Battery module having pad composite having swelling absorption and heat shielding function, battery pack comprising the same and vehicle

Abstract

To provide a battery module having a structure capable of absorbing volume expansion caused by swelling of a battery cell, maintaining a gap between adjacent battery cells constantly even if a temperature in the battery module rises above a critical value due to abnormal heating generated in some battery cells, and delaying propagation of thermal runaway between adjacent battery cells.SOLUTION: A battery module includes: a cell stack including a plurality of battery cells and at least one pad composite interposed between neighboring battery cells; and a module case configured to accommodate the cell stack. The pad composite includes a pair of swelling absorption pads compressed according to volume expansion of the battery cell caused by swelling; and a heat shielding pad interposed between the pair of swelling absorption pads to block heat transfer between the neighboring battery cells and configured to expand at a preset reference temperature or above.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a battery module including a pad composite having a swelling absorption and heat insulation function, a battery pack including the same, and an automobile. More specifically, the present invention relates to a swelling absorption pad compressed by the expansion of a battery cell due to swelling, and a heat insulation pad that expands when the swelling absorption pad is damaged due to an increase in the internal temperature of the battery module and fills the space occupied by the swelling absorption pad. The present invention relates to a battery module, a battery pack including the same, and an automobile to which a pad composite including the same is applied.

[0002] This application claims priority based on Korean Patent Application No. 10-2019-0024840 filed on March 4, 2019, and all of the contents disclosed in the specification and drawings of the application are incorporated into this application.

Background Art

[0003] Generally, a battery module is provided with a cooling system to prevent the life of the battery module from being rapidly shortened by temperature during long-term use. Such a cooling system is designed in consideration of the heat generation amount depending on the usage environment of the battery module.

[0004] However, during the use of the battery module, if some battery cells generate abnormal heat due to a failure and the temperature continuously rises and exceeds the critical temperature, a thermal runaway phenomenon may occur, leading to safety issues.

[0005] That is, if thermal runaway occurs in some battery cells and spreads to adjacent battery cells in a short time, the temperature of the entire battery module will rise rapidly, which may lead to a temperature rise of the entire battery pack including multiple battery modules, causing great damage to property and human life. Therefore, in order to prevent such rapid propagation of the thermal runaway phenomenon, it is necessary to apply a member for thermal insulation between adjacent battery cells.

[0006] In addition, between adjacent battery cells, a buffer member that can be compressed by the expansion of the battery cell due to swelling and absorb the swelling is applied. As such a buffer member, an expanded polypropylene (EPP) pad or a urethane pad can be used.

[0007] The buffer pad made of such a material has a certain level of elasticity under normal use conditions of the battery module, and absorbs the swelling while being compressed when the battery cell expands due to swelling. In addition, by maintaining the distance between adjacent battery cells, it functions to delay the heat transfer between adjacent battery cells during abnormal heat generation.

[0008] However, such a buffer pad made of this material is likely to be damaged and may shrink when thermal runaway occurs in some battery cells, causing the temperature in the battery module to exceed the critical value.

[0009] When the buffer pad is damaged by heat and shrinks in this way, the distance between adjacent battery cells through the buffer pad is reduced, and the propagation speed of the thermal runaway phenomenon between adjacent battery cells can be further increased.

[0010] Therefore, there is a demand for the development of a battery module having a structure that can absorb the volume expansion due to the swelling of battery cells, and at the same time, even if the temperature in the battery module rises above the critical value due to abnormal heat generation occurring in some of the battery cells, the distance between adjacent battery cells can be kept constant, and the propagation of the thermal runaway phenomenon between adjacent battery cells can be delayed.

Summary of the Invention

Problems to be Solved by the Invention

[0011] The present invention has been made in view of the above problems, and an object thereof is to provide a battery module having a structure that can absorb the volume expansion due to the swelling of battery cells, and even if the temperature in the battery module rises above the critical value due to abnormal heat generation occurring in some of the battery cells, the distance between adjacent battery cells can be kept constant, and the propagation of the thermal runaway phenomenon between adjacent battery cells can be delayed.

[0012] The technical problems to be solved by the present invention are not limited to the above problems, and other problems will be clearly understood by those skilled in the art from the following description of the invention.

Means for Solving the Problems

[0013] To solve the above-described problems, a battery module according to an aspect of the present invention includes a cell laminate including a plurality of battery cells and at least one pad composite interposed between adjacent battery cells, and a module case that houses the cell laminate, and the pad composite includes a pair of swelling absorption pads that are compressed by the volume expansion due to the swelling of the battery cells, and a heat insulation pad that is interposed between the pair of swelling absorption pads to block heat transfer between adjacent battery cells and expands at a preset reference temperature or higher.

[0014] The swelling absorption pad may contract above the reference temperature and the thickness may decrease.

[0015] The heat insulation pad can expand at a temperature equal to or higher than the reference temperature to fill the space generated by the contraction of the swelling absorption pad.

[0016] The expansion rate in the thickness direction of the heat insulation pad at a temperature equal to or higher than the reference temperature can be 5 to 40.

[0017] The battery cell can be a pouch-type battery cell.

[0018] One of the pad composites is provided, and one of the pad composites can be arranged at the central part in the stacking direction of the cell laminate.

[0019] The battery module may further include a plurality of swelling absorption pads arranged between every pair of cell groups including a plurality of battery cells.

[0020] A plurality of the pad composites are provided, and the plurality of pad composites can be arranged between every pair of cell groups including a plurality of battery cells.

[0021] The swelling absorption pad may include at least one of EPP and urethane.

[0022] The heat insulation pad may include at least one of epoxy resin, butyl resin, and vinyl chloride resin.

[0023] On the other hand, a battery pack and an automobile according to another aspect of the present invention include a battery module according to one aspect of the present invention as described above.

Effect of the Invention

[0024] According to one aspect of the present invention, it is possible to provide a battery module that can absorb volume expansion due to swelling of battery cells, maintain a constant interval between adjacent battery cells even when the temperature inside the battery module exceeds a critical value due to abnormal heat generation occurring in some battery cells, and can delay the propagation of a thermal runaway phenomenon between adjacent battery cells.

[0025] The following drawings attached to this specification illustrate desirable embodiments of the present invention and serve to further understand the technical idea of the present invention together with the detailed description of the invention. Therefore, the present invention should not be construed as being limited only to the matters described in the drawings.

Brief Description of the Drawings

[0026]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Modes for Carrying Out the Invention

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in this specification and claims should not be construed as being limited to ordinary or dictionary meanings. The inventor himself must interpret them in accordance with the meaning and concept corresponding to the technical idea of the present invention in accordance with the principle that he can appropriately define the concept of terms in order to explain the invention in the best way. Therefore, it should be understood that the embodiments described in this specification and the configurations shown in the drawings are only one of the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, there may be various equivalents and modifications that can replace them at the time of this application.

[0028] First, with reference to FIGS. 1 to 4, a battery module according to an embodiment of the present invention will be described.

[0029] FIG. 1 is a perspective view showing a battery module according to an embodiment of the present invention, and FIG. 2 is a view showing a battery cell applied to the battery module according to an embodiment of the present invention. Further, FIG. 3 is a view showing a cell laminate applied to the battery module according to an embodiment of the present invention, showing a case where the internal temperature of the battery module is lower than the reference temperature. Further, FIG. 4 is a view showing a cell laminate applied to the battery module according to an embodiment of the present invention, showing a case where the internal temperature of the battery module is equal to or higher than the reference temperature.

[0030] Referring to FIGS. 1 to 4, a battery module according to an embodiment of the present invention includes a cell laminate 100 and a module case 200 that houses the cell laminate 100. The cell laminate 100 includes a plurality of battery cells 110 and at least one pad composite 120 interposed between adjacent battery cells 110.

[0031] As the above battery cell 110, for example, a pouch-type battery cell can be applied. When the battery cell 110 is a pouch-type battery cell, as shown in FIG. 2, the battery cell 110 can be embodied in a form including an electrode assembly (not shown), a pouch case 111, an electrode lead 112, and a sealing tape 113.

[0032] Although not shown, the above electrode assembly has a form in which separators are interposed between a positive electrode plate and a negative electrode plate that are alternately and repeatedly laminated, and it is desirable that separators are respectively located on the outermost contours on both sides for insulation.

[0033] The above positive electrode plate is composed of a positive electrode current collector and a positive electrode active material layer coated on one surface thereof, and a positive electrode uncoated region where the positive electrode active material is not coated is formed at one end portion, and this positive electrode uncoated region functions as a positive electrode tab.

[0034] The above negative electrode plate is composed of a negative electrode current collector and a negative electrode active material layer coated on one surface or both surfaces thereof, and a negative electrode uncoated region where the negative electrode active material is not coated is formed at one end portion, and this negative electrode uncoated region functions as a negative electrode tab.

[0035] Also, the above separator is interposed between the positive electrode plate and the negative electrode plate to prevent the electrode plates with different polarities from directly contacting each other, and can be made of a porous material in order to enable the movement of ions mediated by an electrolyte between the positive electrode plate and the negative electrode plate.

[0036] The above cell case 111 includes a housing portion 111a for housing the electrode assembly, and a sealing portion 111b for sealing the cell case 111 by being heat-sealed in a state where the electrode lead 112 is drawn out to the outside and extends in the peripheral direction of the housing portion 111a.

[0037] Although not shown, the above cell case 111 is sealed by the peripheral portions of an upper case and a lower case each composed of a multilayer pouch film in which a resin layer / metal layer / resin layer are sequentially laminated being brought into contact with each other and heat-sealed.

[0038] The pair of electrode leads 112 are each connected to a positive tab (not shown) and a negative tab (not shown) and drawn out to the outside of the cell case 111. The pair of electrode leads 112 are drawn out side by side on one side in the longitudinal direction of the battery cell 110, or are drawn out to one side and the other side in the longitudinal direction of the battery cell 110, respectively. That is, the battery cell 110 applied to the present invention may be a one-way lead-out type battery cell in which the positive electrode lead and the negative electrode lead are drawn out in the same direction, or may be a two-way lead-out type battery cell in which they are drawn out in opposite directions to each other.

[0039] The sealing tape 113 is attached around the electrode lead 112 and is interposed between the inner surface of the sealing portion 111b of the pouch case 111 and the electrode lead 112. The sealing tape 113 prevents a decrease in the sealing performance of the sealing portion 111b due to the drawing out of the electrode lead 112.

[0040] The pad composite body 120 is interposed between adjacent battery cells 110, and only one may be provided in order to minimize an increase in the thickness of the cell laminate 100. When only one pad composite body 120 is provided in this way, it is desirable that the pad composite body 120 be disposed at the central portion in the stacking direction of the cell laminate 100. This is to efficiently block the propagation of the thermal runaway phenomenon between adjacent battery cells 110.

[0041] The pad composite body 120 includes a pair of swelling absorption pads 121 and a heat insulation pad 122 interposed between the pair of swelling absorption pads 121.

[0042] When the battery module repeatedly charges and discharges, swelling occurs in the battery cell 110, and when the battery cell 110 expands so as to bulge in the stacking direction, the swelling absorption pad 121 is compressed to absorb the swelling. In consideration of such a function, the swelling absorption pad 121 is made of an elastic material and can include at least one of, for example, expanded polypropylene (EPP) and urethane.

[0043] When the internal temperature of the battery module becomes as high as about 100°C to 300°C due to abnormal heat generation of the battery module, the swelling absorption pad 121 is damaged and shrinks, and when the high-temperature state continues for a certain period of time or more, its thickness becomes almost close to 0.

[0044] The heat insulation pad 122 is interposed between a pair of swelling absorption pads 121, and minimizes the heat transfer between the battery cells 110 located on both sides via the pad composite 120. Further, the heat insulation pad 122 has a property of expanding when the internal temperature of the battery module rises abnormally and the temperature becomes equal to or higher than the temperature (about 100°C to 300°C) at which the swelling absorption pad 121 is damaged and shrinks.

[0045] Due to such operating characteristics according to temperature, the heat insulation pad 122 can include at least one of, for example, epoxy resin, butyl resin, and vinyl chloride resin.

[0046] When the internal temperature of the battery module rises due to abnormal heat generation of the battery module and becomes equal to or higher than the reference temperature (about 100°C to 300°C), the heat insulation pad 122 expands to fill the space formed by the damage of the swelling absorption pad 121. That is, the heat insulation pad 122 prevents the swelling absorption pad 121 from being damaged due to abnormal heat generation of the battery module and generating a space between adjacent battery cells 110, thereby preventing the distance between adjacent battery cells 110 from becoming close and efficiently blocking the heat transfer.

[0047] The expansion rate of the above-mentioned thermal cut-off pad 122 is about 5 to 40, and the expansion occurs only in the thickness direction. Therefore, when the internal temperature of the battery module becomes equal to or higher than the reference temperature, the thermal cut-off pad 122 can expand sufficiently so that no space is created between adjacent battery cells 110.

[0048] Also, the above-mentioned thermal cut-off pad 122 has a very low thermal conductivity in the range of about 0.05 to 0.5 W / m-k, whereby heat transfer between the battery cells 110 located on both sides via the pad composite 120 can be minimized.

[0049] Hereinafter, with reference to FIG. 5, a battery module according to another embodiment of the present invention will be described.

[0050] FIG. 5 is a diagram showing a cell laminate applied to a battery module according to another embodiment of the present invention.

[0051] The battery module according to another embodiment of the present invention is substantially the same as the battery module according to the above-described embodiment of the present invention, except that the number of applications of the pad composite 120 is different.

[0052] Therefore, in the battery module according to another embodiment of the present invention, only the application positions of the plurality of pad composites 120 will be described, and specific descriptions of matters overlapping with the above-described embodiment will be omitted.

[0053] Referring to FIG. 5, the battery module according to another embodiment of the present invention includes a plurality of pad composites 120. The pad composite 120 is disposed between each of a plurality of cell groups including a plurality of battery cells 110. The number of battery cells 110 included in one cell group can be determined in consideration of the number of battery cells 110 included in the battery module, the capacity of the battery cells 110, the thickness of the pad composite 120, and the like.

[0054] Hereinafter, with reference to FIG. 6, a battery module according to still another embodiment of the present invention will be described.

[0055] FIG. 6 is a diagram showing a cell laminate applied to a battery module according to still another embodiment of the present invention.

[0056] The battery module according to still another embodiment of the present invention differs only in that a swelling absorption pad 121 is further applied in addition to the pad composite 120 as compared with the battery module according to one embodiment of the present invention described above, and other matters are substantially the same.

[0057] Therefore, in the battery module according to still another embodiment of the present invention, only the application position of the additionally applied swelling absorption pad 121 will be described, and specific descriptions of matters overlapping with the above-described embodiments will be omitted.

[0058] The battery module according to still another embodiment of the present invention further includes a plurality of swelling absorption pads 121 arranged between cell groups including a plurality of battery cells 110 in addition to the pad composite 120 arranged at the central portion in the thickness direction of the cell laminate 100.

[0059] When the swelling absorption pads 121 are applied to a plurality of locations of the cell laminate 100 in this way, the volume expansion due to the swelling of the battery cells 110 can be stably absorbed. Further, the battery module according to still another embodiment of the present invention is provided with the pad composite 120 at the central portion of the cell laminate 100 as in the battery module according to one embodiment of the present invention described above. Therefore, even when an abnormal heat generation phenomenon occurs, the propagation of the thermal runaway phenomenon can be prevented or delayed with the central portion in the thickness direction of the cell laminate 100 as a boundary, and the safety in using the battery module can be ensured.

[0060] As described above, the present invention has been explained by way of limited embodiments and drawings. However, the present invention is not limited thereto, and it goes without saying that various modifications and variations can be made by those having ordinary knowledge in the technical field to which the present invention pertains within the equivalent scope of the technical idea and claims of the present invention.

[0061] Furthermore, it is also preferable that the following examples are included in the present invention. [1] A cell laminate including a plurality of battery cells and at least one pad composite interposed between adjacent battery cells, and a module case housing the cell laminate, wherein the pad composite includes a pair of swelling absorption pads compressed by volume expansion due to swelling of the battery cell, and a heat insulation pad interposed between the pair of swelling absorption pads to block heat transfer between adjacent battery cells and expanding at a preset reference temperature or higher, a battery module. [2] The battery module according to [1], wherein the swelling absorption pad shrinks at the reference temperature or higher and the thickness decreases. [3] The battery module according to [2], wherein the heat insulation pad expands at the reference temperature or higher to fill the space generated by the shrinkage of the swelling absorption pad. [4] The battery module according to [3], wherein the expansion rate in the thickness direction of the heat insulation pad at the reference temperature or higher is 5 to 40. [5] The battery module according to any one of [1] to [4], wherein the battery cell is a pouch-type battery cell. [6] The battery module according to any one of [1] to [5], wherein one of the pad composites is provided, and one of the pad composites is disposed at the central portion in the stacking direction of the cell laminate. [7] The battery module according to [6], further including a plurality of swelling absorption pads disposed between each of a plurality of cell groups including a plurality of battery cells. [8] The battery module according to any one of [1] to [5], wherein a plurality of the pad complexes are provided, and the plurality of pad complexes are arranged between cell groups each including a plurality of battery cells. [9] The battery module according to any one of [1] to [8], wherein the swelling absorption pad includes at least one of foamed polypropylene and urethane.

[10] The battery module according to any one of [1] to [9], wherein the heat insulation pad includes at least one of epoxy resin, butyl resin, and vinyl chloride resin.

[11] A battery pack including the battery module according to any one of [1] to

[10] .

[12] An automobile including the battery module according to any one of [1] to

[10] .

Description of reference numerals

[0062] 100 Cell laminate 110 Battery cell 111 Pouch case, cell case 111a Accommodating portion 111b Sealing portion 112 Electrode lead 113 Sealing tape 120 Pad complex 121 Swelling absorption pad 122 Heat insulation pad 200 Module case

Claims

1. A pair of battery cells; a composite member including a pair of first members interposed between the pair of battery cells, and a second member interposed between the pair of first members in a state of contact with the pair of first members and having a thermal expansion coefficient different from that of the first members, The pair of first members are compressed by volume expansion due to swelling, A battery module, wherein the second member expands into a space created by the contraction of the pair of first members when the pair of first members are damaged by heat and contract.

2. The battery module according to claim 1 , wherein the pair of first members shrink and reduce in thickness at a temperature equal to or higher than a reference temperature.

3. The battery module according to claim 1 , wherein the pair of first members includes an elastic material.

4. The battery module according to claim 1 , wherein the pair of first members are configured to absorb swelling of the battery cells.

5. The battery module of claim 1 , wherein the pair of first members are configured to be damaged and contract when an internal temperature of the battery module rises to a temperature of 100° C. to 300° C.

6. The battery module according to claim 2 , wherein the second member is configured to expand at or above the reference temperature to fill a space created by contraction of the pair of first members.

7. The battery module according to claim 6 , wherein the second member is configured to expand under a temperature condition in which the pair of first members are damaged and contract.

8. The battery module according to claim 7, wherein the second member is configured to expand when an internal temperature of the battery module increases to a temperature of 100°C to 300°C.

9. 2 . The battery module of claim 1 , wherein the pair of first members are configured to maintain contact with both sides of the second member regardless of an internal temperature of the battery module.

10. A battery pack comprising the battery module according to any one of claims 1 to 9.

11. A motor vehicle comprising a battery module according to any one of claims 1 to 9.

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