Battery pack, ESS including the same, and motor vehicle

Abstract

A battery pack according to one embodiment of the present invention includes a module assembly including a plurality of battery modules arranged along a first direction; a vent channel arranged on one side of the module assembly and configured to communicate with each of the plurality of battery modules; and a discharge delay member provided within the vent channel and configured to delay discharge of vent gas generated in at least some of the plurality of battery modules and flowing into the vent channel.

Description

Technical Field

[0001] The present invention relates to a battery pack, an ESS (energy storage system) including the same, and a vehicle.

[0002] This application claims priority based on Korean Patent Application No. 10-2021-0188648 filed on December 27, 2021, and all of the content disclosed in the specification and drawings of the application is incorporated into this application.

Background Art

[0003] A battery pack applied to devices such as an ESS (energy storage system) and an electric vehicle can be manufactured in a form including a plurality of battery modules to which lithium secondary batteries capable of achieving high output and high capacity are applied. In order to satisfy the output characteristics of a battery pack applied to devices that require high output and high capacity, such as an energy storage system and an electric vehicle, and to achieve high capacity, the number of lithium secondary batteries included in one battery module can be increased, and the number of battery modules included in one battery pack can be increased.

[0004] However, in the case of a battery pack including such a large number of lithium secondary batteries, if a fire or explosion occurs, it is inevitable that the damage will be even greater.

[0005] A fire occurring in a battery pack starts from an abnormal temperature rise and internal gas generation of a lithium secondary battery disposed inside a battery module. When the temperature of the lithium secondary battery rises abnormally and the internal pressure of the lithium secondary battery rises above a certain level due to the generation of internal gas, venting occurs in the lithium secondary battery, and as a result, high-temperature gas is ejected to the outside of the lithium secondary battery, and high-temperature sparks including electrode active material and aluminum particles are also ejected. There is a risk of fire when such high-temperature gas and sparks come into contact with oxygen.

[0006] In particular, the situation where a large amount of oxygen comes into contact with the high-temperature vent gas and high-temperature sparks generated by the occurrence of a thermal event is likely to occur when the vent gas generated inside the battery pack rapidly flows out to the outside at a high pressure. That is, when the pressure inside the battery pack instantaneously becomes very high due to the venting of the secondary battery caused by a thermal event and then the vent gas is rapidly discharged to the outside, the internal pressure decreases greatly within a short time, and conversely, a large amount of oxygen may flow into the inside from the outside. At this time, there is a risk of fire due to the contact between the high-temperature vent gas and spark substances remaining inside the battery pack and a large amount of oxygen.

[0007] Therefore, when discharging the vent gas generated during a thermal event, there is a need to develop a battery pack structure that can discharge the vent gas at an appropriate speed despite the high vent pressure.

Summary of the Invention

Problems to be Solved by the Invention

[0008] The present invention has been made in view of the above-described problems, and an object thereof is to minimize or prevent the inflow of oxygen from the outside by enabling the vent gas generated during a thermal event to be discharged at an appropriate speed despite the high vent pressure.

[0009] However, the technical problems to be solved by the present invention are not limited to the above problems, and other problems not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

Means for Solving the Problems

[0010] A battery pack according to an embodiment of the present invention for solving the above problems includes a module assembly including a plurality of battery modules arranged along a first direction, a vent channel arranged on one surface of the module assembly and configured to communicate with each of the plurality of battery modules, and a discharge delay member provided in the vent channel and configured to delay the discharge of vent gas generated in at least a part of the plurality of battery modules and flowing into the vent channel.

[0011] A plurality of discharge delay members are provided, and the plurality of discharge delay members can be arranged along the first direction.

[0012] The discharge delay member can be configured to be melted by the vent gas.

[0013] Each of the plurality of battery modules can include an outlet configured to discharge internal vent gas, and the vent channel can include a plurality of inlets formed at positions corresponding to the respective outlets.

[0014] The battery pack can include a flow path cap that covers at least one of the outlet and the inlet and is configured to be melted by the vent gas.

[0015] The space inside the vent channel can include a plurality of compartment spaces configured to be isolated from each other by the discharge delay member, and each of the plurality of compartment spaces can communicate with at least one battery module.

[0016] Each of the plurality of battery modules may include a cell assembly including a plurality of battery cells each having an electrode lead, a module housing configured to accommodate the cell assembly and having a shape with at least one open side, and a cover frame provided with a lead slit configured for the electrode lead to pass through and configured to cover the open side of the module housing.

[0017] The cover frame may be configured to be melted by the vent gas to close the lead slit.

[0018] The cover frame may include a first cover frame configured to have a first melting point and a second cover frame configured to have a second melting point higher than the first melting point.

[0019] The first melting point may be a temperature lower than the temperature of the vent gas, and the second melting point may be a temperature higher than the temperature of the vent gas.

[0020] The cover frame may be configured such that the first cover frame and the second cover frame are in contact with each other or overlap in a separated state, or the first cover frame may be configured to cover the second cover frame.

[0021] The battery pack may include a pack cover configured to cover one side of the module assembly facing the cover frame.

[0022] The battery pack may be provided with a pack opening formed at at least one of both ends in the first direction of a space formed between the module assembly and the cover frame.

[0023] The ESS according to an embodiment of the present invention may include the battery pack of the present invention as described above.

[0024] An automobile according to an embodiment of the present invention can include the battery pack of the present invention as described above.

Advantages of the Invention

[0025] According to one aspect of the present invention, when discharging vent gas generated during a thermal event, the vent gas can be discharged at an appropriate speed despite a high vent pressure, thereby minimizing or preventing the inflow of oxygen from the outside.

[0026] However, the advantageous effects derived through the present invention are not limited to the effects described above, and other advantageous effects not mentioned will be clearly understood by those skilled in the art from the description of the invention described below.

[0027] 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

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Mode for Carrying Out the Invention

[0029] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Prior to this, the terms and words used in this specification and the claims are not to be construed as being limited to their ordinary and dictionary meanings. The inventors themselves interpret them in accordance with the meaning and concept corresponding to the technical idea of the present invention in accordance with the principle that they can appropriately define the concept of the terms in order to explain the invention in the best way. Therefore, it should be understood that the configurations shown in the embodiments described in this specification are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. At the time of this application, there may be various equivalents and modifications that can replace these.

[0030] Referring to FIGS. 1 and 2, a battery pack 1 according to an embodiment of the present invention may include a module assembly M, a vent channel 20, and a discharge delay member 30. The module assembly M may include a plurality of battery modules 10 arranged along a first direction (a direction parallel to the X-axis). The vent channel 20 may be disposed on one surface of the module assembly M (a surface parallel to the X-Y plane). The vent channel 20 may be configured to communicate with each of the plurality of battery modules 10. The discharge delay member 30 may be provided inside the vent channel 20. The discharge delay member 30 may be configured to delay the discharge of vent gas that is generated in at least a part of the plurality of battery modules 10 and flows into the vent channel 20.

[0031] By being configured as described above, when vent gas is discharged due to the occurrence of a thermal event, the battery pack 1 of the present invention can minimize or prevent the inflow of oxygen due to negative pressure that may occur in the direction from the outside to the inside due to the sudden discharge of the vent gas. In another aspect, the battery pack 1 of the present invention does not directly form a discharge portion for venting in a part of the battery module 10, but is provided with a separate channel configured to discharge vent gas generated in each of the plurality of battery modules 10, thereby significantly reducing the possibility of oxygen inflow from the outside.

[0032] When a gas vent occurs due to an abnormality during the use of a secondary battery, it is very important to prevent the inflow of oxygen while reducing the pressure by appropriately discharging the vent gas. That is, when a vent due to a thermal event occurs, high-temperature vent gas and high-temperature spark substances (for example, electrode active materials, metal particles constituting the electrodes, etc.) may be generated. When such high-temperature vent gas and high-temperature spark substances come into contact with oxygen, there is a possibility of ignition, which may cause a larger accident such as an explosion of the battery pack 1.

[0033] When a vent occurs inside the battery pack 1, at the initial stage of the vent, the vent gas can be discharged very rapidly at a high pressure. However, as the vent progresses towards the latter half, the vent pressure decreases, and the vent pressure in the latter half of the vent may rapidly decrease as the discharge of the vent gas becomes more rapid. In this case, a large negative pressure is generated from the outside towards the inside, and as a result, a large amount of oxygen may flow in and come into contact with the high-temperature combustible substances remaining inside, potentially causing a fire. The battery pack 1 of the present invention includes a vent channel 20 and a discharge delay member 30 provided therein, thereby minimizing or preventing the inflow of oxygen due to the generation of such negative pressure, and thereby greatly improving the stability in the use of the battery pack 1.

[0034] On the other hand, the discharge delay member 30 may be, for example, a porous valve configured to allow the vent gas to pass through. In this case, the vent gas can pass through the discharge delay member 30. However, the discharge speed of the vent gas may be slower compared to the case where the discharge delay member 30 is not present.

[0035] Next, referring to FIGS. 1 and 2, a plurality of the discharge delay members 30 can be provided. The plurality of discharge delay members 30 can be arranged along the first direction (a direction parallel to the X-axis). In this case, even if a gas vent occurs in any one of the plurality of battery modules 10, the flow of the vent gas flowing into the vent channel 20 from the battery module 10 can be delayed. On the other hand, the vent channel 20 may have a channel closing portion formed at one end in the extending direction and a channel opening portion 20a formed at the other end. Therefore, as described above, when the plurality of discharge delay members 30 are arranged along the first direction, the vent gas flowing into the vent channel 20 from a position close to the closing portion of the vent channel 20 passes through the plurality of discharge delay members 30 until it is discharged through the channel opening portion 20a, thereby sufficiently reducing the discharge pressure.

[0036] Referring to FIG. 3, the discharge delay member 30 can be configured to melt by the vent gas. That is, the discharge delay member 30 can be configured to have a melting point lower than the temperature of the vent gas generated in the battery module 10 of the present invention.

[0037] The temperature of the vent gas varies depending on the specific configuration and the number of battery cells applied to the battery module 10, etc. The discharge delay member 30 of the present invention can be configured to have an appropriate melting point in consideration of this. For example, the discharge delay member 30 can include a resin and / or a rubber material. Even when the discharge delay member 30 is configured to have a low melting point in this way, the discharge delay member 30 can have the porous valve structure as described above. Since the vent gas can pass through when the discharge delay member 30 melts, the vent gas can be discharged even if the porous valve structure is not applied. However, for example, when the melting point of the discharge delay member 30 does not vary greatly from the temperature of the vent gas and the time required for melting is at a certain level or more, the porous valve structure can prevent the discharge of the vent gas from being excessively delayed.

[0038] Referring to FIGS. 1 to 3, and FIG. 4, the battery module 10 can include an outlet OL formed on one of its surfaces (a surface parallel to the X-Y plane). The outlet OL can be provided in each of the plurality of battery modules 10. The outlet OL can be configured such that the vent gas inside the battery module 10 is discharged. The vent channel 20 can include an inlet IL formed on one of its surfaces (a surface parallel to the X-Y plane). A plurality of the inlets IL can be provided. Each of the plurality of inlets IL can be provided at a position corresponding to each of the plurality of outlets OL.

[0039] The inlet IL and the outlet OL can be configured to communicate with each other. Thereby, the vent gas generated inside the battery module 10 can flow into the internal space of the vent channel 20 through the outlet OL and the inlet IL.

[0040] Referring to FIG. 5, the battery pack 1 of the present invention can include a flow path cap 40 configured to cover at least one of the outlet OL and the inlet IL. The flow path cap 40 can be configured to melt by vent gas. When the flow path cap 40 melts due to contact with the high-temperature vent gas generated inside the battery module 10, the vent gas can flow into the inside of the vent channel 20 through the outlet OL and the inlet IL.

[0041] The flow path cap 40 can be configured to have a melting point lower than the temperature of the vent gas generated in the battery module 10 of the present invention. The temperature of the vent gas varies depending on the specific configuration and the number of battery cells applied to the battery module 10, and the flow path cap 40 of the present invention can be configured to have an appropriate melting point in consideration of this. For example, the flow path cap 40 can include a resin and / or a rubber material.

[0042] Referring to FIGS. 6 and 7, the internal space of the vent channel 20 can include a plurality of compartment spaces configured to be isolated from each other by the discharge delay member 30. In this case, each of the plurality of compartment spaces can be configured to communicate with at least one battery module 10. For example, as shown in FIG. 6, one compartment space can be configured to communicate with one battery module 10. Different from this, as shown in FIG. 7, one compartment space can be configured to communicate with a plurality of battery modules 10. FIG. 7 only shows the case where one compartment space communicates with two battery modules 10, but the present invention is not limited thereby, and it can also be configured to communicate with three or more battery modules 10.

[0043] On the one hand, in the present invention, the configuration in which the partition space inside the vent channel 20 communicates with the battery module 10 means that, as shown in FIG. 4, not only when the outlet OL and the inlet IL respectively formed in the battery module 10 and the vent channel 20 are open, but also when the flow path cap 40 is applied as shown in FIG. 5. This is because, as described above, when vent gas is generated, the flow path cap 40 will eventually melt and the flow path will be opened.

[0044] Referring to FIGS. 8 and 9, the battery module 10 of the present invention can include a cell assembly CS (see FIGS. 4 and 5) including a plurality of battery cells 100, a module housing 200 configured to accommodate the cell assembly CS, and a cover frame 300 configured to cover an open side of the module housing 200. The battery cell 100 can be connected to an electrode assembly (not shown) accommodated therein and include an electrode lead 110 drawn out to the outside of the cell case. The module housing 200 can have a shape with at least one side open. The electrode lead 110 can extend toward the open region of the module housing 200. The cover frame 300 can include a lead slit configured such that the electrode lead 110 can pass through it. A bus bar is located on the cover frame 300, and the plurality of electrode leads 110 can each pass through the lead slit and be coupled to the bus bar.

[0045] When the battery cell 100 of the present invention has such a structure, a module opening P1, which is a gap through which vent gas generated inside the battery module 10 can be discharged, can be formed between the lead slit and the electrode lead 110. Such a module opening P1 can function as a passage through which cooling fluid (e.g., air) can flow during normal use of the battery pack 1, and can function as a passage for discharging vent gas when a thermal event occurs.

[0046] The plurality of battery modules 10 may be arranged such that the module opening portions P1 formed in each of them face the same direction. In the module assembly M, such a module opening portion P1 may be formed on the other surface (a surface parallel to the X-Z plane) that is substantially perpendicular to the one surface (a surface parallel to the X-Y plane) where the vent channel 20 of the present invention is located.

[0047] On the other hand, the cover frame 300 may be configured to melt by the vent gas and close the lead slit. For example, the cover frame 300 may be configured to have a melting point lower than the temperature of the vent gas. The temperature of the vent gas varies depending on the specific configuration and the number of battery cells 100 applied to the battery module 10, and the cover frame 300 of the present invention may be configured to have an appropriate melting point in consideration of this. For example, the cover frame 300 may contain a resin material.

[0048] According to such a configuration, melting of the cover frame 300 occurs at the initial stage of the generation of the vent gas, and the lead slit is closed, thereby blocking the inflow of oxygen through the module opening portion P1 of the battery module 10. Instead, the battery pack 1 of the present invention can guide the flow of the vent gas toward the vent channel 20. The flow of the vent gas guided toward the vent channel 20 in this way is delayed by the discharge delay member 30 (see FIGS. 2 and 3) described above, and thereby the inflow of oxygen through the vent channel 20 due to the generation of negative pressure can also be minimized.

[0049] Considering such functions of the cover frame 300, the cover frame 300 may be configured to have a lower melting point compared to the above-described discharge delay member 30 (see FIGS. 2 and 3) and / or the flow path cap 40 (see FIG. 5). When the cover frame 300 is configured in this way, it is possible to quickly block the discharge of vent gas and the discharge of spark substances through the module opening P1 of the battery module 10, thereby maximizing the effect of preventing oxygen from flowing into the battery module 10.

[0050] Referring to FIGS. 8 and 9, FIGS. 10 and 11, the cover frame 300 may include a first cover frame 310 and a second cover frame 320. The first cover frame 310 may be configured to have a first melting point. The second cover frame 320 may be configured to have a second melting point higher than the first melting point. The first melting point may be a temperature lower than the temperature of the vent gas. The second melting point may be a temperature higher than the temperature of the vent gas. The first cover frame 310 may include, for example, a resin material. The second cover frame 320 may include, for example, a resin material having a higher melting point than the first cover frame 310 and / or a mica material.

[0051] The first cover frame 310 may be configured to melt more quickly than the second cover frame 320 in a high-temperature environment due to the occurrence of a thermal event and cover the module opening P1 of the battery module 10. The second cover frame 320 may be configured not to melt for a longer time than the first cover frame 310 in a high-temperature environment due to the occurrence of a thermal event and hold the electrode lead 110.

[0052] With such a configuration, when the degree of melting of the first cover frame 310 becomes severe and the first cover frame 310 can no longer structurally hold the electrode lead 110, the second cover frame 320 can hold the electrode lead 110. Therefore, it is possible to prevent the occurrence of a hard short caused by unnecessary electrical contact between adjacent electrode leads 110. Furthermore, it is possible to prevent a phenomenon in which a large amount of oxygen flows in due to a complete structural collapse of the cover frame 300, causing a fire or increasing the scale of the fire.

[0053] The first cover frame 310 and the second cover frame 320 can have corresponding shapes. The first cover frame 310 and the second cover frame 320 can each be provided with lead slits at corresponding positions.

[0054] The cover frame 300 can be configured such that the first cover frame 310 and the second cover frame 320 overlap in a state of being in contact with or separated from each other (see FIG. 10). The first cover frame 310 can be disposed further inside than the second cover frame 320. In this case, the first cover frame 310 having a relatively low melting point is melted by being first exposed to the high-temperature vent gas, and the module opening P1 can be quickly closed.

[0055] Alternatively, the cover frame 300 can be configured such that the first cover frame 310 covers the second cover frame 320 (see FIG. 11). The cover frame 300 can be manufactured, for example, by insert injection. In this case, due to the melting of the first cover frame 310 that is first exposed to the high-temperature environment on the outside, the module opening P1 can be quickly closed.

[0056] Referring to FIGS. 8, 9, and 12, the battery pack 1 may include a pack cover 50. The pack cover 50 may be configured to cover one side of the module assembly M facing the cover frame 300. When the pack cover 50 is provided, high-temperature vent gas and spark substances that can be discharged through the module opening P1 due to the occurrence of a thermal event can be blocked.

[0057] Referring to FIGS. 12 and 13, the battery pack 1 may include a pack opening P2. The pack opening P2 may be formed at at least one of both ends in the first direction (a direction parallel to the X-axis) of the space S formed between the module assembly M and the pack cover 50. When the pack opening P2 is provided, the cooling fluid can be efficiently circulated through the space formed between the pack cover 50 and the module assembly M.

[0058] On the other hand, as shown in FIG. 13, module openings P1 can be formed on both sides of the battery module 10, respectively. The pack cover 50 may be provided on both sides of the module assembly M, respectively. The pack opening P2 may be provided at one end in the extension direction (a direction parallel to the X-axis) of the space S formed between one side of the module assembly M and the pack cover 50, and at the other end in the extension direction (a direction parallel to the X-axis) of the space S formed between the other side of the module assembly M and the pack cover 50, respectively.

[0059] According to such a configuration, in the normal use state of the battery pack 1, the cooling fluid flowing in through either one of the pair of pack openings P2 passes through the inside of each battery module 10 and is discharged through the pack opening P2 located on the opposite side, enabling efficient cooling. However, when a thermal event occurs, the battery pack 1 of the invention can be configured to block the inflow of battery oxygen along such a cooling circulation path, thereby greatly improving the safety in the use of the battery pack 1.

[0060] Referring to FIG. 14, an ESS (Energy Storage System) 3 according to an embodiment of the present invention includes a battery pack 1 according to the present invention. The ESS 3 can include, for example, a battery system including a plurality of battery packs 1 and a rack housing 2 configured such that a plurality of battery packs 1 are stacked inside. The ESS 3 can include one or more such battery systems.

[0061] Referring to FIG. 15, an automobile 5 according to an embodiment of the present invention includes a battery pack 1 according to the present invention. The automobile 5 can be configured to be driven by receiving power from one or more battery packs 1. The automobile 5 can be, for example, an electric vehicle (EV) or a hybrid electric vehicle (HEV).

[0062] As described above, the present invention has been described with reference to limited embodiments and drawings. However, the present invention is not limited thereby, 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 of the present invention and the claims described below.

Description of Reference Numerals

[0063] 1: Battery pack 2: Rack housing 3: ESS (Energy Storage System) 5: Automobile 10: Battery module P1: Module opening OL: Outlet M: Module assembly 100: Battery cell CS: Cell assembly 110: Electrode lead 200: Module housing 300: Cover frame 310: First cover frame 320: Second cover frame 20: Vent channel IL: Inlet 20a: Channel opening part 30: Discharge delay member 40: Flow path cap 50: Pack cover S: Space P2: Pack opening part

Claims

1. A module assembly including a plurality of battery modules arranged along a first direction; A vent channel arranged on one surface of the module assembly and configured to communicate with each of the plurality of battery modules; An exhaust delay member provided in the vent channel, configured to delay the discharge of vent gas generated in at least a part of the plurality of battery modules and flowing into the vent channel; Comprising; The exhaust delay member is a porous valve configured to allow the vent gas to pass through; Battery pack.

2. A plurality of exhaust delay members are provided; The plurality of exhaust delay members are arranged along the first direction; The battery pack according to claim 1, characterized in that.

3. The exhaust delay member is; Configured to be melted by the vent gas; The battery pack according to claim 1, characterized in that.

4. Each of the plurality of battery modules is provided with an outlet configured to discharge internal vent gas; The vent channel is provided with a plurality of inlets formed at positions corresponding to the respective outlets; The battery pack according to claim 1, characterized in that.

5. The battery pack is; Including a flow path cap covering at least one of the outlet and the inlet and configured to be melted by the vent gas; The battery pack according to claim 4, characterized in that.

6. The space inside the vent channel includes a plurality of partition spaces configured to be isolated from each other by the exhaust delay member; Each of the plurality of partition spaces communicates with at least one battery module; The battery pack according to claim 1, characterized in that.

7. Each of the plurality of battery modules is; A cell assembly including a plurality of battery cells provided with electrode leads; A module housing configured to accommodate the cell assembly and having a shape with at least one side open; A cover frame provided with a lead slit configured to allow the electrode leads to pass through and configured to cover the open side of the module housing; Including; The battery pack according to claim 1, characterized in that.

8. The cover frame is; configured to be melted by the vent gas to close the lead slit The battery pack according to claim 7, characterized in that.

9. The cover frame a first cover frame configured to have a first melting point; a second cover frame configured to have a second melting point higher than the first melting point; including The battery pack according to claim 7, characterized in that.

10. The first melting point is a temperature lower than the temperature of the vent gas, and the second melting point is a temperature higher than the temperature of the vent gas The battery pack according to claim 9, characterized in that.

11. The cover frame configured such that the first cover frame and the second cover frame are in contact with each other or overlap in a separated state, or the first cover frame is configured to cover the second cover frame The battery pack according to claim 9, characterized in that.

12. The battery pack includes a pack cover configured to cover one side of the module assembly facing the cover frame The battery pack according to claim 7, characterized in that.

13. The battery pack comprises a pack opening formed at at least one of both ends in the first direction of a space formed between the module assembly and the cover frame The battery pack according to claim 12, characterized in that.

14. An ESS including the battery pack according to any one of claims 1 to 13.

15. An automobile including the battery pack according to any one of claims 1 to 13.

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