Battery module, battery pack including the same, and vehicle

Abstract

The present invention provides a battery module including a first battery cell, a second battery cell positioned opposite and in contact with the first battery cell, and a graphite sheet provided between the first and second battery cells, with both sides in surface contact with the opposing sides of the first and second battery cells, respectively; a battery pack including the same; and a vehicle.

Description

Technical Field

[0001] The present invention relates to a battery module, a battery pack including the same, and a vehicle, which can eliminate thermal imbalance in battery cells, achieve thermal balancing, prevent deterioration of battery cells, enhance performance, and enhance the safety of battery cells by preventing heat concentration at specific sites.

Background Art

[0002] In recent years, technologies for carbon reduction have been actively developed to address environmental issues such as abnormal temperatures. To reduce carbon, it is necessary to produce energy in an environmentally friendly way rather than from fossil fuels, store the produced energy in the form of electrical energy, and use this stored electrical energy in vehicles, various industrial sites, and households.

[0003] To utilize electrical energy for carbon reduction, the use of a battery that can store and derive electrical energy is essential. Therefore, to ensure sufficient storage of electrical energy and use it without inconvenience, ensuring the performance of the battery is essential.

[0004] Batteries mainly use the oxidation-reduction reaction of metal ions. To increase the capacity, charge-discharge performance, and efficiency of batteries, metal ions are used at high density, and much research has also been conducted on substances constituting electrolytes and solid electrolytes. However, generally, there is a problem that as the performance of batteries develops, the safety decreases.

[0005] Batteries used in vehicles, industries, or homes are manufactured in physical units called battery packs. A battery pack encloses numerous battery cells inside a sealed battery case, preventing fire from spreading to the outside in the event of an accident such as battery overheating, and protecting the internal battery cells from degradation due to external environmental factors or physical damage.

[0006] A battery pack contains numerous battery cells in an intermediate form between a module and an assembly (CMA, Cell module assembly). In the case of battery modules or assemblies, numerous battery cells are assembled into a single module or assembly, and the battery pack is completed by fastening these numerous modules inside the pack case. Maintenance is made easier by allowing maintenance to be performed in these module or assembly units.

[0007] The numerous unit battery cells that make up a module or assembly consist of a positive electrode, a negative electrode, and an electrolyte. Since battery cells generate heat during charging and discharging, effective heat dissipation is necessary. Furthermore, from the perspective of battery modules, assemblies, or battery packs, efficient heat dissipation design is essential to prevent safety accidents.

[0008] On the other hand, batteries can deteriorate due to manufacturing errors, excessive charging and discharging, and aging. If battery deterioration persists, it can eventually lead to a fire. Therefore, it is necessary to take precautions in advance to prevent fires caused by batteries.

[0009] For this reason, batteries require cooling of the battery modules and assemblies by a cooling system, and overall temperature balancing must be achieved among the battery cells that make up the modules and assemblies.

[0010] The matters described above as background technology are merely for the purpose of enhancing understanding of the background of the present invention and should not be accepted as constituting prior art already known to those with ordinary skill in the art. [Overview of the project] [Problems that the invention aims to solve]

[0011] This invention was proposed to solve these problems and aims to provide a battery module, a battery pack including the same, and a vehicle that improve the performance and safety of battery cells by performing thermal balancing of the battery cells.

[0012] The technical problems that this invention aims to solve are not limited to those mentioned above, and other technical problems not mentioned will be clearly understandable to a person with ordinary skill in the art to which this invention belongs from the following description. [Means for solving the problem]

[0013] To achieve the above objective, the battery module according to the present invention includes a first battery cell, a second battery cell arranged to face and be in contact with the first battery cell, and a first graphite sheet provided between the first battery cell and the second battery cell, with both sides in surface contact with the opposing sides of the first and second battery cells, respectively.

[0014] The first graphite sheet is bonded and fixed to the side of either the first or second battery cell, and can make surface contact with the sides of the remaining battery cell during assembly.

[0015] The first graphite sheet can be bonded and fixed to each side of the first battery cell, and the second battery cells can be assembled so that they are in close contact with each side of the first battery cell.

[0016] Compression pads may be provided between a plurality of adjacent first battery cells or between a plurality of adjacent second battery cells.

[0017] The compression pad is equipped with a second graphite sheet on both sides, and the second graphite sheet can be in close contact with the compression pad and the battery cell.

[0018] The edge of the first graphite sheet can be folded to one side to surround the end face of the first or second battery cell.

[0019] The bent end of the first graphite sheet can come into contact with the cooling section.

[0020] A thermally conductive resin may be provided between the bent end of the first graphite sheet and the cooling section.

[0021] Through-holes are formed at the bent ends of the first graphite sheet, allowing the thermally conductive resin to contact the end face of the first or second battery cell through the through-holes.

[0022] A second battery cell is positioned on each side of the first battery cell, and the first graphite sheet can be folded multiple times to surround both sides and the end face of the first battery cell.

[0023] A second graphite sheet may be provided between a pair of adjacent second battery cells.

[0024] A second battery cell and a compression pad are positioned on each side of the first battery cell, and the first graphite sheet can be folded multiple times to surround both sides and the end face of the first battery cell together.

[0025] Between a pair of compression pads, a pair of first battery cells are provided. Between the pair of first battery cells, a pair of second battery cells are provided adjacent to each other. The first graphite sheet can be folded multiple times to surround both side surfaces and end surfaces of each first battery cell together.

[0026] A second graphite sheet may be provided between a pair of second battery cells adjacent to each other.

[0027] Between a pair of compression pads, a pair of first battery cells are provided. Between the pair of first battery cells, a second battery cell is provided. The first graphite sheet can be folded multiple times to surround both side surfaces and end surfaces of the second battery cell together.

[0028] A second graphite sheet may be provided between the compression pad and the first battery cell.

[0029] Between a pair of compression pads, a first battery cell and a second battery cell are provided adjacent to each other. The first graphite sheet is provided between the first battery cell and the second battery cell, and the end portion is folded to one side to surround the end surface of the first battery cell or the second battery cell.

[0030] ​​​​​​​​​​​​​​​

[0034] According to the battery module, battery pack, and vehicle of the present invention, self-thermal balancing is achieved in the battery cells included in the module or assembly, thereby improving the overall efficiency of thermal management and enhancing performance and safety.

[0035] Furthermore, because thermal balancing can be achieved within a single battery cell, overall thermal management efficiency is improved, and performance and safety can be significantly enhanced while using the existing cooling system.

[0036] Furthermore, by effectively using the necessary graphite sheets to achieve thermal balancing of each battery cell, manufacturing costs can be reduced and assembly man-hours can be significantly decreased.

[0037] The effects obtained by the present invention are not limited to those mentioned above, and other effects not mentioned will be clearly understandable to a person with ordinary skill in the art to which the present invention belongs from the following description. [Brief explanation of the drawing]

[0038] [Figure 1] This is a perspective view of a battery module according to one embodiment of the present invention. [Figure 2] This figure shows a state in which a graphite sheet is attached to the battery cells of a battery module according to one embodiment of the present invention. [Figure 3] This is an unfolded view of a graphite sheet for a battery module according to one embodiment of the present invention. [Figure 4] This figure shows a state in which a graphite sheet is attached to the compression pad of a battery module according to one embodiment of the present invention. [Figure 5] This figure shows a battery module according to various embodiments of the present invention. [Figure 6] This figure shows a battery module according to various embodiments of the present invention. [Figure 7] This figure shows a battery module according to various embodiments of the present invention. [Figure 8] This figure shows a battery pack including a battery module and a vehicle according to one embodiment of the present invention. [Modes for carrying out the invention]

[0039] In describing the embodiments disclosed herein, if it is determined that a specific description of related known technology may obscure the essence of the embodiments disclosed herein, such detailed description will be omitted. Furthermore, the accompanying drawings are merely for the purpose of facilitating the understanding of the embodiments disclosed herein, and should not be understood as limiting the technical ideas disclosed herein, but rather as including all modifications, equivalents, or substitutions that fall within the concept and technical scope of the present invention.

[0040] Terms including ordinal numbers such as "first," "second," etc., can be used to describe a variety of components, but the components are not limited by such terms. These terms are used solely for the purpose of distinguishing one component from another.

[0041] A singular expression includes plural expressions unless explicitly indicated otherwise in the context.

[0042] In this specification, terms such as “includes” or “have” are intended to indicate the presence of features, figures, stages, operations, components, parts, or combinations thereof as described in the specification, and should be understood not to preemptively exclude the possibility of the presence or addition of one or more other features, figures, stages, operations, components, parts, or combinations thereof.

[0043] The suffixes "module" and "part" used with respect to the constituent elements in the following description are added or used interchangeably solely for the purpose of facilitating the preparation of the specification, and do not in themselves have a distinct meaning or role from one another.

[0044] When it is mentioned that one component is “connected” or “linked” to another component, it should be understood that this may mean that it is directly connected or linked to the other component, or that there may be other components in between. On the other hand, when it is mentioned that one component is “directly connected” or “directly linked” to another component, it should be understood that there are no other components in between.

[0045] The embodiments disclosed herein will now be described in detail with reference to the attached drawings. Identical or similar components will be given the same reference numerals regardless of their relationship to the drawings, and redundant descriptions thereof will be omitted.

[0046] Figure 1 is a perspective view of a battery module according to one embodiment of the present invention; Figure 2 shows a state in which a graphite sheet is attached to the battery cells of a battery module according to one embodiment of the present invention; Figure 3 is an unfolded view of the graphite sheet of a battery module according to one embodiment of the present invention; Figure 4 shows a state in which a graphite sheet is attached to the compression pad of a battery module according to one embodiment of the present invention; Figures 5 to 7 show battery modules according to various embodiments of the present invention; and Figure 8 shows a battery pack and vehicle including a battery module according to one embodiment of the present invention.

[0047] Battery cells heat up during charging and discharging, and such temperature increases reduce the performance and lifespan of the battery itself. Therefore, a cooling structure is necessary to keep the battery cells below a certain temperature at all times. One such structure is a bottom cooling structure that uses cooling water to cool the bottom of the battery module inside the battery pack. However, this type of cooling method creates a temperature difference between the bottom and top of the battery cell, reducing the efficiency of battery use. To improve this, it is necessary to cool the entire temperature of the battery cell uniformly. In other words, thermal balancing is necessary not only for the battery module but also for the battery cell itself.

[0048] The present invention aims to improve rapid charging performance and lifespan performance in battery modules, assemblies, or stack structures by reducing temperature deviations between battery cells at different locations (between top and bottom, and between side and center) and effectively balancing the temperature of the battery cells.

[0049] To address the problem of temperature differences occurring at different locations within a single battery cell, a thin-film thermal conductive material is added between battery cells in the structure of stacks, assemblies, and modules in which multiple battery cells are combined, thereby reducing the temperature deviation in the planar direction of the battery cells.

[0050] Battery cells can be classified into prismatic batteries, cylindrical batteries, or pouch-type batteries, each consisting of a can. The various packaging materials for these battery cells are primarily made of aluminum. For the packaging of these battery cells, a thin-film graphite sheet is applied, which is lighter and slimmer than aluminum while still offering excellent thermal conductivity. Graphite sheets can be applied in various ways, and a heat-resistant barrier can be added inside the compression pad to further suppress heat transfer between adjacent battery cells.

[0051] Specifically, as shown in Figure 1, the battery module according to the present invention can be configured as a single stack, assembly, or module by stacking a large number of battery cells. In this invention, such a collection of battery cells is commonly referred to as a battery module. In this invention, the term "battery module" refers to such a collection of a large number of battery cells, and this includes all cases where a large number of battery cells are assembled, such as battery stacks and assemblies.

[0052] As shown in Figure 1, the battery module consists of a stack of numerous battery cells 100, with compression pads 500 sandwiched in some sections. Each battery cell 100 is fitted with a graphite sheet 300 on its side. A thermal resin 720 is provided on the underside for heat conduction with the cooling section.

[0053] While the cooling section 700 can be implemented in various ways, a typical example is a cooling channel through which cooling water flows. Since such a cooling section 700 and the battery cell 100 or graphite sheet 300 are in surface contact, a thermally conductive resin 720 is filled between them to improve conductivity.

[0054] The battery module of the present invention includes a first battery cell 100, a second battery cell 100' arranged to face and contact the first battery cell 100, and a graphite sheet 300 provided between the first battery cell 100 and the second battery cell 100', with both sides of the graphite sheet in surface contact with the opposing sides of the first battery cell 100 and the second battery cell 100', respectively.

[0055] The battery module of the present invention is composed of a large number of battery cells stacked in a continuous manner, and each battery cell is defined and distinguished as a first battery cell and a second battery cell, respectively. The first battery cell 100 and the second battery cell 100' are arranged so that their sides face each other and are assembled so that they are pressed together. A graphite sheet 300 is provided between them.

[0056] Graphite Sheet 300 is designed for use in environments ranging from -40°C to 400°C, and therefore possesses extremely high heat resistance. Furthermore, it exhibits significantly superior thermal conductivity in the planar direction compared to metals such as aluminum. Consequently, when graphite sheets are applied between adjacent battery cells, the high thermal conductivity in the planar direction enables cell-level thermal balancing within a single battery cell.

[0057] Of course, since the battery cell packaging is made of aluminum, it has basic thermal conductivity properties, but despite this, aluminum does not have sufficient thermal conductivity in the planar direction, and high temperatures are observed at points away from the electrode area or cooling area.

[0058] However, in the case of graphite sheets, they can be molded to be thinner than aluminum, and the internal carbon arrangement improves heat conduction in the width direction rather than the thickness direction, making them very effective for thermal balancing at the cell level.

[0059] In the present invention, by attaching the graphite sheet 300 between the adjacent first battery cell 100 and second battery cell 100' in this manner, thermal balancing in the planar direction is effectively achieved in each battery cell. Furthermore, because it is located between the two battery cells, overheating in a specific part of one battery cell is easily transferred to the entire surface of the adjacent battery cell, resulting in high thermal balancing performance not only in the battery cells but also in the battery module.

[0060] As shown in Figure 5, the graphite sheet 300 is bonded and fixed to the side of either the first battery cell 100 or the second battery cell 100', and can make surface contact with the sides of the remaining battery cells during assembly. In other words, if a graphite sheet 300 were applied to each side of all the battery cells constituting the battery module, manufacturing costs would increase, weight would increase, and assembly man-hours would become excessive. Therefore, efficiency can be improved by applying the graphite sheet only to the necessary locations. For this purpose, at the point where two battery cells face each other and make contact, the graphite sheet is attached to only one of the battery cells. Then, the two battery cells are assembled so that they are in contact with each other. This allows the two battery cells to share one graphite sheet, reducing the number of graphite sheets that need to be applied. In addition, since the battery cells are pressed against each other during assembly, thermal balancing is possible between the battery cells positioned on either side of a single graphite sheet, and thermal balancing is also possible between adjacent battery cells. Furthermore, by pre-attaching the graphite sheet to the surface of one side of the battery cell prior to assembly, manufacturing control becomes easier and errors during assembly are reduced.

[0061] Furthermore, in such cases, the graphite sheet 300 can be bent at one end to surround the end face of the first or second battery cell. That is, the graphite sheet is attached so as to cover one side of the battery cell, and its lower end is bent at a 90-degree angle to cover the lower end 120 of the battery cell together. In this case, the lower end of the graphite sheet 300 comes into contact with the lower cooling section 700. In other words, the bent end of the graphite sheet can come into contact with the cooling section. Therefore, the graphite sheet provides thermal balancing in the planar direction of the battery cell and also improves overall cooling performance by quickly dissipating heat to the lower cooling section.

[0062] In particular, a thermally conductive resin 720 is provided between the bent end portion 302 of the graphite sheet 300 and the cooling portion 700, and a through hole 303 is formed in the bent end portion 302 of the graphite sheet 300, allowing the thermally conductive resin 720 to contact the end faces 120, 120' of the first battery cell 100 or the second battery cell 100' through the through hole 303.

[0063] In other words, by applying a thermally conductive resin or the like between the bent end 302 of the graphite sheet 300 and the cooling section 700, the heat conduction efficiency is increased. Here, as shown in Figure 3, if multiple through holes 303 are formed in the bent end 302 of the graphite sheet 300, the thermally conductive resin 720 is filled through the through holes 303, which strengthens the bond between the end 302 of the graphite sheet 300 and the battery cell 100, thereby improving the heat conduction efficiency between the battery cell 100, the graphite sheet 300 and the cooling section 700.

[0064] On the other hand, as in the case of Figure 6, a pair of first battery cells 100 may be provided between a pair of compression pads 500, and a second battery cell 100' may be provided between the first battery cells 100. In this case, the graphite sheet 300 is bonded and fixed to both sides of the second battery cell 100' located in the center, and the first battery cells 100 are assembled to be in close contact with both sides of the second battery cell 100'. This is the case when three battery cells are assembled to form a stack. In this case, the graphite sheet 300 is attached to both sides of the second battery cell 100' located in the middle. When the second battery cell 100' with the graphite sheet 300 attached is positioned between the first battery cells 100 on both sides, thermal balancing of the three battery cells can be performed simultaneously in just one assembly step.

[0065] In such cases, the heat dissipation performance of the lower cooling section 700 can also be improved by folding the graphite sheet 300 multiple times to surround both sides and the end face 120' of the second battery cell 100'. This can ultimately be achieved by manufacturing and attaching the graphite sheet 300, as shown in Figure 3. Specifically, as shown in Figure 3, the graphite sheet has two sides 301 and a bottom surface 302, and multiple through-holes 303 are formed in the bottom surface 302. As shown in Figure 6, the sheet surrounds both sides and the bottom surface of the battery cell, and heat is also dissipated through the lower end, thereby accelerating thermal balancing on the sides.

[0066] In particular, in the case of Figure 6, a single graphite sheet must balance the two battery cells on either side, so sufficient balancing performance can be ensured by adding heat dissipation.

[0067] As shown in the figure, compression pads 500 can be provided between a plurality of adjacent first battery cells or between a plurality of adjacent second battery cells. In such cases, it is also possible to add graphite sheets to both sides of the compression pads 500 and make the graphite sheets adhere closely to the compression pads and battery cells, thereby achieving thermal balancing on both sides of the battery cells simultaneously.

[0068] Alternatively, as shown in Figure 7, a pair of first battery cells 100 can be placed between a pair of compression pads 500, and a pair of second battery cells 100' can be placed adjacent to each other between the pair of first battery cells 100, with the graphite sheet 300 folded multiple times to surround both sides and end faces 120 of each first battery cell 100. In this case, four battery cells are mounted between the compression pads 500. In this case, a pair of first battery cells 100 can be placed between a pair of compression pads 500, and a pair of second battery cells 100' can be placed adjacent to each other between the pair of first battery cells 100.

[0069] Then, the graphite sheet 300 is folded multiple times to surround the first battery cells 100 which are spaced apart from each other. Furthermore, a graphite sheet 300 can be provided between a pair of adjacent second battery cells 100'. In this way, a graphite sheet is present on each side of each battery cell, and each battery cell can achieve sufficient thermal balancing. In addition, some of the graphite sheets come into contact with the cooling section 700 below to dissipate heat, so that even if a large number of battery cells are stacked, balancing and heat dissipation can be achieved without difficulty.

[0070] On the other hand, as shown in Figure 2, a graphite sheet 300 can be bonded to both sides and the bottom of the battery cell simultaneously, and a heat-resistant layer 320 made of a heat-resistant material can be attached to each of its outer surfaces. The heat-resistant layer is insulated by forming it with metal, mica (Mica), or the like. This provides thermal balancing for the battery cell and blocks heat transfer to adjacent battery cells.

[0071] Furthermore, in the case of the compression pad 500, as shown in Figure 4, by attaching graphite sheets 300 to both sides and providing a heat-resistant layer 540 inside, it is possible to balance the heat of adjacent battery cells while blocking heat transfer from one side to the other. A compression pad of this shape can be applied to any of the embodiments shown in Figures 5 to 7.

[0072] In this invention, by attaching graphite sheets to the sides of battery cells or compression pads during assembly, cell-level thermal balancing can be effectively achieved. Furthermore, by folding the graphite sheets to bring them into contact with the cooling section below, heat dissipation performance is improved, and by fixing them to a heat-conducting resin through through-holes, fixing force and heat dissipation are enhanced.

[0073] Furthermore, by folding a single graphite sheet twice to simultaneously cover both sides and the bottom of a single battery cell, the assembly is easy, and by having a heat-resistant layer in the compression pad along with the graphite sheet, the thermal balancing of the battery cell is improved while preventing heat transfer.

[0074] Although the present invention has been described with reference to specific embodiments, it will be apparent to those with ordinary skill in the art that the present invention can be improved and modified in various ways without departing from the technical spirit of the invention as defined by the following claims. [Explanation of symbols]

[0075] 100 First battery cells 100' Second battery cell 120, 120' end face 300 Graphite Sheets 301 Side view 302 Bent end 303 Through Hole 320 Heat resistant layer 500 Compression Pads 540 Heat resistant layer 700 Cooling section 720 Thermally conductive resin

Claims

1. The first battery cell and A second battery cell is positioned to face and be in contact with the first battery cell, A battery module comprising: a first graphite sheet provided between the first battery cell and the second battery cell, the first graphite sheet having both sides in surface contact with the opposing sides of the first and second battery cells, respectively.

2. The battery module according to claim 1, characterized in that the first graphite sheet is bonded and fixed to the side surface of either the first battery cell or the second battery cell, and is in surface contact with the side surface of the remaining battery cell.

3. The battery module according to claim 1, characterized in that the first graphite sheet is bonded and fixed to both sides of the first battery cell, and the second battery cells are in close contact with both sides of the first battery cell.

4. The battery module according to claim 1, characterized in that compression pads are provided between a plurality of adjacent first battery cells or between a plurality of adjacent second battery cells.

5. The battery module according to claim 4, characterized in that a second graphite sheet is provided on both sides of the compression pad, and the second graphite sheet is in close contact with the compression pad and the first battery cell or the second battery cell.

6. The battery module according to claim 1, characterized in that the end of the first graphite sheet is bent to one side to surround the end face of the first battery cell or the second battery cell.

7. The battery module according to claim 6, characterized in that the bent end of the first graphite sheet is in contact with the cooling section.

8. The battery module according to claim 6, characterized in that a thermally conductive resin is provided between the bent end of the first graphite sheet and the cooling section.

9. The battery module according to claim 8, characterized in that a through hole is formed at the bent end of the first graphite sheet, and the thermally conductive resin contacts the end face of the first battery cell or the second battery cell through the through hole.

10. The battery module according to claim 1, characterized in that the second battery cells are arranged on both sides of the first battery cell, and the first graphite sheet is folded multiple times to surround both sides and the end face of the first battery cell together.

11. The battery module according to claim 10, characterized in that a second graphite sheet is provided between a pair of adjacent second battery cells.

12. The battery module according to claim 1, characterized in that the second battery cell and compression pad are arranged on both sides of the first battery cell, and the first graphite sheet is folded multiple times to surround both sides and end faces of the first battery cell together.

13. The battery module according to claim 1, characterized in that a pair of first battery cells are provided between a pair of compression pads, a pair of second battery cells are provided adjacent to each other between the pair of first battery cells, and the first graphite sheet is folded multiple times to surround both sides and end faces of each of the first battery cells together.

14. The battery module according to claim 13, characterized in that a second graphite sheet is provided between the pair of adjacent second battery cells.

15. The battery module according to claim 1, characterized in that a pair of first battery cells are provided between a pair of compression pads, a second battery cell is provided between the pair of first battery cells, and the first graphite sheet is folded multiple times to surround both sides and end faces of the second battery cell together.

16. The battery module according to claim 15, characterized in that a second graphite sheet is provided between the compression pad and the first battery cell.

17. The battery module according to claim 1, characterized in that the first battery cell and the second battery cell are provided adjacent to each other between a pair of compression pads, and the first graphite sheet is provided between the first battery cell and the second battery cell, with its end bent to one side to surround the end face of the first battery cell or the second battery cell.

18. The battery module according to claim 17, characterized in that a second graphite sheet is provided between the compression pad and the first battery cell or the second battery cell.

19. The battery module according to claim 1, characterized in that a heat-resistant layer made of a heat-resistant material is attached to one side surface of the first graphite sheet.

20. The battery module according to claim 1, characterized in that compression pads are provided between a plurality of adjacent first battery cells or between a plurality of adjacent second battery cells, and a heat-resistant layer of a heat-resistant material is formed inside the compression pads.

21. A battery pack comprising a battery module according to any one of claims 1 to 20.

22. A vehicle characterized by including a battery module according to any one of claims 1 to 20.

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