Battery pack and device including the same

Abstract

A battery pack according to an embodiment of the present invention includes a battery module including a plurality of battery cells; and a pack frame in which the battery module is housed. At least two battery modules are assembled to form a first battery module group, and at least two battery modules are assembled to form a second battery module group, the second battery module group being located above the first battery module group. A partition member is disposed between the first battery module group and the second battery module group, and the partition member includes an insulating sheet having thermal and electrical insulation properties.

Description

Technical Field

[0001] [Cross - reference to Related Applications] This application claims the benefit of priority based on Korean Patent Application No. 10 - 2021 - 0046488, filed on Apr. 9, 2021, and all the contents disclosed in the literature of the Korean patent application are included as part of this specification.

[0002] The present invention relates to a battery pack and a device including the same, and more specifically, to a battery pack having improved safety against flame generation and a device including the same.

Background Art

[0003] In modern society, with the daily use of portable devices such as mobile phones, notebook computers, camcorders, and digital cameras, the development of technologies in fields related to such mobile devices has become active. In addition, rechargeable secondary batteries are used as power sources for electric vehicles (EVs), hybrid electric vehicles (HEVs), plug - in hybrid electric vehicles (P - HEVs), etc. as a solution to problems such as air pollution of existing gasoline vehicles that use fossil fuels, and thus the need for the development of secondary batteries is increasing.

[0004] Currently commercialized secondary batteries include nickel - cadmium batteries, nickel - metal hydride batteries, nickel - zinc batteries, lithium secondary batteries, etc. Among these, lithium secondary batteries have attracted attention because they have almost no memory effect compared to nickel - based secondary batteries, are free from charge and discharge, have a very low self - discharge rate, and have a high energy density.

[0005] Such lithium secondary batteries mainly use lithium - based oxides and carbon materials as the positive electrode active material and the negative electrode active material, respectively. A lithium secondary battery includes an electrode assembly in which a positive electrode plate and a negative electrode plate, each coated with such a positive electrode active material and a negative electrode active material, are arranged with a separator therebetween, and a battery case for hermetically storing the electrode assembly together with an electrolytic solution.

[0006] Generally, lithium secondary batteries can be classified into can-type secondary batteries in which the electrode assembly is built into a metal can and pouch-type secondary batteries in which the electrode assembly is built into a pouch of an aluminum laminate sheet according to the shape of the exterior material.

[0007] In the case of secondary batteries used in small devices, 2 to 3 battery cells are arranged. In the case of secondary batteries used in medium and large devices such as automobiles, a battery module in which a large number of battery cells are electrically connected is used. In such a battery module, the capacity and output are improved by connecting a large number of battery cells in series or in parallel with each other to form a battery cell stack. In addition, one or more battery modules can be mounted together with various control and protection systems such as a BMS (Battery Management System) and a cooling system to form a battery pack.

[0008] In a battery pack in which a large number of battery modules are gathered, the heat generated from a large number of battery cells may be combined in a narrow space, and the temperature may rise quickly and drastically. In other words, in the case of a battery module in which a large number of battery cells are stacked and a battery pack in which such a battery module is mounted, a high output can be obtained, but it is not easy to remove the heat generated in the battery cells during charging and discharging. If the heat dissipation of the battery cells is not achieved well, the deterioration of the battery cells will accelerate, the life will be shortened, and the possibility of explosion and ignition will increase.

[0009] In addition, in the case of the battery modules included in a vehicle battery pack, they may be frequently exposed to direct sunlight and placed under high-temperature conditions such as in summer or in desert areas. In addition, in order to increase the driving distance of the vehicle, a large number of battery modules are intensively arranged. Therefore, the flame and heat generated in any one battery module may be easily propagated to adjacent battery modules, which may ultimately lead to the explosion and ignition of the battery pack itself.

[0010] Therefore, even if a thermal runaway phenomenon occurs in any one of the battery cells, it is necessary to design a model that does not lead to a fire or explosion of the battery pack itself.

Summary of the Invention

Problems to be Solved by the Invention

[0011] The problem to be solved by the present invention is to provide a battery pack and a device including the same that can prevent the thermal runaway phenomenon from leading to a fire or explosion even if the thermal runaway phenomenon occurs in any one of the battery cells.

[0012] However, the problems to be solved by the embodiments of the present invention are not limited to the above-described problems, and can be variously extended within the scope of the technical idea included in the present invention.

Means for Solving the Problems

[0013] A battery pack according to an embodiment of the present invention includes a battery module including a plurality of battery cells; and a pack frame in which the battery module is housed. At least two battery modules gather to form a first battery module group, and at least two battery modules gather to form a second battery module group, and the second battery module group is located above the first battery module group. A partition member is disposed between the first battery module group and the second battery module group, and the partition member includes an insulating sheet having heat insulation and electrical insulation properties.

[0014] The partition member can cover the entire upper surface of the first battery module group.

[0015] The battery cells can be stacked along a direction parallel to the width direction while standing upright so that one surface of the cell body of the battery cell is perpendicular to the bottom of the pack frame.

[0016] The battery modules included in the first battery module group may be arranged in a single row along the width direction.

[0017] The battery modules included in the second battery module group may be arranged in a single row along the width direction.

[0018] The battery cell may be a pouch-type battery cell.

[0019] The insulating sheet may contain a polymer resin.

[0020] The partition member may further include a base plate, and the insulating sheet may be inserted between the base plates.

Advantages of the Invention

[0021] According to an embodiment of the present invention, even if a thermal runaway phenomenon occurs in any one of the battery cells, by designing so that thermal propagation is sequentially performed, it is possible to prevent fires and explosions in the battery pack unit.

[0022] Also, by providing an insulating sheet on the partition member that divides each layer, it is possible to suppress thermal propagation between the layers, and ultimately prevent fires and explosions in the battery pack unit.

[0023] The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

Brief Description of the Drawings

[0024]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Mode for Carrying Out the Invention

[0025] Hereinafter, with reference to the accompanying drawings, various embodiments of the present invention will be described in detail so that those having ordinary knowledge in the technical field to which the present invention belongs can easily implement them. The present invention can be realized in various different forms and is not limited to the embodiments described here.

[0026] In order to clearly explain the present invention, parts that are unnecessary for the description are omitted, and the same reference numerals are given to the same or similar components throughout the specification.

[0027] Also, the sizes and thicknesses of the respective configurations shown in the drawings are arbitrarily shown for convenience of explanation, and the present invention is not necessarily limited to the places shown in the drawings. In the drawings, the thicknesses are enlarged to clearly show a plurality of layers and regions. And in the drawings, for convenience of explanation, the thicknesses of some layers and regions are exaggerated.

[0028] Also, when a part such as a layer, a film, a region, or a plate is “above” another part, this includes not only the case where it is “directly above” the other part but also the case where there are other parts in between. Conversely, when a part is “directly above” another part, it means that there are no other parts in between. Also, being “above” the reference part means being located above or below the reference part, and does not necessarily mean being located “above” in the direction opposite to the direction of gravity.

[0029] Also, throughout the specification, when a part "includes" a certain component, this means that, unless there is a contrary description, other components are not excluded and other components can be further included.

[0030] Also, throughout the specification, when it is said "on a plane", this means when looking at the target part from above, and when it is said "in a cross-section", this means when looking at the cross-section obtained by vertically cutting the target part from the side.

[0031] FIG. 1 is a perspective view showing a battery module and a connecting member according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the battery module of FIG. 1. FIG. 3 is a perspective view of a battery cell included in the battery module of FIG. 2.

[0032] Referring to FIGS. 1 to 3, a battery module 100 according to an embodiment of the present invention includes a plurality of battery cells 110. The battery cells 110 are preferably pouch-type battery cells and can be formed in a rectangular sheet-like structure. For example, the battery cell 110 according to the present embodiment has a structure in which two electrode leads 111 and 112 project from one end and the other end respectively with the two facing each other.

[0033] In particular, referring to FIG. 3, the battery cell 110 according to the present embodiment has a structure in which two electrode leads 111 and 112 project from one end 114a and the other end 114b of the cell body 113 respectively with the two facing each other. More specifically, the electrode leads 111 and 112 are connected to an electrode assembly (not shown) and project outside the battery cell 110 from the electrode assembly (not shown).

[0034] On the one hand, the battery cell 110 can be manufactured by adhering both end portions 114a and 114b of the cell case 114 and one side portion 114c connecting these end portions in a state where an electrode assembly (not shown) is housed in the cell 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 are sealed by a method such as heat fusion, and the other side portion can be composed of a connecting portion 115. The cell case 114 can be made of a laminate sheet including a resin layer and a metal layer.

[0035] Further, the connecting portion 115 can extend long along one edge of the battery cell 110, and a protruding portion 110p of the battery cell 110 called a bat-ear can be formed at the end of the connecting portion 15. However, the protruding portion 110p is one exemplary structure, and the battery cell 110 according to another embodiment of the present invention can have a form in which no protruding portion is formed and the connecting portion 115 extends in a straight line.

[0036] Although FIG. 3 has described only the battery cell 110 having a structure in which the electrode leads 111 and 112 protrude in both directions, as another embodiment of the present invention, it is needless to say that a unidirectional pouch-type battery cell in which the electrode leads protrude in one direction together is also possible.

[0037] Such battery cells 110 can be configured in a plurality, and the plurality of battery cells 110 can be stacked so as to be electrically connected to each other to form a battery cell laminate 120. In particular, as shown in FIG. 2, a plurality of battery cells 110 can be stacked along a direction parallel to the y-axis. For this purpose, one electrode lead 111 of the battery cells 110 can protrude in the x-axis direction, and the other electrode lead 112 can protrude in the -x-axis direction.

[0038] The battery cell stack 120 can be housed in the module frame 200. The module frame 200 can be a metal frame with both sides open. More specifically, based on the battery cell stack 120, the module frame 200 can be open in both directions in which the electrode leads 111 and 112 protrude.

[0039] End plates 410 and 420 can be positioned on the two open sides of the module frame 200. The two end plates 410 and 420 are respectively referred to as the first end plate 410 and the second end plate 420. The end plates 410 and 420 can cover the two open sides of the module frame 200 respectively. By housing the battery cell stack 120 in the space formed by the module frame 200 and the end plates 410 and 420, the battery cell stack 120 can be physically protected. For this purpose, the module frame 200 and the end plates 410 and 420 can include a metal material having a predetermined strength such as aluminum. The module frame 200 and the end plates 410 and 420 can be joined by a method such as welding in a state where the corresponding edge portions are in contact with each other.

[0040] On the other hand, the battery module 100 according to the present embodiment can further include a bus bar frame 300 to which a bus bar 510 and a terminal bus bar 520 are attached.

[0041] The bus bar 510 and the terminal bus bar 520 can be joined to the electrode leads 111 and 112 of the battery cells 110 in order to electrically connect a plurality of battery cells 110. Specifically, the bus bar frame 300 to which the bus bar 510 and the terminal bus bar 520 are attached can be respectively positioned on one side (x-axis direction) and the other side (-x-axis direction) of the battery cell stack 120. In other words, any one of the bus bar frames 300 can be positioned between any one of the end plates 410 and 420 and the battery cell stack 120. The bus bar frame positioned on the other side (-x-axis direction) of the battery cell stack 120 in FIG. 2 is not shown.

[0042] The bus bar frame 300 is formed with lead slits, and after the electrode leads 111 and 112 pass through the lead slits, they can be bent and joined to the bus bar 510 or the terminal bus bar 520. If physical and electrical connection is possible, there is no special restriction on the joining method, and for example, welding can be performed.

[0043] On the other hand, a part of the terminal bus bar 520 can be exposed outside the battery module 100. Specifically, a first terminal bus bar opening 410H is formed in the first end plate 410 so that a part of the terminal bus bar 520 can be exposed. A part of the exposed terminal bus bar 520 can be joined to the connecting member 1400 as shown in FIG. 1 in order to form an HV (High Voltage) connection by being connected to other battery modules, a BDU (Battery Disconnect Unit), etc. Here, the HV connection is a connection serving as a power source for supplying power, and means a connection between battery cells or between battery modules.

[0044] If the connecting member 1400 can enable electrical connection, there is no special restriction on its material, and a metal material can be applied.

[0045] Hereinafter, with reference to FIG. 4, the battery pack 1000 according to an embodiment of the present invention will be described in detail.

[0046] FIG. 4 is a cross-sectional view of a battery pack according to an embodiment of the present invention. Specifically, it shows a state in which the battery module 100 shown in FIGS. 1 and 2 is housed in the pack frame 1200 and the battery pack 1000 is cut along the yz plane.

[0047] Referring to FIGS. 2 to 4, a battery pack 1000 according to an embodiment of the present invention includes a battery module 100 including a plurality of battery cells 110, and a pack frame 1200 for housing the battery module 100. In this embodiment, the battery module 100 can be the battery module 100 shown in FIGS. 1 and 2. In FIG. 4, the battery cells 110 included in the battery module 100 are schematically represented by dotted lines for convenience of explanation. Further, the battery modules 100 can be electrically connected to each other through a connecting member 1400 to form an HV connection. In FIG. 4, such a connecting member 1400 is schematically represented differently from FIG. 1.

[0048] The pack frame 1200 can include an upper frame 1210 and a lower frame 1220. The upper frame 1210 can be in a plate-like form, and the lower frame 1220 can include a bottom 1200F on which the battery module 100 is placed and can be in a form with an open upper part. The upper frame 1210 is positioned on the open upper part of the lower frame 1220, and the upper frame 1210 and the lower frame 1220 can be joined at corresponding edges to complete the pack frame 1200. The space between the upper frame 1210 and the lower frame 1220 is the space in which the battery module 100 is housed. However, the above structure is an exemplary structure of the pack frame 1200 according to this embodiment, and it goes without saying that a deformed form is also possible as long as the battery module 100 can be housed.

[0049] Inside the pack frame 1200, at least two battery modules 100 gather to form a first battery module group 100Ga, and at least two battery modules 100 gather to form a second battery module group 100Gb, and the second battery module group 100Gb is located above the first battery module group 100Ga. That is, the battery pack 1000 according to this embodiment forms a two-layer structure of a first battery module group 100Ga and a second battery module group 100Gb. However, this is an exemplary structure, and a battery pack having a multi-layer structure of three or more layers is also possible.

[0050] On one side, a partition member 1300 is disposed between the first battery module group 100Ga and the second battery module group 100Gb, and the partition member 1300 includes an insulating sheet 1310 having thermal insulation and electrical insulation. The insulating sheet 1310 will be described later.

[0051] Inside the battery module 100, battery cells 110 are stacked along the width direction d1 to form a battery cell stack. Specifically, the battery cells 110 can be stacked along the width direction d1 while standing upright such that one surface of the cell body 113 (see FIG. 3) of the battery cell 110 is perpendicular to one surface of the bottom 1200F of the pack frame 1200. In this specification, the width direction d1 is one of the directions parallel to the ground or one surface of the bottom 1200F of the pack frame 1200, and in other words, it is one of the directions parallel to the xy plane.

[0052] At this time, the battery modules 100 included in the first battery module group 100Ga can be arranged in a row along the width direction d1, and the battery modules 100 included in the second battery module group 100Gb can be arranged in a row along the width direction d1. That is, the direction in which the battery modules 100 are arranged within the battery module groups 100Ga and 100Gb can be the same as the direction in which the battery cells 110 are stacked.

[0053] The above-described partition member 1300 can be in a plate-like form and can cover the entire upper surface of the first battery module group 100Ga. There is no particular limitation on the material of the insulating sheet 1310 included in the partition member 1300 as long as it has thermal insulation and electrical insulation properties. As an example, it can include a polymer resin. Also, the insulating sheet 1310 can be, for example, an FRS pad. The FRS pad is a product of MORGAN and can include MICA and Superwool. The insulating sheet 1310 which is an FRS pad can have a thickness of 1 mm to 3 mm and can have a thermal conductivity of 0.12 W / mK or more and 0.18 W / mK or less in the temperature range of 810 degrees Celsius to 820 degrees Celsius.

[0054] The partition member 1300 can further include a base plate 1320, and the insulating sheet 1310 can be inserted between the base plates 1320. At the same time, the insulating sheet 1310 and the base plate 1320 can be adhered with a double-sided tape.

[0055] The first battery module group 100Ga and the second battery module group 100Gb are spatially separated by the partition member 1300, and the first battery module group 100Ga and the second battery module group 100Gb are thermally and electrically separated from each other by the insulating sheet 1310 included in the partition member 1300.

[0056] Hereinafter, with reference to FIGS. 3 to 5, the advantages of the battery pack 1000 according to the present embodiment when a thermal runaway phenomenon of the battery cell occurs will be described.

[0057] FIG. 5 is a cross-sectional view schematically showing a state in which a thermal runaway phenomenon has occurred in any one of the battery cells in the battery pack of FIG. 4.

[0058] Referring to FIGS. 3 to 5, a thermal runaway phenomenon may occur in any one of the battery cells 110 included in the battery pack 1000 according to the present embodiment. An exemplary case of the thermal runaway phenomenon is as follows. Physical, thermal, and electrical damage may occur in the battery cell 110, starting with overcharging, and the internal pressure of the battery cell 110 may increase. When the fusion strength limit value of the cell case 114 of the battery cell 110 is exceeded, the high-temperature heat, venting gas, etc. generated in the battery cell 110 may be ejected to the outside of the battery cell 110.

[0059] The thermal runaway phenomenon occurring in any one battery cell may be expanded to adjacent battery cells due to the convection effect, and may even be expanded to adjacent battery modules. In particular, due to the structure of the battery pack in which the battery modules are densely arranged to increase the space utilization rate, the thermal runaway phenomenon is not sequentially propagated to the battery modules, but may occur simultaneously in many densely arranged battery modules. That is, the thermal runaway phenomenon that starts from a battery cell and is expanded to many battery modules simultaneously may lead to ignition and explosion of the battery pack itself, resulting in a serious problem.

[0060] However, in the battery pack 1000 according to the present embodiment, a partition member 1300 is disposed between the battery module groups 100Ga and 100Gb, and the battery modules 100 are arranged in a single row within the battery module groups 100Ga and 100Gb, so that the propagation of the thermal runaway phenomenon occurs sequentially not only in units of the battery modules 100 but also in units of the battery cells 110. That is, as shown in FIG. 5, when a thermal runaway phenomenon occurs in a battery cell inside any one of the battery modules in the first battery module group 100Ga, bending gas, heat, etc. can be sequentially propagated to adjacent battery cells 110. As an example, in FIG. 5, the state in which the thermal runaway phenomenon is propagated from the battery cell 110' of the battery module located on the far left in the first battery module group 100Ga to the battery cell 110'' of the battery module located third from the left in the first battery module group 100Ga is shown.

[0061] In addition, the bending gas and heat are not immediately propagated to the second battery module group 100Gb by the partition member 1300 including the insulating sheet 1310 having heat insulation properties. In the present embodiment, a heat insulation structure is designed so that the thermal runaway phenomenon does not propagate across the HV connection order of the connection members 1400 between the battery module groups 100Ga and 100Gb.

[0062] As described above, by designing so that the propagation is performed sequentially, the time for the bending gas and heat to propagate can be increased, and the intensity of the thermal runaway can be gradually reduced during the sequential propagation. That is, the battery pack 1000 according to the present embodiment can prevent the occurrence of thermal runaway in any one battery cell 110 from leading to the ignition or explosion of the battery pack 1000 itself. If there is no partition member 1300, the thermal runaway phenomenon starting from any one battery cell 110 is immediately propagated to the battery modules 100 in the other battery module group 100Gb, and a large amount of bending gas and high-temperature heat may be discharged simultaneously from many battery modules 100 in a short time. This is highly likely to lead to the ignition and explosion of the battery pack 1000.

[0063] On the one hand, as described above, in the present embodiment, the direction in which the battery modules 100 are arranged within the battery module groups 100Ga and 100Gb can be made to coincide with the direction in which the battery cells 110 are stacked. Therefore, within the battery module groups 100Ga and 100Gb, the propagation of the thermal runaway phenomenon between the battery cells 110 can also occur sequentially. By making the arrangement direction of the battery modules 100 coincide with the stacking direction of the battery cells 110, an attempt was made to further delay the propagation of the thermal runaway phenomenon.

[0064] On the other hand, although not specifically shown, there may be cases where the thermal runaway phenomenon occurs individually in each of the first battery module group 100Ga and the second battery module group 100Gb. In this case, since the insulating sheet 1310 has electrical insulation and heat insulation properties, the sequential propagation of the thermal runaway phenomenon occurs individually in each of the first battery module group 100Ga and the second battery module group 100Gb. The first battery module group 100Ga and the second battery module group 100Gb are electrically separated by the insulating sheet 1310 to prevent the occurrence of sparks and short circuits. Overall, by designing such that the thermal runaway phenomena occurring in each of the first battery module group 100Ga and the second battery module group 100Gb are propagated along separate paths from each other, ignition and explosion of the battery pack 1000 can be prevented. If the insulating sheet 1310 is not provided, the thermal runaway phenomena occurring in each of the first battery module group 100Ga and the second battery module group 100Gb combine and spread into one large thermal runaway phenomenon, and a large amount of venting gas and high-temperature heat are discharged in the unit of the battery pack, and eventually, the battery pack may explode.

[0065] In the present embodiment, terms indicating directions such as front, rear, left, right, up, and down are used, but such terms are only for convenience of explanation and can vary depending on the position of the object and the position of the observer, etc.

[0066] The battery pack according to the above-described embodiment of the present invention can include various control and protection systems such as a BMS (Battery Management System), a BDU (Battery Disconnect Unit), and a cooling system, in addition to the battery module.

[0067] The battery pack can be applied to various devices. Specifically, it can be applied to transportation means such as electric bicycles, electric vehicles, and hybrids, but is not limited thereto, and is applicable to various devices that can use secondary batteries.

[0068] Although the preferred embodiments of the present invention have been described in detail above, the scope of the rights of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention defined in the claims also belong to the scope of the rights of the present invention.

Description of Reference Numerals

[0069] 1000: Battery pack 100: Battery module 100Ga: First battery module group 100Gb: Second battery module group 1300: Partition member 1310: Insulating sheet

Claims

1. A battery module including a plurality of battery cells; and A pack frame in which the battery module is housed, At least two battery modules are arranged horizontally to form a first battery module group, At least two battery modules are arranged horizontally to form a second battery module group, The second battery module group is located above the first battery module group, Between the first battery module group and the second battery module group, a partition member is disposed that covers all the battery modules constituting the first battery module group and the gaps between the battery modules from above, The partition member includes an insulating sheet having heat insulation and electrical insulation properties, a battery pack.

2. The partition member covers the entire upper surface of the first battery module group, The battery pack according to Claim 1.

3. While one side of the cell body of the battery cell stands perpendicular to the bottom of the pack frame, the battery cells are stacked along a direction parallel to the width direction, The battery pack according to Claim 1 or 2.

4. The battery modules included in the first battery module group are arranged in a single row along the width direction, The battery pack according to Claim 3.

5. The battery modules included in the second battery module group are arranged in a single row along the width direction, The battery pack according to Claim 3.

6. The battery cell is a pouch-type battery cell, The battery pack according to Claim 1 or 2.

7. The insulating sheet includes a polymer resin, The battery pack according to Claim 1 or 2.

8. The partition member further includes a base plate, The insulating sheet is inserted between the base plates, The battery pack according to Claim 1 or 2.

9. A device including the battery pack according to Claim 1 or 2.

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