Battery module and battery case thereof

Abstract

To provide a battery module including a battery case, a plurality of battery cells, and a fire extinguishing material.SOLUTION: The battery case includes a case body, a lid, and a pressure relief valve. The case body has an accommodation space and an opening. The cover body is disposed on the opening and has a flow channel and a first surface and a second surface opposite to each other, the flow channel is disposed between the first surface and the second surface, the first surface has a first pressure relief hole, the second surface has a second pressure relief hole, and two ends of the flow channel are respectively communicated with the first pressure relief hole and the second pressure relief hole. The pressure relief valve is disposed in the first pressure relief hole. The battery cell is housed in the housing space of the case body. The fire extinguishing material is accommodated in the accommodating space and distributed around the battery cell. The present invention also provides a battery case for a battery module.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an energy storage structure, and more particularly to a secondary battery and a case structure for accommodating the secondary battery. [Background technology]

[0002] As problems such as air pollution and the depletion of oil reserves become apparent, the use of fuel energy is gradually being restricted. The transportation industry, which consumes particularly large amounts of fuel energy, has traditionally used fuel energy as a power source, but with growing awareness of environmental conservation, a trend toward using electricity as a power source is already emerging.

[0003] Among the battery types of power storage devices, lithium batteries have advantages such as light weight, long driving range, high operating voltage, high energy density, long life, and environmental friendliness. Therefore, if lithium batteries are used as an energy storage medium for transportation and supply electricity as energy, the transportation will not only not cause air pollution during operation, but also reduce fuel consumption, thereby achieving the goals of energy conservation and carbon dioxide emission reduction. Therefore, in the transportation industry, more and more major automobile manufacturers are continuously developing vehicle models that use lithium batteries as the main energy storage medium. Due to the advantages of lithium batteries, lithium batteries are not only applicable in the transportation industry, but also widely used in various electronic devices, powered vehicles, and various energy storage systems.

[0004] However, because the interior of a lithium battery is mainly composed of a positive electrode, an electrolyte, a negative electrode, and a separator separating the positive and negative electrodes, the lithium battery contains flammable materials and has a very narrow safe operating temperature range, which means that if the operating temperature of the lithium battery exceeds a critical temperature, thermal runaway will occur.

[0005] Thermal runaway is a phenomenon in which the temperature rises rapidly and uncontrollably due to heat release reactions inside a lithium battery. Possible causes of thermal runaway include dendrites that form on the anode of a lithium battery during repeated charging and discharging, penetrating the separator and causing a short circuit between the cathode and anode; improper design of the lithium battery itself; poor quality separators; or improper use of the lithium battery (overcharging, overdischarging, dropping, external impact, etc.). In the early stages of lithium battery thermal runaway, the separator separating the positive and negative electrodes melts and develops a hole, worsening the internal short circuit. At the same time, more heat is generated inside the lithium battery, accelerating the dissolution of the separator, further worsening the internal short circuit, triggering a more violent chemical reaction and generating large amounts of gas. If the lithium battery's exterior cannot withstand the pressure, it may burst, catch fire, or explode.

[0006] In actual applications, in a lithium battery pack consisting of multiple lithium batteries, problems often occur in only one lithium battery at a time. However, in the pursuit of higher energy density, the lithium batteries in a lithium battery pack are arranged very compactly. Therefore, if a single lithium battery experiences thermal runaway, the generated high temperature is transmitted to the surrounding lithium batteries, causing the separators of the surrounding lithium batteries to rupture, leading to thermal runaway and the spread of fire to the entire lithium battery pack.

[0007] Currently, lithium battery packs consisting of multiple lithium battery cells are equipped with a battery management system (BMS) that monitors the voltage of each lithium battery and prevents abnormal conditions such as over-discharge, over-charge, or overheating.In addition, in the mechanical structural design of individual lithium batteries such as cylindrical lithium batteries, prismatic lithium batteries, or soft-pack lithium batteries, the shell itself is explosion-proof, and when the internal pressure reaches a certain value, the shell breaks to release the internal pressure, preventing the lithium battery from exploding.

[0008] Although the problem of explosion of individual lithium batteries has been solved, thermal runaway causes the chemical reaction of the lithium battery to continue, and the high temperature generated is rapidly transmitted to nearby lithium batteries, causing them to malfunction. Since the lithium battery pack itself is sealed in a case, if the large amount of gas generated by thermal runaway of multiple lithium batteries is not released, it can cause a more violent explosion. In addition, to ensure human safety, various batteries also have safety requirements as long as there is a possibility of combustion or explosion. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Taiwan Patent Application Publication No. 202400271 Summary of the Invention [Means for solving the problem]

[0010] One aspect of the present invention provides a battery case comprising a case body, a lid body, and a pressure relief valve. The case body has an accommodation space and an opening. The lid body is provided in the opening and has a flow path and a first surface and a twentieth surface opposite each other. The flow path is provided between the first surface and the second surface, with a first pressure relief hole in the first surface and a second pressure relief hole in the second surface, and both ends of the flow path are connected to the first pressure relief hole and the second pressure relief hole, respectively. The pressure relief valve is provided in the first pressure relief hole.

[0011] In another aspect of the present invention, there is further provided a battery module including the battery case described above, a plurality of battery cells, and a fire-extinguishing material, the battery cells being accommodated in the accommodation space of the case body, and the fire-extinguishing material being accommodated in the accommodation space and distributed around the battery cells.

[0012] "As a result, when a battery cell explodes due to thermal runaway, the fire-extinguishing material distributed around the battery cell immediately absorbs the electrolyte, preventing the battery cell from continuing to undergo an electrochemical reaction, shortening the duration of the electrochemical reaction and reducing damage to the surrounding area caused by the electrochemical reaction. In addition, the gas generated when a battery cell explodes flows through the flow path and is released through the pressure relief valve after the pressure is reduced, preventing damage or malfunction of the pressure relief valve due to excessive pressure and shortening the time it takes for the fire to spread after a battery module catches fire, buying time for disaster relief and preventing the damage from spreading."

[0013] In the above aspect, the area of ​​the first pressure relief hole may be larger than the area of ​​the second pressure relief hole.

[0014] In the above aspect, the number of the second pressure relief holes may be plural, and the total area of ​​the second pressure relief holes may be 90% to 100% of the area of ​​the first pressure relief holes.

[0015] In addition, in the above aspect, the first surface may extend along a first direction and a second direction perpendicular to the first direction, the flow path may have a plurality of communication portions that communicate with each other, and some of the communication portions may extend along the first direction and some of the communication portions may extend along the second direction.

[0016] In addition, in the above aspect, the lid body may further have a partition wall, and in a third direction perpendicular to the first direction and the second direction, one end of the partition wall may be partially connected to the second surface, and the other end of the partition wall may extend to the first surface.

[0017] In the above aspect, the partition wall may have a plurality of partition surfaces each having a planar structure.

[0018] In the above aspect, the lid may be made of a fire-resistant material.

[0019] In the above aspect, the refractory material may be metal, fireproof plaster, or fireproof fiber material.

[0020] In the above aspect, the fire-resistant fiber material may be made of a carbon fiber material, a glass fiber material, a stone fiber material, or a calcium silicate fiber material.

[0021] In the above aspect, the fire-extinguishing material may be a dry powder fire-extinguishing agent such as sodium bicarbonate, sodium chloride, or potassium chloride.

[0022] In the above aspect, the battery module may further include a filter provided in the pressure relief valve. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a three-dimensional external view of a battery module according to an embodiment of the present invention; [Figure 2] 1 is an exploded view of a three-dimensional structure of a battery module according to an embodiment of the present invention. [Figure 3] 2 is a schematic diagram of a lid of a battery module according to one embodiment of the present invention. FIG. [Figure 4] FIG. 2 is a schematic plan view of a lid of a battery module according to one embodiment of the present invention. [Figure 5] 1 is a three-dimensional cross-sectional view of a partial structure of a battery module of the present invention. [Figure 6] FIG. 6 is a plan view of a partial structure of FIG. 5. [Figure 7] FIG. 10 is a first simulation diagram of the flow path pressure in the lid of the battery module of the present invention. [Figure 8] FIG. 10 is a second simulation diagram of the flow path pressure in the lid of the battery module of the present invention. [Figure 9] FIG. 10 is a schematic plan view of a lid of a battery module according to another embodiment of the present invention. [Figure 10] FIG. 10 is an exploded view of the three-dimensional structure of a battery module according to a further embodiment of the present invention. [Figure 11] 10 is a partial schematic view of a lid of a battery module according to a further embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0024] Referring to Figures 1 to 4, Figure 1 is a three-dimensional external view of a battery module according to one embodiment of the present invention, Figure 2 is an exploded view of the three-dimensional structure of a battery module according to one embodiment of the present invention, Figure 3 is a schematic diagram of a lid body of a battery module according to one embodiment of the present invention, and Figure 4 is a schematic plan view of a lid body of a battery module according to one embodiment of the present invention. The present invention provides a battery module and a battery case therefor. The battery module includes a battery case H, a battery cell B, and a fire-extinguishing material E. The battery cell B and fire extinguishing material E are contained within the storage space 11 of the battery case H. A pressure relief valve 30 is provided on the lid 20 of the battery case H, and a flow path P is designed inside the battery case H to connect the storage space 11 to the outside. When the battery cell B explodes, the flow path P is designed to guide the gas generated by the explosion to be discharged to the outside along the flow path P, and the gas pressure continues to decrease as it flows through the flow path P, preventing the pressure relief valve 30 from being directly damaged or broken down by excessive pressure.

[0025] 1 to 4, a battery case H includes a case body 10, a lid body 20, and a pressure relief valve 30. The case body 10 has an accommodation space 11 and an opening 12. The lid body 20 is provided at the opening 12 and has a flow path P and a first surface 211 and a second surface 221 that are opposite each other. The flow path P is provided between the first surface 211 and the second surface 221. The first surface 211 has a first pressure relief hole 2111, and the second surface 221 has a second pressure relief hole 2211. Both ends of the flow path P are in communication with the first pressure relief hole 2111 and the second pressure relief hole 2211, respectively. The pressure relief valve 30 is provided at the first pressure relief hole 2111.

[0026] As a result, immediately after battery cell B explodes due to thermal runaway, the fire extinguishing material E distributed around battery cell B immediately absorbs the electrolyte, preventing battery cell B from continuing to generate an electrochemical reaction, shortening the duration of the electrochemical reaction and reducing damage to the surrounding area caused by the electrochemical reaction. In addition, the gas generated when battery cell B explodes flows through flow path P and is discharged from pressure relief valve 30 after the pressure is reduced, preventing damage or malfunction of pressure relief valve 30 due to excessive pressure, shortening the time for the fire to spread after the battery module burns, buying time for disaster relief and preventing the damage from expanding.

[0027] Please refer to FIG. 2 in conjunction with FIGS. 5 and 6. FIG. 5 is a three-dimensional cross-sectional view of a partial structure of a battery module of the present invention, and FIG. 6 is a plan view of the partial structure of FIG. 5. The storage space 11 of the case body 10 is used to store battery cells B. In some embodiments, the case body 10 is a hollow rectangular parallelepiped with one side open, but the present invention is not limited thereto. In other embodiments, the shape of the case body 10 may be determined depending on the number of battery cells B to be stored or the shape of the application environment.

[0028] 2 and 5, each battery cell B has a cylindrical battery can structure, such as, but not limited to, an 18650 lithium battery (a cylindrical battery with a diameter of 18 mm and a length of 65 mm). In some embodiments, multiple battery cells B may be connected in parallel or series and arranged in a matrix-like battery module. In some embodiments, the battery cells B are not limited to lithium battery cells B. In other embodiments, the battery case H of the present invention is applicable to various battery cells B that may explode or catch fire.

[0029] 2 to 6, the cover 20 is provided at the opening 12 of the case body 10. In some embodiments, the cover 20 has a first member 21 and a second member 22, and the first member 21 and the second member 22 define a flow path P. In these embodiments, the first member 21 has a first surface 211 and a circumferential surface 212, and one end of the circumferential surface 212 is connected to the periphery of the first surface 211 and is not coplanar with the first surface 211. In some embodiments in which the case body 10 is a hollow rectangular parallelepiped, the first surface 211 is a rectangle extending in a first direction D1 and a second direction D2 that are perpendicular to each other, and the circumferential surface 212 extends along a third direction D3 that is perpendicular to the first direction D1 and the second direction D2. In these embodiments, the first pressure relief hole 2111 is formed through the first surface 211.

[0030] 2 to 6, in some embodiments, the second member 22 has a second surface 221 and a partition wall 222, the second surface 221 is flat, and one end of the partition wall 222 is partially connected to the second surface 221 and extends along the third direction D3. In these embodiments, one end of the partition wall 222 has a plurality of cutouts 2221 formed therethrough to partially separate it from the second surface 221. The second member 22 is connected to the circumferential surface 212 of the first member 21 via the second surface 221. When the second member 22 is connected to the first member 21, the other end of the partition wall 222 of the second member 22 is connected to the first surface 211, thereby creating a gap between the first surface 211 of the first member 21 and the second surface 221 of the second member 22, and the first surface 211, the second surface 221, the partition wall 222, and the cutout portion 2221 can collectively define the flow path P. In these embodiments, the second pressure relief hole 2211 is formed through the second surface 221 of the second member 22.

[0031] Referring to FIGS. 2-6, in some embodiments, the area of ​​the first pressure relief hole 2111 may be larger than the area of ​​each of the second pressure relief holes 2211. As a result, when battery cell B inside case body 10 explodes and high-pressure gas is generated, the high-pressure gas will enter flow path P from second pressure relief hole 2211, and the fluid resistance at first pressure relief hole 2111 is smaller than the fluid resistance at second pressure relief hole 2211. The fluid that enters flow path P from second pressure relief hole 2211 can flow naturally to first pressure relief hole 2111. The fluid flows naturally throughout flow path P, and the fluid pressure decreases as the fluid flows through flow path P. Therefore, the pressure at which the fluid flows into first pressure relief hole 2111 is smaller than the pressure at which the fluid enters flow path P from second pressure relief hole 2211. This prevents excessive pressure from damaging pressure relief valve 30 provided in first pressure relief hole 2111, ensures that pressure relief valve 30 can reliably perform its pressure relief effect, and reduces the possibility of case body 10 exploding.

[0032] 2 to 6 , in some embodiments in which the area of ​​first pressure relief hole 2111 is larger than the area of ​​each second pressure relief hole 2211, there may be a plurality of second pressure relief holes 2211, and the total area of ​​each second pressure relief hole 2211 may be 90% to 100% of the area of ​​first pressure relief hole 2111. This increases the chances of fluid entering flow path P because the pressure at the inlet of flow path P (location of second pressure relief hole 2211) is larger than the pressure at the outlet of flow path P (location of first pressure relief hole 2111), thereby improving the durability of case body 10.

[0033] 2 to 6, in some embodiments, the flow path P in the lid 20 has a plurality of communication regions P1 that are connected to one another, some of the communication regions P1 extending along the first direction D1 and some of the communication regions P1 extending along the second direction D2, and the communication regions P1 extending in different directions may be connected to one another by notches 2221. Thus, the flow path P extends in a meandering manner within the lid 20, thereby inducing the fluid to flow in a meandering manner within the lid 20 and achieving a pressure drop effect. It is worth noting that each communication region P1 is a section of the flow path P that is used for the inflow and outflow of the fluid and has two notches 2221, and the connecting direction of the two notches 2221 of each communication region P1 is the extension direction of the communication region P1.

[0034] 2 to 6, in some embodiments, the communication region P1 may have a plurality of first communication regions P11 and a plurality of second communication regions P12, where the first communication regions P11 extend along the first direction D1 and the second communication regions P12 extend along the second direction D2. In these embodiments, the number of first communication regions P11 is four, the number of second communication regions P12 is two, both ends of each second communication region P12 are connected to the first communication regions P11, and the first communication regions P11 connected to each second communication region P12 may be parallel to each other.

[0035] 2 to 6, in some embodiments, the first pressure relief hole 2111 and the second pressure relief hole 2211 are located at the respective second communication portions P12, so that the high-pressure gas that enters the flow path P from the second pressure relief hole 2211 must pass through the tortuous flow path P before being discharged from the first pressure relief hole 2111, ensuring that the high-pressure gas is decompressed and that the fluid pressure discharged from the first pressure relief hole 2111 is lower than the fluid pressure entering the flow path P from the second pressure relief hole 2211, thereby preventing damage to the pressure relief valve 30 and effectively relieving pressure.

[0036] 2 to 6, in some embodiments, the partition wall 222 of the cover 20 has a plurality of partition surfaces 2222, each of which may have a planar structure. In these embodiments, the partition surfaces 2222 include two first partition surfaces 2222A, one second partition surface 2222B, and two third partition surfaces 2222C. Each first partition surface 2222A extends between opposing sides of the second surface 221 along the first direction D1, and the two first partition surfaces 2222A are parallel to each other and spaced apart. The second partition surface 2222B extends between the two first partition surfaces 2222A along the second direction D2. Each third partition surface 2222C extends between one side of the second partition surface 2222B and one side of the second surface 221 along the first direction D1. In these embodiments, the length of the third partition surface 2222C in the first direction D1 is shorter than the length of each of the first partition surfaces 2222A in the first direction D1.

[0037] 2 to 6, in these embodiments, each first partition surface 2222A has a cutout portion 2221 at both ends in the first direction D1, and each third partition surface 2222C has a cutout portion 2221 at the end connecting to the second partition surface 2222B. As a result, two first communication regions P11 extending along the first direction D1 are defined between the first member 21 and the cutout portions 2221 at both ends of each first partition surface 2222A. On the side of the second partition surface 2222B opposite the third partition surface 2222C, one second communication region P12 extending along the second direction D2 is defined between the two first partition surfaces 2222A and the first member 21. Two other first communication regions P11 extending along the first direction D1 are defined between each of the first partition surfaces 2222A and each of the third partition surfaces 2222C and the first member 21. Two other second communication regions P12 extending along the second direction D2 are defined between each of the two third partition surfaces 2222C and the first member 21.

[0038] Referring to Figures 2 to 6, in some embodiments, the partition surface 2222 further has a fourth partition surface 2222D, which may extend between the two third partition surfaces 2222C along the second direction D2, thereby limiting the volume of the second communication region P12 defined by the second partition surface 2222B, the third partition surface 2222C, the fourth partition surface 2222D and the first member 21.

[0039] Referring to Figures 2 to 6, in some embodiments, the first pressure relief hole 2111 is provided in the second communication region P12 defined by the two first partition surfaces 2222A, the second partition surface 2222B and the first member 21, and the second pressure relief hole 2211 may be provided in the second communication region P12 defined by the second partition surface 2222B, the third partition surface 2222C, the fourth partition surface 2222D and the first member 21. In these embodiments, when high-pressure gas is generated in the storage space 11 of the case body 10, the high-pressure gas enters the flow path P of the cover body 20 through the second pressure relief hole 2211, then flows sequentially through the first communication area P11 defined by the first partition surface 2222A, the second partition surface 2222B, the third partition surface 2222C and the first member 21 and the first communication area P11 defined by the first partition surface 2222A and the first member 21, and finally enters the second communication area P12 defined by the two first partition surfaces 2222A, the second partition surface 2222B and the first member 21, and is discharged from the first pressure relief hole 2111.

[0040] 2 to 6, in some embodiments, the second communication region P12 defined by the second partition surface 2222B, the third partition surface 2222C, the fourth partition surface 2222D, and the first member 21 has a first volume V1. The first communication region P11 defined by the first partition surface 2222A, the second partition surface 2222B, the third partition surface 2222C, and the first member 21 has a second volume V2. The first communication region P11 defined by the first partition surface 2222A and the first member 21 has a third volume V3. The second communication region P12 defined by the two first partition surfaces 2222A, the second partition surface 2222B, and the first member 21 has a fourth volume V4. The fourth volume V4 is larger than the third volume V3, which is larger than the second volume V2, which is larger than the first volume V1. That is, after the fluid enters the flow path P from the second pressure relief hole 2211, the volume of each communication part P1 through which the fluid flows gradually increases in sequence. This causes the flow rate of the fluid to gradually decrease as it enters the communication parts P1 with gradually increasing volumes, thereby reliably achieving the effect of dropping pressure.

[0041] Please refer to FIGS. 4 to 6 in addition to FIGS. 7 and 8. FIG. 7 is a first simulation diagram of the flow path pressure in the lid of the battery module of the present invention, and FIG. 8 is a second simulation diagram of the flow path pressure in the lid of the battery module of the present invention. It is noteworthy that FIGS. 7 and 8 were analyzed using finite element analysis software (Ansys Mechanical) suitable for structural engineering. FIG. 7 is a flow path pressure distribution diagram of the lid 20 corresponding to the viewing angle shown in FIG. 4, and FIG. 8 is a flow path pressure distribution diagram of the lid 20 corresponding to the viewing angle shown in FIG. 6. FIGS. 7 and 8 show that the pressure at the second pressure relief hole 2211 of the lid 20 is clearly greater than the pressure at the first pressure relief hole 2111, confirming that the lid 20 of the battery case H of the present invention can reliably achieve a pressure drop effect by providing the flow path P.

[0042] In some embodiments, the overall length of flow path P may depend on the pressure that pressure relief valve 30 can withstand. The lower the pressure that pressure relief valve 30 can withstand, the higher the pressure requirement that flow path P must reduce, and the longer the length of flow path P. Conversely, the higher the pressure that pressure relief valve 30 can withstand, the lower the pressure requirement that flow path P must reduce, and the shorter the length of flow path P can be.

[0043] In some embodiments, in order to increase the length of the flow path P within the limited space of the lid 20, a winding communication region P1 can be provided to increase the overall length of the flow path P. In some embodiments of FIGS. 2 to 4, the communication region P1 is shown as an example in which four first communication regions P11 and two second communication regions P12 are connected in a winding manner, but the present invention is not limited to this.

[0044] In some embodiments, the flow path P is not limited to being composed of communication portions P1 connected perpendicularly to each other. In other embodiments, the shape of the flow path P can be changed to achieve the purpose of increasing the length of the flow path P. In some embodiments, the length of the flow path P can be increased within a limited space by arranging the entire flow path P in a continuous spiral shape.

[0045] 9, the configuration of the partition wall 222 is not limited to the above embodiment. In some embodiments, the partition surface 2222 of the partition wall 222 may have two first partition surfaces 2222A, two second partition surfaces 2222B, four third partition surfaces 2222C, and two fourth partition surfaces 2222D. In these embodiments, each first partition surface 2222A extends between opposing sides of the second surface 221 along the first direction D1, and the two first partition surfaces 2222A are parallel to each other and spaced apart. Each second partition surface 2222B extends between the two first partition surfaces 2222A along the second direction D2, and the two second partition surfaces 2222B are parallel to each other and spaced apart. The two third partition surfaces 2222C are parallel to each other and extend along the first direction D1 between one side of one second partition surface 2222B and one side of the second surface 221, while the other two third partition surfaces 2222C are parallel to each other and extend along the first direction D1 between one side of the other second partition surface 2222B and the other side of the second surface 221. In these embodiments, the length of the third partition surfaces 2222C in the first direction D1 is shorter than the length of each first partition surface 2222A in the first direction D1. Each fourth partition surface 2222D extends along the second direction D2 and is located between two third partition surfaces 2222C that are parallel to each other.

[0046] 9, in these embodiments, each first partition surface 2222A is provided with three spaced-apart cutouts 2221, two of which are located at both ends of the first partition surface 2222A in the first direction D1, and the remaining cutout 2221 is located between the two cutouts 2221. A cutout 2221 is provided at the end of each third partition surface 2222C that connects to the second partition surface 2222B. As a result, two first communication regions P11 extending along the first direction D1 are defined between the first member 21 and the cutouts 2221 at both ends of each first partition surface 2222A. Two second communication regions P12 extending along the second direction D2 are defined between the second partition surface 2222B, the third partition surface 2222C, and the fourth partition surface 2222D and the first member 21. Another second communication region P12 is defined between the two first partition surfaces 2222A and the two second partition surfaces 2222B and the first member 210. Four first communication regions P11 extending along the first direction D1 are defined between each of the first partition surfaces 2222A, each of the second partition surfaces 2222B, and each of the third partition surfaces 2222C.

[0047] In these embodiments, the first pressure relief hole 2111 is provided within the second communication region P12 defined by the two first partition surfaces 2222A, the two second partition surfaces 2222B and the first member 21, and the second pressure relief hole 2211 is provided within the second communication region P12 defined by the second partition surface 2222B, the two third partition surfaces 2222C and the fourth partition surface 2222D. In these embodiments, when high-pressure gas is generated in the storage space 11 of the case body 10, the high-pressure gas enters the flow path P of the cover body 20 through the second pressure relief hole 2211, then flows sequentially through the first communication region P11 defined by the first partition surface 2222A, the second partition surface 2222B, the third partition surface 2222C and the first member 21, and the first communication region P11 defined by the first partition surface 2222A and the first member 21, and finally enters the second communication region P12 defined by the two first partition surfaces 2222A, the two second partition surfaces 2222B and the first member 21, and is discharged through the first pressure relief hole 2111. This not only increases the length of the flow path P, but also allows the first pressure relief hole 2111 to be located in the center of the second surface 221 of the second member 22, thereby enabling adaptation to different battery cell B positioning arrangements and improving applicability.

[0048] The fire-extinguishing material E is a substance capable of exerting a fire-extinguishing effect. The fire-extinguishing material E is distributed around the battery cells B, and when one of the battery cells B catches fire, the fire-extinguishing material E can exert a fire-extinguishing effect. In some embodiments, the fire-extinguishing material E is in a dry powder state. In some embodiments in which the fire-extinguishing material E is in a dry powder state, the fire-extinguishing material E may be, but is not limited to, a dry powder fire-extinguishing agent such as sodium bicarbonate, sodium chloride, or potassium chloride. In some embodiments in which the fire-extinguishing material E is sodium bicarbonate, the sodium bicarbonate undergoes an endothermic reaction when exposed to heat and decomposes into carbon dioxide and water. The carbon dioxide makes it difficult for the battery cells B to continue burning, and the water absorbs the heat generated during combustion, thereby effectively exerting a fire-extinguishing effect and a cooling effect. In some embodiments, the fire-extinguishing material E may include ammonium dihydrogen phosphate and barbituric acid / barbituric acid derivative. The ammonium dihydrogen phosphate absorbs heat during the combustion process and decomposes into phosphoric acid and ammonia, which then undergo an endothermic chemical reaction to produce phosphorus pentoxide and water, thereby exerting a cooling effect. Barbituric acid or a barbituric acid derivative (e.g., a barbiturate, in which one of the hydrogen atoms bonded to the carbon atom in the barbituric acid is replaced with a methyl group, an ethyl group, or an isotope) can mitigate or stop the combustion of battery cell B by reducing the concentration of free radicals during the combustion process. Furthermore, the barbituric acid or a barbituric acid derivative can produce water and carbon dioxide after being heated and / or burned, where the water can lower the ambient temperature and the carbon dioxide can suppress the combustion. In some embodiments, the weight percentage of the barbituric acid or a barbituric acid derivative in fire-extinguishing material E is X, and the weight percentage of ammonium dihydrogen phosphate in fire-extinguishing material E is Y, with X:Y ranging from 1:99 to 99:1. In some embodiments, fire-extinguishing material E can be selected from the fire-extinguishing materials with a cooling effect described in Patent Document 1.

[0049] It is worth noting that the fire-extinguishing material E is not limited to a dry powder state. In some embodiments, the fire-extinguishing material E may be in the form of agglomerated lumps. In these embodiments, if the agglomerated fire-extinguishing material E is distributed around the battery cells B and one of the battery cells B catches fire, the fire-extinguishing material E exerts its fire-extinguishing effect, but is blocked between the cover body 20 and the case body 10 due to the shape of the fire-extinguishing material E itself, thereby extending the time the fire-extinguishing material E remains within the case body 10 and exerts its fire-extinguishing effect.

[0050] In some embodiments, the fire-extinguishing material E may be in the form of granules. In these embodiments, the particle size of the fire-extinguishing material E is larger than the hole diameter of each second pressure relief hole 2211. This traps the fire-extinguishing material E within the case body 10, making it difficult for the fire-extinguishing material E to exit the case body 10 through the second pressure relief holes 2211, thereby lengthening the time the fire-extinguishing material E remains within the case body 10 and exerts its fire-extinguishing effect.

[0051] In some embodiments, the case body 10 of the battery case H is made of a fire-resistant material. This makes it more difficult for the battery case H to catch fire and reduces safety risks due to thermal runaway of the battery module. In some embodiments, the fire-resistant material may be, but is not limited to, metal, fireproof plaster, or fireproof fiber material. In some embodiments, the fireproof fiber material may be, but is not limited to, carbon fiber material, glass fiber material, stone fiber material, or calcium silicate fiber material. This reduces the weight of the case body 10 of the battery case H and improves the applicability of the battery module, without affecting the fire-resistant performance of the battery case H.

[0052] In some embodiments, the battery module further includes a filter 40 attached to the pressure relief valve 30, so that when the battery cell B explodes, the filter 40 filters the fire-extinguishing material E as it is ejected from the pressure relief valve 30 together with the explosion gas, and the gas passes through the pressure relief valve 30 and escapes from the filter 40, while the fire-extinguishing material E is filtered and retained within the battery case H. This allows the unused fire-extinguishing material E to be retained within the battery case H and continue to exert its fire-extinguishing and cooling effects, and also prevents the fire-extinguishing material E from being ejected together with the high-pressure gas and polluting the surrounding environment.

[0053] It is worth noting that in some embodiments, the exterior appearance of the case body 10 and the lid body 20 shown in Figures 1 to 7 is substantially rectangular, but the present invention is not limited thereto. Referring to Figures 10 and 11, in other embodiments, the exterior contours of the case body 10 and the lid body 20 may also be circular to suit cylindrically arranged battery cells B or different usage spaces.

[0054] 10 and 11, in some embodiments in which the outer contours of the case body 10 and the lid body 20 are circular, the flow path P of the lid body 20 has multiple communication portions P1 having a circular contour. Referring to Fig. 9, the communication portion P1 has a circular first communication portion P11 and an annular second communication portion P12. In these embodiments, the first pressure relief hole 2111 corresponds to the position of the first communication portion P11, and the second pressure relief hole 2211 is located at the position of the second communication portion P12, which is farthest from the first communication portion P11.

[0055] In some embodiments, the number of second communication regions P12 is plural, and each second communication region P12 is arranged concentrically with the first communication region P11 at intervals, and the first communication region P11 communicates with the adjacent second communication region P12, and the adjacent second communication regions P12 may also communicate with each other. This allows the arrangement of flow paths P with different shapes to similarly achieve a pressure drop effect. [Explanation of symbols]

[0056] 10 Case body 11 Containment Space 12 Opening 20 Lid 21 First member 211 Page 1 2111 First pressure relief port 212 Circumference 22 Second member 221 2nd page 2211 Second pressure relief port 222 Bulkhead 2221 Notch 2222 Partition surface 2222A First partition 2222B Second partition 2222C Third partition 2222D 4th partition 30 Pressure relief valve 40 filters B Battery cell D1 1st direction D2 2nd direction D3 Third direction E Fire extinguishing materials H Battery Case P flow path P1 communication part P11 1st communication part P12 2nd communication part V1 1st volume V2 2nd volume V3 3rd volume V4 4th volume

Claims

1. a case body having a storage space and an opening; a cover provided at the opening, the cover having a flow path and a first surface and a second surface opposite to each other, the flow path being provided between the first surface and the second surface, the cover having a first pressure relief hole in the first surface and a second pressure relief hole in the second surface, and both ends of the flow path being connected to the first pressure relief hole and the second pressure relief hole, respectively; a pressure relief valve provided in the first pressure relief hole.

2. The battery case according to claim 1 , wherein an area of ​​the first pressure relief hole is larger than an area of ​​the second pressure relief hole.

3. 3. The battery case according to claim 2, wherein the number of the second pressure relief holes is plural, and the total area of ​​the second pressure relief holes is 90% to 100% of the area of ​​the first pressure relief holes.

4. 2. The battery case of claim 1, wherein the first surface extends along a first direction and a second direction perpendicular to the first direction, the flow path has a plurality of communication portions that communicate with each other, some of the communication portions extending along the first direction, and some of the communication portions extending along the second direction.

5. 5. The battery case according to claim 4, wherein the lid further includes a partition wall, one end of the partition wall being partially connected to the second surface in a third direction perpendicular to the first direction and the second direction, and the other end of the partition wall extending to the first surface.

6. The battery case according to claim 5 , wherein the partition wall has a plurality of partition surfaces, each of which has a planar structure.

7. The battery case according to claim 1 , wherein the lid is made of a fire-resistant material.

8. 8. The battery case according to claim 7, wherein the fire-resistant material is metal, fire-resistant gypsum, or fire-resistant fiber material.

9. 9. The battery case according to claim 8, wherein the fire-resistant fiber material is made of a carbon fiber material, a glass fiber material, a stone fiber material, or a calcium silicate fiber material.

10. The battery case according to any one of claims 1 to 9, a plurality of battery cells housed in the housing space of the case body; a fire-extinguishing material accommodated in the accommodation space and distributed around the battery cells.

11. The battery module according to claim 10 , further comprising a filter provided in the pressure relief valve.

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