Automatic Fire Suppression System Using Refrigerant-Type Extinguishing Fluid for Preventing Thermal Runaway in Lithium-Ion Battery Modules

Abstract

The present invention relates to a fire suppression system for preventing thermal runaway in lithium-ion batteries. The system of the present invention comprises a cold plate in thermal contact with a battery module, a fire suppression liquid that doubles as a refrigerant injected therein, an electronic control valve, a gas safety valve, and a liquid storage tank. The refrigerant normally performs a cooling function and vaporizes above a set temperature to increase pressure; upon reaching this pressure, the gas safety valve automatically opens, thereby spraying the fire suppression liquid. The present invention implements both cooling and fire suppression using a single fluid and enables rapid and stable fire response through an electronic and mechanical dual-operation structure.

Description

Technology Field

[0001] The present invention relates to a safety system for a lithium-ion battery, and more particularly to an automatic refrigerant-fire extinguishing liquid injection system configured to simultaneously perform cooling and extinguishing in the event of a thermal runaway of a lithium-ion battery. Background Technology

[0002] Lithium-ion batteries are widely used in electric vehicles, energy storage systems (ESS), and various portable electronic devices due to their high energy density. However, if thermal runaway occurs due to external impact, internal short circuits, or high-temperature environments, it can lead to fire or explosion.

[0003] Generally, when the internal temperature of a lithium-ion battery increases to 170°C or higher, a thermal runaway phenomenon occurs. When the thermal runaway phenomenon occurs, the internal pressure of the lithium-ion battery increases, and the internal electrolyte vaporizes. Subsequently, the lithium-ion battery expands, causing the electrolyte to be ejected and smoke (off gas) to be generated, which increases the hydrogen concentration and leads to an explosion and a loud bang, and eventually develops into a fire.

[0004] The fire caused by the aforementioned thermal runaway phenomenon continues until all the energy charged in the battery is released, even if the oxygen required for combustion is cut off, and a large amount of toxic gas is released along with the fire.

[0005] Conventional fire extinguishing systems generally use electronic control based on temperature sensors, but they have the problem of not operating in the event of power failure or sensor error. The problem to be solved

[0006] The objective of the present invention is to provide a system that prevents or suppresses battery fires by using internal pressure to automatically spray a fire extinguishing liquid that acts as both a refrigerant and a fire extinguishing agent, which normally performs a cooling function and becomes gaseous when the temperature rises. means of solving the problem

[0007] To solve the above technical problem, the present invention provides a fire suppression system that operates automatically in a thermal runaway situation of a lithium-ion battery module (100). Specifically, a refrigerant-fire suppression liquid that combines cooling and fire suppression functions is placed inside a cold plate, and when the battery temperature rises, the refrigerant is converted into a gas, causing the pressure to rise, and the gas safety valve is automatically opened by this pressure so that the fire suppression liquid is sprayed.

[0008] In addition, the present invention is equipped with an electronically controlled valve operated by a temperature sensor, which includes a function in which the valve automatically opens and fire extinguishing liquid is sprayed when the temperature exceeds a certain level. This dual-operation mechanism significantly improves stability and reliability by ensuring that the fire extinguishing function operates normally even in situations such as power failures or sensor malfunctions.

[0009] With this structure, the present invention solves existing problems by the following means.

[0010] Achieving system simplification and lightweighting by integrating cooling and extinguishing into a single fluid.

[0011] Fire extinguishing function operates even in the event of a failure through an electronic and mechanical dual-operation structure

[0012] Rapid fire suppression possible through an automatic spraying method utilizing the pressure action resulting from gasification.

[0013] Ensuring electrical safety and compliance with environmental regulations through the use of non-conductive and eco-friendly fluids

[0014] As a result, the present invention can suppress fires and explosions caused by thermal runaway of lithium-ion batteries more quickly and stably, and can be effectively applied to various application fields such as electric vehicles and ESS. Effects of the invention

[0015] According to the present invention, the following effects can be obtained:

[0016] 1. Perform cooling and extinguishing simultaneously with a single fluid

[0017] Since the refrigerant-fire extinguishing agent acts as a coolant in normal times and becomes a gaseous fire extinguishing agent in emergencies, dual functions can be implemented in a single system without a separate complex system, thereby effectively reducing the number of parts, system configuration complexity, weight, and manufacturing costs.

[0018] 2. Implementation of a Dual Electronic and Mechanical Operating Mechanism

[0019] By configuring an electronically controlled valve linked to a temperature sensor and a gas safety valve that operates in response to pressure rise in parallel, the system can be extinguished in a different manner even if one system fails, thereby improving the reliability and safety of the entire system.

[0020] 3. Enables rapid and proactive response in the event of a fire

[0021] When the internal temperature of the battery exceeds a critical threshold, the refrigerant immediately vaporizes to form pressure, and consequently, automatic injection occurs, which can rapidly suppress the spread of fire.

[0022] It has a fast response speed and operates based on pressure even if the sensor is not functioning, ensuring high responsiveness even in emergency situations such as power loss.

[0023] 4. Ensuring electrical stability through the use of non-conductive and eco-friendly refrigerants

[0024] The refrigerant-fire extinguishing agent used is non-conductive, so there is no risk of electrical short circuits or secondary fires even when sprayed, and by using eco-friendly materials with a low GWP (Global Warming Potential), it satisfies environmental regulations and has high applicability to actual products such as electric vehicles and ESS.

[0025] 4. Applicable to various fields such as electric vehicles and ESS

[0026] The system of the present invention can be applied to battery cell units, module units, and pack units, and can be flexibly applied to various high-output battery products such as next-generation electric vehicles, energy storage systems, drones, and aircraft batteries. Brief explanation of the drawing

[0027] FIG. 1 is a conceptual diagram of the automatic extinguishing liquid spraying system for refrigerants according to the present invention. FIG. 2 is an assembly diagram of the automatic extinguishing liquid spraying system for refrigerants according to the present invention. Figure 3 is a diagram showing the connection of the cooling plate of the automatic extinguishing liquid spraying system for refrigerant and fire extinguishing agents according to the present invention. Figure 4 is a simplified operation diagram of the automatic extinguishing liquid spraying system for refrigerants according to the present invention. Specific details for implementing the invention

[0028] The present invention will be described in detail below through specific embodiments. However, these embodiments are intended to aid in understanding the invention and do not limit the technical scope of the invention.

[0029] 1. System Configuration

[0030] The fire suppression system according to the present invention is configured to be directly integrated into a lithium-ion battery module (100), and the main components are as follows:

[0031] (1) Battery module (100)

[0032] It is a module composed of multiple lithium-ion cells and is a target requiring cooling and extinguishing.

[0033] (2) Cooling plate (200)

[0034] A metal plate installed in close contact with the lower part of the battery module (100) has a fluid channel formed therein through which a refrigerant and fire extinguishing liquid can flow.

[0035] The cooling plate (200) is made of aluminum or copper and is formed with a structure having high thermal conductivity and excellent pressure resistance.

[0036] (3) Coolant and fire extinguishing agent (201)

[0037] It is a non-conductive liquid that performs cooling and extinguishing functions simultaneously, with a boiling point located between approximately 45°C and 55°C.

[0038] In this embodiment, an eco-friendly fire extinguishing agent of the Novec 1230 or FK-5-1-12 series is used.

[0039] (4) Temperature sensor (101)

[0040] It is installed inside the battery module (100) to check the temperature status of the battery module (100) and is connected to an electronic control valve to transmit a signal.

[0041] (4) Electronic control valve (202)

[0042] It is connected to the liquid path inside the cooling plate (200) and opens according to a signal from the temperature sensor (101).

[0043] The sensor is installed on the surface of the battery cell or inside the module and generates a control signal when the temperature is above a set temperature (e.g., 100°C).

[0044] (5) Gas safety valve (203)

[0045] When the internal pressure of the cooling plate (200) exceeds a set value (e.g., 1.5 atm), it automatically opens and sprays gaseous refrigerant out of the module or toward the heat dissipation structure.

[0046] (6) Liquid storage tank (205)

[0047] A tank for storing a refrigerant and fire extinguishing liquid, connected to a cooling plate (200) via piping, which allows for the supply of fluid or replenishment after spraying.

[0048] 2. Operating Procedure

[0049] ▶ Normal state

[0050] The refrigerant-fire extinguishing liquid circulates inside the cooling plate (200) in a liquid state, absorbs heat from the battery module (100), and disperses heat.

[0051] In this state, the system operates as a standard cooling system.

[0052] ▶ Emergency situation (precursor to heat runaway)

[0053] When the battery temperature rises above 50℃, the temperature sensor (101) detects this and opens the electronic control valve.

[0054] At the same time, the refrigerant inside the cooling plate (200) vaporizes and the pressure rises.

[0055] As the refrigerant evaporates, it rapidly absorbs heat and becomes a gas, performing both cooling and extinguishing simultaneously.

[0056] ▶ Heat runaway occurs

[0057] If the electronic control valve (202) does not operate normally or if a rapid increase in temperature occurs, the internal pressure rises rapidly.

[0058] At this time, the gas safety valve (203) operates to automatically spray the fire extinguishing liquid using a pressure spray method.

[0059] The extinguishing agent is sprayed through the top of the module or external heat vents, performing heat insulation, cooling, and suffocation functions. Explanation of the symbols

[0060] 100 battery modules 101 temperature sensor 200 cooling plates 201 Coolant-compatible Fire Extinguishing Liquid 202 Electronic Control Valve 203 Gas safety valve 204 liquid storage tanks

Claims

Claim 1 A fire suppression system for preventing thermal runaway of a lithium-ion battery module, wherein the fire suppression system comprises a battery module including lithium-ion cells, a cooling plate that is thermally in contact with the battery module and has a fluid circulation channel formed therein, a refrigerant-fire suppression liquid that circulates inside the cooling plate and normally performs a cooling function, and converts into a gas to increase internal pressure when the temperature rises above a set temperature, and a gas safety valve that automatically opens in response to the pressure increase to spray the refrigerant-fire suppression liquid to the outside, and wherein the fire suppression system is characterized by operating automatically in response to pressure changes without power supply. Claim 2 A fire extinguishing system according to claim 1, wherein the refrigerant-compatible fire extinguishing liquid is non-conductive and has a boiling point within the range of 45°C to 55°C. Claim 3 A fire extinguishing system according to claim 1, characterized in that a plurality of fluid circulation channels are formed inside the cooling plate so that a fire extinguishing liquid that serves as both a refrigerant can flow therethrough. Claim 4 The fire extinguishing system according to claim 1 further comprises a temperature sensor that detects the temperature of a battery module in real time and an electronic control valve that opens when the temperature is above a set temperature according to the detection signal of the temperature sensor, wherein the electronic control valve is configured in parallel with the gas safety valve. Claim 5 A fire extinguishing system according to claim 4, wherein the electronic control valve is opened when a temperature above a set temperature (e.g., about 50°C) is detected by a temperature sensor, and configured to spray a fire extinguishing liquid that doubles as a refrigerant to the outside of the battery module or inside the housing. Claim 6 A fire extinguishing system according to claim 1, wherein the fire extinguishing system further comprises a liquid storage tank for storing a fire extinguishing liquid that also serves as a refrigerant, and wherein the liquid storage tank is fluidly connected to cooling plates and valves. Claim 7 A fire extinguishing system according to claim 6, wherein the liquid storage tank is made of a composite material or a pressure-resistant metal material resistant to external shock or leakage, and is configured to allow for refrigerant replenishment according to a set period or event.

Images