Battery cell assembly including a cutoff plate and battery pack including the battery cell assembly

Abstract

The present invention relates to a battery cell assembly including a pouch-type battery cell, a cell housing that accommodates the pouch-type battery cell, blocking plates located at both ends of the cell housing in the overall length direction, and a venting plate that exhausts gas released from the pouch-type battery cell, with a thermal expansion material provided on the inner surface of the blocking plate, which can completely block the transfer of flames generated in the pouch-type battery cell and exhaust gas in the direction of the venting plate.

Description

[Technical field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 2022-0024477 filed on February 24, 2022, and all contents disclosed in the documents of that Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a battery cell assembly including a blocking plate and a battery pack including the battery cell assembly, and more particularly, to a battery cell assembly that can prevent a flame from a battery cell from transferring to other battery cells, ensure venting direction of the battery cell, and enable cell-to-pack assembly, and a battery pack including the battery cell assembly. [Background technology]

[0003] Rechargeable lithium secondary batteries are not only used as energy sources for small devices such as mobile devices, but also for medium and large devices such as electric vehicles and power storage devices due to technological developments such as increased capacity and improved safety.

[0004] As lithium secondary batteries are used as large-capacity, high-output energy sources, the issue of ensuring the safety of lithium secondary batteries has become an important concern.

[0005] Since normal charging and discharging processes of a lithium secondary battery are heat generating processes, the temperature inevitably rises, and such an increase in temperature can cause a decrease in the performance of the battery cells.

[0006] In addition, lithium secondary batteries have a risk of explosion due to overheating, and if the flames caused by the explosion spread to adjacent battery cells, it is difficult to extinguish the fire until the entire battery cell is burned. When a thermal runaway phenomenon occurs in a battery cell, flames, sparks, and gas venting that are higher than the ignition point may occur and spread to adjacent battery cells, which may ultimately lead to the explosion of the battery cell.

[0007] In this regard, FIG. 1 is an exploded perspective view of a conventional battery pack.

[0008] Referring to FIG. 1, the battery pack includes a battery cell stack 10 in which a number of battery cells are closely arranged, a pack frame 20 that houses the battery cell stack 10, a thermally conductive resin 21 for heat transfer in the battery cell stack 10, a bus bar frame assembly 31 for electrically connecting the battery cells, a top plate 30 located on top of the battery cell stack 10 and coupled to the pack frame 20, and end plates 40 coupled to each of both ends of the battery cell stack 10 so as to face the bus bar frame assembly 31.

[0009] The conventional battery cell stack 10 simply has a number of battery cells arranged in close contact with one another, and does not include a structure for preventing the spread of flames to adjacent battery cells in the event of a battery cell ignition.

[0010] In addition, since there is no function to delay or suppress a fire once it has started, the fire will inevitably spread to all battery cells.

[0011] Therefore, it is important to prevent additional damage caused by the explosion of a battery cell by lowering the temperature of the flame or spark generated in the battery cell and preventing the flame or spark from spreading.

[0012] In this regard, Patent Document 1 discloses an embodiment in which a composite sheet is provided that extends from one side of a battery cell along the bottom and is joined to the other side. The composite sheet includes a heat insulating layer that is disposed between the battery cell to which the composite sheet is joined and another adjacent battery cell. Therefore, when the temperature of any one battery cell increases, the transfer of heat to the other adjacent battery cell can be suppressed.

[0013] Patent Document 1 discloses a battery cell equipped with a composite sheet that prevents heat transfer between adjacent battery cells, but does not disclose any technology for preventing the transfer of flames, etc. to adjacent battery cells when flames, spark gases, etc. are ejected in the direction of the electrode lead of the battery cell.

[0014] Therefore, if a fire occurs in one of the closely-arranged battery cells, a technology is needed that can completely block the transmission of flames to adjacent battery cells and that can prevent explosions by providing a gas exhaust structure. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] International Patent Publication No. 2017-159527 Summary of the Invention [Problem to be solved by the invention]

[0016] The present invention has been made to solve the above problems, and has an object to provide a battery cell assembly having a structure for preventing the spread of flames and sparks generated when a pouch-type battery cell ignites, and a structure for discharging gas generated in the pouch-type battery cell. [Means for solving the problem]

[0017] To achieve this object, a battery cell assembly according to the present invention includes a pouch-type battery cell, a cell housing that accommodates the pouch-type battery cell, a blocking plate located at each end of the overall length of the cell housing, and a venting plate that exhausts gas released from the pouch-type battery cell, and a thermal expansion material is provided on the inner surface of the blocking plate.

[0018] The thermally expansive material may be expandable graphite.

[0019] The thermal expansion material may be positioned adjacent to an electrode lead of the pouch-type battery cell and may be expanded and deformed to fill a space between the electrode lead and the blocking plate when the temperature of the pouch-type battery cell increases.

[0020] The cell housing may include a first surface and a second surface positioned parallel to a bottom of the electrode assembly receiving portion of the pouch-type battery cell, and a third surface coupled to one side ends of the first surface and the second surface to connect them.

[0021] The venting plate may be coupled to the other side opposite to one side of the first and second surfaces.

[0022] The ventilation plate may have a notch formed therein.

[0023] The notch can be broken by the pressure of gas discharged from the pouch-type battery cell.

[0024] The vent plate may include an aperture.

[0025] The cell housing housing the pouch-type battery cells may include one cell housing, or may include two or more cell housings housing the pouch-type battery cells.

[0026] The cell housing may comprise an insulating material and / or a high temperature resistant material.

[0027] The cell housing may have a clad form in which an inner metal and an outer metal are joined together, the inner metal being made of a highly rigid material, and the outer metal being made of a material having excellent thermal conductivity.

[0028] The cell housing may be made of reinforced plastic.

[0029] The blocking plate may be provided with a connector that is directly or indirectly connected to an electrode lead.

[0030] The present invention provides a battery pack including the battery cell assembly. Specifically, the battery pack according to the present invention includes a cell stack in which a plurality of battery cell assemblies are closely arranged, and a pack frame that houses the cell stack, the pack frame having a rectangular frame shape that surrounds an outer periphery of the cell stack, and at least one of an upper surface and a lower surface of the cell stack may constitute an outer surface of the battery pack.

[0031] Furthermore, the present invention can be provided in the form of various combinations of the above configurations. Effect of the Invention

[0032] As described above, the battery cell assembly according to the present invention contains pouch-type battery cells in a cell housing made of a highly heat-resistant material that surrounds the battery cells, so that in the event of a fire in the pouch-type battery cell, flames can be induced to progress to both ends in the overall length direction.

[0033] In addition, since the battery cell assembly includes a venting plate that can prevent flames or sparks from escaping to the outside of the battery cell assembly and can exhaust gas released from the pouch-type battery cells, the battery cell assembly can be prevented from exploding. [Brief description of the drawings]

[0034] [Figure 1] FIG. 1 is an exploded perspective view of a conventional battery pack. [Diagram 2] FIG. 2 is an exploded perspective view of a battery cell assembly according to the present invention; [Diagram 3] 3A and 3B are perspective and vertical cross-sectional views of the battery cell assembly shown in FIG. 2. [Figure 4] FIG. 2 is a perspective view of a battery cell assembly according to the present invention. [Diagram 5]FIG. 2 is a vertical cross-sectional view of a cell housing according to the present invention. [Figure 6] 1 is a perspective view of a battery pack according to the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0035] Hereinafter, a detailed description will be given of an embodiment of the present invention that can be easily implemented by a person having ordinary skill in the art to which the present invention pertains, with reference to the accompanying drawings. However, when describing the operation principle of the preferred embodiment of the present invention in detail, detailed description of related well-known functions or configurations may be omitted if it is determined that such detailed description may unnecessarily obscure the gist of the present invention.

[0036] In addition, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Throughout the specification, when a part is said to be connected to another part, this includes not only the case where the part is directly connected to another part, but also the case where the part is indirectly connected via another element between the two parts. In addition, when a part includes a certain component, it does not mean that the other component is excluded, but that the part may further include the other component, unless otherwise specified.

[0037] Furthermore, descriptions that limit or add specific elements are applicable to all inventions and are not limited to a particular invention unless otherwise specified.

[0038] Furthermore, throughout the description of the present invention and the claims, the singular includes the plural unless otherwise stated.

[0039] In addition, throughout the description of the present invention and the claims, unless otherwise specified, "or" includes "and." Therefore, "including A or B" means three cases: including A, including B, or including both A and B.

[0040] The invention will now be explained with reference to the drawings and in conjunction with detailed embodiments.

[0041] FIG. 2 is an exploded perspective view of a battery cell assembly according to the present invention, and FIG. 3 is a perspective view and a vertical sectional view of the battery cell assembly shown in FIG.

[0042] FIG. 3 is a perspective view of the battery cell assembly and a vertical cross-sectional view taken along line AA.

[0043] 2 and 3, the battery cell assembly according to the present invention includes a pouch-type battery cell 101, a cell housing 200 that accommodates the pouch-type battery cell 101, blocking plates 300 located at both ends of the overall length direction L of the cell housing 200, and a venting plate 400 that exhausts gas released from the pouch-type battery cell 101. Since a thermal expansion material 310 is provided on the inner surface of the blocking plate 300, when heat due to an increase in temperature of the pouch-type battery cell is transferred to the thermal expansion material 310, the volume of the thermal expansion material 310 increases rapidly.

[0044] The thermal expansion material 310 is flame retardant and expands to several hundred times its original volume at 180°C to 220°C in the event of a fire, and may be, for example, expandable graphite. The expandable graphite expands in volume and forms a barrier film that prevents oxygen from approaching the sparks, so it can physically extinguish the fire.

[0045] The thermal expansion material 310 is located near the electrode lead 102 of the pouch-type battery cell 101, and expands and deforms to fill the space between the electrode lead 102 and the blocking plate 300 when the temperature of the pouch-type battery cell 101 increases.

[0046] The thermally expandable material 310 thus expanded can prevent the flames erupting from the pouch-type battery cell from being discharged to the outside of the blocking plate 300.

[0047] In addition, when the blocking plate 300 is attached to the ends of multiple pouch-type battery cells, the thermal expansion material has the property of expanding rapidly when the temperature rises, so it can prevent the flames from being transmitted to other battery cells inside the blocking plate that have not ignited.

[0048] The cell housing 200 is made of an insulating, or highly heat-resistant, or insulating and highly heat-resistant material, and one pouch-type battery cell 101 is disposed inside the cell housing 200. Therefore, even if a flame erupts due to thermal runaway caused by abnormal use of the pouch-type battery cell 101 inside the cell housing 200, the cell housing 200 can block the spread of the flame and prevent it from spreading to the outside of the cell housing 200.

[0049] The cell housing 200 includes a first surface 201 and a second surface 202 located parallel to the bottom of the electrode assembly receiving portion of the pouch-type battery cell 101, and a third surface 203 coupled to one side ends of the first surface 201 and the second surface 202 to connect them. In other words, the cell housing 200 is configured in a U-shape that surrounds the outer surface of the pouch-type battery cell 101 in the overall length direction L.

[0050] Generally, the sealing portion where the electrode lead protrudes from the pouch-type battery cell is an area where venting can easily occur due to weak bonding strength, so by disposing a blocking plate containing a thermal expansion material adjacent to the electrode lead, it is possible to prevent flames or sparks from spreading to other battery cells.

[0051] Meanwhile, when the cell housing 200 is made of an insulating material, problems such as short circuits do not occur even if the cell housing comes into contact with the electrode leads of the pouch-type battery cells arranged inside the cell housing. Therefore, when a cell housing made of an insulating material is used, a separate member for ensuring insulation between the pouch-type battery cells and electrical connecting members or connectors is not required. Therefore, it is possible to save space and costs for providing an insulating structure.

[0052] 2 and 3 show a configuration in which two cell housings 200 accommodating pouch-type battery cells 101 are arranged adjacent to each other, one blocking plate 300 is positioned at each end of the overall length direction L of the two cell housings 200, and a venting plate 400 is attached to the top of the two cell housings 200.

[0053] However, instead, one blocking plate 300 may be located at each end in the overall length direction of one cell housing 200 housing a pouch-type battery cell 101, and a venting plate 400 may be coupled to the upper portion of the cell housing 200.

[0054] Alternatively, the battery cell assembly may include three or more cell housings 200 housing the pouch-type battery cells 101 .

[0055] As such, in the present invention, the battery cell assembly may have a configuration in which one or more cell housings are arranged in close contact with each other, a blocking plate is coupled to each end of the cell housing in the overall length direction, and a venting plate is coupled to the top of the cell housing.

[0056] The venting plate 400 is coupled to the other side end of the cell housing 200, which is opposite to one side end where the third surface 203 is coupled to the first surface 201 and the second surface 202 of the cell housing 200. That is, the venting plate 400 can be provided on the outer surface of the pouch-type battery cell 101 on which the cell housing 200 is not provided, and coupled to the cell housing 200.

[0057] Since the pouch-type battery cell 101 is housed in a space formed inside the cell housing 200, the blocking plate 300, and the venting plate 400, when the pressure in the space formed by the cell housing 200, the blocking plate 300, and the venting plate 400 increases due to gas discharge from the pouch-type battery cell 101, the gas can be discharged in the direction of the venting plate 400.

[0058] Since the venting plate 400 has a notch 410, the notch 410 can be broken by the pressure of the gas discharged from the pouch-type battery cell 101 to form a gas discharge path.

[0059] In this way, the battery cell assembly according to the present invention includes a venting plate having a notch formed on one side of the pouch-type battery cell to prevent gas from being easily discharged due to the addition of a cell housing made of a high-strength material, thereby guiding the gas to be discharged in a specific direction.

[0060] FIG. 4 is a perspective view of a battery cell assembly according to the present invention.

[0061] 4, the battery cell assembly shown in FIG. 4 has the same configuration as the battery cell assemblies shown in FIGS. 2 and 3 except that the battery cell assembly shown in FIG. 4 has a structure in which a through hole 420 is formed in a venting plate 400.

[0062] When the through hole 420 is formed in this manner, gas inside the cell housing can be discharged, thereby reducing the increase in internal pressure, or delaying or preventing the venting plate 400 from breaking.

[0063] In one embodiment, the blocking plate 300 may be equipped with a connector (not shown) that is directly or indirectly connected to the electrode lead 102 .

[0064] The connector is disposed to penetrate the blocking plate 300, is connected to the electrode lead 102 on the inside, and can function as an LV connector or an HV connector on the outside.

[0065] In the above, the term "directly connected" means that the electrode lead and the connector are directly connected without any member between the connector and the electrode lead, and the term "indirectly connected" means that the electrode lead and the connector are connected with at least one additional member, such as a bus bar, disposed between the connector and the electrode lead.

[0066] In addition, the description of the battery cell assembly shown in FIG. 4 can be similarly applied to the description of the battery cell assembly shown in FIG. 2 and FIG.

[0067] FIG. 5 is a vertical cross-sectional view of a cell housing according to the present invention.

[0068] 5, (a) cell housing 200 has a clad form in which inner metal 211 and outer metal 212 are joined, and inner metal 211 can be made of a material with high salt resistance, acid resistance, corrosion resistance and high rigidity such as stainless steel, or a material with excellent thermal conductivity, heat retention and thermal efficiency such as MICA or special coating. Aluminum with excellent formability can be used for outer metal 212.

[0069] (b) The cell housing 200 has a form composed of a single material, and can be made of reinforced plastic that is stronger than iron. For example, glass fiber reinforced plastic can be used. Glass fiber reinforced plastic has the advantages of being stronger than iron, lighter than aluminum, and not rusting.

[0070] As such, the battery cell assembly according to the present invention uses a cell housing made of insulating and / or highly heat-resistant material, so that in the event of a fire in a pouch-type battery cell housed inside the cell housing, the transmission of flames or sparks to the outside of the cell housing can be completely prevented.

[0071] FIG. 6 is a perspective view of a battery pack according to the present invention.

[0072] Referring to FIG. 6, the battery pack according to the present invention includes a cell stack 500 in which a number of battery cell assemblies 510 are closely arranged, and a pack frame 600 that houses the cell stack 500 therein, the pack frame 600 having the form of a rectangular frame that surrounds the outer periphery of the cell stack 500.

[0073] Optionally, the pack frame 600 may include an outer surface surrounding at least one of the upper and lower surfaces of the cell stack 500, so that at least one of the upper and lower surfaces of the cell stack 500 is not blocked by the pack frame 600 and may be exposed to the outside.

[0074] In other words, since at least one of the upper and lower surfaces of the cell stack 500 constitutes the outer surface of the battery pack, the battery pack can be constructed using only the battery cell assembly 510 and the pack frame 600, without separate components such as a top plate and an end plate as in conventional battery packs.

[0075] Therefore, it is possible to manufacture a battery pack having a simple cell-to-pack structure in which the battery pack can be manufactured directly from the battery cell assembly.

[0076] The pack frame, unlike that shown in FIG. 6, may include coupling parts extending outward or inward, and the battery pack may be directly attached to the device by bolting to the coupling parts.

[0077] Those skilled in the art will appreciate that various applications and modifications within the scope of the present invention will be possible based on the above content. [Explanation of symbols]

[0078] 10,500 cell stack 20 Pack Frames 21 Thermally conductive resin 30 Top Plate 31 Busbar frame assembly 40 End Plate 101 Pouch-type battery cell 102 Electrode Lead 200 Cell Housing 201 Page 1 202 2nd page 203 Page 3 211 Inner metal 212 Outer metal 300 Blocking Plate 310 Thermal expansion material 400 Venting Plate 410 Notch 420 Through hole 500 Cell Stack 510 Battery cell assembly 600 Pack Frame

Claims

1. A pouch-type battery cell; a cell housing that accommodates the pouch-type battery cell; a blocking plate located at each end of the cell housing in the overall length direction; a venting plate for discharging gas released from the pouch-type battery cell; Including, The blocking plate has an inner surface provided with a thermal expansion material; the cell housing includes a first surface and a second surface positioned parallel to a bottom of an electrode assembly receiving portion of the pouch-type battery cell, and a third surface coupled to one side ends of the first surface and the second surface to connect them, The vent plate is coupled to an opposite side end of the first and second sides of the battery cell assembly.

2. 2. The battery cell assembly of claim 1, wherein the thermally expansive material is expanded graphite.

3. 2. The battery cell assembly according to claim 1, wherein the thermal expansion material is located adjacent to an electrode lead of the pouch-type battery cell and expands and deforms to fill a space between the electrode lead and the blocking plate when the temperature of the pouch-type battery cell increases.

4. 2. The battery cell assembly of claim 1, wherein the venting plate has a notch formed therein.

5. 5. The battery cell assembly of claim 4, wherein the notch is ruptured by pressure of gas discharged from the pouch-type battery cell.

6. The battery cell assembly of claim 1 , wherein the vent plate includes a through hole.

7. 2. The battery cell assembly according to claim 1, wherein the cell housing housing the pouch-type battery cells includes one cell housing or includes two or more cell housings housing the pouch-type battery cells.

8. 10. The battery cell assembly of claim 1, wherein the cell housing comprises an insulating material and / or a highly heat resistant material.

9. The cell housing has a clad configuration in which an inner metal and an outer metal are joined together; 9. The battery cell assembly according to claim 8, wherein the inner metal is made of a highly rigid material, and the outer metal is made of a material having excellent thermal conductivity.

10. 9. The battery cell assembly of claim 8, wherein said cell housing is made of reinforced plastic.

11. The battery cell assembly of claim 1 , wherein the blocking plate is equipped with a connector that is directly or indirectly connected to an electrode lead.

12. A battery pack including the battery cell assembly according to any one of claims 1 to 11, a cell stack in which a plurality of battery cell assemblies are closely arranged; a pack frame that houses the cell stack therein; Including, the pack frame has a rectangular frame shape surrounding an outer periphery of the cell stack, At least one of the upper and lower surfaces of the cell stack constitutes an outer surface of the battery pack.

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