An energy storage system that effectively copes with thermal runaway of battery packs

Abstract

The present invention provides an energy storage system that effectively copes with thermal runaway of a battery pack, which includes a battery cell, a battery box, and a waterproof breathable valve arranged at the bottom of the battery box. The waterproof breathable valve includes a valve body, a valve core, a wind chime shell, a breathable membrane, and a sealing ring. The valve body is provided with an air inlet cavity, a pressure relief chamber, and a through hole. The through hole is used to connect the air inlet cavity and the pressure relief chamber. The wind chime shell covers the valve core, and a sound window is provided on the wind chime shell; a ventilation hole and a pressure relief hole are provided on the valve core, and a breathable membrane covers the ventilation hole, and a spring is provided at the position of the pressure relief hole. The spring blocks the pressure relief hole to make it in a normally closed state. When the battery pack is thermally runaway, the rising air pressure drives the spring to bend, and the pressure can be quickly released through the pressure relief hole to balance the pressure difference inside and outside the battery pack, reduce the probability of fire in the battery pack, and improve safety; when exhausting air through the pressure relief hole, the airflow is ejected from the sound window on the wind chime cover and an alarm sound is generated, which can alert people inside and outside the vehicle, so that the driver can get off the vehicle to avoid danger and keep pedestrians away from the vehicle.

Description

Technical Field

[0001] The present invention relates to the field of battery pack energy storage, and in particular to an energy storage system that effectively copes with thermal runaway of a battery pack. Background Art

[0002] The battery pack is one of the core components of new energy vehicles. The amount of electrical energy stored in the battery pack is related to the vehicle's endurance. At the same time, the safety of the battery pack is also a concern for users. At present, new energy vehicles use lithium-ion batteries as functional modules. During the charging and discharging process of lithium-ion batteries, gas will be generated due to the heating of the electrolyte. Especially when the battery is in thermal runaway, the amount of gas generated is abnormal, resulting in excessive temperature and pressure in the battery pack, which will cause the battery pack to malfunction or even catch fire, causing the car to spontaneously combust. The car is equipped with an alarm system to allow the driver to get out of the car to avoid danger, but pedestrians and passing vehicles cannot detect the alarm in the car and cannot detect it to avoid danger.

[0003] Therefore, how to improve the safety of new energy vehicle energy storage systems, reduce the risk of fire when the battery pack is thermally runaway, and promptly warn people inside and outside the vehicle are issues that need to be addressed. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art, provide an energy storage system that effectively copes with thermal runaway of battery packs, improve the safety of energy storage systems for new energy vehicles, reduce the risk of fire when the battery packs thermal runaway, and promptly warn people inside and outside the vehicle.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] An energy storage system that effectively copes with thermal runaway of a battery pack comprises: a battery cell, a battery box, and a waterproof vent valve disposed at the bottom of the battery box;

[0007] The waterproof breathable valve comprises a valve body, a valve core, a wind chime shell, a breathable membrane and a sealing ring. The valve body is provided with an air inlet cavity, a pressure relief chamber and a through hole. The through hole is used to connect the air inlet cavity and the pressure relief chamber. The valve core is located in the pressure relief chamber. The valve core is provided with a ventilation hole and a pressure relief hole. The breathable membrane covers the ventilation hole. A spring is provided at the location of the pressure relief hole. The spring is used to block the pressure relief hole.

[0008] The wind chime shell is covered on the valve core, and a sound window is provided on the side of the wind chime shell.

[0009] In one embodiment, the waterproof and breathable valve also includes a protective cover, an air guide tube, a plurality of balls and a plurality of flame-retardant balls, the protective cover is arranged on the valve core, the protective cover is funnel-shaped, the diameter of the protective cover decreases from the end connected to the valve core toward the end away from the valve core, the protective cover and the valve core together form a cooling chamber, the pressure relief hole is used to connect the pressure relief chamber and the cooling chamber, the protective cover is provided with a plurality of mesh holes connected to the cooling chamber, and the flame-retardant ball is located in the cooling chamber; the two ends of the air guide tube are respectively abutted against the protective cover and the valve core, and the diameter of the air guide tube increases from the end in contact with the valve core toward the end in contact with the protective cover, and the outer wall of the air guide tube is used to guide the gas to diffuse toward the mesh holes; a limiting groove is provided on the pressure relief chamber, the ball is arranged in the limiting groove, a flange ring is provided on the outer side of the valve core, and the ball fits with the flange ring.

[0010] In one of the embodiments, the waterproof breathable valve further includes a limiting ring, which is located at the opening side of the pressure relief chamber and is used to abut against the flange ring.

[0011] In one embodiment, the diameter of the flame retardant ball is larger than the diameter of the mesh.

[0012] In one embodiment, a plurality of blades are provided on the outer wall of the protective cover, and the blades include a windshield and a spoiler. The extension direction of the windshield is parallel to the axis of the wind chime shell, and the spoiler is used to connect the windshield and the protective cover.

[0013] In one of the embodiments, a plurality of the pressure relief holes are provided, and the plurality of the pressure relief holes are distributed in a circular array with the axis of the valve core as the center.

[0014] In one of the embodiments, the through hole is arranged toward the pressure relief hole.

[0015] In one of the embodiments, the cross-section of the spring piece is in a "Z" shape, and the spring piece includes a fixed portion, a transition portion and a bent portion, the fixed portion is connected to the valve core, the transition portion is in contact with the hole wall of the pressure relief hole, the bent portion blocks the pressure relief hole, and a protrusion that abuts against the bent portion is provided on the inner wall of the pressure relief hole.

[0016] In one embodiment, the bending portion is made of memory metal.

[0017] The above energy storage system that effectively copes with thermal runaway of battery packs has the following advantages:

[0018] 1. The spring piece blocks the pressure relief hole to keep it in a normally closed state. When the battery pack is in thermal runaway, the rising air pressure drives the spring piece to bend, and the pressure can be quickly released through the pressure relief hole to balance the pressure difference inside and outside the battery pack, reduce the probability of battery pack fire, and improve safety;

[0019] 2. When exhausting through the pressure relief hole, the air flow will be ejected from the sound window on the wind hood and produce an alarm sound, which can alert people inside and outside the vehicle, let the driver know when to get off the vehicle to avoid danger, and keep pedestrians away from the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 A schematic diagram of the structure of an energy storage system that effectively copes with thermal runaway of a battery pack;

[0022] Figure 2 It is a partial cross-sectional view of the waterproof breathable valve;

[0023] Figure 3 This is a schematic diagram of the disassembly of the waterproof breathable valve;

[0024] Figure 4 This is a view of the internal structure of the waterproof breathable valve during normal ventilation;

[0025] Figure 5 This is a view of the internal structure of the waterproof breathable valve in the thermal runaway state;

[0026] Figure 6 is a cross-sectional schematic diagram of a valve body;

[0027] Figure 7 This is a schematic diagram of the state where the shrapnel blocks the pressure relief hole;

[0028] Figure 8 This is a schematic diagram of the coordination between the spring piece and the pressure relief hole after the pressure relief hole is opened;

[0029] Figure numerals: 10. Energy storage system for effectively coping with thermal runaway of battery pack; 11. Battery cell; 12. Battery box; 13. Waterproof breathable valve; 100. Valve body; 110. Air inlet cavity; 120. Pressure relief chamber; 121. Limiting groove; 130. Through hole; 200. Valve core; 210. Ventilation hole; 220. Pressure relief hole; 221. Protrusion; 230. Shrapnel; 231. Fixing part; 232. Transition part; 233. Bending part; 240. Flange ring; 250. Limiting ring; 300. Wind chime shell; 310. Sound window; 400. Breathable membrane; 500. Sealing ring; 600. Protective cover; 610. Mesh; 620. Blade; 621. Wind deflector; 622. Spoiler; 700. Air guide cylinder; 800. Ball; 900. Flame retardant ball; 1. Cooling chamber; DETAILED DESCRIPTION

[0030] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. The preferred embodiments of the present invention are given in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly understood.

[0031] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0033] See also Figure 1 The present invention provides an energy storage system 10 for effectively coping with thermal runaway of a battery pack, comprising: a battery cell 11, a battery box 12 and a waterproof air valve 13 arranged at the bottom of the battery box 12.

[0034] See also Figure 2 and Figure 3The waterproof breathable valve 13 includes a valve body 100, a valve core 200, a wind chime shell 300, a breathable membrane 400 and a sealing ring 500. The valve body 100 is provided with an air inlet cavity 110, a pressure relief chamber 120 and a through hole 130. The through hole 130 is used to connect the air inlet cavity 110 and the pressure relief chamber 120. The valve core 200 is located in the pressure relief chamber 120. The valve core 200 is provided with a ventilation hole 210 and a pressure relief hole 220. The breathable membrane 400 covers the ventilation hole 210. A spring 230 is provided at the position of the pressure relief hole 220. The spring 230 is used to block the pressure relief hole 220.

[0035] See also Figure 2 and Figure 4 The wind chime housing 300 covers the valve core 200 , and a sound window 310 is provided on the side of the wind chime housing 300 .

[0036] See also Figure 1 When fixing the waterproof breathable valve 13, a mounting hole is opened at the bottom of the battery box 12, the valve body 100 is passed through the mounting hole and locked with a nut, and the sealing ring 500 is set at the contact position between the valve body 100 and the battery box 12, and the sealing ring 500 is used for sealing.

[0037] The gas generated by the battery cell 11 during the charge and discharge process will increase the air pressure in the battery box 12. At this time, the gas in the battery box 12 enters the air inlet chamber 110 and enters the pressure relief chamber 120 through the through hole 130. These gases are discharged after passing through the valve core 200. The valve core 200 is provided with a ventilation hole 210 and a pressure relief hole 220. Since the spring sheet 230 blocks the pressure relief hole 220, the air pressure in the battery box 12 is not enough to push open the spring sheet 230. The gas passes through the ventilation hole 210 and the breathable membrane 400 before being discharged. The breathable membrane 400 acts as a barrier to prevent external water vapor from entering the battery box 12 through the valve body 100, and allows the gas in the battery box 12 to be discharged, thereby maintaining the air pressure in the battery box 12 stable and reducing the probability of failure of the battery cell 11.

[0038] When the battery pack is abnormal, the pressure and temperature in the battery box 12 will rise sharply. If the air pressure in the battery box 12 is greater than the elasticity of the spring 230 itself, the spring 230 will bend and the pressure relief hole 220 will open. At this time, the waterproof air valve 13 passes through the pressure relief hole 220 and is finally discharged from the sound window 31. Since there is no air permeable membrane 400 to block the pressure relief hole 220, the gas can be discharged faster, achieving the purpose of pressure relief and explosion prevention. After the air pressure in the battery box 12 drops, the spring 230 can recover and re-seal the pressure relief hole 220 under the action of its own elastic force.

[0039] Similarly, when the battery pack is in thermal runaway, the pressure in the battery box 12 will also rise sharply. In this state, the air pressure in the battery box is higher and lasts longer, and may even be accompanied by the combustion of the battery cell 11. At this time, the spring 230 is also bent and the pressure relief hole 220 is opened to discharge the high-temperature gas. Due to the fast flow rate of the discharged gas, a vortex is formed when passing through the sound window 31 to vibrate the air and produce a sound. The sound can alert people inside and outside the vehicle, thereby reminding the driver to get off the vehicle to avoid danger, keep pedestrians away from danger, and improve the safety of new energy vehicles.

[0040] It should be noted that thermal runaway of the battery pack is the biggest cause of spontaneous combustion of new energy vehicles. The design of the power battery system of existing national standard new energy vehicles needs to ensure that in the case of a fire caused by thermal runaway, the intermediate interval time is at least 5 minutes, providing enough time for the driver and passengers to escape the vehicle. When the battery pack is thermally runaway and catches fire, the smoke generated will first be discharged through the waterproof breathable valve 13. The smoke spreads into the car and affects the vision of the people in the car, causing coughing, and hindering them from escaping the car. On the other hand, although the battery system will sound an alarm in the car to remind the people in the car when thermal runaway occurs, pedestrians and vehicles outside the car cannot know the situation inside the car at this time, and can only judge by the smoke generated during combustion, that is, the existing alarm system lacks warnings to people outside the car.

[0041] See also Figure 3 and Figure 4 In order to solve the above problems, the waterproof breathable valve 13 also includes a protective cover 600, an air guide tube 700, a plurality of balls 800 and a plurality of flame-retardant balls 900. The protective cover 600 is arranged on the valve core 200. The protective cover 600 is funnel-shaped. The diameter of the protective cover 600 decreases from the end connected to the valve core 200 to the end away from the valve core 200. The protective cover 600 and the valve core 200 together form a cooling chamber 1. The pressure relief hole 220 is used to connect the pressure relief chamber 120 and the cooling chamber 1. The protective cover 600 is provided with a plurality of mesh holes 610 connected to the cooling chamber 1. The flame-retardant balls 900 are located in the cooling chamber 1. Since the waterproof breathable valve 13 is arranged at the bottom of the battery box 12, the flame-retardant balls 900 are accumulated on the lower side of the cooling chamber 1 in a static state. Figure 4 As shown. In the present invention, the flame retardant balls 900 do not need to fill the cooling chamber 1. If the flame retardant balls 900 fill the cooling chamber 1, it will cause difficulties in normal pressure relief. Some flame retardant balls 900 are loaded at the bottom of the cooling chamber 1. Once thermal runaway occurs, the valve core 200 and the protective cover 600 rotate together, and the flame retardant balls 900 are driven to rise and lay on the inner wall of the protective cover 600 under the action of centrifugal force, achieving better flame retardant, smoke-proof and heat-absorbing effects. The flame retardant balls 900 can absorb the smoke escaping from the battery box 12 and reduce the speed of the flame spreading outward from the waterproof breathable valve 13, so as to buy more time for the people in the car to avoid danger.

[0042] See also Figure 4The two ends of the air guide cylinder 700 are respectively against the protective cover 600 and the valve core 200, and the diameter of the air guide cylinder 700 increases from the end in contact with the valve core 200 toward the end in contact with the protective cover 600. The outer wall of the air guide cylinder 700 is used to guide the gas to diffuse toward the mesh 610; the cross-sectional shape of the air guide cylinder 700 is opposite to that of the protective cover 600, being narrow at the top and wide at the bottom. When the gas enters the cooling chamber 1, it will diffuse in a direction away from the center of the cooling chamber 1 under the guidance of the outer wall of the air guide cylinder 700, guiding the gas to move toward the mesh 610.

[0043] See also Figure 4 , a limiting groove 121 is provided on the pressure relief chamber 120, a ball 800 is arranged in the limiting groove 121, a flange ring 240 is provided on the outer side of the valve core 200, and the ball 800 fits with the flange ring 240. In one embodiment, the waterproof breathable valve 13 also includes a limiting ring 250, the limiting ring 250 is located on the opening side of the pressure relief chamber 120, and the limiting ring 250 is used to abut against the flange ring 240. The valve core 200 is rotatably arranged in the pressure relief chamber 120, and the ball 800 makes the rotation process of the valve core 200 smoother. The power driving the valve core 200 to rotate is the airflow passing through the pressure relief hole 220 during thermal runaway, as follows:

[0044] See also Figure 4 There are multiple pressure relief holes 220, and the multiple pressure relief holes 220 are distributed in a circular array with the axis of the valve core 200 as the center. The through hole 130 is arranged toward the pressure relief hole 220. The gas entering from the through hole 130 directly faces the pressure relief hole 220, making it easier for the gas to squeeze the spring piece 230 to release pressure.

[0045] See also Figure 7 and Figure 8 The cross section of the spring piece 230 is in a "Z" shape. The spring piece 230 includes a fixed portion 231, a transition portion 232 and a bent portion 233. The fixed portion 231 is connected to the valve core 200, the transition portion 232 is in contact with the hole wall of the pressure relief hole 220, and the bent portion 233 blocks the pressure relief hole 220. A protrusion 221 that abuts against the bent portion 233 is provided on the inner wall of the pressure relief hole 220. The high-pressure gas generated during thermal runaway will drive the bent portion 233 to stretch to open the pressure relief hole 220, and the stretched bent portion 233 is parallel to the transition portion 232. At this time, the gas flows in the direction of Figure 8 As shown by the arrow, the curved portion 233 is obliquely arranged in the pressure relief hole 220. When the gas passes through the pressure relief hole 220, it needs to pass through the curved portion 233 and generate a radial component of force. There are multiple pressure relief holes 220, and the multiple pressure relief holes 220 are distributed in a circular array with the axis of the valve core 200 as the center. The radial component of force exerted on the curved portion 233 by the gas passing through the pressure relief hole 220 can push the valve core 200 to rotate.

[0046] Preferably, the material of the curved portion 233 is memory metal. The gas discharged when the battery pack is thermally runaway is high-temperature gas, which can heat up the curved portion 233 when in contact with the spring 230, thereby driving the curved portion 233 to deform. In this way, when the temperature of the discharged gas causes the curved portion 233 to heat up, the pressure relief hole 220 can also be opened to relieve pressure.

[0047] The above structure works as follows:

[0048] See also Figure 4 When the battery pack is in normal working condition, the gas generated by the battery cell 11 during the charging and discharging process enters the pressure relief chamber 120 through the air inlet cavity 110. At this time, the air pressure in the battery box 12 is not enough to drive the spring 230 to bend. The gas will enter the ventilation hole 210, be filtered through the breathable membrane 400, and then be discharged from the inner cavity of the air guide tube 700.

[0049] See also Figure 5 When the battery pack has a thermal runaway problem, the air pressure in the battery box 12 is abnormal, and the spring sheet 230 is bent. The shape of the spring sheet 230 is changed from Figure 7 The status changes to Figure 8 In the state shown, the gas in the pressure relief chamber 120 enters the cooling chamber 1 from the pressure relief hole 220, passes through the mesh 610, and is discharged from the sound window 31 of the wind chime shell 300.

[0050] Among them, the impact of the air flow passing through the pressure relief hole 220 acts on the spring 230 and then generates a radial component force to drive the valve core 200 to rotate. The valve core 200 rotates together with the protective cover 600. The centrifugal force generated during the rotation process causes the flame retardant ball 900 to roll and spread on the inner wall of the protective cover 600, forming a protective layer on the protective cover 600. In this way, when the gas is discharged from the cooling room 1, it needs to pass through the protective layer formed by the flame retardant ball 900 first. The flame retardant ball 900 is made of flame retardant materials (such as magnesium hydroxide, phosphorus compounds, etc.). The flame retardant ball 900 can absorb heat in the high-temperature gas and reduce the temperature of the discharged gas. The protective layer formed by the flame retardant ball 900 can preliminarily filter out harmful smoke particles carried in the gas, which can reduce the diffusion rate of the smoke, prevent the smoke from blocking the line of sight of people in the car, and buy them time to evacuate.

[0051] See also Figure 4 and Figure 5 Preferably, the diameter of the flame retardant ball 900 is larger than the diameter of the mesh 610 , so as to prevent the flame retardant ball 900 from escaping from the mesh 610 .

[0052] See also Figure 3 and Figure 4In one embodiment, a plurality of blades 620 are provided on the outer wall of the protective cover 600. The blades 620 include a windshield 621 and a spoiler 622. The extension direction of the windshield 621 is parallel to the axis of the wind chime shell 300. The spoiler 622 is used to connect the windshield 621 and the protective cover 600. When the protective cover 600 rotates with the valve core 200, the spoiler 622 fans the gas in the wind chime shell 300 to accelerate it and discharge it from the sound window 31. When the accelerated gas passes through the windshield 621, friction is generated. The vibration generated by the friction causes the surrounding air to vibrate rapidly, forming vibrating air waves. These vibrating air waves are alarm sounds, which remind people inside and outside the car to stay away from the car to avoid danger.

[0053] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. An energy storage system that effectively copes with thermal runaway of a battery pack, characterized in that: include: A battery cell, a battery box, and a waterproof vent valve disposed at the bottom of the battery box; The waterproof breathable valve comprises a valve body, a valve core, a wind chime shell, a breathable membrane and a sealing ring. The valve body is provided with an air inlet cavity, a pressure relief chamber and a through hole. The through hole is used to connect the air inlet cavity and the pressure relief chamber. The valve core is located in the pressure relief chamber. The valve core is provided with a ventilation hole and a pressure relief hole. The breathable membrane covers the ventilation hole. A spring is provided at the location of the pressure relief hole. The spring is used to block the pressure relief hole. The wind chime shell is covered on the valve core, and a sound window is provided on the side of the wind chime shell; The waterproof breathable valve also includes a protective cover, an air guide tube, a plurality of ball bearings and a plurality of flame retardant balls. The protective cover is arranged on the valve core and is funnel-shaped. The diameter of the protective cover decreases from the end connected to the valve core toward the end away from the valve core. The protective cover and the valve core together form a cooling chamber. The pressure relief hole is used to connect the pressure relief chamber and the cooling chamber. The protective cover is provided with a plurality of mesh holes connected to the cooling chamber. The flame retardant balls are located in the cooling chamber. The two ends of the air guide tube are respectively against the protective cover and the valve core. , and the diameter of the air guide cylinder increases gradually from the end in contact with the valve core toward the end in contact with the protective cover, and the outer wall of the air guide cylinder is used to guide the gas to diffuse toward the mesh; a limiting groove is provided on the pressure relief chamber, and the ball is arranged in the limiting groove, and a flange ring is provided on the outer side of the valve core, and the ball is fitted with the flange ring; a plurality of blades are provided on the outer wall of the protective cover, and the blades include a wind shield and a spoiler, the extension direction of the wind shield is parallel to the axis of the wind shell, and the spoiler is used to connect the wind shield and the protective cover.

2. The energy storage system for effectively coping with thermal runaway of a battery pack according to claim 1, characterized in that: The waterproof breathable valve further comprises a limiting ring, which is located at the opening side of the pressure relief chamber and is used for abutting against the flange ring.

3. The energy storage system for effectively coping with thermal runaway of a battery pack according to claim 1, characterized in that: The diameter of the flame retardant ball is greater than the diameter of the mesh.

4. The energy storage system for effectively coping with thermal runaway of a battery pack according to claim 1, characterized in that: There are a plurality of pressure relief holes, and the plurality of pressure relief holes are distributed in a circular array with the axis of the valve core as the center.

5. The energy storage system for effectively coping with thermal runaway of a battery pack according to claim 1, characterized in that: The through hole is arranged toward the pressure relief hole.

6. The energy storage system for effectively coping with thermal runaway of a battery pack according to claim 1, characterized in that: The cross section of the spring piece is in a "Z" shape. The spring piece includes a fixed portion, a transition portion and a bent portion. The fixed portion is connected to the valve core, the transition portion is in contact with the hole wall of the pressure relief hole, the bent portion blocks the pressure relief hole, and a protrusion that abuts against the bent portion is provided on the inner wall of the pressure relief hole.

7. The energy storage system for effectively coping with thermal runaway of a battery pack according to claim 6, characterized in that: The material of the bending portion is memory metal.

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