Method and system for reducing thermal runaway in battery pack

Abstract

Disclosed are a method and a system for reducing thermal runaway in a battery pack (1), the method comprising the steps of: detecting a temperature inside the battery pack (1); when the detected temperature is higher than a predetermined temperature, a gas containing nitrogen gas and oxygen gas is injected into the battery pack (1), the volume of the oxygen gas being less than 10%, and the oxygen gas is removed from the inside of the battery pack (1). The system comprises a temperature sensor (2); the inerting system (4) is used for injecting gas containing nitrogen and oxygen into the battery pack (1) under the condition that the temperature detected by the temperature sensor (2) is higher than a preset temperature, and the volume of the oxygen is smaller than 10%; and an outlet duct (7) through which oxygen is removed from the battery pack (1) when the temperature detected by the temperature sensor (2) is higher than a predetermined temperature.

Description

TECHNICAL FIELD

[0001] The present invention relates to a method and system for reducing thermal runaway in a battery pack, in particular for an aircraft, for reducing runaway energy and propagation, reducing the amount of oxygen inside the battery pack. BACKGROUND

[0002] Battery packs are widely used in various industries, from consumer electronics to automotive applications, providing portable power for a wide range of devices. However, one major challenge associated with battery packs is the risk of thermal runaway, which can lead to consequences including fire and explosion.

[0003] Thermal runaway occurs when the internal temperature of a battery cell or battery pack increases uncontrollably, usually due to factors such as overcharging, overheating, internal short circuits, or manufacturing defects. As the temperature rises, the chemical reactions inside the battery accelerate, releasing additional heat, and causing a self-reinforcing cycle of thermal runaway. This phenomenon is particularly prevalent in lithium-ion batteries, which are commonly used in modern battery packs due to their high energy density and rechargeable characteristics.

[0004] The consequences of thermal runaway can be severe, posing a significant safety risk to both users and the surrounding environment. Traditional methods of mitigating thermal runaway, such as incorporating thermal protection devices or improving battery management systems, have limitations in effectively reducing or suppressing thermal runaway events. SUMMARY

[0005] Therefore, it is an object of the present invention to provide a method and system for reducing thermal runaway in a battery pack, in particular for an aircraft, which adds a minimum number of components, reducing the damage that thermal runaway can cause by reducing the amount of oxygen inside the battery pack.

[0006] The method and system for reducing thermal runaway in a battery pack of the present invention solve the above-mentioned drawbacks and have other advantages that will be described below.

[0007] The method and system for reducing thermal runaway in a battery pack according to the present invention are described below and include optional additional features.

[0008] In particular, the method for reducing thermal runaway in a battery pack comprises the steps of:

[0009] - detecting the temperature inside the battery pack;

[0010] - in the event that the detected temperature is higher than a predetermined temperature, injecting a gas with nitrogen and oxygen inside the battery pack, the volume of oxygen being less than 10%, and removing oxygen from the inside of the battery pack.

[0011] Thanks to this feature, when a potential thermal runaway scenario is detected, the use of a gas with nitrogen creates a lack of oxygen inside the battery pack and the reduction of oxygen in the battery pack reduces the heat and the fire time of the thermal runaway.

[0012] According to a preferred embodiment, the injection of the gas with nitrogen and the removal of oxygen are performed until the temperature inside the battery pack decreases below the initial thermal runaway temperature.

[0013] Moreover, the voltage drop inside the battery pack can also indicate the beginning of a thermal runaway and the injection of nitrogen and the removal of oxygen are also performed.

[0014] If necessary, the method according to the application can also comprise a step of cooling the gas with nitrogen before injecting it inside the battery pack.

[0015] According to a second aspect, a system for reducing thermal runaway in a battery pack comprises:

[0016] - a temperature sensor placed inside the battery pack;

[0017] - an inerting system in communication with the battery pack through an inlet duct provided with an inlet valve for injecting a gas with nitrogen and oxygen inside the battery pack in case the temperature detected by the temperature sensor is higher than a predetermined temperature, the volume of oxygen being less than 10%; and

[0018] - an outlet duct provided with an outlet valve in the battery pack for removing oxygen from the battery pack through the outlet duct in case the temperature detected by the temperature sensor is higher than a predetermined temperature.

[0019] In particular, the inerting system is the inerting system of an aircraft for inerting the fuel tank.

[0020] Moreover, the system can also comprise a voltage sensor placed inside the battery pack and the system can also comprise a cooling unit placed between the inerting system and the battery pack for cooling the nitrogen before injecting it inside the battery pack. BRIEF DESCRIPTION OF DRAWINGS

[0021] In order to better understand what has been stated above, some drawings are included, in which the practicalities of the embodiments are represented schematically and by way of non-limiting example only.

[0022] Figure 1 is a block diagram of a system for reducing thermal runaway in a battery pack according to the application. DETAILED DESCRIPTION

[0023] Figure 1A block diagram of a system for reducing thermal runaway in a battery pack, preferably of an aircraft, according to the application is shown, which shows the components of the system.

[0024] The system comprises a battery pack 1 which houses a temperature sensor 2 and optionally a voltage sensor 3 for detecting the temperature and the voltage inside the battery pack 1 respectively.

[0025] The system also comprises an inerting system 4 of the aircraft, which delivers or injects a gas with nitrogen and oxygen, the volume of oxygen being less than 10%, to the battery pack 1 through an inlet duct 5 provided with an inlet valve 6 if necessary, and the gas can be introduced into said inerting system 4.

[0026] Preferably, the inerting system 4 is the inerting system of the aircraft for inerting the fuel tank.

[0027] The battery pack 1 also comprises an outlet duct 7 provided with an outlet valve 8 through which the oxygen is removed from the battery pack 1.

[0028] Even if the cooling unit is optional, the system can comprise a cooling unit 9 placed between the inerting system 4 and the battery pack 1 which cools the nitrogen before it is injected into the battery pack 1.

[0029] It must be pointed out that the injection of the gas with nitrogen is preferably carried out by injecting a gas rich in nitrogen and the removal of oxygen is preferably carried out by removing a gas rich in oxygen.

[0030] Thus, in order to reduce the thermal runaway inside the battery pack 1, the amount of oxygen in the battery pack 1 is reduced before the thermal runaway occurs. To do this, the system should follow the following steps:

[0031] First, a possible thermal runaway is detected using the temperature sensor 2 placed inside the battery pack and also possibly the voltage sensor 3.

[0032] The system can predict the thermal runaway a few minutes before the battery pack 1 catches fire. For example, in the automotive field, the thermal runaway should be detected at least 5 minutes before the battery pack 1 catches fire.

[0033] By using the ducts 5, 7 and the valves 6, 8, a gas rich in nitrogen is injected into the battery pack 1. The gas rich in nitrogen will come from the inerting system 4 which should be able to deliver a gas rich in nitrogen to the battery pack 1 in emergency situations.

[0034] The inlet valve 6 and the outlet valve 8 should be opened, the first valve allowing the gas rich in nitrogen to enter the battery pack 1 and the second valve allowing the gas rich in oxygen to leave the battery pack 1.

[0035] If the cooling unit 9 is present, the gas rich in nitrogen can be cooled to reduce the temperature, for example, from between 40°C and 80°C to a maximum temperature of 40°C.

[0036] By reducing the amount of oxygen inside the battery, the amount of energy released by the system will be reduced, thus lightening the weight of the battery pack 1 to contain thermal runaway.

Claims

1. A method for reducing thermal runaway in a battery pack (1), characterized in that The method comprises the steps of: - detecting the temperature inside the battery pack (1); - in the event that the detected temperature is higher than a predetermined temperature, injecting a gas with nitrogen and oxygen inside the battery pack (1), the volume of oxygen being less than 10%, and removing the oxygen from the inside of the battery pack (1).

2. The method for reducing thermal runaway in a battery pack (1) according to claim 1, wherein, The injection of the gas with nitrogen and the removal of the oxygen are performed until the temperature inside the battery pack (1) decreases with respect to the detected temperature.

3. The method for reducing thermal runaway in a battery pack (1) according to claim 1 or 2, wherein, The voltage inside the battery pack (1) is also detected, and in the event that the detected voltage is higher than a predetermined voltage, the injection of the nitrogen and the removal of the oxygen are also performed.

4. The method for reducing thermal runaway in a battery pack of any of the preceding claims, wherein, The method also comprises the step of cooling the nitrogen before injecting it inside the battery pack (1).

5. A system for reducing thermal runaway in a battery pack (1), characterized by The system comprises: - a temperature sensor (2) placed inside the battery pack (1); - an inerting system (4) in communication with the battery pack (1) through an inlet duct (5) provided with an inlet valve (6) for injecting a gas with nitrogen and oxygen inside the battery pack (1) in the event that the temperature detected by the temperature sensor (2) is higher than a predetermined temperature, the volume of oxygen being less than 10%; and - an outlet duct (7) provided with an outlet valve (8) in the battery pack (1) for removing oxygen from the battery pack (1) through the outlet duct in the event that the temperature detected by the temperature sensor (2) is higher than a predetermined temperature.

6. The system for reducing thermal runaway in a battery pack (1) according to claim 5, wherein, The system also comprises a voltage sensor (3) placed inside the battery pack (1).

7. The system for reducing thermal runaway in a battery pack (1) according to claim 5 or 6, wherein, The system also comprises a cooling unit (9) placed between the inerting system (4) and the battery pack (1) for cooling the nitrogen before injecting it inside the battery pack (1). The system also comprises a voltage sensor (3) placed inside the battery pack (1). The system also comprises a cooling unit (9) placed between the inerting system (4) and the battery pack (1) for cooling the nitrogen before injecting it inside the battery pack (1).

Images