An electric cell, a battery pack and an energy storage system

Abstract

This application provides a battery cell, a battery pack, and an energy storage system. The battery pack includes a battery casing, an insulating coolant, and at least one battery cell. The battery cell includes a casing, a core, and a separator. An explosion-proof valve is provided on the top wall of the casing. The explosion-proof valve includes an exhaust port, a liquid inlet, an explosion-proof plate, and a protective plate. The exhaust port and the liquid inlet penetrate the top wall. The explosion-proof plate seals the exhaust port, and the protective plate covers the exhaust port and the liquid inlet. The insulating coolant submerges the explosion-proof valve. The separator is located inside the casing, and the core is at least partially located inside the separator, forming a liquid inlet channel between the separator and the casing, and an exhaust channel between the separator and the core. The liquid inlet communicates with the liquid inlet channel, and the exhaust port, through-hole, and exhaust channel are sequentially connected. When the battery cell experiences thermal runaway, the explosion-proof valve opens, and high-temperature gas and liquid are discharged from the battery cell through the exhaust port. Simultaneously, the insulating coolant enters the battery cell through the liquid inlet, reducing the battery cell temperature and mitigating the side reactions of thermal runaway, thereby suppressing heat propagation between the battery cells within the battery pack.

Description

Technical Field

[0001] This application relates to the field of energy technology, and in particular to a battery cell, battery pack, and energy storage system. Background Technology

[0002] Lithium-ion batteries, characterized by high energy density and long cycle life, are widely used in energy storage, electric vehicles, and backup power. During charging and discharging, lithium-ion battery packs generate significant heat. Overheating accelerates side reactions within the battery cells, reducing battery performance and lifespan. To prevent fires or even explosions in the event of thermal runaway, each cell typically has an explosion-proof valve at its top to release high-temperature gases and prevent explosions. Additionally, thermal insulation materials are placed between adjacent cells within the battery pack to slow heat spread. However, these methods only prevent heat transfer from the outside of the cell; heat continues to be generated inside, limiting the effectiveness of heat spread suppression. Summary of the Invention

[0003] This application provides a battery cell, a battery pack, and an energy storage system to reduce the heat generated by thermal runaway inside the battery cell, thereby suppressing the thermal propagation between battery cells within the battery pack.

[0004] In a first aspect, this application provides a battery pack. The battery pack may include a battery casing, an insulating coolant, and at least one battery cell, wherein the insulating coolant and at least one battery cell are located within the battery casing. Each of the at least one battery cell includes a casing, a core pack, and a separator, wherein the core pack and separator are located within the casing. The casing includes a top wall and a bottom wall disposed opposite to each other. An explosion-proof valve is provided on the top wall, specifically including an exhaust port, a liquid inlet, an explosion-proof plate, and a protective plate. The exhaust port and the liquid inlet respectively penetrate the top wall. A baffle wall is provided between the exhaust port and the liquid inlet to isolate the exhaust port and the liquid inlet. The protective plate is located on the side of the top wall opposite to the bottom wall and covers the exhaust port and the liquid inlet. The explosion-proof plate is located on the side of the protective plate facing the top wall and is used to seal the exhaust port. The insulating coolant immerses the explosion-proof valve of each battery cell. Additionally, the separator includes a top plate and multiple side plates, the top plate being located between the top wall and the core pack, and the multiple side plates being located on the side of the top plate facing the core pack. The multiple side plates are connected sequentially and to the top plate to form a receiving space. The core package is at least partially located within the receiving space. There are gaps between the multiple side walls and the bottom wall. A liquid inlet channel is formed between the partition and the shell, and a venting channel is formed between the partition and the core package. The liquid inlet is connected to the liquid inlet channel, and the top plate is also provided with a through hole, through which the venting port and the venting channel are connected.

[0005] In the battery pack of this application, the explosion-proof valve of the battery cell is immersed in insulating coolant. When the cell is not in a state of explosion, the explosion-proof valve isolates the inside and outside of the cell, preventing insulating coolant from entering the cell through the vent and inlet ports, and preventing electrolyte from flowing out of the cell through the vent and inlet ports. When the cell experiences thermal runaway, the core and electrolyte generate a large amount of heat, increasing the internal pressure of the cell. Under this pressure, the explosion-proof valve opens, allowing the high-temperature gas and electrolyte inside the cell to escape through the vent channel and vent, thereby removing at least some of the heat from the cell. Simultaneously with the opening of the explosion-proof valve, insulating coolant enters the cell through the inlet port and mixes with the electrolyte after passing through the inlet channel. During the mixing process of the insulating coolant and electrolyte, on the one hand, the insulating coolant can absorb heat from inside the cell, reducing the internal temperature; on the other hand, the mixing of the insulating coolant and electrolyte can slow down the side reactions between the core and electrolyte, thereby reducing the heat generation inside the cell. In this way, the heat generated by thermal runaway within the battery cell can be effectively reduced, thereby suppressing the thermal spread between the cells within the battery pack.

[0006] The aforementioned explosion-proof plate can be used solely to seal the vent. In one possible implementation, the explosion-proof plate is located inside the vent and welded to the inner wall of the vent. The explosion-proof plate allows air to pass through both ends of the vent and prevents electrolyte from flowing out of the cell through the vent. In this technical solution, the protective plate can seal the liquid inlet to prevent electrolyte and insulating coolant from flowing through the liquid inlet. Thus, the vent and liquid inlet are sealed by the protective plate and the explosion-proof plate. Alternatively, in another possible implementation, both the vent and liquid inlet can be sealed by the explosion-proof plate. Specifically, the explosion-proof plate covers the vent and liquid inlet, sealing them to prevent electrolyte from flowing out of the cell through the vent and liquid inlet, and to prevent insulating coolant from flowing into the cell through the vent and liquid inlet.

[0007] In one possible implementation, the baffle wall can be an annular baffle wall, with the vent located inside the annular baffle wall. The liquid inlet can be an annular liquid inlet, arranged around the outer periphery of the annular baffle wall. During explosion venting, the high-temperature gas and electrolyte inside the battery cell are discharged through the vent, while the insulating coolant outside the battery cell can enter the battery cell through the liquid inlet on the outer periphery. This allows venting and liquid inlet to be achieved simultaneously without interfering with each other, accelerating the cooling of the battery cell's interior and the on-site thermal runaway side reactions.

[0008] In one possible implementation, an annular protrusion is provided on the surface of the top plate facing the top wall. The annular protrusion is arranged around the outer periphery of the through hole and is sealed to the annular baffle. In this way, the partition and the top wall are fixedly connected by the annular protrusion and the annular baffle, and the through hole in the annular protrusion communicates with the vent in the annular baffle, which can connect the outside of the cell and the receiving space inside the partition.

[0009] In one possible implementation, at least two-thirds of the core package is located within the containment space along the height of the cell. In this technical solution, the side plates can extend the dimensions of the venting and inlet channels as much as possible, thereby increasing the spacing between the venting and inlet channels. This way, when side reactions occur between the core package and the electrolyte, most of the electrolyte is discharged from the venting channels and vents under pressure, reducing the amount of electrolyte inside the cell and further mitigating the side reactions.

[0010] In one possible implementation, each of the aforementioned side plates has a notch on the side closest to the bottom wall. The insulating coolant can enter the venting channel through the notch and mix with the electrolyte, thus accelerating the mixing of the insulating coolant and electrolyte and consequently accelerating heat absorption.

[0011] In one possible implementation, at least one of the aforementioned side plates is provided with a plurality of small holes, each of which is smaller than the size of the vent. When a side reaction occurs between the core and the electrolyte, the electrolyte flows towards the vent under pressure because the size of the small hole is smaller than the vent. When the electrolyte in the vent channel decreases, a pressure difference may occur on both sides of the small hole, allowing a portion of the insulating coolant entering the cell to pass through the small hole into the vent channel and mix with the electrolyte, thereby accelerating the prevention of the thermal runaway side reaction.

[0012] In one possible implementation, the through-hole has multiple vents connected to an exhaust port. When passing through the through-hole in the top plate, the electrolyte passes through the aforementioned multiple vents. Since the cross-sectional area of ​​the aforementioned multiple vents is smaller than that of the through-hole, the flow rate of the electrolyte passing through the aforementioned multiple vents increases, thereby allowing the electrolyte to be discharged more quickly.

[0013] In the battery pack of this application, the top wall of the casing is further provided with a positive terminal and a negative terminal, and the positive terminal, negative terminal, and explosion-proof valve are located on the same side of the casing. The cell pack may include a positive tab and a negative tab. The top plate of the separator is also provided with a positive opening and a negative opening. In practical applications, the placement position of the cell pack is not limited. In one possible implementation, the cell pack can be placed upright. The positive tab and negative tab are located on the side of the cell pack facing the top plate, the positive tab passes through the positive opening and connects to the positive terminal, and the negative tab passes through the negative opening and connects to the negative terminal. Alternatively, in another possible implementation, the cell pack may also be placed on its side. The positive tab and negative tab are located opposite each other on both sides of the cell pack, and the positive tab and negative tab are respectively arranged facing multiple side plates. The cell also includes a positive conductor and a negative conductor. One end of the positive conductor is connected to the positive tab, and the other end passes through the positive opening and connects to the positive terminal. One end of the negative conductor is connected to the negative tab, and the other end passes through the negative opening and connects to the negative terminal. In this way, the tabs of the core package are not oriented towards the terminal post, which reduces the phenomenon of heat dissipation through the terminal post and improves the phenomenon of high terminal post temperature.

[0014] In the battery pack of this application, the insulating coolant may include oil or fluorinated liquid to achieve heat absorption and block side reactions.

[0015] Secondly, this application provides a battery cell. The battery cell includes a housing, a core package, and a separator, with the core package and separator located within the housing. The housing includes a top wall and a bottom wall disposed opposite to each other. An explosion-proof valve is provided on the top wall, specifically including an exhaust port, a liquid inlet, an explosion-proof plate, and a protective plate. The exhaust port and the liquid inlet respectively penetrate the top wall. A baffle wall is provided between the exhaust port and the liquid inlet to isolate them. The explosion-proof plate is used to seal the exhaust port. The protective plate is located on the side of the protective plate opposite to the bottom wall and covers the exhaust port and the liquid inlet. The protective plate is located on the side of the top wall opposite to the bottom wall and covers the exhaust port and the liquid inlet. The explosion-proof plate is located on the side of the protective plate facing the top wall and seals the exhaust port. Additionally, the separator includes a top plate and multiple side plates, with the top plate located between the top wall and the core package, and the multiple side plates located on the side of the top plate facing the core package. The multiple side plates are sequentially connected and connected to the top plate, thereby forming a receiving space. The core package is at least partially located within the receiving space. Gaps exist between the aforementioned sidewalls and the bottom wall. A liquid inlet channel is formed between the partition and the housing, and a venting channel is formed between the partition and the core package. The liquid inlet communicates with the liquid inlet channel, and the top plate also has a through-hole, through which the vent and the venting channel communicate.

[0016] The battery cell of this application can be used in a battery pack, with the explosion-proof valve immersed in the insulating coolant of the battery pack. When the battery cell is not in a state of explosion, the explosion-proof valve isolates the inside and outside of the cell, preventing the insulating coolant from entering the cell through the vent and inlet ports, and preventing the electrolyte from flowing out of the cell through the vent and inlet ports. When the battery cell experiences thermal runaway, the core and electrolyte generate a large amount of heat, increasing the internal pressure of the cell. Under this pressure, the explosion-proof valve opens, allowing the high-temperature gas and electrolyte inside the cell to escape through the vent channel and vent, thereby removing at least some of the heat from the cell. Simultaneously with the opening of the explosion-proof valve, the insulating coolant enters the cell through the inlet port and mixes with the electrolyte after passing through the inlet. During the mixing process of the insulating coolant and electrolyte, on the one hand, the insulating coolant can absorb heat from inside the cell, reducing the internal temperature; on the other hand, the cooling effect of the insulating coolant and electrolyte can mitigate the side reactions between the core and electrolyte, thereby reducing the heat generation inside the cell. This can effectively reduce the heat generated by thermal runaway within the battery cell.

[0017] The aforementioned explosion-proof plate can be used solely to seal the vent. In one possible implementation, the explosion-proof plate is located inside the vent and welded to the inner wall of the vent. The explosion-proof plate allows air to pass through both ends of the vent and prevents electrolyte from flowing out of the cell through the vent. In this technical solution, the protective plate can seal the liquid inlet to prevent electrolyte and insulating coolant from flowing through the liquid inlet. Thus, the vent and liquid inlet are sealed by the protective plate and the explosion-proof plate. Alternatively, in another possible implementation, both the vent and liquid inlet can be sealed by the explosion-proof plate. Specifically, the explosion-proof plate covers the vent and liquid inlet, sealing them to prevent electrolyte from flowing out of the cell through the vent and liquid inlet, and to prevent insulating coolant from flowing into the cell through the vent and liquid inlet.

[0018] In one possible implementation, the baffle wall can be an annular baffle wall, with the vent located inside the annular baffle wall. The liquid inlet can be an annular liquid inlet, arranged around the outer periphery of the annular baffle wall. During explosion venting, the high-temperature gas and electrolyte inside the battery cell are discharged through the vent, while the insulating coolant outside the battery cell can enter the battery cell through the liquid inlet on the outer periphery. This allows venting and liquid inlet to be achieved simultaneously without interfering with each other, accelerating the cooling of the battery cell's interior and the on-site thermal runaway side reactions.

[0019] In one possible implementation, an annular protrusion is provided on the surface of the top plate facing the top wall. The annular protrusion is arranged around the outer periphery of the through hole and is sealed to the annular baffle. In this way, the partition and the top wall are fixedly connected by the annular protrusion and the annular baffle, and the through hole in the annular protrusion communicates with the vent in the annular baffle, which can connect the outside of the cell and the receiving space inside the partition.

[0020] In one possible implementation, at least two-thirds of the core package is located within the containment space along the height of the cell. In this technical solution, the side plates can extend the dimensions of the venting and inlet channels as much as possible, thereby increasing the spacing between the venting and inlet channels. This way, when side reactions occur between the core package and the electrolyte, most of the electrolyte is discharged from the venting channels and vents under pressure, reducing the amount of electrolyte inside the cell and further mitigating the side reactions.

[0021] In one possible implementation, each of the aforementioned side plates has a notch on the side closest to the bottom wall. The insulating coolant can enter the venting channel through the notch and mix with the electrolyte, thus accelerating the mixing of the insulating coolant and electrolyte and consequently accelerating heat absorption.

[0022] In one possible implementation, at least one of the aforementioned side plates is provided with a plurality of small holes, each of which is smaller than the size of the vent. When a side reaction occurs between the core and the electrolyte, the electrolyte flows towards the vent under pressure because the size of the small hole is smaller than the vent. When the electrolyte in the vent channel decreases, a pressure difference may occur on both sides of the small hole, allowing a portion of the insulating coolant entering the cell to pass through the small hole into the vent channel and mix with the electrolyte, thereby accelerating the prevention of the thermal runaway side reaction.

[0023] In one possible implementation, the through-hole has multiple vents connected to an exhaust port. When passing through the through-hole in the top plate, the electrolyte passes through the aforementioned multiple vents. Since the cross-sectional area of ​​the aforementioned multiple vents is smaller than that of the through-hole, the flow rate of the electrolyte passing through the aforementioned multiple vents increases, thereby allowing the electrolyte to be discharged more quickly.

[0024] In the battery cell of this application, a positive terminal and a negative terminal are further provided on the top wall of the casing, and the positive terminal, the negative terminal, and the explosion-proof valve are located on the same side of the casing. The core pack may include a positive tab and a negative tab. The top plate of the partition is also provided with a positive opening and a negative opening. In practical applications, the placement position of the core pack is not limited. In one possible implementation, the core pack can be placed upright. The positive tab and the negative tab are located on the side of the core pack facing the top plate, the positive tab passes through the positive opening and connects to the positive terminal, and the negative tab passes through the negative opening and connects to the negative terminal. Alternatively, in another possible implementation, the core pack may also be placed on its side. The positive tab and the negative tab are located opposite each other on both sides of the core pack, and the positive tab and the negative tab are respectively arranged facing multiple side plates. The battery cell also includes a positive conductor and a negative conductor. One end of the positive conductor is connected to the positive tab, and the other end passes through the positive opening and connects to the positive terminal. One end of the negative conductor is connected to the negative tab, and the other end passes through the negative opening and connects to the negative terminal. In this way, the tabs of the core package are not oriented towards the terminal post, which reduces the phenomenon of heat dissipation through the terminal post and improves the phenomenon of high terminal post temperature.

[0025] Thirdly, this application provides an energy storage system. The energy storage system includes a power converter and the battery pack described in the first aspect. The power converter converts electrical energy output from an external power source into power and outputs it to the battery pack. Inside the battery pack of the energy storage system of this application, the insulating coolant can mitigate thermal runaway within the battery cells, thereby suppressing thermal propagation between the cells and reducing the risks of short circuits and explosions, thus improving the safety of the energy storage system. Attached Figure Description

[0026] Figure 1 A schematic diagram of a battery pack provided in an embodiment of this application;

[0027] Figure 2A schematic diagram of a battery cell provided in an embodiment of this application;

[0028] Figure 3 Another schematic diagram of the battery cell provided in the embodiments of this application;

[0029] Figure 4 for Figure 3 A top view of the battery cell;

[0030] Figure 5 for Figure 3 A schematic diagram of a cross-section of the battery cell along the AA direction;

[0031] Figure 6 A schematic diagram of a partition provided in an embodiment of this application;

[0032] Figure 7 Another schematic diagram of the partition provided in the embodiments of this application;

[0033] Figure 8 Another schematic diagram of the partition provided in the embodiments of this application;

[0034] Figure 9 for Figure 3 Another cross-sectional schematic diagram of the battery cell along the AA direction.

[0035] Figure label:

[0036] 10-Battery pack 11-Battery casing 12-Battery cell

[0037] 121-Shell; 122-Explosion-proof valve; 123-Core package

[0038] 124-Separator 125-Positive terminal 126-Negative terminal

[0039] 127 - Positive conduction busbar; 128 - Negative conduction busbar; 1211 - Top wall

[0040] 1212-Bottom wall 1221-Exhaust port 1222-Liquid inlet

[0041] 1223 - Explosion-proof sheet; 1224 - Protective sheet; 1225 - Retaining wall

[0042] 1231 - Positive tab; 1232 - Negative tab; 1241 - Liquid inlet channel

[0043] 1242 - Exhaust passage; 1243 - Top plate; 1244 - Side plate

[0044] 1245 - Notch 1246 - Small hole 1247 - Air pore

[0045] 1248 - Positive electrode opening; 1249 - Negative electrode opening; 12431 - Through hole

[0046] 12432- Annular protrusion Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this application clearer, the application will now be described in further detail with reference to the accompanying drawings.

[0048] To facilitate understanding of the battery cells, battery packs, and energy storage systems provided in this application embodiment, their application scenarios are described below. This application provides an energy storage system that can be used in various application scenarios, including industrial and commercial energy storage and power plant energy storage. Industrial and commercial energy storage may include, for example, small-scale industrial and commercial (small factories, etc.) energy storage, medium-scale industrial and commercial energy storage, large-scale industrial and commercial energy storage, photovoltaic-energy storage-charging station energy storage, and small and medium-sized microgrid (island, etc.) energy storage. Power plant energy storage may include, for example, wind-solar-energy storage power stations, grid-connected energy storage power stations, and large-scale microgrid power stations. In addition, the energy storage system can also be used in application scenarios such as data centers and vehicle charging stations. In this application, the energy storage system includes a power converter and at least one battery pack. The power converter is used to convert the electrical energy output from an external power source and output it to the aforementioned at least one battery pack.

[0049] Figure 1 This is a schematic diagram of a battery pack provided in an embodiment of this application. Figure 1 As shown, the battery pack 10 may include a battery casing 11, which houses a power module (not shown) and at least one battery cell 12. The power module is connected to the aforementioned at least one battery cell 12 and can be used to manage the charging and discharging of the battery cell 12, and to acquire data such as the voltage, current, temperature, state of charge (SOC) parameters, and state of health (SOH) parameters of the battery cell 12. In this application, the battery cell 12 includes a housing 121, which is provided with an explosion-proof valve 122. When the battery cell 12 experiences thermal runaway, the internal gas pressure of the battery cell 12 increases, causing the explosion-proof valve 122 to open, thereby releasing high-temperature gas and electrolyte to prevent the battery cell 12 from exploding.

[0050] However, even after the explosion-proof valve 122 releases the high-temperature gas and electrolyte inside the battery cell 12, side effects continue to occur inside the battery cell 12, causing it to continuously generate heat. Therefore, the effectiveness of this measure to suppress thermal runaway is limited.

[0051] In view of this, this application provides a battery cell, a battery pack, and an energy storage system to reduce the heat generated by thermal runaway inside the battery cell, thereby suppressing the thermal propagation between battery cells within the battery pack.

[0052] It should be noted that the terminology used in the following embodiments is for the purpose of describing specific embodiments only and is not intended to be a limitation of this application. As used in the specification and appended claims of this application, the singular expressions “a,” “an,” “the,” “the,” “the,” and “this” are intended to also include expressions such as “one or more,” unless the context clearly indicates otherwise.

[0053] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0054] In embodiments of this application, the battery pack 10 further includes an insulating coolant. The insulating coolant is located inside the battery casing 11 and submerges the explosion-proof valve 122 of at least one of the aforementioned battery cells 12. When the battery cell 12 is not venting an explosion, the explosion-proof valve 122 can isolate the inside and outside of the battery cell 12, preventing the insulating coolant from entering the battery cell 12 and preventing the electrolyte inside the battery cell 12 from flowing out of the battery cell 12, thereby improving the sealing performance of the battery pack 10.

[0055] Figure 2 This is a schematic diagram of a battery cell provided in an embodiment of this application. Figure 3 Another schematic diagram of the battery cell provided in the embodiments of this application, wherein, Figure 2 Showing the protective film, Figure 3 Omitted protective film. (e.g.) Figure 2 and Figure 3 As shown, the battery cell 12 includes a housing 121, and a core pack 123 and a separator 124 located within the housing 121. Specifically, the housing 121 includes a top wall 1211 and a bottom wall disposed opposite to each other. Figure 4 for Figure 3 A top view of a battery cell. (e.g.) Figure 4As shown, an explosion-proof valve 122 is provided on the top wall 1211. The explosion-proof valve 122 includes an exhaust port 1221, a liquid inlet 1222, an explosion-proof disc 1223, and a protective disc 1224. The exhaust port 1221 and the liquid inlet 1222 penetrate the top wall 1211. A baffle 1225 is provided between the exhaust port 1221 and the liquid inlet 1222, which isolates the exhaust port 1221 and the liquid inlet 1222. The protective disc 1224 is located on the side of the top wall 1211 facing away from the bottom wall, and the protective disc 1224 covers the exhaust port 1221 and the liquid inlet 1222. The explosion-proof disc 1223 is located on the side of the protective disc 1224 facing the top wall 1211, and the explosion-proof disc 1223 is used to seal the exhaust port 1221.

[0056] In this application, the core package 123 includes a positive electrode sheet, a separator, and a negative electrode sheet, with the separator located between the positive and negative electrode sheets. In this application, the core package 123 can be a stacked core package, meaning it includes multiple positive electrode sheets, multiple separators, and multiple negative electrode sheets, which are stacked sequentially in the order of positive electrode sheet, separator, and negative electrode sheet to form the core package 123. Alternatively, the core package 123 can also be a wound core package, meaning it includes one positive electrode sheet, one separator, and one negative electrode sheet, which are stacked sequentially and wound to form the core package 123, which has a cylindrical shape.

[0057] Figure 5 for Figure 3 A schematic diagram of a cross-section of the battery cell along the AA direction. (See diagram below.) Figure 3 and Figure 5 As shown, the partition 124 is located between the housing 121 and the core package 123. There is a gap between the partition 124 and the inner wall of the housing 121, and a gap between the partition 124 and the outer surface of the core package 123. Thus, a liquid inlet channel 1241 is formed between the partition 124 and the housing 121, and a venting channel 1242 is formed between the partition 124 and the core package 123. There is a gap between the partition 124 and the bottom wall 1212.

[0058] Figure 6 This is a schematic diagram of a partition provided in an embodiment of this application. Figure 6As shown, the partition 124 specifically includes a top plate 1243 and multiple side plates 1244. The top plate 1243 is located between the top wall 1211 and the core package 123, and is disposed opposite to the explosion-proof valve 122. The aforementioned multiple side plates 1244 are connected in sequence, and these side plates 1244 are connected to the side of the top plate 1243 away from the explosion-proof valve 122. The aforementioned multiple side plates 1244 extend in a direction away from the explosion-proof valve 122. That is, the aforementioned multiple side plates 1244 are connected to the top plate 1243 and form a receiving space. The core package 123 is at least partially located within the receiving space. The liquid inlet channel 1241 and the vent channel 1242 extend toward the bottom wall 1212, respectively. The liquid inlet 1222 communicates with the liquid inlet channel 1241. The top plate 1243 is also provided with a through hole 12431, through which the vent port 1221 and the vent channel 1242 communicate. Therefore, in the event of thermal runaway of cell 12, the high pressure generated by the core package 123 and the electrolyte is directly released from the exhaust port 1221 along the exhaust channel 1242, and the insulating coolant outside cell 12 mixes with the electrolyte from the end near the bottom wall 1212 after entering the liquid inlet channel 1241. In this way, the internal pressure of cell 12 is rapidly released through the explosion-proof valve 122, and the insulating coolant enters cell 12 to cool the inside of cell 12 and alleviate the side reactions, thereby quickly blocking the thermal runaway side reactions of cell 12 and further preventing the thermal propagation between cells 12.

[0059] In the battery pack 10 of this application, the insulating coolant includes oil or fluorinated liquid to achieve heat absorption and block side reactions. Specifically, when the cell 12 is not leaking, the explosion-proof valve 122 can isolate the inside and outside of the cell 12, thereby preventing the insulating coolant from entering the inside of the cell 12 through the vent 1221 and the inlet 1222, and preventing the electrolyte from flowing out of the cell 12 through the vent 1221 and the inlet 1222, thereby improving the sealing performance of the cell 12. When the cell 12 experiences thermal runaway, the heat generated by the core pack 123 increases the pressure inside the cell 12, and under the action of this pressure, the explosion-proof valve 122 opens, allowing the high-temperature gas and electrolyte inside the cell 12 to be discharged from the vent 1221 through the vent channel 1242, and carrying away at least part of the heat inside the cell 12. When the explosion-proof valve 122 is opened, the insulating coolant outside the cell 12 can enter the inlet channel 1241 through the inlet port 1222 and mix with the electrolyte inside the cell 12. The insulating coolant can improve the thermal runaway phenomenon inside the cell 12, thereby suppressing the thermal propagation between the cells 12 in the battery pack 10, thus reducing the risk of short circuits and explosions in the battery pack 10 and improving the safety of the energy storage system.

[0060] Because the explosion-proof disc 1223 seals the vent 1221, when the explosion-proof valve 122 releases the pressure, the internal pressure of the battery cell 12 breaks through the explosion-proof disc 1223, causing the protective disc 1224 to detach. Figure 3 and Figure 4As shown, in one embodiment, the explosion-proof plate 1223 may be used solely to seal the vent 1221. The explosion-proof plate 1223 is located within the vent 1221 and is welded to the inner wall of the vent 1221. The explosion-proof plate 1223 allows air to pass through both ends of the vent 1221 and prevents electrolyte from flowing out of the cell 12 through the vent 1221. In this embodiment, the liquid inlet 1222 may be sealed by a protective plate 1224 to prevent electrolyte and insulating coolant from passing through the liquid inlet 1222. For example, the protective plate 1224 has a protrusion on one side surface facing the liquid inlet 1222. When the protective plate 1224 covers the liquid inlet 1222, the protrusion fills the liquid inlet 1222, thereby sealing the liquid inlet 1222.

[0061] In another embodiment, both the vent 1221 and the inlet 1222 can be sealed by an explosion-proof plate 1223. That is, the explosion-proof plate 1223 can be used to seal the vent 1221 and the inlet 1222. The explosion-proof plate 1223 covers the vent 1221 and the inlet 1222 and is welded to the baffle 1225 and the top wall 1211, thereby preventing electrolyte from flowing out of the cell 12 through the vent 1221 and the inlet 1222, and preventing insulating coolant from flowing into the cell 12 through the vent 1221 and the inlet 1222.

[0062] like Figure 3 and Figure 4 As shown, in one embodiment, the baffle 1225 can be an annular baffle, which is arranged around the outer periphery of the vent 1221. The liquid inlet 1222 can be an annular liquid inlet, which is arranged around the outer periphery of the annular baffle. During explosion venting, the gas and electrolyte inside the battery cell 12 are discharged through the vent 1221, while the insulating coolant outside the battery cell 12 can enter the interior of the battery cell 12 through the annular liquid inlet, thereby enabling simultaneous venting and liquid inlet, accelerating the cooling and thermal runaway side reactions inside the battery cell 12.

[0063] In one embodiment, an annular protrusion 12432 is provided on the side surface of the top plate 1243 facing the top wall 1211. The annular protrusion 12432 is arranged around the outer periphery of the through hole 12431 and is sealed to the annular baffle. In this way, the partition 124 and the top wall 1211 are fixedly connected through the annular protrusion 12432 and the annular baffle, and the through hole 12431 in the annular protrusion 12432 communicates with the exhaust port 1221 in the annular baffle, thereby connecting the outside of the battery cell 12 and the exhaust channel 1242 through the exhaust port 1221 and the through hole 12431.

[0064] In the aforementioned battery cell 12, along the height direction of the battery cell 12 (e.g.) Figure 5In the vertical direction (i.e., the direction from the top wall 1211 to the bottom wall 1212), each of the plurality of side plates 1244 covers at least two-thirds of the height of the core package 123. In other words, in this embodiment, at least two-thirds of the core package 123 is located within the receiving space of the partition 124 along the height direction of the cell 12. This allows the partition 124 to extend the venting channel 1242 and the liquid inlet channel 1241 as much as possible, increasing the gap between them. Thus, in the event of thermal runaway and side reactions in the core package 123, the electrolyte is forced to drain from the venting channel 1242 and the vent 1221, reducing the amount of electrolyte inside the cell 12 and further mitigating the side reactions.

[0065] Figure 7 Another schematic diagram of the partition provided in an embodiment of this application. (See diagram below.) Figure 7 As shown, in one embodiment, at least one of the plurality of side plates 1244 has a notch 1245 at the end of the side plate 1244 furthest from the explosion-proof valve 122. The insulating coolant outside the cell 12 can enter the exhaust channel 1242 through the notch 1245 and mix with the electrolyte, thereby increasing the amount of mixing between the insulating coolant and the electrolyte and thus accelerating the absorption of heat.

[0066] Figure 8 Another schematic diagram of the partition provided in an embodiment of this application. (See diagram below.) Figure 8 As shown, in one embodiment, at least one of the plurality of side plates 1244 is provided with a plurality of small holes 1246. The size of each small hole 1246 is smaller than the size of the vent 1221. Thus, when a side reaction occurs in the core package 123, because the size of the small hole 1246 is smaller than the vent 1221, the electrolyte flows towards the vent 1221 under pressure. When the electrolyte in the vent channel 1242 decreases, a pressure difference occurs on both sides of the small hole 1246, allowing a portion of the insulating coolant entering the cell 12 to pass through the small hole 1246 into the vent channel 1242 and mix with the electrolyte, thereby accelerating the blocking of the thermal runaway side reaction.

[0067] like Figures 6 to 8 As shown, in one embodiment, a plurality of vents 1247 are provided within the through hole 12431, and the aforementioned plurality of vents 1247 are connected to the exhaust port 1221. When passing through the through hole 12431 of the top plate 1243, the electrolyte first passes through the aforementioned plurality of vents 1247. According to the principle that flow rate equals flow velocity multiplied by the cross-sectional area of ​​the hole, the cross-sectional area of ​​the hole is inversely proportional to the flow velocity. That is, the smaller the cross-sectional area of ​​the hole, the greater the flow velocity. Since the cross-sectional area of ​​the aforementioned plurality of vents 1247 is smaller than the cross-sectional area of ​​the through hole 12431, the flow velocity of the electrolyte increases when passing through the vents 1247, thereby allowing the electrolyte to be discharged more quickly.

[0068] In the battery cell 12 of this application, the casing 121 is further provided with a positive terminal 125 and a negative terminal 126. For example... Figure 2 As shown, in one embodiment, the positive terminal 125, the negative terminal 126, and the explosion-proof valve 122 may be located on the top wall 1211 of the housing 121. Figure 5 As shown, the core package 123 is provided with a positive electrode tab 1231 and a negative electrode tab 1232. In this embodiment, the partition 124 has a positive electrode opening 1248 and a negative electrode opening 1249 on the side facing the explosion-proof valve 122. The positive electrode tab 1231 passes through the positive electrode opening 1248 and is electrically connected to the positive electrode post 125, and the negative electrode tab 1232 passes through the negative electrode opening 1249 and is electrically connected to the negative electrode post 126. In this way, the positive electrode post 125, the negative electrode post 126, and the explosion-proof valve 122 are concentrated on the top wall 1211 of the housing 121, which facilitates the maintenance of the battery cell 12. Of course, the positive electrode post 125 and the negative electrode post 126 can also be located on different sides of the housing 121 from the explosion-proof valve 122. For example, in one embodiment, the explosion-proof valve 122 is located on the top wall 1211 of the housing 121, and the positive electrode post 125 and the negative electrode post 126 are located on the bottom wall 1212 of the housing 121. In another embodiment, the housing 121 further includes a plurality of sidewalls located between the top wall 1211 and the bottom wall 1212, and the plurality of sidewalls are connected sequentially. The explosion-proof valve 122 is located on the top wall 1211 of the housing 121, and the positive terminal 125 and the negative terminal 126 may be located on the sidewalls of the housing 121. In this embodiment, the positive terminal 125 and the negative terminal 126 may be located on the same sidewall, or they may be located on different sidewalls.

[0069] In practical applications, the placement orientation of the core package 123 within the battery cell 12 relative to the top wall 1211 is not restricted. Taking the positive terminal 125 and negative terminal 126 located on the top wall 1211 as an example, ... Figure 5 As shown, in one embodiment, the core package 123 can be placed upright. Specifically, the positive electrode tab 1231 and the negative electrode tab 1232 can be located on the same side of the core package 123 and facing the top wall 1211. The positive electrode tab 1231 passes through the positive electrode opening 1248 and connects to the positive electrode post 125. The negative electrode tab 1232 passes through the negative electrode opening 1249 and connects to the negative electrode post 126. In this way, the tabs of the core package 123 can be directly connected to the electrode post, which is convenient for installation.

[0070] Figure 9 for Figure 3 Another cross-sectional diagram of the battery cell along the AA direction. (See diagram below.) Figure 9As shown, in another embodiment, the core package 123 can also be placed on its side. Specifically, the positive tab 1231 and the negative tab 1232 are located opposite each other on both sides of the core package 123, and the positive tab 1231 and the negative tab 1232 are positioned facing the side plate 1244 of the separator 124. The cell 12 also includes a positive conductive bus 127 and a negative conductive bus 128. The positive conductive bus 127 and the negative conductive bus 128 are located inside the separator 124. One end of the positive conductive bus 127 is connected to the positive tab 1231, and the positive electrode post 125 passes through the positive electrode opening 1248 and is connected to the other end of the positive conductive bus 127. One end of the negative conductive bus 128 is connected to the negative tab 1232, and the negative electrode post 126 passes through the negative electrode opening 1249 and is connected to the other end of the negative conductive bus 128. In this way, the tabs of the core package 123 are not positioned facing the electrode post, which can reduce the phenomenon of heat dissipation through the tabs and improve the phenomenon of high electrode post temperature.

[0071] The above are merely specific embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A battery pack, characterized in that, Includes a battery casing, an insulating coolant located within the battery casing, and at least one battery cell, wherein: Each of the at least one battery cell includes a housing, and a core pack and a partition located within the housing; the housing includes a top wall and a bottom wall disposed opposite to each other; the top wall is provided with an explosion-proof valve, the explosion-proof valve including an exhaust port, a liquid inlet, an explosion-proof plate, and a protective plate, the exhaust port and the liquid inlet respectively penetrating the top wall, a baffle wall provided between the exhaust port and the liquid inlet, the baffle wall being used to isolate the exhaust port and the liquid inlet; the protective plate is located on the side of the top wall opposite to the bottom wall, and the protective plate covers the exhaust port and the liquid inlet; the explosion-proof plate is located on the side of the protective plate facing the top wall, the explosion-proof plate being used to seal the exhaust port; the insulating coolant immerses the explosion-proof valve of each battery cell; The partition includes a top plate and multiple side plates. The top plate is located between the top wall and the core package. The multiple side plates are located on the side of the top plate facing the core package. The multiple side plates are connected in sequence and connected to the top plate to form a receiving space. The core package is at least partially located within the receiving space. There is a gap between the multiple side plates and the bottom wall. A liquid inlet channel is formed between the partition and the housing. An exhaust channel is formed between the partition and the core package. The liquid inlet is connected to the liquid inlet channel. The top plate is provided with a through hole. The exhaust port and the exhaust channel are connected through the through hole.

2. The battery pack as described in claim 1, characterized in that, The explosion-proof plate is located inside the vent and is welded to the inner wall of the vent; the protective plate seals the liquid inlet; or The explosion-proof plate is also used to seal the liquid inlet, and the explosion-proof plate covers the exhaust port and the liquid inlet.

3. The battery pack as described in claim 1 or 2, characterized in that, The baffle wall is an annular baffle wall, and the exhaust port is located inside the annular baffle wall; the liquid inlet is an annular liquid inlet, and the annular liquid inlet is arranged around the outer periphery of the annular baffle wall.

4. The battery pack as described in claim 3, characterized in that, The top plate has an annular protrusion on one side of the top wall. The annular protrusion is arranged around the outer periphery of the through hole and is sealed to the annular retaining wall.

5. The battery pack as described in claim 1 or 2, characterized in that, Along the height direction of the cell, at least two-thirds of the core package is located within the receiving space.

6. The battery pack as described in claim 1 or 2, characterized in that, In the plurality of side plates, each side plate has a notch on the side closest to the bottom wall.

7. The battery pack as described in claim 1 or 2, characterized in that, At least one of the multiple side plates is provided with multiple small holes, and the size of each of the multiple small holes is smaller than the size of the exhaust port.

8. The battery pack as described in claim 1 or 2, characterized in that, The through hole is provided with multiple air holes, which are connected to the exhaust port.

9. The battery pack as described in claim 1 or 2, characterized in that, The top wall is also provided with a positive terminal and a negative terminal, the positive terminal, the negative terminal and the explosion-proof valve are located on the same side of the housing; the core package includes a positive terminal lug and a negative terminal lug; the top plate is also provided with a positive terminal opening and a negative terminal opening; The positive electrode tab and the negative electrode tab are located on the side of the core package facing the top plate. The positive electrode tab passes through the positive electrode opening and is connected to the positive electrode post, and the negative electrode tab passes through the negative electrode opening and is connected to the negative electrode post; or The positive and negative tabs are located opposite each other on both sides of the core package, and the positive and negative tabs are respectively arranged facing the plurality of side plates; the cell also includes a positive conductive bus and a negative conductive bus; one end of the positive conductive bus is connected to the positive tab, and the other end passes through the positive opening and is connected to the positive terminal; one end of the negative conductive bus is connected to the negative tab, and the other end passes through the negative opening and is connected to the negative terminal.

10. The battery pack as described in claim 1 or 2, characterized in that, The insulating coolant includes oil or fluorinated liquid.

11. A battery cell, characterized in that, Includes a housing, and a core and partition located within the housing, wherein: The housing includes a top wall and a bottom wall disposed opposite to each other; the top wall is provided with an explosion-proof valve, the explosion-proof valve including an exhaust port, a liquid inlet, an explosion-proof plate, and a protective plate, the exhaust port and the liquid inlet respectively penetrating the top wall, a baffle wall provided between the exhaust port and the liquid inlet, the baffle wall being used to isolate the exhaust port and the liquid inlet; the protective plate is located on the side of the top wall opposite to the bottom wall, and the protective plate covers the exhaust port and the liquid inlet; the explosion-proof plate is located on the side of the protective plate facing the top wall, the explosion-proof plate being used to seal the exhaust port; The partition includes a top plate and multiple side plates. The top plate is located between the top wall and the core package. The multiple side plates are located on the side of the top plate facing the core package. The multiple side plates are connected in sequence and connected to the top plate to form a receiving space. The core package is at least partially located within the receiving space. There is a gap between the multiple side plates and the bottom wall. The top plate is provided with a through hole. A liquid inlet channel is formed between the partition and the housing. An exhaust channel is formed between the partition and the core package. The liquid inlet is connected to the liquid inlet channel. The exhaust port and the exhaust channel are connected through the through hole.

12. An energy storage system, characterized in that, The energy storage system includes a power converter and a battery pack as described in any one of claims 1 to 10, wherein the power converter is used to convert electrical energy output from an external power source into power and output it to the battery pack.

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