Battery pack

Abstract

According to exemplary embodiments, a battery pack is provided. The battery pack comprises: a pack housing including a base plate and a sidewall; a plurality of battery cell assemblies on the base plate; a lead coupled to the sidewall of the pack housing; and a foaming device configured to discharge a foamed layer into an inner space defined by the pack housing and the lead.

Description

battery pack

[0001] The present invention relates to a battery pack. This application claims the benefit of Korean Application No. 10-2024-0099399, filed July 26, 2024, which is incorporated herein by reference in its entirety.

[0002] Unlike primary batteries, secondary batteries can be charged and discharged multiple times. They are widely used as a power source for various wireless devices, including handsets, laptops, and cordless vacuum cleaners. Recently, improved energy density and economies of scale have dramatically reduced the per-unit manufacturing cost of secondary batteries. Furthermore, as the range of battery electric vehicles (BEVs) has increased to match that of fuel-powered vehicles, the primary use of secondary batteries is shifting from mobile devices to mobility.

[0003] The technological development trend for secondary batteries for mobility is improving energy density and safety. The safety of secondary batteries for mobility is crucial, as it directly impacts the lives of passengers. Safety in secondary batteries can be achieved through mechanical robustness, reliable electrical insulation, and delayed heat transfer in the event of thermal runaway.

[0004] The technical idea of ​​the present invention aims to solve a problem by providing a battery pack with improved safety.

[0005] According to exemplary embodiments for solving the above-described problem, a battery pack is provided. The battery pack includes a pack housing including a base plate and side walls; a plurality of battery cell assemblies on the base plate; a lid coupled to the side walls of the pack housing; and a foaming device configured to release a foamed layer into an internal space defined by the pack housing and the lid.

[0006] The foaming device is configured to release the foamed layer in response to a thermal runaway event or external impact.

[0007] The battery pack further includes electrical components on the base plate, and the space occupancy of the foamed layer, the electrical components, and the plurality of battery cell assemblies released from the foaming device in the internal space is 90% or more.

[0008] The foaming device is located outside the pack housing.

[0009] The above foaming device is located in the internal space.

[0010] The foaming device includes a foaming agent configured to form the foamed layer and a case containing the foaming agent.

[0011] The above foaming agent includes Silmagel.

[0012] The above foaming device is either a spring type or a rupture disc type.

[0013] The foaming device is coupled to the side wall of the pack housing.

[0014] The foaming device is coupled to the base plate of the pack housing.

[0015] The foaming device is coupled to the lead of the pack housing.

[0016] The above foamed layer is porous.

[0017] The above foamed layer is an insulating carbonized layer.

[0018] A battery pack according to exemplary embodiments of the present invention may include a foaming device configured to release a foamed layer into the internal space of the battery pack during a thermal runaway event. Accordingly, if a thermal runaway event occurs in the battery pack, the propagation of the thermal runaway event can be blocked by the foamed layer, thereby enhancing the safety of the battery pack.

[0019] The effects that can be obtained from the exemplary embodiments of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly derived and understood by those skilled in the art to which the exemplary embodiments of the present disclosure pertain from the following description. In other words, unintended effects resulting from practicing the exemplary embodiments of the present disclosure can also be derived by those skilled in the art from the exemplary embodiments of the present disclosure.

[0020] FIG. 1 is a plan view of a battery pack according to exemplary embodiments.

[0021] Figure 2 is a cross-sectional view taken along the cutting line 1I-1I' of Figure 1.

[0022] FIG. 3 is a diagram showing the effectiveness of a battery pack according to exemplary embodiments.

[0023] FIG. 4 is a cross-sectional view of a battery pack according to other exemplary embodiments.

[0024] FIG. 5 is a cross-sectional view of a battery pack according to other exemplary embodiments.

[0025] FIG. 6 is a cross-sectional view of a battery pack according to other exemplary embodiments.

[0026] FIG. 7 is a cross-sectional view of a battery pack according to other exemplary embodiments.

[0027] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, it should be noted that the terms and words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings. Based on the principle that the inventor can appropriately define the concepts of terms to best explain his or her invention, they should be interpreted in a way that aligns with the technical spirit of the present invention.

[0028] Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely the most preferred embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that there may be various equivalents and modified examples that can replace them at the time of filing this application.

[0029] In addition, when describing the present invention, if it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description is omitted.

[0030] Since the embodiments of the present invention are provided to more fully explain the present invention to those skilled in the art, the shapes and sizes of components in the drawings may be exaggerated, omitted, or schematically illustrated for clearer explanation. Accordingly, the sizes and proportions of each component do not fully reflect the actual sizes or proportions.

[0031]

[0032] (Example 1)

[0033] FIG. 1 is a plan view of a battery pack (100) according to exemplary embodiments.

[0034] Figure 2 is a cross-sectional view taken along the cutting line 1I-1I' of Figure 1.

[0035] FIG. 3 is a drawing showing the effect of a battery pack (100) according to exemplary embodiments.

[0036] Referring to FIGS. 1 to 3, a battery pack (100) may include a pack housing (110), a plurality of battery cell assemblies (120), a lead (130), a foaming device (140), and electrical components (150). The battery pack (100) is the final form of a battery system mounted on mobility, etc.

[0037] The pack housing (110) may include a base plate (111) and side walls (112, 113, 114, 115). Here, two directions substantially parallel to the mounting surface (111M) of the base plate (111) are defined as the X direction and the Y direction, and a direction substantially perpendicular to the mounting surface (111M) of the base plate (111) is defined as the Z direction. The mounting surface (111M) may face a plurality of battery cell assemblies (120). The X direction, the Y direction, and the Z direction may be substantially perpendicular to each other.

[0038] The base plate (111) may have a flat shape. The side walls (112, 113, 114, 115) may be substantially perpendicular to the base plate (111). The side walls (112, 113, 114, 115) may be adjacent to edge portions of the base plate (111). The side walls (112, 113, 114, 115) may be joined to edge portions of the base plate (111).

[0039] Each of the base plate (111) and the side walls (112, 113) may be provided by an extrusion process. The extrusion direction of each of the base plate (111) and the side walls (112, 113) may be the X direction. That is, the YZ cross-section of each of the base plate (111) and the side walls (112, 113) may be constant depending on the position in the X direction except for deformation due to additional tooling. Here, the YZ cross-section may be substantially parallel to the Y direction and the Z direction, and substantially perpendicular to the X direction. The base plate (111) and the side walls (112, 113) may be arranged in the Y direction. The side walls (114, 115) may also be provided by an extrusion process.

[0040] According to exemplary embodiments, the base plate (111) and side walls (112, 113) may be joined by friction stir welding. The base plate (111) may include a plurality of unit plates joined by friction stir welding.

[0041] The pack housing (110) may include a center beam (116). The center beam (116) may extend in the X direction. The center beam (116) may be interposed between the side walls (112, 113). The center beam (116) may be included in a center plate that is positioned at the center of a plurality of unit plates that are friction stir welded to each other. Accordingly, the center beam (116) may be formed together with the center plate in an extrusion process, and the center beam (116) may be a continuous element integral with the center plate.

[0042] The base plate (111) may include a plurality of cooling channels. The plurality of cooling channels may provide passages for the movement of a coolant, such as water, for example. The plurality of cooling channels may be formed by an extrusion process. The plurality of cooling channels may extend in the X direction. The plurality of cooling channels may be spaced apart in the Y direction.

[0043] A plurality of battery cell assemblies (120) may be on a mounting surface (111M) of a base plate (111) of a pack housing (110). The base plate (111) may support the plurality of battery cell assemblies (120). Side walls (112, 113, 114, 115) may horizontally surround the plurality of battery cell assemblies (120).

[0044] Battery cell assemblies (120) can be arranged in the X direction and the Y direction. In this example, two battery cell assemblies (120) are arranged in the X direction, and two battery cell assemblies are arranged in the Y direction, so that the plurality of battery cell assemblies (120) form a matrix of two rows and two columns. However, this is for illustrative purposes and does not limit the technical idea of ​​the present invention in any way.

[0045] Hereinafter, the technical idea of ​​the present invention will be described with reference to an embodiment in which a battery pack (100) is a modular type and each of a plurality of battery cell assemblies (120) does not include a module frame. However, this is a non-limiting example and does not limit the technical idea of ​​the present invention in any sense. A person skilled in the art will be able to easily arrive at a plurality of battery cell assemblies including a module frame and a module-type battery pack including the same based on the description herein. Each of the plurality of battery cell assemblies (120) may include a plurality of battery cells, a plurality of pads, and first and second integrated circuit assemblies.

[0046] Each of the plurality of battery cells may include an electrode assembly, an electrolyte, and a case. Each of the plurality of battery cells may be any one of a cylindrical battery cell, a prismatic battery cell, and a pouch-type battery cell. The electrode assembly of the cylindrical battery cell is housed in a cylindrical metal can. The electrode assembly of the prismatic battery cell is housed in a prismatic metal can. The electrode assembly of the pouch-type battery cell is housed in a pouch case including an aluminum laminate sheet.

[0047] The electrode assembly includes an anode, a cathode, and a separator interposed between the anode and the cathode. A jelly roll type electrode assembly is formed by winding an anode, a cathode, and a separator interposed between them. A stack type electrode assembly includes a plurality of sequentially stacked anodes, a plurality of cathodes, and a plurality of separators interposed between them.

[0048] According to exemplary embodiments, a plurality of battery cells may constitute a plurality of banks. The plurality of banks may include one or more parallel-connected battery cells. The plurality of banks may be connected in series with each other. The number of battery cells included in each of the plurality of banks and the number of banks connected in series with each other may be determined according to the voltage and current to be output through each of the plurality of battery cell assemblies (120).

[0049] According to exemplary embodiments, the cell stack may further include a plurality of separators. The plurality of separators may be interposed between the plurality of battery cells. The plurality of separators may include a flexible material and may absorb swelling of the plurality of battery cells. According to exemplary embodiments, the plurality of separators may be thermal barriers. According to exemplary embodiments, each of the plurality of separators may have a high melting temperature and low thermal conductivity. According to exemplary embodiments, each of the plurality of separators may include a flame retardant material, such as a ceramic or coated glass material. According to exemplary embodiments, the plurality of separators may be configured to release a fire retardant material and a fire extinguishing agent when a thermal runaway event occurs.

[0050] A first integrated circuit assembly may include an insulating frame, an integrated circuit, busbars, wiring, and an insulating cover. The integrated circuit assembly may include physical and functional components for providing electrical connections between a plurality of battery cells, outputting a resulting voltage of the plurality of battery cells, and measuring voltages (or currents) of nodes within a circuit composed of the plurality of battery cells.

[0051] The insulating frame may include an insulating material, such as plastic. The insulating frame may cover the front of a plurality of battery cells. The insulating frame may support integrated circuits, bus bars, and wiring.

[0052] The bus bars may be short-circuited to the positive leads of the battery cells of the first bank and the negative leads of one or more battery cells of the last bank. The bus bars may be welded to the positive leads of the battery cells of the first bank and the negative leads of one or more battery cells of the last bank. The resulting voltage of the plurality of battery cells of the battery cell assembly (120) may be output through the bus bars. The bus bars may be fixed to the insulating frame.

[0053] The integrated circuit may be mounted on an insulating frame. The positive and negative leads, which are welded together, may form nodes within the battery cell assembly (120). The integrated circuit may be configured to measure the voltages of the nodes via sensing plates and sensing bars.

[0054] The sensing bars may include a conductive material. The sensing bars may have a rod-like shape. The sensing bars may be short-circuited to the bus bars. The sensing bars may be coupled to the bus bars. The voltage of the bus bars may be measured through the sensing bars.

[0055] Each of the plurality of sensing plates may have a patch shape or a pad shape. The plurality of sensing plates may include a conductive material. The plurality of sensing plates may be short-circuited to corresponding positive and negative leads of the plurality of battery cells.

[0056] Each of the plurality of sensing plates can be connected to an integrated circuit. Through the plurality of sensing plates, the voltages of the plurality of nodes within the battery cell assembly (120) can be measured.

[0057] The insulating cover may include an insulating material, such as plastic. The insulating cover may be fitted to the insulating frame. The insulating cover may cover the integrated circuit and bus bars, thereby protecting the electrical components of the first and second integrated circuit assemblies.

[0058] The first integrated circuit assembly may include an insulating frame, an integrated circuit, busbars, wiring, and an insulating cover. The second integrated circuit assembly is substantially identical to the first integrated circuit assembly except that it does not include busbars.

[0059] The lead (130) can be coupled to the side walls (112, 113, 114, 115). The lead (130) can cover elements arranged in the internal space (100IS) of the battery pack (100), such as battery cell assemblies (120) and electrical components (150). The lead (130) can be fixed to the battery pack (100) by a mechanical coupling means, such as a bolt.

[0060] According to exemplary embodiments, the discharge device (140) may be coupled to the pack housing (110). According to exemplary embodiments, the discharge device (140) may be coupled to a side wall (115) of the pack housing (110). According to exemplary embodiments, the discharge device (140) may be external to the pack housing (110) and the lid (130). The discharge device (140) may be spaced apart from the plurality of battery cell assemblies (120) with the side wall (115) therebetween. The side wall (115) may include a foaming hole (115H) connected to the discharge device (140). The discharge device (140) may include a case (141) and a foaming agent (143).

[0061] The foaming agent (143) may be contained in the case (141). According to exemplary embodiments, the case (141) may include a rupture disk. When a thermal runaway event occurs inside the battery pack (100), the rupture disk of the case (141) may be ruptured due to an increase in pressure in the internal space (100IS), thereby connecting the inside of the case (141) and the internal space (100IS) of the battery pack (100).

[0062] According to other exemplary embodiments, the case (141) may include a valve. When a thermal runaway event occurs inside the battery pack (100), the valve of the case (141) may open due to an increase in pressure in the internal space (100IS), thereby connecting the inside of the case (141) and the internal space (100IS) of the battery pack (100).

[0063] The foaming agent (143) may include a foamable refractory material. The foamable refractory material may be configured to foam when heated. The foaming action may include melting, bubbling, swelling, forming an insulating layer, and forming a ceramic layer of the surface coating.

[0064] The foaming agent (143) may be configured to form a foamed layer (145) when a thermal runaway event occurs. The foamed layer (145) may be introduced into the internal space (100IS) through the foaming hole (115H). The foamed layer (145) may have a larger volume than the foaming agent (143). The foamed layer (145) may fill the internal space (100IS).

[0065] According to exemplary embodiments, the occupancy of the internal space (100IS) of the battery pack (100) of the foamed layer (145), the battery cell assembly (120), and the electrical components (150) may be about 80% or more. According to exemplary embodiments, the occupancy of the internal space (100IS) of the battery pack (100) of the foamed layer (145), the battery cell assembly (120), and the electrical components (150) may be about 85% or more. According to exemplary embodiments, the occupancy of the internal space (100IS) of the battery pack (100) of the foamed layer (145), the battery cell assembly (120), and the electrical components (150) may be about 90% or more. According to exemplary embodiments, the occupancy of the internal space (100IS) of the battery pack (100) of the foamed layer (145), the battery cell assembly (120) and the electrical components (150) may be about 95% or more.

[0066] The foamed layer (145) may be an insulating carbonized layer. The foamed layer (145) may be porous. The foamed layer (145) may have a high ignition point, a high melting point, and low thermal conductivity. Accordingly, the foamed layer (145) may prevent a fire in one of the battery cell assemblies (120) from spreading to adjacent battery cell assemblies (120).

[0067] The foaming agent (143) may include any one of a polyurethane foaming agent containing a flame retardant additive, a polystyrene foaming agent such as flame retardant EPS (Expandable Polystyrene) and XPS (Extruded Polystyrene), a melamine foam, a PVC foaming agent, a flame retardant polyisocyanurate foam, a flame retardant polyethylene foaming agent, a flame retardant silicone foam, a phenolic foam, a flame retardant EVA foaming agent, a flame retardant polyurea foam, and Silmagel.

[0068] The battery pack (100) may include exhaust devices. The exhaust devices may be coupled to at least some of the side walls (112, 113, 114, 115). The side walls (112, 113, 114, 115) coupled to the exhaust devices may include exhaust paths connected to the exhaust devices. The exhaust devices may be configured to delay thermal propagation by releasing high-temperature gas within the battery pack (100) to the outside when at least one of the plurality of battery cell assemblies (120) is in a thermal runway state.

[0069] Here, thermal runaway of multiple battery cell assemblies (120) is a state in which temperature changes of multiple battery cell assemblies (120) further accelerate the temperature change, which is an uncontrollable positive feedback. Multiple battery cell assemblies (120) in a state of thermal runaway exhibit a rapid temperature increase and emit a large amount of high-pressure gas and combustion debris.

[0070] The battery pack (100) may further include inter-busbars. A plurality of battery cell assemblies (120) may be connected in series by the inter-busbars, and the battery pack (100) may output a high voltage.

[0071] The electrical components (150) may be placed on the pack housing (110). The electrical components (150) may be placed between any one of the side walls (112, 113, 114, 115) on which the exhaust devices are installed and the plurality of battery cell assemblies (120).

[0072] The electrical components (150) may include, for example, a BMS. The BMS may be configured to monitor, balance, and control the battery pack. Monitoring of the battery pack (100) may include measuring voltage and current of specific nodes within a plurality of battery cell assemblies (120) and measuring temperature of set locations within the battery pack (100). The battery pack (100) may include sensors for measuring the voltage, current, and temperature described above.

[0073] Balancing of a battery pack (100) is an operation that reduces the deviation between multiple battery cell assemblies (120). Control of the battery pack (100) includes preventing overcharge, overdischarge, and overcurrent. Through monitoring, balancing, and control, the battery pack (100) can operate under optimal conditions, thereby preventing shortening of the lifespan of each of the multiple battery cell assemblies (120).

[0074] The electrical components (150) may further include a cooling device, a PRA (Power Relay Assembly), a safety plug, etc. The cooling device may include a cooling fan. The cooling fan may prevent overheating of each of the plurality of battery cell assemblies (120) by circulating air inside the battery pack (100). The PRA may be configured to supply or cut off power from the high-voltage battery to an external load (e.g., a motor of a vehicle). The PRA may protect the plurality of battery cell assemblies (120) and the external load (e.g., a motor of a vehicle) by cutting off power supply to the external load (e.g., a motor of a vehicle) in a situation where an abnormal voltage, such as a voltage surge, occurs.

[0075]

[0076] (Example 2)

[0077] FIG. 4 is a plan view of a battery pack (101) according to other exemplary embodiments.

[0078] Referring to FIG. 4, a battery pack (101) may include a pack housing (110'), a plurality of battery cell assemblies (120), a lead (130), and a foaming device (140). The battery pack (101) may include a pack housing (110') instead of the pack housing (110, see FIG. 2). The pack housing (110') is substantially the same as the pack housing (110, see FIG. 2) except for the side wall (115').

[0079] According to exemplary embodiments, the foaming device (140) may be coupled to the side wall (115'). According to exemplary embodiments, the foaming device (140) may be located in the interior space (100IS) of the pack housing (100). Accordingly, the side wall (115') may not include a foaming hole.

[0080]

[0081] (Example 3)

[0082] FIG. 5 is a plan view of a battery pack (102) according to other exemplary embodiments.

[0083] Referring to FIG. 5, the battery pack (102) may include a pack housing (110"), a plurality of battery cell assemblies (120), a lead (130), and a foaming device (140). The battery pack (101) may include a pack housing (110") instead of the pack housing (110, see FIG. 2). The pack housing (110") is substantially the same as the pack housing (110, see FIG. 2), except for the side walls (115') and the base plate (111').

[0084] According to exemplary embodiments, the foaming device (140) may be coupled to a base plate (111'). The base plate (111') may include a foaming hole (111H) connected to the foaming device (140). The side wall (115') may not include a foaming hole.

[0085]

[0086] (Example 4)

[0087] FIG. 6 is a plan view of a battery pack (103) according to other exemplary embodiments.

[0088] Referring to FIG. 6, the battery pack (103) may include a pack housing (110'), a plurality of battery cell assemblies (120), a lead (130'), and a foaming device (140). The battery pack (101) may include a pack housing (110') and a lead (130') instead of the pack housing (110, see FIG. 2) and the lead (130, see FIG. 2). The pack housing (110') is substantially the same as that described with reference to FIG. 4.

[0089] According to exemplary embodiments, the foaming device (140) may be coupled to a lead (130'). The lead (130') may include a foaming hole (130H) connected to the foaming device (140).

[0090]

[0091] (Example 5)

[0092] FIG. 7 is a plan view of a battery pack (104) according to other exemplary embodiments.

[0093] Referring to FIG. 7, the battery pack (104) may include a pack housing (110'), a plurality of battery cell assemblies (120), a lead (130), and a foamed layer (145). The pack housing (110') is substantially the same as that described with reference to FIG. 4. The foamed layer (145) is substantially the same as that described with reference to FIGS. 1 to 3.

[0094] According to exemplary embodiments, the battery pack (100) may include a pre-formed foamed layer (145). The foamed layer (145) may block moisture and air from the outside and may maintain the operating temperature of each of the plurality of battery cell assemblies (120) relatively constant. In addition, the foamed layer (145) may support each of the plurality of battery cell assemblies (120), thereby improving the seismic resistance and impact resistance of the battery pack (100). In addition, the foamed layer (145) may absorb swelling of each of the plurality of battery cells of each of the plurality of battery cell assemblies (120).

[0095]

[0096] The present invention has been described in more detail through drawings and examples. However, the configurations described in the drawings or examples described in this specification are merely embodiments of the present invention and do not represent all of the technical ideas of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as of the time of this application.

Claims

1. Pack housing including base plate and side walls; A plurality of battery cell assemblies on the base plate; a lead coupled to the side wall of the pack housing; and A battery pack comprising a foaming device configured to release a foamed layer into an internal space defined by the pack housing and the lead.

2. In paragraph 1, A battery pack characterized in that the foaming device is configured to release the foamed layer in response to a thermal runaway event or external impact.

3. In paragraph 1, Further comprising electrical components on the base plate, and A battery pack characterized in that the space occupancy of the foamed layer, the electric components and the plurality of battery cell assemblies released from the foaming device in the internal space is 90% or more.

4. In paragraph 1, A battery pack, characterized in that the foaming device is located outside the pack housing.

5. In paragraph 1, A battery pack characterized in that the foaming device is located in the internal space.

6. In paragraph 1, A battery pack characterized in that the foaming device includes a foaming agent configured to form the foamed layer and a case containing the foaming agent.

7. In paragraph 6, A battery pack characterized in that the foaming agent comprises Silmagel.

8. In paragraph 1, A battery pack characterized in that the foaming device is either a spring type or a rupture disk type.

9. In paragraph 1, A battery pack, characterized in that the foaming device is coupled to the side wall of the pack housing.

10. In paragraph 1, A battery pack, characterized in that the foaming device is coupled to the base plate of the pack housing.

11. In paragraph 1, A battery pack, characterized in that the foaming device is coupled to the lead of the pack housing.

12. In paragraph 1, A battery pack characterized in that the foamed layer is porous.

13. In paragraph 1, A battery pack characterized in that the foamed layer is an insulating carbonized layer.

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