and claims. Attached Figure Description

[0030] Figure 1 A battery module according to a first exemplary embodiment of the present invention is shown.

[0031] Figure 2 For along Figure 1 A cross-sectional view taken from line A-A'.

[0032] Figure 3 The illustration shows an event occurring in a battery cell according to a first exemplary embodiment of the invention.

[0033] Figure 4 A view illustrating the side pad in a first exemplary embodiment of the present invention.

[0034] Figure 5 A battery module according to a second exemplary embodiment of the present invention is shown.

[0035] Figure 6 For along Figure 5 The cross-sectional view taken by line B-B'.

[0036] Figure 7 A view showing a comparison of the lengths of the side pads and the battery cell in a second exemplary embodiment of the present invention.

[0037] Figure 8A situation in which an event occurs in a battery cell when a high-temperature expandable material is included in an upper pad in a second exemplary embodiment of the present application is shown.

[0038] Figure 9 A situation in which an event occurs in a battery cell when a high-temperature expandable material is included in an upper pad and a side pad according to a third exemplary embodiment of the present application is shown. DETAILED DESCRIPTION

[0039] Hereinafter, the present application will be described in detail with reference to the accompanying drawings. Detailed descriptions of known functions and components that can unnecessarily obscure the subject matter of the present application will be omitted.

[0040] In addition, terms such as "one surface", "another surface", "one side", "another side", "first", and "second" are used to distinguish one component from other components, and the components are not limited by the terms.

[0041] Figure 1 A battery module 1 according to a first exemplary embodiment of the present application is shown, Figure 2 is taken along a line A-A' of Figure 1 .

[0042] The battery module 1 according to the first exemplary embodiment of the present application includes a plurality of stacked battery cells 100, a side pad 200 disposed between stacked surfaces of the plurality of stacked battery cells 100, and a case 300 accommodating the plurality of battery cells 100 and the side pad 200.

[0043] First, the structure and direction of the case 300 of the battery module 1 will be described. Figure 1

[0044] The case 300 has a hexahedral shape, and for convenience of explanation, components disposed in a Z-axis direction of Figure 1 are defined as an upper plate 310, and components disposed on a surface opposite to the upper plate 310 are defined as a lower plate 320. In addition, components disposed in an X-axis direction of Figure 1 are defined as a first side plate 330 and a second side plate 340, and remaining components disposed in a Y-axis direction of Figure 1 are defined as a front plate 350 and a rear plate 360.

[0045] That is, the case 300 can include the upper plate 310, the lower plate 320, the first side plate 330, the second side plate 340, the front plate 350, and the rear plate 360. The case 300 can be configured by combining the respective detachable plates, or two or more plates can be integrated to constitute the case 300.

[0046] ​The housing 300 can be configured by connecting its respective detachable plates, or two or more plates can be integrated to form the housing 300.

[0047] The reference shows Figure 1 The cross section A-A' Figure 2 According to a first exemplary embodiment of the present invention, the housing 300 of the battery module 1 includes a plurality of battery cells 100 and side pads 200 disposed between the battery cells 100.

[0048] The surface orientation of the battery cell 100, i.e. the stacking direction of the battery cells 100, is the X-axis direction, and the tabs 110-1 and 110-2 of the battery cell 100 are drawn out in the Y-axis direction. When a surface of the battery cell 100 formed along the stacking direction of the battery cells 100 is called the stacking surface, the side pads 200 are disposed between the first side plate 330 and the stacking surface of the battery cell 100, between the stacking surfaces of each battery cell 100, and between the second side plate 340 and the stacking surface of the battery cell 100.

[0049] That is, the first side plate 330, side pad 200-1, battery unit 100-1, side pad 200-2, and battery unit 100-2 are stacked in this order. Although Figure 2 Only two battery cells 100 and two side pads 200 are shown. It will be apparent to those skilled in the art that the number of battery cells 100 and the number of side pads 200 can be increased or decreased as needed.

[0050] Here, the side pad 200 comprises a flame-retardant material that expands in volume at a predetermined temperature or higher (hereinafter referred to as "high-temperature expandable material").

[0051] In this case, the high-temperature expandable material may include a mineral that expands in volume as its internal moisture evaporates at a predetermined temperature or higher, and preferably, the mineral may be vermiculite.

[0052] Vermiculite is a monoclinic mineral with a mica-like crystal structure. Structurally, it is a three-layered mica-like mineral containing 8%-16% of its total weight in three types of water: hygroscopic water, interlayer water, and crystal water. When vermiculite is heated to a temperature range of 800℃ to 1100℃, the water in the interlayers turns into water vapor and expands. The vermiculite undergoes exfoliation, expanding to 6 to 30 times its original volume, becoming expanded vermiculite or foamed vermiculite, a porous crystal.

[0053] In addition to vermiculite, the side pad 200 of the battery module 1 of the present invention may include minerals that contain moisture and have the property of expanding in volume at a predetermined temperature or higher. For example, the mineral may be pearlite.

[0054] For example, mats containing mica can be cured at temperatures approaching 500°C to prevent heat transfer, and typical fire barrier pads expand in volume at 150°C to 200°C.

[0055] Figure 3 The illustration shows an event occurring in a battery cell 100 according to a first exemplary embodiment of the present invention.

[0056] Here, "event occurrence" refers to any situation that may cause the temperature of battery cell 100 to rise, such as partial damage to the battery cell due to physical impact, fire, or leakage of the battery cell.

[0057] refer to Figure 3 When an event occurs in any of the battery cells 100-1, the temperature of the corresponding battery cell 100-1 rises, and the temperature of the side pads 200-1 and 200-2 disposed on the two stacked surfaces of the corresponding battery cell 100-1 also rises. As the temperature of the side pads 200-1 and 200-2 continues to rise, due to the influence of the high-temperature expandable material contained therein, the volume of the side pads 200-1 and 200-2 expands in the Z-axis direction from a predetermined temperature or higher (the side pads 200-1 and 200-2 may also expand in the X-axis and Y-axis directions). Figure 3 The solid arrows in the diagram indicate the expansion direction of side pad 200. Due to volume expansion, the upper surfaces of side pads 200-1 and 200-2 are in close contact with the inner wall 310a of the upper plate, and the lower surfaces of side pads 200-1 and 200-2 are in close contact with the inner wall 320a of the lower plate. Here, the upper and lower surfaces of side pads 200-1 and 200-2 are the end faces at both ends in the Z-axis direction.

[0058] Therefore, the path of the high-temperature, high-pressure gas discharged from the battery cell 100-1 where the incident occurred to the other battery cell where the incident did not occur can be blocked. Figure 3 (The dashed arrow in the middle).

[0059] In other words, in the battery module 10 according to the first exemplary embodiment of the present invention, even when an event occurs in battery cell 100-1, its impact on other battery cells 100-2 can be minimized and the progress of the event can be delayed so that the event can be suppressed at an early stage.

[0060] Meanwhile, in the battery module 1 according to the first exemplary embodiment of the present application, the side pad 200 can further include a high-temperature curable material.

[0061] The battery cell 100-1 in which the event occurs can be swollen due to high temperature. The swelling phenomenon is a phenomenon in which the battery cell 100-1 swells, and when the battery cell 100-1 in which the event occurs swells and the volume expands, pressure is applied to the adjacent battery cell 100-2. If excessive pressure is applied to the adjacent battery cell 100-2 in which no event occurs, even the adjacent battery cell 100-2 can be damaged, and eventually, the event can spread to the entire battery module 1.

[0062] The battery module 1 according to the first exemplary embodiment of the present application, the side pad 200 is expanded by the high-temperature expandable material at a predetermined temperature or higher, thereby being in close contact with the inner wall 310a of the upper plate and the inner wall 320a of the lower plate, and then is cured in the expanded state by the high-temperature curable material.

[0063] Accordingly, since the battery cell 100-1 in which the event occurs and the other battery cell 100-2 in which no event occurs are isolated, and the side pad 200-1 and the side pad 200-2 are cured in a state of being in close contact with the inner wall of the upper plate 310a and the inner wall of the lower plate 320a, a position fixing barrier wall is formed which fixes the upper surface and the lower surface on both sides in the Z-axis direction.

[0064] Accordingly, even if the battery cell 100-1 in which the event occurs is expanded due to high temperature, excessive pressure applied to the adjacent battery cell 100-2 can be blocked by the position fixing barrier wall.

[0065] Here, the high-temperature curable material can include a ceramic.

[0066] For example, a pad including mica can include 80 to 90% by weight of mica and 10 to 20% by weight of silicone.

[0067] Meanwhile, the side pad 200 can include the high-temperature expandable material or the high-temperature curable material only in a portion thereof.

[0068] For example, with reference to Figure 4In the side pad 200, h1 is a portion 200a not including the high-temperature expandable material or the high-temperature curable material, and h2 is a portion 200b including the high-temperature expandable material or the high-temperature curable material. That is, the side pad 200 can be manufactured to include the high-temperature expandable material or the high-temperature curable material only in specific regions of both ends in the Z-axis direction (i.e., the up-and-down direction) of the side pad 200. In this way, when the high-temperature expandable material or the high-temperature curable material is included only in the specific regions of the side pad 200, the manufacturing cost can be reduced compared to a case in which the entire side pad 200 includes the above-described material.

[0069] Here, h1 can be manufactured to be greater than or equal to the length h3 of the battery cell 100 in the Z-axis direction. In this case, the region h2 of the side pad 200 is located outside the region in which the battery cell 100 exists in the housing 300. In the related art, the side pad 200 functions to absorb the dimensional tolerance of the battery cell 100, and thus the side pad 200 is formed of a material having elasticity. However, when the side pad 200 includes the high-temperature expandable material or the high-temperature curable material, such elasticity can be reduced, thereby weakening the original function of the tolerance absorption function, and thus the region h2 can be located outside the region in which the battery cell 100 exists. The lengths of h1 and h2 can be freely adjusted according to the manufacturing cost of the side pad 200, the strength required for the side pad 200, or the degree of expansion required for the side pad 200.

[0070] Figure 5 To show a view of the battery module 2 according to the second exemplary embodiment of the present application, Figure 6 To show a cross-sectional view taken along Figure 5 line B-B'.

[0071] Referring to Figure 5 , the housing 800 of the battery module 2 according to the second exemplary embodiment of the present application includes an upper plate 810 disposed in the Z-axis direction of Figure 5 , a lower plate 820 disposed on a side facing the upper plate 810, a first side plate 830 and a second side plate 840 disposed in the X-axis direction of Figure 5 , and a front plate 850 and a rear plate 860 disposed in the Y-axis direction of Figure 5 .

[0072] Here, referring to Figure 6 , the housing 800 includes a plurality of stacked battery cells 600 and an upper pad 700 disposed between the battery cells 600 and the upper plate 810.

[0073] Here, the upper pad 700 can be attached to the inner wall 810a of the upper plate to fill the space between the upper plate 810 and the battery cells 600 or to insulate the upper plate 810 and the battery cells 600.

[0074] Further, the upper pad 700 can include a high-temperature swellable material that is flame retardant and swells in volume at a predetermined temperature or higher, where the high-temperature swellable material can include a mineral that swells in volume as internal moisture evaporates at a predetermined temperature or higher, and the mineral can be vermiculite.

[0075] Further, the battery module 2 according to the second exemplary embodiment can further include side pads 900 disposed between the stacked surfaces of the plurality of battery cells 600 to absorb dimensional tolerances of the battery cells 600.

[0076] Here, as Figure 7 shown, the length of the side pad 900 in the up-and-down vertical direction, i.e., the length h4 in the Z-axis direction, is greater than the length h5 of the battery cell 600 in the Z-axis direction, so that the upper pad 700 can be in close contact with the side pad 900 when it swells, rather than being in close contact with the battery cell 600.

[0077] Figure 8 A case where an event occurs in the battery cell 600 when the high-temperature swellable material is included in the upper pad 700 is shown in the second exemplary embodiment according to the present application.

[0078] Referring to Figure 8 , when an event occurs in any one of the battery cells 600-1, the temperature of the corresponding battery cell 600-1 increases and the temperature of the upper pad 700 disposed between the corresponding battery cell 600-1 and the upper plate 810 also increases. As the temperature of the upper pad 700 continues to increase, the volume of the upper pad 700 swells in the Z-axis direction starting from a predetermined temperature or higher (the upper pad 700 can also swell in the X-axis and Y-axis directions, Figure 8 the solid arrow in the drawing indicates the swelling direction of the upper pad 700).

[0079] Due to the volume swelling, the upper pad 700 is in close contact with the upper surface of the side pad 900. In other words, when one side of the upper pad 700 in the Z-axis direction is attached to and in close contact with the inner wall 810a of the upper plate, the other side of the upper pad 700 in the Z-axis direction swells in volume in the direction of the battery cell 600, thereby being in close contact with the upper surface of the side pad 900, and as Figure 8 shown, the battery cell 600-1 in which the event has occurred is trapped between the upper pad 700 and the side pads 900-1 and 900-2.

[0080] Therefore, the path of the high-temperature high-pressure gas discharged from the battery cell 600-1 in which the event has occurred to another battery cell 600-2 in which no event has occurred can be blocked.

[0081] That is, the battery module 2 according to the second exemplary embodiment of the present application has an effect that the progress of an event can be delayed and the event can be suppressed at an early stage even when the event occurs in the battery cell 600.

[0082] Meanwhile, in the battery module 2 according to the second exemplary embodiment of the present application, the upper pad 700 can further include a high-temperature curable material, where the high-temperature curable material can be ceramic. In addition, the high-temperature curable material can be a pad including 80 to 90 wt% of mica and 10 to 20 wt% of silicone resin.

[0083] That is, the upper pad 700 can be volumetrically expanded at a predetermined temperature or higher by the high-temperature expandable material, thereby being in close contact with the inner wall 810a of the upper plate and the upper surface of the side pad 900, and can be cured in the expanded state by the high-temperature curable material.

[0084] Figure 9 An event occurring in the battery cell 600 when the high-temperature expandable material is included in the upper pad 700 and the side pad 900 in the third exemplary embodiment of the present application is illustrated.

[0085] In the battery module 2 according to the third exemplary embodiment, the side pad 900 can include a high-temperature expandable material that is flame retardant and is volumetrically expanded at a predetermined temperature or higher, like the upper pad 700.

[0086] In addition, in the battery module 2 according to the third exemplary embodiment, the side pad 900 can further include a high-temperature curable material.

[0087] In the battery module 2 according to the third exemplary embodiment of the present application, in the case where the high-temperature expandable material is included in both the upper pad 700 and the side pad 900, if an event occurs in the battery cell 600, the upper pad 700 and the side pad 900 are both expanded in the Z-axis direction as Figure 9 indicated by the solid arrows in FIG. 10 (the upper pad 700 and the side pad 900 can also be expanded in the X-axis and Y-axis directions, Figure 9 the expansion directions of the upper pad 700 and the side pad 900 are indicated by the solid arrows in FIG. 10).

[0088] More specifically, the upper pad 700 is expanded in the Z-axis direction, i.e., in the direction in which the battery cell 600 is located, and the side pad 900 is expanded on both sides of the Z-axis direction until the side pad 900 is in close contact with the upper pad 700 and the inner wall 820a of the lower plate. As a result, the upper surface on one side of the Z-axis direction of the side pad 900 is in close contact with and fixed to the upper pad 700, while the lower surface on the other side of the side pad 900 is in close contact with and fixed to the inner wall 820a of the lower plate, and as Figure 9As shown, the battery cell 600-1 in which the event occurs is trapped between the upper pad 700 and the side pads 900-1 and 900-2.

[0089] That is, when the event occurs, the side pads 900 and the upper pad 700 expand together to block the moving path of the high-temperature, high-pressure gas occurring due to the event.

[0090] Further, in this case, the side pads 900 are solidified in the expanded state, so that they can serve as a barrier wall between the battery cells as in the first exemplary embodiment.

[0091] As described above, since the battery module of the present application includes the pads having the property of expanding at a temperature of a predetermined temperature or more, the high-temperature, high-pressure gas discharged from the battery cell in which the event occurs can be blocked along the moving path, and thus, the gas can be prevented from spreading to other battery cells.

[0092] Further, since the battery module of the present application includes the pads which are solidified after expanding at a temperature of a predetermined temperature or more, a barrier isolating the battery cell in which the event occurs from other battery cells can be formed, and thus, the progress of the event can be delayed.

[0093] Although the present application has been described through limited exemplary embodiments and drawings, the present application is not limited to the above-described exemplary embodiments, and various modifications and changes can be made by those skilled in the art in light of the above description. Therefore, the spirit of the present application is limited only by the appended claims, and includes all modifications and equivalents falling within the scope of the appended claims.

[0094]

Detailed description of main elements

[0095] 1, 2: battery module

[0096] 100, 100-1, 100-2, 600, 600-1, 600-2: battery cell

[0097] 110-1, 110-2: electrode tab

[0098] 200, 200-1, 200-2, 900, 900-1, 900-2: side pad

[0099] 300, 800: case

[0100] 310, 810: upper plate

[0101] 320, 820: lower plate

[0102] 330, 830: first side plate

[0103] 340, 840: second side plate

[0104] 350, 850: front plate

[0105] 360, 860: back plate

[0106] 700: upper pad

Claims

1. A battery module comprising: a plurality of stacked battery cells; a side pad disposed between stacked surfaces of the plurality of battery cells; and a case accommodating the plurality of battery cells and the side pad, wherein only in a predetermined region of both ends in an up-and-down direction of the side pad, a material that is flame retardant and volumetrically expands or solidifies at a predetermined temperature or higher is included, the predetermined region is a region other than a region in which the battery cells exist. The side pad volumetrically expands at a predetermined temperature or higher, thereby being in close contact with upper and lower inner walls of the case, to block a path of gas discharged from a battery cell in which an event has occurred among the plurality of battery cells to a battery cell in which no event has occurred among the plurality of battery cells.

2. The battery module of claim 1, wherein, The material includes a mineral that volumetrically expands as internal moisture thereof evaporates at a predetermined temperature or higher.

3. The battery module of claim 1, wherein, 4.The battery module of claim 3, wherein the mineral is vermiculite. The side pad further includes a high-temperature solidifiable material.

5. The battery module of claim 1, wherein, The high-temperature solidifiable material includes a ceramic.

6. The battery module of claim 5, wherein, The high-temperature solidifiable material includes 80 to 90% by weight of mica and 10 to 20% by weight of silicone resin.

7. The battery module of claim 5, wherein, The side pad volumetrically expands at a predetermined temperature or higher, thereby being in close contact with upper and lower inner walls of the case, and then solidifies to form a barrier wall that isolates a battery cell in which an event has occurred among the plurality of battery cells from a battery cell in which no event has occurred among the plurality of battery cells.

8. The battery module of claim 6, wherein, 9.A battery module comprising: a plurality of stacked battery cells; a case accommodating the plurality of battery cells; an upper pad disposed between the plurality of battery cells and an upper inner wall of the case; and a side pad disposed between stacked surfaces of the plurality of battery cells, wherein the upper pad and the side pad include a material that is flame retardant and volumetrically expands or solidifies at a predetermined temperature or higher, a vertical length of the side pad is longer than a vertical length of the battery cells, such that the upper pad is in close contact with the side pad, not the battery cells, when it expands. The upper pad volumetrically expands at a predetermined temperature or higher, thereby being in close contact with an upper inner wall of the case and an upper surface of the side pad, to block a path of gas discharged from a battery cell in which an event has occurred among the plurality of battery cells to a battery cell in which no event has occurred among the plurality of battery cells. The material includes a mineral that volumetrically expands as internal moisture thereof evaporates at a predetermined temperature or higher.

10. The battery module of claim 9, wherein, 12.The battery module of claim 11, wherein the mineral is vermiculite.

11. The battery module of claim 9, wherein, The upper pad further includes a high-temperature solidifiable material. 14.The battery module of claim 13, wherein the high-temperature solidifiable material includes a ceramic.

13. The battery module of claim 9, wherein, The side pad further includes a high-temperature solidifiable material. ​ 15. The battery module of claim 9, wherein, ​

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