Battery pack

Abstract

This utility model discloses a battery pack, including a battery housing. The battery housing includes a bottom plate and side plates. A pressure relief valve is provided on the side plates. A fire extinguishing element and a blocking element are provided on the side of the pressure relief valve near the inner cavity of the battery housing. The fire extinguishing element is located on the side of the blocking element near the pressure relief valve. The fire extinguishing element has multiple first through holes for flame arrest, and the blocking element has multiple second through holes for blocking particles in the airflow. This utility model's battery pack effectively prevents flames from flammable gas combustion from erupting from the pressure relief location during battery thermal runaway, reducing the safety risk of the battery pack.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a battery pack. Background Technology

[0002] The power battery pack is an energy storage and supply device for new energy vehicles. The battery pack includes a battery box and multiple battery cells set inside the box. The battery cells are lithium batteries. During use, especially during overcharging, over-discharging, compression and puncture, thermal runaway is likely to occur. Battery thermal runaway is accompanied by the release of a large amount of gas and heat. In order to prevent the closed battery box from being subjected to too much pressure and exploding, a pressure relief valve needs to be installed on the battery box to actively relieve pressure.

[0003] When a battery experiences thermal runaway, it releases various gases at very high temperatures. Some of these gases are flammable and can easily ignite when ejected from the pressure relief valve at high temperatures, posing a safety risk. Utility Model Content

[0004] In view of this, the present invention provides a battery pack that effectively prevents flames from flammable gas combustion from being ejected from the pressure relief position during battery thermal runaway, thereby reducing safety risks.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A battery pack includes a battery housing, the battery housing including a bottom plate and a side plate, a pressure relief valve being provided on the side plate, a fire extinguishing element and a blocking element being provided on the side of the pressure relief valve near the inner cavity of the battery housing, the fire extinguishing element being provided on the side of the blocking element near the pressure relief valve; the fire extinguishing element having a plurality of first through holes for fire blocking, and the blocking element having a plurality of second through holes for blocking particles in the airflow.

[0007] As can be seen from the above technical solution, the battery pack provided by this utility model, by setting a blocking component to block larger solid impurities in the thermal runaway airflow, and the second through hole to provide a flow channel for airflow, can initially prevent the flame of high-temperature gas combustion; further, a fire extinguishing component is set, and a first through hole is set on the fire extinguishing component to prevent the flame of high-temperature gas combustion from being ejected, thereby preventing the flame of flammable gas combustion from being ejected from the pressure relief valve when the battery is thermally runaway, avoiding the flame from being ejected from the battery pack and igniting other parts, and reducing the safety risk. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 A schematic diagram of the battery pack from one angle provided in an embodiment of this utility model;

[0010] Figure 2 This is a structural schematic diagram of the battery pack provided in an embodiment of the present invention from another angle;

[0011] Figure 3 A cross-sectional view of the AA position of a battery pack according to an embodiment of the present invention;

[0012] Figure 4 A cross-sectional view of the AA position of the battery pack provided in another embodiment of the present invention;

[0013] Figure 5 for Figure 4 A partially enlarged structural diagram of part B in the diagram;

[0014] Figure 6 This is a structural schematic diagram showing the positions of the fire extinguishing component and the blocking component according to an embodiment of the present invention;

[0015] Figure 7 This is a structural schematic diagram showing the positions of the fire extinguishing component and the blocking component according to another embodiment of the present invention;

[0016] Figure 8 A schematic diagram of a two-layered blocking member provided in an embodiment of this utility model;

[0017] Figure 9 for Figure 8 Another structural diagram from another angle.

[0018] in:

[0019] 1. Battery housing; 101. Side panel of housing; 102. Cover of housing; 103. Bottom plate; 2. Pressure relief valve; 201. Pressure relief surface; 3. Connecting port; 4. Exhaust channel; 5. Air chamber; 6. Electrical compartment; 7. Battery cell; 8. Fire extinguishing device; 801. First through hole; 9. Blocking device; 901. Second through hole; 10. Partition plate; 11. Rotating shaft. Detailed Implementation

[0020] This utility model discloses a battery pack that effectively prevents flames from flammable gas combustion from being ejected from the pressure relief position during battery thermal runaway, thereby reducing the safety risks of the battery pack.

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] See Figures 1 to 6 The battery pack of this utility model includes a battery box 1, which includes a bottom plate 103 and a side plate 101. The bottom plate 103 and the side plate 101 form a cavity with a bottom seal and a top opening for placing individual battery cells 7. The top opening of the cavity is connected to a box cover plate 102. A pressure relief valve 2 is provided on the side plate 101. A fire extinguishing element 8 and a blocking element 9 are provided on the side of the pressure relief valve 2 near the inner cavity of the battery box 1. The fire extinguishing element 8 is located on the side of the blocking element 9 near the pressure relief valve 2. The fire extinguishing element 8 has multiple first through holes 801 for fire prevention, and the blocking element 9 has multiple second through holes 901 for blocking particles in the airflow.

[0023] The base plate 103 is equipped with an exhaust channel 4, which is connected to the explosion-proof valve of the battery cell 7. When the battery cell 7 experiences thermal runaway, the high-temperature gas inside flows into the exhaust channel 4 through the explosion-proof valve. The airflow in the exhaust channel 4 flows sequentially through the second through-hole 901 and the first through-hole 801 to the pressure relief valve 2, where the high-temperature gas is released. During thermal runaway, the high-temperature gas can easily melt components such as electrodes, generating particles and other impurities. To prevent solid impurities from clogging the first through-hole 801 on the fire extinguishing element 8, a blocking element 9 is installed upstream of the fire extinguishing element 8 to block solid impurities. The blocking element 9 has a second through-hole 901 for airflow passage. The first through-hole 801 is a narrow channel, and its wall effect prevents flame propagation. Free radicals in the airflow frequently collide with and are absorbed by the pore wall of the first through-hole 801, reducing the number of free radicals and their kinetic energy, thus preventing the combustion reaction of the high-temperature gas from continuing. The smaller the size of the first through hole 801, the more dominant the collision between free radicals and the container wall, resulting in a more significant flame extinguishing effect. The upstream of the fire extinguishing component 8 is the side closest to the battery cell 7. The blocking component 9 is used to block the aluminum foil, copper foil, separator, or metal components inside the battery from melting at high temperatures. The retainer will also melt, generating small particles. When the battery pack explodes, these particles will rush towards the pressure relief valve 2 with the gas. These particles can easily clog the first through hole 801, preventing the fire extinguishing component 8 from venting. By setting the blocking component 9, the service life of the fire extinguishing component 8 is extended. Multiple second through holes 901 are evenly distributed on the blocking component 9, and multiple first through holes 801 are evenly distributed on the fire extinguishing component 8.

[0024] The battery pack of this invention features a blocking component 9 to block larger solid impurities in the thermal runaway airflow, and a second through hole 901 to provide a flow channel for airflow and to initially prevent the flame of high-temperature gas combustion. Furthermore, a fire extinguishing component 8 is provided, with a first through hole 801 to prevent the flame of high-temperature gas combustion from being ejected. This prevents the flame of flammable gas combustion from being ejected from the pressure relief valve 2 during battery thermal runaway, avoiding the flame from igniting other parts of the battery pack and reducing safety risks.

[0025] Understandably, to achieve the flame-retardant purpose of the first through-hole 801, its size is smaller than that of the second through-hole 901. Specifically, the size of the first through-hole 801 is no greater than the MESG value. The MESG value, or Maximum Test Safe Clearance, is an important parameter used to evaluate the explosion-proof performance of electrical equipment in environments containing flammable gases. It is the channel size that can extinguish a flame under specific conditions (typically 0.1 MPa pressure and 20°C temperature). When the battery cell 7 experiences thermal runaway, a mixture of various gases is generated. The MESG value can be taken as the value of the gas component with the lowest MESG value in the mixture, serving as the basis for the size of the first through-hole 801. The MESG value can also be obtained using the following formula: Where Xi is the volume fraction of the component, MESGi is the MESG value of each component, and the MESG of the gas mixture is finally calculated. mix The value is used as a reference to the calculated MESG value to match the corresponding hole size of the fire extinguishing component 8.

[0026] In one embodiment, both the first through hole 801 and the second through hole 901 are circular holes, and the diameter of the first through hole 801 is smaller than the diameter of the second through hole 901. In another embodiment, both the first through hole 801 and the second through hole 901 are polygonal holes, and the diameter of the circumcircle of the cross-section of the first through hole 801 is smaller than the diameter of the circumcircle of the cross-section of the second through hole 901. In a third embodiment, the first through hole 801 is a circular hole, and the second through hole 901 is a polygonal hole, and the diameter of the circular hole is smaller than the diameter of the circumcircle of the cross-section of the second through hole 901. In a fourth embodiment, the first through hole 801 is a polygonal hole, and the second through hole 901 is a circular hole, and the diameter of the circular hole is larger than the diameter of the circumcircle of the cross-section of the first through hole 801.

[0027] Specifically, the fire extinguishing device 8 is located inside the battery pack, that is, inside the battery housing 1, as shown in the reference. Figure 5 or Figure 6 As shown, the blocking element 9 is also located inside the battery housing 1. By placing the fire extinguishing element 8 inside the battery pack, it can extinguish the fire within the battery, enabling timely fire suppression. Alternatively, the fire extinguishing element 8 can be located outside the battery pack, i.e., outside the battery housing 1, as shown in the reference diagram. Figure 7 As shown, the blocking element 9 is also located inside the battery housing 1. By placing the fire extinguishing element 8 on the outside of the battery pack, the path of the thermal runaway airflow is longer, the temperature on the outside of the battery pack is lower, and the temperature of the gas flowing to the location of the fire extinguishing element 8 is lower, resulting in a better fire extinguishing effect.

[0028] In one embodiment, the fire extinguishing element 8 is provided with a layer, and the fire extinguishing element 8 is arranged parallel to the pressure relief surface 201 of the pressure relief valve 2, such as... Figure 6As shown, the distance between the fire extinguishing element 8 and the pressure relief surface 201 of the pressure relief valve 2 is the first distance d1, which is 5mm to 50mm. Specifically, when the fire extinguishing element 8 is installed in one layer, the value of the first distance d1 can be any value among 5mm, 15mm, 25mm, 35mm, 45mm, and 50mm, or a value between any two values. Although the fire extinguishing element 8 is provided with a first through hole 801, the hole is relatively small, and the position of the fire extinguishing element 8 will have a certain obstruction effect on the gas, thus affecting the pressure relief. Therefore, the first distance d1 needs to be limited. If the first distance d1 is too large, that is, the fire extinguishing element 8 is too far from the pressure relief valve 2, it will occupy part of the unobstructed gas storage space inside the battery pack, reducing the gas storage space inside the battery pack. During thermal runaway, the gas pressure in the gas storage space will increase more rapidly, the venting effect at the location of the fire extinguishing element 8 will be poor, and the high-pressure gas inside the battery pack will be more likely to explode at the bottom plate 103, resulting in a more violent explosion. If the distance d1 is too small, meaning that the fire extinguishing device 8 is too close to the pressure relief valve 2, there will be a problem with timely fire extinguishing and it will also be difficult for the pressure relief valve 2 to open.

[0029] To improve the fire extinguishing effect, the fire extinguishing element 8 is provided in multiple layers. In this embodiment, in the multi-layer fire extinguishing element 8, at least one layer close to the pressure relief valve 2 is arranged parallel to the pressure relief surface 201 of the pressure relief valve 2, and the layer close to the pressure relief valve 2 is spaced from the pressure relief surface 201 of the pressure relief valve 2 by a first distance d1, which is 3mm to 45mm. The fire extinguishing effect is better when the fire extinguishing element 8 is multi-layered than when it is single-layered. Therefore, the probability of open flame at the pressure relief valve 2 position is greatly reduced. Thus, when the fire extinguishing element 8 is multi-layered, the first distance d1 can be set to a smaller value. Specifically, when the fire extinguishing element 8 is multi-layered, the value of the first distance d1 can be any value among 3mm, 10mm, 20mm, 30mm, 45mm, etc., or a value between any two values.

[0030] Specifically, the blocking element 9 can be provided in one layer, and the blocking element 9 is arranged parallel to the fire extinguishing element 8, with a second distance d2 between the blocking element 9 and the fire extinguishing element 8. The second distance d2 is 2mm to 30mm. Specifically, the value of the second distance d2 can be any value among 2mm, 10mm, 20mm, 30mm, etc., or a value between any two values. Setting the second distance d2 within the above range can ensure timely pressure relief and extend the service life of the blocking element 9. If the second distance d2 is too small, the blocking element 9 and the fire extinguishing element 8 will be too close. Since the positions of the through holes on the blocking element 9 and the fire extinguishing element 8 are not in a one-to-one correspondence, the airflow between the blocking element 9 and the fire extinguishing element 8 needs sufficient space to flow up and down to be discharged more quickly. If the blocking element 9 and the fire extinguishing element 8 are too close, the space between them will be too small, which will increase the resistance to airflow discharge, and the gas discharge effect between the blocking element 9 and the fire extinguishing element 8 will be worse, affecting timely pressure relief. If the second distance d2 is too large, then the position of the blocking component 9 will be closer to the battery compartment containing the battery cell 7. The blocking component 9 will be more affected by the high temperature airflow, and the blocking component 9 will be more prone to heat deformation, affecting the blocking effect.

[0031] Furthermore, in order to improve the blocking effect, such as Figure 8 and Figure 9 The blocking element 9 is provided in multiple layers. Among the multiple layers of blocking elements 9, at least one layer of blocking element 9 closest to the fire extinguishing element 8 is arranged parallel to the fire extinguishing element 8. The layer of blocking element 9 closest to the fire extinguishing element 8 is separated from the fire extinguishing element 8 by a second distance d2, which is 1mm to 25mm. Specifically, the value of the second distance d2 can be any value among 1mm, 10mm, 20mm, 25mm, etc., or a value between any two values.

[0032] Among them, the thickness of fire extinguishing component 8 is a1, such as Figure 6As shown, the thickness a1 ranges from 0.5mm to 25mm. Specifically, the value of thickness a1 can be any value among 0.5mm, 5mm, 10mm, 25mm, etc., or a value between any two values. Using the above-mentioned range for the thickness a1 of the fire extinguishing element 8 ensures the fire extinguishing effect while reducing the impact on pressure relief. A larger thickness a1 in the fire extinguishing element 8 results in a longer length of the first through hole 801 along the thickness direction of the fire extinguishing element 8, leading to a longer path for molecules moving in the gas to collide with the hole wall of the first through hole 801, thus improving the fire extinguishing effect. However, this also increases the impact on pressure relief, increasing exhaust resistance. A smaller thickness a1 in the fire extinguishing element 8, while reducing the impact on airflow pressure relief, also affects the fire extinguishing effect. The thickness a2 of the blocking element 9 is 0.5mm to 10mm. Specifically, the value of thickness a2 can be any value among 0.5mm, 3mm, 6mm, 10mm, etc., or a value between any two values. The thickness a2 of the blocking component 9 is limited within the above range, which can ensure structural strength and minimize the exhaust resistance to airflow, thus avoiding affecting the pressure relief.

[0033] To extend the service life of the barrier component 9 and the extinguishing component 8, both are made of metal mesh. The use of metal material improves the strength of the barrier component 9 and the extinguishing component 8, preventing them from melting when exposed to high-temperature airflow, thus significantly extending their service life.

[0034] In one embodiment, the fire extinguishing element 8 is provided in multiple layers, and the first through hole 801 on different layers of the fire extinguishing element 8 has the same hole size. Similarly, the blocking element 9 is provided in multiple layers, and the second through hole 901 on different layers of the blocking element 9 has the same hole size. In another embodiment, the fire extinguishing element 8 is provided in multiple layers, and the first through hole 801 on different layers of the fire extinguishing element 8 has different hole sizes. Similarly, the blocking element 9 is provided in multiple layers, and the second through hole 901 on different layers of the blocking element 9 has different hole sizes. When the hole sizes of the first through holes 801 on different layers are different, the fire extinguishing elements 8 on different layers are arranged in descending order of the hole size of the first through hole 801, with the fire extinguishing element 8 with the largest hole size of the first through hole 801 placed closer to the blocking element 9, and the fire extinguishing element 8 with the smallest hole size of the first through hole 801 placed closer to the pressure relief valve 2. When the second through holes 901 of different layers have different hole sizes, the blocking members 9 of different layers are arranged in descending order of the hole size of the second through holes 901. The blocking member 9 with the largest hole size of the second through holes 901 is placed near the battery compartment, and the blocking member 9 with the smallest hole size of the second through holes 901 is placed near the fire extinguishing member 8. That is, the hole size of the first through holes 801 on the fire extinguishing member 8 of different layers decreases sequentially along the airflow direction; the hole size of the second through holes 901 on the blocking members 9 of different layers decreases sequentially along the airflow direction.

[0035] In order to reduce the exhaust resistance of the parallel fire extinguishing element 8 and the blocking element 9, the projection area of ​​the fire extinguishing element 8 falls within the projection area of ​​the blocking element 9, that is, the area of ​​the blocking element 9 is larger than the area of ​​the fire extinguishing element 8, thereby reducing the resistance of airflow through the blocking element 9.

[0036] Reference Figures 3 to 5 As shown, the inner cavity of the battery housing 1 is divided into a battery compartment, an air chamber 5, and an electrical compartment 6. The electrical compartment 6 is used to house the electrical components of the battery pack, and the battery compartment is used to house individual battery cells 7. The air chamber 5 is separated from the exhaust channel 4 by a partition 10. The partition 10 is provided with a connecting port 3 that connects the air chamber 5 and the exhaust channel 4. A blocking member 9 may or may not be provided at the connecting port 3. In one embodiment, a blocking member 9 is provided at the connecting port 3. The blocking member 9 may be fixedly connected to the connecting port 3 or rotatably connected to the connecting port 3 via a rotating shaft 11. When the blocking member 9 is connected via the rotating shaft 11, the end of the blocking member 9 away from the rotating shaft 11 overlaps the surface of the partition 10 near the air chamber 5, so that when the air pressure is too high, the airflow can directly reopen the blocking member 9 at this position to release pressure, thereby improving the pressure release efficiency. Another blocking member 9 is provided at the position of the air chamber 5 near the fire extinguishing element 8. Figure 3 and Figure 4 The arrows in the diagram indicate the direction of gas flow.

[0037] The battery pack of this utility model improves the safety performance in the event of thermal runaway by setting fire extinguishing component 8 and blocking component 9.

[0038] In the description of this solution, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this solution, "multiple" means two or more, unless otherwise explicitly specified.

[0039] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0040] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A battery pack comprising a battery case including a bottom plate and a case side plate, the case side plate being provided with a pressure relief valve, characterized by, The pressure relief valve is provided with a fire extinguishing component and a blocking component on the inner cavity side near the battery box. The fire extinguishing component is located on the side of the blocking component near the pressure relief valve. The fire extinguishing component is provided with a plurality of first through holes for fire blocking, and the blocking component is provided with a plurality of second through holes for blocking particles in the airflow.

2. The battery pack of claim 1, wherein, The size of the first through hole is smaller than the size of the second through hole.

3. The battery pack of claim 1 or 2, wherein, Both the first through hole and the second through hole are circular holes, and the diameter of the first through hole is smaller than the diameter of the second through hole; Alternatively, both the first through hole and the second through hole are polygonal holes, and the diameter of the circumcircle of the cross-section of the first through hole is smaller than the diameter of the circumcircle of the cross-section of the second through hole. Alternatively, the first through hole is a circular hole, and the second through hole is a polygonal hole, wherein the diameter of the circular hole is smaller than the diameter of the circumcircle of the cross-section of the second through hole.

4. The battery pack of claim 1, wherein, The fire extinguishing component is located on the inside or outside of the battery pack, and the blocking component is located on the inside of the battery pack.

5. The battery pack of claim 1, wherein, The fire extinguishing device is provided with one layer, and the fire extinguishing device is arranged parallel to the pressure relief surface of the pressure relief valve. The distance between the fire extinguishing device and the pressure relief surface of the pressure relief valve is a first distance d1, which is 5mm to 50mm.

6. The battery pack of claim 1, wherein, The fire extinguishing device is provided in multiple layers. Among the multiple layers of the fire extinguishing device, at least one layer close to the pressure relief valve is arranged parallel to the pressure relief surface of the pressure relief valve. The layer close to the pressure relief valve is spaced from the pressure relief surface of the pressure relief valve by a first distance d1, where the first distance d1 is 3mm to 45mm.

7. The battery pack of claim 1, wherein, The blocking element is provided in one layer, and the blocking element is arranged parallel to the fire extinguishing element. The blocking element and the fire extinguishing element are separated by a second distance d2, which is 2mm to 30mm.

8. The battery pack of claim 1, wherein, The blocking member is provided in multiple layers. Among the multiple layers of the blocking member, at least one layer close to the fire extinguishing member is arranged parallel to the fire extinguishing member. The blocking member close to the fire extinguishing member is spaced from the fire extinguishing member by a second distance d2, where the second distance d2 is 1mm to 25mm.

9. The battery pack of claim 1, wherein, The thickness of the fire extinguishing component is a1, and the thickness a1 ranges from 0.5mm to 25mm. The thickness of the blocking element is a2, and the thickness a2 ranges from 0.5mm to 10mm.

10. The battery pack of claim 1, wherein, Both the fire extinguishing and blocking components are made of metal mesh.

11. The battery pack of claim 1, wherein, The fire extinguishing element has multiple layers, and the first through holes on the fire extinguishing elements of different layers have the same or different hole sizes; the blocking element has multiple layers, and the second through holes on the blocking elements of different layers have the same or different hole sizes.

12. The battery pack of claim 11, wherein, The size of the first through hole on the fire extinguishing components of different layers decreases sequentially along the airflow direction; the size of the second through hole on the blocking components of different layers decreases sequentially along the airflow direction.

13. The battery pack of claim 1, wherein, The fire extinguishing element and the blocking element are arranged in parallel, and the projection of the fire extinguishing element is located within the projection area of ​​the blocking element.

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