A thermal runaway prevention and control assembly and a battery pack

Abstract

The present application relates to the technical field of battery, in particular to a thermal runaway prevention and control assembly and a battery pack, which is arranged in the battery pack, and the battery pack comprises: a battery module comprising a plurality of battery cells, at least one explosion-proof valve is arranged on each battery cell; a conductive connecting body arranged on each adjacent two battery cells and electrically connecting the adjacent two battery cells; the thermal runaway prevention and control assembly comprises: a lower shell, a plurality of one-way valves, a phase change layer, and an upper cover matched with the lower shell, each one-way valve is arranged on the body of the lower shell and corresponds to each explosion-proof valve, and the one-way valve is in a normally closed state; the phase change layer is arranged on the upper side of the lower shell and on the conductive connecting body and the plurality of battery cells; the phase change layer is used for absorbing heat released when at least one battery cell and the conductive connecting body are heated; the normally closed one-way valve and the lower shell are used for preventing the phase change layer from entering the battery cell after phase change due to heat. In this way, the temperature difference between the battery cells can be reduced, and the performance and safety of the battery pack can be improved.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically to a thermal runaway prevention component and battery pack in the field of battery technology. Background Technology

[0002] In the new energy industry, a common solution for preventing thermal runaway is to add thermal insulation materials to give personnel time to escape. Due to energy density and performance requirements, large battery cells and bottom liquid cooling are common industry practices. However, these solutions generally suffer from high temperatures at the top of the battery and weak rapid cooling capabilities. This results in limited effectiveness in suppressing thermal runaway, and the lack of treatment for thermal runaway gases means that if the battery pack opens its valves and releases large amounts of harmful gases, it will cause significant harm to surrounding personnel and the environment, leading to severe consequences. Summary of the Invention

[0003] The purpose of this invention is to provide a thermal runaway prevention component and battery pack, and the specific technical solution adopted is as follows:

[0004] This invention provides a thermal runaway prevention component, disposed within a battery pack. The battery pack includes a battery module, which includes multiple battery cells, and each battery cell is provided with at least one explosion-proof valve.

[0005] A conductive connector is disposed on each pair of adjacent battery cells, and electrically connects the two adjacent battery cells; the thermal runaway prevention component includes: a lower shell, a plurality of one-way valves and a phase change layer, and a top cover, each of the one-way valves is disposed on the lower shell body and is correspondingly disposed on each of the explosion-proof valves, and the one-way valves are normally closed; the top cover fits into the lower shell;

[0006] The phase change layer is disposed on the upper side of the lower shell, and on the conductive connector and the plurality of battery cells;

[0007] The phase change layer is used to absorb the heat released when the at least one battery cell and the conductive connector are heated; the normally closed one-way valve and the lower shell are used to prevent the phase change layer from entering the battery cell after being heated and undergoing a phase change.

[0008] In some possible implementations, the cell includes at least two terminals, and the conductive connector is connected to at least two terminals of each of two adjacent cells, so that the two adjacent cells are electrically connected in series or in parallel.

[0009] In some possible implementations, the phase transition temperature of the phase transition layer is between 50°C and 60°C; the material of the phase transition layer includes one or more of paraffin wax, foamed metal, fatty acid, and metal salt.

[0010] In some possible implementations, when the battery cell experiences thermal runaway, the one-way valve is pushed upward by the gas and liquid ejected from the battery cell.

[0011] In some possible implementations, the thermal runaway prevention component further includes a gas-liquid collection chamber; wherein:

[0012] The gas-liquid collection chamber is placed above the phase change layer and the one-way valve. The phase change layer is located on the upper side of the lower shell, avoiding the one-way valve. The one-way valve is opened by the gas and liquid ejected from the battery cell, and the gas and liquid directly enter the gas-liquid collection chamber.

[0013] In some possible implementations, the one-way valve includes a support and a one-way valve body; when the one-way valve is in a normally closed state, the bottom end of the support is fixed to the lower shell, and the top end of the support supports the one-way valve body; when the battery cell experiences thermal runaway, the one-way valve body is pushed upward by the gas and liquid ejected from the battery cell; the one-way valve body is provided with a reset structure, and the automatic reset structure is connected to the lower shell; when the battery cell stops ejecting gas and liquid, under the action of the automatic reset structure and gravity, the one-way valve switches from an open state to a closed state; the automatic reset structure provided on the one-way valve body is a hinge structure.

[0014] In some possible implementations, when the temperature of the battery cell is greater than a preset temperature threshold, the conductive connector and the battery cell transfer heat to the phase change layer to reduce the upper temperature of the battery cell; a liquid cooling channel is provided below the battery module.

[0015] In some possible implementations, the opening pressure of the one-way valve is less than the opening pressure of the battery cell, so that the gas-liquid ejected from the battery cell can enter the gas-liquid collection chamber.

[0016] This invention provides a battery pack that includes the thermal runaway prevention component described above.

[0017] In some possible implementations, a heat insulation layer is also included between the cells; the battery pack is a lithium-ion battery pack.

[0018] The present invention has the following beneficial effects: A thermal runaway prevention component disposed within a battery pack includes a phase change layer and a plurality of one-way valves, each one-way valve being correspondingly disposed above each explosion-proof valve, and the one-way valves being normally closed; the phase change layer is disposed on the upper side of the lower shell, and also on the conductive connector and the plurality of battery cells; thus, the phase change layer in the thermal runaway prevention component undergoes a phase change upon heating, absorbing a large amount of heat and simultaneously transferring the heat to the entire phase change layer, significantly reducing the temperature of the upper part of the battery cells. Combined with bottom liquid cooling, this effectively suppresses the continued development and spread of thermal runaway. The phase change layer is used to absorb the heat released when at least one battery cell and the conductive connector heat up; the normally closed one-way valves and the lower shell are used to prevent the phase change layer from undergoing a phase change upon heating and entering the battery cells. In this way, the generated heat can be transferred to the phase change layer of the thermal runaway prevention component, and the heat on the upper part of the cell can also be transferred to the phase change layer, thereby reducing the temperature of the upper part of the cell. Thus, the heat transfer within the phase change layer can reduce the temperature difference between cells and the temperature difference between the upper and lower parts of the cell, improving the performance and life of the battery pack, thereby improving the safety of the battery pack. A gas-liquid collection chamber is provided on the phase change layer, so that when thermal runaway occurs in the battery pack, the phase change layer in the thermal runaway prevention component can also effectively absorb the heat of the ejected gas and liquid, reduce the cell temperature, and suppress the spread of local thermal runaway. Attached Figure Description

[0019] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the composition structure of a thermal runaway prevention and control component provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of another component structure of a thermal runaway prevention and control component provided in an embodiment of the present invention;

[0022] Figure 3 This is a partial structural diagram of a thermal runaway prevention and control component provided in an embodiment of the present invention;

[0023] Figure 4 This is a schematic diagram of the composition structure of a battery pack provided in an embodiment of the present invention;

[0024] Figure 5 This is a schematic diagram of the structure of the module in the battery pack provided in an embodiment of the present invention;

[0025] Figure 6 This is a partially enlarged schematic diagram of region A of module provided in an embodiment of the present invention;

[0026] Figure 7 This is a cross-sectional schematic diagram of a battery pack provided in an embodiment of the present invention;

[0027] Figure 8 This is a partially enlarged schematic diagram of a battery pack in cross-section B region during thermal runaway, provided in an embodiment of the present invention.

[0028] Explanation of the numbers in the attached diagram: 100-Battery pack lower housing; 200-Module; 300-Thermal runaway prevention component; 400-Battery pack upper cover; 210-Battery cell; 211-Explosion-proof valve of the battery cell; 212-Battery cell terminal; 220-High heat insulation material; 230-Module aluminum bar; 310-Lower housing; 320-Phase change layer; 330-One-way valve; 331-Support component; 332-One-way valve; 340-Gas-liquid collection chamber; 350-Upper cover. Detailed Implementation

[0029] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following detailed description, in conjunction with the accompanying drawings and preferred embodiments, provides a thermal runaway prevention component according to the present invention, including its specific implementation, structure, features, and effects. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments may be combined from any suitable form.

[0030] In the description of the embodiments of the present invention, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of the present invention, "multiple" means two or more.

[0031] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0033] With the transformation of the global energy structure, lithium batteries are rapidly developing in the power and energy storage industries. As a core component of new energy power and new energy storage systems, the safety and reliability of lithium-ion batteries have become the focus of industry attention. Battery safety regulations are becoming increasingly stringent, requiring that the battery pack, after thermal runaway, should not catch fire or explode, and that the smoke should not cause harm to occupants.

[0034] As demands for performance and cost gradually increase, battery cells are constantly iterating towards larger capacities. Compared to small battery cells, large battery cells have reduced material stability, concentrated mechanical stress, and a smaller heat dissipation area. This results in a lower thermal runaway trigger temperature, an increased rate of concentrated energy release and temperature rise, a shorter propagation time, and a more severe thermal runaway.

[0035] In related technologies, thermal runaway prevention involves using aerogel insulation to delay or prevent its propagation. Simultaneously, monitoring methods such as voltage, temperature, and smoke are employed to detect the occurrence of thermal runaway and alert occupants. Currently, feasible prevention and control measures for battery thermal runaway are relatively few.

[0036] In some embodiments, a thermal runaway suppression device is implemented through a battery box, a battery placed inside the battery box, a short-circuit mechanism, a pull-wire mechanism for activating the short-circuit mechanism, a water-spraying mechanism, and a temperature sensing system. The battery includes a top cover with positive and negative terminals. When an abnormal temperature rise is detected in a lithium battery within the box, and thermal runaway is anticipated, the pull-wire mechanism is activated to actively create an external short circuit in the lithium battery, rapidly depleting its charge. The water-spraying mechanism continuously cools the short-circuit structure by spraying water. However, this water spraying can cause secondary damage to the battery system, posing a high risk of external short circuits. Furthermore, the system is complex, requiring significant modifications to existing battery packs, occupying considerable space, and drastically reducing the battery pack's energy density. Additionally, the lack of gas treatment poses a hazard to personnel during battery pack disassembly.

[0037] In some embodiments, a thermal runaway suppression device is implemented using a lithium battery box, a cylindrical shell, and a Venturi mixer. By guiding the thermal runaway gas from the lithium battery out, mixing it with a fire extinguishing agent, and then venting it, the release of energy from the thermal runaway battery is ensured, while delaying the spread of fire. The generated perfluorohexanone gas-liquid two-phase gas mixes with the thermal runaway gas, efficiently inerting and cooling it, preventing spontaneous combustion upon contact with air or ignition by external short-circuit sparks. While this allows for gas collection and contributes to the prevention of thermal runaway hazards, it is ineffective in preventing the spread of thermal runaway. If the battery pack experiences large-area thermal runaway, the device will fail. Furthermore, the external device is large, and since the battery pack is integrated into the energy storage or power system, such a device can significantly impact the system structure.

[0038] Based on this, this invention combines mainstream battery pack structure schemes, thermal runaway trigger temperature of large cells, maximum temperature and other data to provide a thermal runaway prevention component, which suppresses the spread of thermal runaway in the battery pack and prevents the gas and liquid ejected from the battery from causing harm to personnel, thus greatly improving the safety of the battery pack.

[0039] The specific solution of a thermal runaway prevention component provided by the present invention will be described in detail below with reference to the accompanying drawings. Please refer to... Figure 1 The diagram illustrates a schematic representation of the thermal runaway prevention component according to an embodiment of the present invention. The thermal runaway prevention component is disposed within a battery pack, which includes: a battery module comprising multiple battery cells, each battery cell having at least one explosion-proof valve; and a conductive connector disposed on each pair of adjacent battery cells, electrically connecting the adjacent battery cells; wherein each battery cell includes at least two terminals, and the conductive connector is connected to at least two terminals of each pair of adjacent battery cells, electrically connecting the adjacent battery cells in series or parallel.

[0040] The thermal runaway prevention component includes: a lower shell 310, a phase change layer 320, several one-way valves 330, a phase change layer, and a top cover that fits with the lower shell. Each one-way valve is located on the lower shell body and is correspondingly positioned above each explosion-proof valve. The one-way valves are normally closed. When thermal runaway of the battery pack does not occur, the one-way valves are closed, working together with the lower shell to prevent contamination of the battery pack during phase change of the phase change material. The explosion-proof valves open upwards when the internal pressure of the battery pack is too high, releasing the internal high-pressure gas and liquid. Moreover, the opening pressure of the explosion-proof valve is greater than the opening pressure of the one-way valve, so that when the pressure of the ejected gas and liquid reaches the opening pressure of the explosion-proof valve, the gas and liquid ejected from the battery cell opens the explosion-proof valve and simultaneously causes the one-way valve to open upwards.

[0041] In some possible implementations, the conductive connector is a module aluminum bar.

[0042] The lower shell contacts the module aluminum bar and the battery cell in the corresponding battery pack. The Joule heat generated by the module aluminum bar and the heat generated on the upper part of the battery cell are transferred to the phase change layer through the lower shell. The lower shell of the thermal runaway prevention component can be made of a shapeable material, such as metal or metal alloy. In this way, the surface of the lower shell can be coated with some thermally conductive and non-conductive coatings, such as ceramic alumina coating, so that the lower shell can have a more fitting physical contact with the top cover of the module aluminum bar and the battery cell.

[0043] The phase change layer is disposed on the upper side of the lower shell, and on the conductive connector and the plurality of battery cells; the phase change temperature of the phase change layer is lower than the thermal runaway temperature of the battery cell; the material of the phase change layer includes one or more of paraffin wax, foam metal, fatty acid, and metal salt.

[0044] Here, the phase transition temperature of the phase transition layer can be between 50℃ and 60℃. For example, the material of the phase transition layer can be a single paraffin wax, or a suitable amount of additives can be added to the paraffin wax (additives can be, but are not limited to, foamed metals, metal salts, etc.). The material of the phase transition layer can also be a single fatty acid, or a suitable amount of additives can be added to the fatty acid (additives can be, but are not limited to, foamed metals, metal salts, etc.) so that the phase transition temperature of the material is between 50℃ and 60℃.

[0045] The phase change layer is used to absorb the heat released when the at least one battery cell and the conductive connector are heated. A normally closed one-way valve and a lower shell are used to prevent the phase change layer from entering the battery cell after undergoing a phase change due to heat. The one-way valve is configured to prevent the phase change layer from entering the battery cell after undergoing a phase change due to heat when it is closed. In the event of thermal runaway of the battery cell, the one-way valve is pushed upwards and opened by the gas and liquid ejected from the battery cell.

[0046] In this embodiment of the invention, the phase change layer in the thermal runaway prevention component can absorb heat from the upper part of the battery cell during normal use of the battery pack, thereby reducing the cell temperature and the temperature difference between the upper and lower parts of the cell. Heat transfer through the phase change layer also reduces the temperature difference between the cells. The phase change layer plays a crucial role in fully utilizing cell performance and improving cell lifespan, significantly enhancing the economic value of this thermal runaway prevention component.

[0047] In some possible implementations, the thermal runaway prevention component further includes a gas-liquid collection chamber; the gas-liquid collection chamber is placed above the phase change layer and the one-way valve. In the lateral direction, the phase change layer is disposed on the upper side of the lower shell, avoiding the one-way valve, and when the one-way valve is open, it is directly connected to the gas-liquid collection chamber. The one-way valve is opened by the gas and liquid ejected from the battery cell, and the gas and liquid directly enter the gas-liquid collection chamber.

[0048] In some possible implementations, the one-way valve includes a support and a one-way valve itself. When the one-way valve is normally closed, the bottom end of the support is fixed to the lower housing, and the top end of the support supports the one-way valve. When the battery cell experiences thermal runaway, the one-way valve is pushed upwards and opened by the gas and liquid ejected from the battery cell. The one-way valve and the explosion-proof valve are correspondingly connected. For example, a gas-liquid channel is also provided below the one-way valve on the lower housing to allow the gas and liquid ejected from the explosion-proof valve to flow through the gas-liquid channel to the one-way valve and open it when the battery cell experiences thermal runaway.

[0049] In some possible implementations, the one-way valve can be a metal plate with a certain weight. When thermal runaway occurs, the battery cell ejects gas and liquid, which, under pressure, pushes open the metal plate, allowing the gas and liquid to directly enter the gas-liquid collection chamber. The one-way valve also features an automatic reset structure. After thermal runaway ends, the pressure of the ejected gas and liquid decreases, and the one-way valve closes under the action of the automatic reset structure. The automatic reset structure is a hinge structure, such as a spring hinge, a gravity hinge, or a magnetic hinge.

[0050] The one-way valve is fixed to the lower housing body by a hinge structure. This hinge structure has a certain automatic reset force. When thermal runaway occurs, the cell ejects gas and liquid. The pressure of the ejected gas and liquid is relatively large, which overcomes the automatic reset force of the hinge structure, allowing the gas and liquid to directly enter the gas and liquid collection chamber. After thermal runaway ends, the pressure of the ejected gas and liquid decreases, and the one-way valve closes under the action of the automatic reset force. The automatic reset force can be generated by a combination of a spring (torsion spring or tension spring), magnetic force, or gravity and the hinge structure.

[0051] The thermal runaway prevention and control assembly also includes a top cover. The top cover is positioned above the gas-liquid collection chamber. The top cover of the thermal runaway prevention and control assembly can be made of a puncture-resistant material, such as mica, which prevents the top cover from deforming and thus protects the various components within the thermal runaway prevention and control assembly from damage.

[0052] In a preferred embodiment, a gas-liquid collection layer is formed within the gas-liquid collection cavity formed inside the upper cover. For example, the inner wall can be coated, plated, or assembled with an absorbent material for absorbing ejected gas or liquid. This gas-liquid collection layer is used to absorb toxic, harmful, or flammable and explosive gases in the gas or liquid, such as hydrogen, carbon monoxide, hydrogen fluoride, etc., or electrolytes; thereby preventing toxic and harmful gases and liquids from being released into the atmosphere. As an example, the surface of the inner wall material of the upper cover is locally treated (e.g., chemical etching, laser etching, etc.) to form an uneven or porous structure, and a gas-liquid collection layer is coated or plated, such as one or more adsorbent materials such as cerium dioxide, titanium dioxide, etc. The adsorbent material can be porous or nano-sized, thereby improving the gas-liquid collection effect.

[0053] The phase change layer is formed by injecting phase change material into the housing of the thermal runaway prevention component. The volume of the injected phase change layer is smaller than the volume inside the housing of the thermal runaway prevention component. Thus, after the phase change layer is formed inside the housing of the thermal runaway prevention component, the remaining space forms a cavity, which can be used as a gas-liquid collection chamber for gas and liquid collection. This gas-liquid collection chamber can also be equipped with a switch. By opening the switch, the gas and liquid in the gas-liquid collection chamber are released. When gas and liquid release is not required, the switch is closed. This ensures that the gas and liquid in the gas-liquid collection chamber will not leak when the battery cell needs maintenance or replacement, thereby guaranteeing the safety of the battery cell.

[0054] In some possible implementations, an insulating material can be placed above the phase change layer and below the top cover within the housing of the thermal runaway prevention component to form a cavity that is isolated from both the phase change layer and the top cover, serving as the gas-liquid collection chamber. In this way, when the amount of gas and liquid in the gas-liquid collection chamber is large, the gas and liquid can be released or the gas-liquid collection chamber can be replaced.

[0055] like Figure 2 As shown, the gas-liquid collection chamber 340 is positioned above the phase change layer and in contact with the top cover, used to collect the ejected gas and liquid from the battery cell. The opening pressure of the one-way valve is lower than the opening pressure of the explosion-proof valve of the battery cell, so that the ejected gas and liquid from the battery cell can directly enter the gas-liquid collection chamber. In this way, the gas-liquid collection chamber in the thermal runaway suppression and control structure can collect the ejected gas and liquid from the battery cell, preventing the gas and liquid from harming other battery cells, and also preventing harmful gases from harming personnel. When thermal runaway occurs in the battery pack, the phase change layer in the thermal runaway control component can also effectively absorb the heat of the ejected gas and liquid, reduce the battery cell temperature, and suppress the spread of local thermal runaway.

[0056] like Figure 3 As shown, the thermal runaway prevention component includes a lower shell 310, a phase change layer 320, a one-way valve 330, a gas-liquid collection chamber 340, and a top cover 350. The one-way valve comprises a support member 331 and a one-way valve 332. The lower shell of the thermal runaway prevention component contacts the module aluminum bar 230 and the top cover of the battery cell. The one-way valve 330 of the prevention component is located at the explosion-proof valve 211 of the battery cell and corresponds one-to-one with the explosion-proof valve 211 of the battery cell. The one-way valve 330 of the prevention component is composed of the support member 331 and the one-way valve 332. When thermal runaway does not occur, under harsh operating conditions such as high temperature or high current charging and discharging of the battery cell, the Joule heat generated by the module aluminum bar 230 can be transferred to the phase change layer 320, and the heat at the top of the battery cell can be transferred to the phase change layer 320, reducing the temperature at the top of the battery cell. The heat transfer within the phase change layer 320 can reduce the temperature difference between the battery cells, improving the performance and lifespan of the battery pack.

[0057] In some possible implementations, when the temperature of the battery cell exceeds a preset temperature threshold, the conductive connector and the battery cell transfer heat to the phase change layer, and the phase change of the phase change layer absorbs heat to reduce the temperature of the upper part of the battery cell; a liquid cooling channel is provided below the battery module. When thermal runaway occurs in the battery pack, the control system of the battery pack increases the system flow rate so that the liquid flow rate in the liquid cooling channel exceeds a preset flow rate threshold. The preset temperature threshold is the phase change temperature of the phase change material.

[0058] Here, when thermal runaway of the battery pack to which the cell belongs has not occurred, under harsh conditions such as high temperature and high current charging and discharging of the cell, the aluminum barjoule heat can be transferred to the phase change layer, and the heat on the upper part of the cell can be transferred to the phase change layer, reducing the temperature on the upper part of the cell. The heat is transferred within the phase change layer, which can reduce the temperature difference between cells and improve the performance and life of the battery pack.

[0059] In some possible implementations, when thermal runaway occurs in the battery pack to which the cell belongs, the heat generated by the cell is transferred to the phase change layer through the module aluminum bar and the top cover of the cell; when thermal runaway occurs in the cell, the one-way valve enters the open state based on gas-liquid pressure; when thermal runaway occurs in the battery pack to which the cell belongs, the one-way valve enters the closed state based on gravity.

[0060] The phase change layer is used for phase change heat absorption. The heat generated is transferred laterally to the phase change layer so that the temperature of the battery cell drops back to below the thermal runaway trigger temperature.

[0061] Here, when thermal runaway occurs, the module's thermal insulation material can slow down heat transfer, providing cooling time for the cooling system; the bottom liquid cooling increases flow rate and improves cooling efficiency; the phase change layer in the thermal runaway suppression and control structure absorbs heat during phase change; the combination of these two can quickly reduce the battery pack temperature, allowing the cell temperature to return to below the trigger temperature.

[0062] If the battery pack experiences thermal runaway due to misuse, the heat generated by the runaway cell is transferred to the phase change layer (PCL) through the aluminum foil and the cell's top cover. The PCL absorbs heat during the phase change process, and simultaneously, the heat is transferred laterally throughout the entire PCL, absorbing a significant amount of heat and causing the cell temperature to return below the thermal runaway trigger temperature. When thermal runaway occurs, the one-way valve opens under gas-liquid pressure; after thermal runaway occurs, the one-way valve closes under gravity.

[0063] like Figure 3 As shown, due to the high temperature of the large battery cell, heat transfer from the upper part of the cell to the lower liquid cooling plate is slow. When thermal runaway occurs, the heat from the thermally runaway cell is transferred to the phase change layer 320 of the thermal runaway prevention component through the module aluminum bar 230 and the top cover of the cell. The phase change layer 320 absorbs heat during phase change, and simultaneously, heat is transferred laterally throughout the entire phase change layer 320, absorbing a large amount of heat and causing the cell temperature to return below the thermal runaway trigger temperature. At the same time, heat from adjacent cells of the thermally runaway cell can also be transferred to the phase change layer, preventing the temperature of adjacent cells from rising above the thermal runaway trigger temperature.

[0064] By using thermal insulation materials to slow down heat transfer, bottom liquid cooling to increase coolant flow rate, and top thermal runaway prevention components with phase change layer to absorb a large amount of heat, the combination of these three technologies can efficiently remove heat from the thermal runaway cell and adjacent cells within a limited time, reduce cell temperature, and prevent thermal runaway from continuing to develop and spread.

[0065] In the thermal runaway prevention component, the opening pressure of the one-way valve 330 is lower than the opening pressure of the battery cell, so that the gas and liquid ejected from the battery cell can enter the gas and liquid collection chamber 340. When thermal runaway occurs, the one-way valve 330 opens under the pressure of the gas and liquid ejected from the battery cell; after thermal runaway occurs, the one-way valve 330 closes under the automatic reset force of the automatic reset structure.

[0066] In some possible implementations, when thermal runaway occurs in the battery pack to which the cell belongs, the heat generated by the adjacent cells is transferred to the phase change layer to control the cell temperature below the thermal runaway trigger temperature; when thermal runaway occurs in the battery pack to which the cell belongs, the one-way valve opens, and the ejected gas and liquid from the cell directly enter the gas-liquid collection chamber, and the generated heat is transferred to the phase change layer; when the process of the cell ejecting gas and liquid ends, the one-way valve closes.

[0067] Here, when thermal runaway occurs, the one-way valve opens, and the gas and liquid ejected from the battery cell directly enter the gas-liquid collection chamber. Heat is transferred to the phase change layer for cooling, and the temperature decreases. After the ejection ends, the one-way valve closes, and the gas and liquid are collected in the thermal runaway prevention and control component, which will not cause secondary damage to the battery cell. During battery pack disassembly and maintenance, it can prevent the spread of harmful gases from causing harm to personnel.

[0068] In summary, the thermal runaway prevention component of the present invention has a simple structure, can be easily disassembled and replaced, and can simultaneously solve the overheating problem at the top of the battery and the thermal runaway problem caused by high current, and effectively collect the ejected gas and liquid to avoid pollution and damage.

[0069] This invention provides a battery pack, including: a thermal runaway prevention component, and may further include: a lower battery pack housing, a module, and a upper battery pack cover; wherein: the module is positioned above the lower battery pack housing, and the thermal runaway prevention component is positioned between the module and the upper battery pack cover.

[0070] like Figure 4 As shown, the battery pack includes: a lower battery pack housing 100, a module 200, a thermal runaway prevention component 300, and a battery pack upper cover 400. The lower battery pack housing contains liquid cooling channels. The cross-section of the battery pack is shown below. Figure 7 As shown.

[0071] In some possible implementations, the module includes: a battery cell, thermal insulation material, and a module aluminum bar; wherein the battery cell includes: an explosion-proof valve for the battery cell and battery cell terminals. For example... Figure 5 and Figure 6 As shown, module 200 includes: battery cell 210, high heat insulation material 220, module aluminum bar 230, and the battery cell includes an explosion-proof valve 211 and a battery cell terminal 212.

[0072] The cells are also separated by a heat insulation layer, and the heat insulation coefficient of the heat insulation material is less than 0.03 W / (m*K); the battery pack is a lithium-ion battery pack.

[0073] In some possible implementations, the insulation material can be mica sheets. For example... Figure 3 As shown, when thermal runaway is triggered by mechanical abuse, thermal abuse, or electrical abuse, the cell temperature rises rapidly. The high-insulation material 220 in the module can delay the transfer of heat to adjacent cells, providing cooling time for the cooling system. Bottom liquid cooling increases flow rate, improves cooling efficiency, and increases the cell cooling rate. Based on data such as the thermal runaway temperature of large cells, the high-insulation material in the module with a thermal conductivity of less than 0.03 W / (m*K) has a good effect. In the event of thermal runaway, controlling the liquid flow rate in the lower casing of the battery pack to be higher than 0.3 m / s has a good effect. When thermal runaway occurs, the one-way valve 330 opens, and the gas and liquid ejected from the battery cell directly enter the gas-liquid collection chamber 340. Heat is transferred to the phase change layer 320 for cooling, and the temperature decreases. After the ejection ends, the one-way valve 330 closes, and the gas and liquid are collected in the thermal runaway prevention and control structure, which will not cause secondary damage to the battery cell. During battery pack disassembly and maintenance, it can prevent the diffusion of harmful gases from causing harm to personnel.

[0074] In some possible implementations, when thermal runaway occurs in the battery pack, the thermal insulation material in the module is used to delay heat transfer.

[0075] Here, when thermal runaway occurs, the module's thermal insulation material can slow down heat transfer, providing time for the cooling system; bottom liquid cooling increases flow rate and improves cooling efficiency; the phase change layer in the thermal runaway prevention component absorbs heat during phase change, rapidly reducing battery temperature and bringing the cell temperature back below the trigger temperature; the gas-liquid collection chamber in the thermal runaway prevention component can collect the gas and liquid ejected from the cells, preventing them from harming other cells and also preventing harmful gases from posing a hazard to personnel. When thermal runaway occurs in area B of the battery pack cross-section, the position of the one-way valve 332 is as follows... Figure 8 As shown.

[0076] In this embodiment of the invention, to improve energy density, large cells and bottom liquid cooling are common industry solutions. A mica upper shell is also included on the module to prevent thermal runaway of the cells from ejecting gas and liquid, burning through the battery pack. This embodiment of the invention is based on the mainstream battery pack structure in the industry, offering high adaptability, minimal modification to the battery pack structure, and high reliability. When thermal runaway has not occurred, under high-current charging and discharging conditions of the cells, the Joule heat generated by the module's aluminum bar can be transferred to the phase change layer of the thermal runaway prevention component. Heat from the upper part of the cells can also be transferred to the phase change layer, reducing the temperature at the top of the cells. Heat transfer within the phase change layer reduces the temperature difference between cells, improving battery pack performance and lifespan. This function plays a crucial role throughout the battery pack's lifespan, significantly improving economic efficiency. In the event of thermal runaway, the module's thermal insulation material can delay heat transfer, providing time for the cooling system to cool. Bottom liquid cooling increases flow rate and improves cooling efficiency. The phase change layer in the thermal runaway prevention component absorbs heat during phase change, rapidly reducing battery temperature and bringing the cell temperature back below the trigger temperature, thus preventing thermal propagation in the large-cell battery pack. The gas-liquid collection chamber in the thermal runaway prevention component collects the gas and liquid ejected from the cells, absorbing heat through the phase change layer to prevent the gas and liquid from harming other cells and also to prevent harmful gases from posing a danger to personnel.

[0077] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. The processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some embodiments, multiple task processing and parallel processing are possible or may be advantageous. The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. The above content is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be covered within the protection scope of the present invention.

Claims

1. A thermal runaway prevention component, disposed within a battery pack, the battery pack comprising: A battery module, the battery module comprising multiple battery cells, each of which is provided with at least one explosion-proof valve; A conductive connector is disposed on each pair of adjacent battery cells, thereby electrically connecting the two adjacent battery cells. The thermal runaway prevention and control component is characterized by comprising: a lower shell, a plurality of one-way valves and a phase change layer, and a top cover; each of the one-way valves is disposed on the lower shell body and is correspondingly disposed on each of the explosion-proof valves; the one-way valves are normally closed; the top cover fits into the lower shell. The phase change layer is disposed on the upper side of the lower shell, and on the conductive connector and the plurality of battery cells; The phase change layer is used to absorb the heat released when the plurality of battery cells and the conductive connector are heated; the normally closed one-way valve and the lower shell are used to prevent the phase change layer from entering the battery cells after being heated and undergoing a phase change; wherein, the phase change layer is formed by injecting phase change material into the shell of the thermal runaway prevention and control component, the volume of the injected phase change layer is smaller than the volume inside the shell of the thermal runaway prevention and control component, and after the phase change layer is injected into the shell of the thermal runaway prevention and control component to form a gas-liquid collection chamber; the shell of the thermal runaway prevention and control component includes: the lower shell, and an upper cover that fits with the lower shell; The gas-liquid collection chamber is placed above the phase change layer and the one-way valve. The phase change layer is located on the upper side of the lower shell, avoiding the one-way valve. The one-way valve is opened by the gas and liquid ejected from the battery cell, and the gas and liquid directly enter the gas-liquid collection chamber. The phase change layer is also used to absorb the heat of the ejected gas and liquid when thermal runaway of the battery pack occurs.

2. The thermal runaway prevention and control component according to claim 1, characterized in that: The battery cell includes at least two terminals, and the conductive connector is connected to the terminals of each of two adjacent battery cells, so that the two adjacent battery cells are electrically connected in series or in parallel.

3. The thermal runaway prevention component according to claim 1, characterized in that: The phase transition temperature of the phase transition layer is between 50°C and 60°C; the material of the phase transition layer includes one or more of paraffin wax, foamed metal, fatty acid, and metal salt.

4. The thermal runaway prevention and control component according to claim 1, characterized in that: When the battery cell experiences thermal runaway, the one-way valve is pushed upwards and opened by the gas and liquid ejected from the battery cell.

5. The thermal runaway prevention and control component according to claim 4, characterized in that: The one-way valve includes a support member and a one-way valve itself. When the one-way valve is in a normally closed state, the bottom end of the support member is fixed to the lower shell, and the top end of the support member supports the one-way valve. When the battery cell experiences thermal runaway, the one-way valve is pushed upward by the gas and liquid ejected from the battery cell. The one-way valve is equipped with an automatic reset structure, which is connected to the lower shell. When the battery cell stops ejecting gas and liquid, the one-way valve switches from open to closed under the action of the automatic reset structure. The automatic reset structure on the one-way valve is a hinge structure.

6. The thermal runaway prevention component according to claim 1, characterized in that: When the temperature of the battery cell exceeds a preset temperature threshold, the conductive connector and the battery cell transfer heat to the phase change layer to reduce the temperature of the upper part of the battery cell; a liquid cooling channel is provided below the battery module.

7. The thermal runaway prevention component according to claim 4, characterized in that: The opening pressure of the one-way valve is less than the opening pressure of the battery cell, so that the gas and liquid ejected from the battery cell can enter the gas and liquid collection chamber.

8. A battery pack, characterized in that: It includes the thermal runaway prevention component as described in any one of claims 1 to 7.

9. A battery pack according to claim 8, characterized in that: The cells also include a heat insulation layer; the battery pack is a lithium-ion battery pack.

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