Pressure relief structure for dual-layer battery and battery pack

Abstract

Pressure relief structure for a double-layer battery, characterized in that it comprises: an upper cell module (1) provided with a plurality of upper cell pressure relief openings (11); a lower cell module (2) provided with a plurality of lower cell pressure relief openings (21); a pressure relief layer (3) clamped between the upper cell module (1) and the lower cell module (2), wherein a pressure relief chamber (33) communicating with the plurality of upper cell pressure relief openings (11) and the plurality of lower cell pressure relief openings (21) is formed within the pressure relief layer (3), and the plurality of upper cell pressure relief openings (11) and the plurality of lower cell pressure relief openings (21) are offset in their position.

Description

Technical FieldThe present disclosure relates to the technical field of the battery, and more particularly, to a pressure relief structure for a dual-layer battery and a battery pack.Prior ArtWith the rapid progress of new power technology for vehicles, the demands on the performance and space utilization of battery systems as their core components also become more stringent. In particular in the case of SUVs, commercial vehicles and models which are operated with oil and are then switched over to electric drive, the question of how this relatively large space can be used efficiently in order to improve the performance of the battery system has come into the focus of the attention of the industry.Currently, dual layer modules or dual layer MTP (multiple module) battery systems have proven promising applications on the market. These systems significantly increase the overall energy density of the battery pack by stacking two layers of cells, which in turn increases the range of the vehicle.Disclosure of Utility ModelIn a dual layer module design, efficient space utilization is limited to some extent due to the independent pressure relief chamber present in each battery module. Due to the double layer pressure relief chamber, the space utilization of the double layer module is compressed, resulting in a limited capacity of the cell for the same volume.How the space occupied by the pressure relief chamber in the dual layer module can be effectively reduced without jeopardizing safety of cell pressure relief has become an urgent technical problem that must be solved urgent.In a first aspect, the present disclosure provides a pressure relief structure for a dual-layer battery, including an upper cell module, a lower cell module, and a pressure relief layer. The upper cell module is provided with a plurality of upper cell pressure relief ports. The lower cell module is provided with a plurality of lower cell pressure relief ports. The pressure relief layer is pinched between the upper cell module and the lower cell module, wherein a pressure relief chamber communicating with the plurality of upper cell pressure relief ports and the plurality of lower cell pressure relief ports is formed in the pressure relief layer, and the plurality of upper cell pressure relief ports and the plurality of lower cell pressure relief ports are displaced in position.In a second aspect, the present disclosure provides a battery pack including a battery housing, an explosion-proof valve, an electrical compartment, a liquid cooling system, and one or more pressure relief structures for a dual-layer battery. The battery housing is provided with a receiving chamber. The electrical compartment, the liquid cooling system, the upper cell module, the lower cell module, and the pressure relief layer are all located in the receiving chamber. The explosion-proof valve is located on a side wall of the battery case and is in communication with the pressure relief chamber of the pressure relief layer.1. The pressure relief layer is located between the upper and lower cell modules, so that the construction of the common pressure relief chamber structure of the two cell sets is achieved. When a thermal runaway occurs in a cell of the system, gas flows into the common pressure relief chamber to generate a hydraulic pressure. Compared to the structure of a pressure relief chamber that is set up for each cell module, it saves space and makes it possible to reserve more space for the cells with the same volume, thereby increasing the energy density of the battery.2. The upper cell pressure relief port and the lower cell pressure relief port are offset in position to effectively avoid the risk of interfering with the gases in the event of an abnormality in the cell. This ensures that the gas can be discharged quickly and effectively without adverse effects on each other. This significantly reduces the risk of thermal runaway and improves the safety of the battery.Brief Description of the DrawingsFIG. 1 is a simple schematic diagram of the pressure relief structure of an embodiment of the present disclosure; FIG. 2 is a schematic structural diagram of the pressure relief structure of the embodiment of the present disclosure in a perspective view; FIG. 3 is a schematic structural diagram of the battery pack of the embodiment of the present disclosure; FIG. 4 is a schematic structural diagram of the battery pack of the embodiment of the present disclosure in a sectional view; FIG. 5 is an enlarged view of FIG. 4 at A; FIG. 6 is a schematic structural diagram of partially disassembling the fixed frame of the pressure release layer of the embodiment of the present disclosure; and FIG. 7 is a schematic structural diagram of the liquid cooling system of the embodiment of the present disclosure.The meanings of the reference numerals are as follows: 1 upper cell module; 11 upper cell pressure relief port; 2 lower cell module; 21 lower cell pressure relief port; 3 pressure relief layer; 31 first side surface; 32 second side surface; 33 pressure relief chamber; 331 first pressure relief chamber; 332 second pressure relief chamber; 34 first partition wall; 35 support wall; 36 pressure relief passage; 37 pressure relief outlet; 4 first support; 41 first pressure relief through hole; 5 second support; 51 second pressure relief through hole; 6 fixed frame; 7 battery case; 71 accommodation chamber; 72 collection chamber; 8 explosion-proof valve; 9 liquid cooling system; 91 first liquid cooling mechanism; 911 serpentine liquid cooling plate; 912 current collector; 913 connection pipe; 92 second liquid cooling mechanism; 93 outlet main pipe; 94 inlet main pipe; 10 Electrical compartment.Embodiment(s)Referring to FIGS. 1 and 4, in the embodiment of the present disclosure, a pressure relief structure for a dual-layer battery is disclosed, which includes an upper cell module 1, a lower cell module 2, and a pressure relief layer 3. The upper cell module 1 and the lower cell module 2 each include a bus bar and a plurality of cells, the pressure release layer 3 includes a first side surface 31 and a second side surface 32 opposing the first side surface 31, the pressure release layer 3 is hollow to form a pressure release chamber 33. The upper cell module 1 is attached to the first side surface 31, and the lower cell module 2 is attached to the second side surface 32 such that the pressure release layer 3 is sandwiched between the upper cell module 1 and the lower cell module 2. Each of the cells in the upper cell module 1 has an upper cell pressure relief port 11 facing the first side surface 31; each of the cells in the lower cell module 2 has an upper cell pressure relief port 11 facing the second side surface 32; the upper cell pressure relief port 11 and the lower cell pressure relief port 21 are both in communication with the pressure relief chamber 33, and the upper cell pressure relief port 11 and the lower cell pressure relief port 21 are offset in position. By sharing the pressure relief chamber 33 between the upper cell module 1 and the lower cell module 2, the space occupied by the pressure relief chamber 33 in a height direction can be minimized, thereby improving the cell capacity at the same volume. At the same time, the offset arrangement of the upper cell pressure relief port 11 and the lower cell pressure relief port 21 ensures that the gases do not interfere with each other when the cells are not functioning normally, but can quickly and effectively enter the pressure relief chamber 33, thereby preventing the occurrence of thermal runaway. Such a construction ensures the safety of the battery system and simultaneously optimizes the use of space.In order to prevent the upper cell pressure relief port 11 and the lower cell pressure relief port 21 from being disturbed by hot gas when thermal runaway occurs in the cells, in some implementations referring to FIGS. 5 to 6, a first partition wall 34 is provided in the pressure relief chamber 33, the first partition wall 34 being parallel to the first side surface 31 and the second side surface 32, and the first partition wall 34 partitioning the pressure relief chamber 33 into a first pressure relief chamber 331 and a second pressure relief chamber 332. The first pressure relief chamber 331 communicates with the upper cell pressure relief port 11 and the second pressure relief chamber 332 communicates with the lower cell pressure relief port 21, The separating action of the first partition wall 34 enables more independent and insulated gas release from the upper cell module 1 and the lower cell module 2, and the resulting flame or hot gas cannot directly spread to the other module, thereby improving the safety of the battery system.It should be noted that the plurality of upper cell pressure relief ports 11 and the plurality of lower cell pressure relief ports 21 may not be displaced in position when the pressure relief chamber 33 is provided with a first partition wall 34.In some implementations related to FIG. 6, based on the location of the first partition 34, one or more support partitions 35 are also provided in the pressure relief chamber 33 perpendicular to the first partition 34. Specifically, the number of the support walls 35 corresponds to the number of cell stack rows minus one, and the support wall 35 and the first wall 34 divide the pressure relief chamber 33 into a plurality of pressure relief passages 36. This contributes to improvement of discharge efficiency and ensures safety performance of the battery system. At the same time, the support wall 35 may provide additional support to prevent the pressure relief chamber 33 from deforming or breaking when subjected to a compression shock, thereby maintaining its structural integrity and stability.In order to improve the connection strength and connection stability of the upper cell module 1, the lower cell module 2, and the pressure release layer 3, in some implementations related to FIGS. 4 and 6, a first support 4 is mounted between the upper cell module 1 and the first side surface 31, and a second support 5 is mounted between the lower cell module 2 and the second side surface 32. To ensure that the cells can be properly depressurized, a first pressure relief passageway tube 41 is provided on the first support 4 corresponding to the upper cell pressure relief port 11 and a second pressure relief passageway tube 51 is provided on the second support 5 corresponding to the lower cell pressure relief port 21. The first support 4 and the second support 5 fix the upper cell module 1 and the lower cell module 2, respectively, thus enabling a more secure connection between them and the pressure relief layer 3, which improves the efficiency and accuracy of the assembly process and prevents possible displacement or loosening during operation of the battery.In some implementations, see FIG. 6, a fixed frame 6 is provided on both the first pressure relief through hole 41 and the second pressure relief through hole 51, the fixed frame 6 being configured to fix cells within the upper cell module 1 or the lower cell module 2 such that each of the first pressure relief through holes 41 and each of the second pressure relief through holes 51 corresponds to one of the cells. In some implementations, see FIG. 6, based on the first partition 34, one or more support partitions 35 are also provided in the pressure relief chamber 33 perpendicular to the first partition 34. The fixed frame 6 can ensure that each of the cells is stably fixed at a corresponding position, thereby preventing the cells from shifting or shaking during operation of the battery.In the present disclosure, a battery pack is also used, the inside of which may be provided with a plurality of sets of the above pressure relief structure for a dual-layer battery as long as it is ensured that a pressure relief layer 3 is provided between each two of the battery modules. In addition, a pressure relief layer 3 can be provided between each two adjacent battery modules, which is not expressly restricted in the present disclosure. Specifically, in some implementations, as shown in FIGS. 3 to 5, the battery pack also includes a battery case 7, an explosion-proof valve 8, an electric compartment 10, and a liquid cooling system 9. The battery case 7 is provided with a receiving chamber 71. The electric compartment 10, the liquid cooling system 9, the upper cell module 1, the lower cell module 2, and the pressure release layer 3 are all provided in the accommodation chamber 71, the explosion-proof valve 8 is provided on a side wall of the battery case 7, and the explosion-proof valve 8 is in communication with the pressure release chamber 33 of the pressure release layer 3. In some implementations, one or more pressure relief outlets 37 communicate with one end of the plurality of pressure relief channels 36. The number of pressure relief outlets 37 is identical to that of explosion-proof valves 8. In some implementations, it is also possible for multiple outlets to converge to communicate with only one explosion-proof valve 8. When thermal runaway or other abnormality occurs in cells, the generated gas and heat can quickly flow through the pressure relief passage 36 to the pressure relief outlet 37 and be discharged from the pressure relief valve to the outside of the battery case 7, thereby preventing the risk of explosion or burning due to excessive internal pressure in the battery, which greatly improves the safety of the battery system.In some implementations, see FIG. 5, a plenum 72 is provided in the battery housing 7, the explosion-proof valve 8 is attached to an outer sidewall of the battery housing 7, the explosion-proof valve 8 is in communication with the plenum 72, the pressure relief layer 3 is attached to an inner sidewall of the battery housing 7, and the pressure relief outlets 37 at one end of the plurality of pressure relief channels 36 of the pressure relief chamber 3. When thermal runaway occurs in the cell and pressure builds up, the gas can quickly enter the plenum 72 through the pressure relief passage 36 and then be purged from the battery through the explosion-proof valve 8. The rapid increase in pressure in the collecting chamber 72 facilitates the opening of the explosion-proof valve 8 and thus avoids dangerous situations such as explosion or thermal runaway of the battery due to excessively high pressure.In some implementations, see FIG. 7, the liquid cooling system 9 is provided with a first liquid cooling mechanism 91 corresponding to the upper cell module 1 and a second liquid cooling mechanism 92 corresponding to the lower cell module 2, The first liquid cooling mechanism 91 and the second liquid cooling mechanism 92 both include a plurality of serpentine liquid cooling plates 911, a plurality of current collectors 912, and a plurality of connection pipes 913. The current collectors 912 are disposed at one end of the serpentine liquid cooling plates 911. The first liquid cooling mechanism 91 and the second liquid cooling mechanism 92 are connected in parallel and are in communication with an outlet main pipe 93 and an inlet main pipe 94, so that the connection pipe 913 connects the plurality of current collectors 912 to the outlet main pipe 93 or the inlet main pipe 94. The serpentine liquid cooling plate 911 is disposed between each cell row such that the first liquid cooling mechanism 91 is attached to one side of the cell in the upper cell module 1 and the second liquid cooling mechanism 92 is attached to one side of the cell in the lower cell module 2, thereby ensuring that each cell module can be cooled appropriately. At the same time, the first liquid cooling mechanism 91 and the second liquid cooling mechanism 92 are connected in parallel and are in communication with the outlet main pipe 93 and the inlet main pipe 94, and such a parallel construction can ensure uniform distribution and circulation of the coolant and reduce the system pressure drop. The coolant enters the two liquid cooling mechanisms via the inlet main tube 94. After cooling the cell module, the coolant drains through the outlet main pipe 93 to form a complete cooling circuit. The outlet of the outlet header 93 and the inlet of the inlet header 94 are disposed in the electric compartment 10. The terminals of the electrical compartment 10 are arranged next to each other, which facilitates the connection of pipes and the insertion.In the present disclosure, it is necessary to pre-assemble the upper cell module 1 and the lower cell module 2 at the time of assembly. Pre-installing involves stacking and connecting the cells to a CCS (cell contact system) and then preparing a battery case that can be opened up and down. The battery case 7 is provided with a pressure release layer 3 at the center, and the battery case 7 may be integrally injection molded with the pressure release layer 3 or later mounted. Then, the upper cell module 1 is fixed to the first side surface 31 of the pressure release layer 3 in the accommodation chamber 71 of the battery case 7 by a vacuum cleaner, and then an appropriate amount of foam adhesive is injected to cover the top surface of the battery case 7. After the foam adhesive has cured, the battery housing 7 is turned over so that the bottom side of the housing is located at the top. Then, the lower cell module 2 is attached to the second side surface 32 of the pressure release layer 3 in the accommodation chamber 71 of the battery case 7, an appropriate amount of foam adhesive is injected to cover the upper cover of the battery case 7, and finally, the BMS, the battery management system, the BDU, the battery separating unit, and the connectors are mounted in the electric compartment 10 of the battery pack, and then the cover of the electric compartment 7 may be closed.In summary, the pressure relief structure for a dual-layer battery disclosed in the present disclosure has the following technical effects:1. The pressure relief layer 3 is located between the upper cell module 1 and the lower cell module 2, so that the construction of the common pressure relief chamber 33 of the two cell sets is achieved. When a thermal runaway occurs in a cell of the system, gas flows into the common pressure relief chamber 33 to generate a hydraulic pressure. Compared to the structure of a pressure relief chamber 33 provided for each cell module, it saves space and allows more space to be reserved for the cells for the same volume, thereby increasing the energy density of the battery.2. The upper cell pressure relief port 11 and the lower cell pressure relief port 21 are displaced in position to effectively avoid the risk of interfering with the gases in the event of an abnormality in the cell. This ensures that the gas can be discharged quickly and effectively without adverse effects on each other. This significantly reduces the risk of thermal runaway and improves the safety of the battery.3. The first partition wall 34 and the support wall 35 are configured such that the pressure relief chamber 33 is divided into a plurality of independent pressure relief passages 36. During battery operation, large pressure fluctuations can occur in the cell, in particular in the event of an abnormality in a cell. The support wall 35 may provide additional support to prevent the pressure relief chamber 33 from deforming or cracking when subjected to a surge, thereby maintaining its structural integrity and stability. When thermal runaway occurs in the cell, multiple channels may more effectively dissipate and dissipate the heat, lower the temperature in the cell, and reduce the risk of thermal runaway diffusion. This helps to protect the remaining battery system from chain reactions.4. The first support 4 and the second support 5 as well as the fixed frame 6 are arranged in such a way that a secure connection between the cell module and the pressure relief layer 3 is ensured. This not only improves the structural stability of the battery, but also helps the cells not shift or shake during battery operation, which increases the safety of the battery.

Claims

A pressure relief structure for a dual-layer battery, characterized by comprising: an upper cell module (1) provided with a plurality of upper cell pressure relief ports (11); a lower cell module (2) provided with a plurality of lower cell pressure relief ports (21); a pressure relief layer (3) clamped between the upper cell module (1) and the lower cell module (2), wherein a pressure relief chamber (33) communicating with the plurality of upper cell pressure relief ports (11) and the plurality of lower cell pressure relief ports (21) is formed within the pressure relief layer (3), and the plurality of upper cell pressure relief ports (11) and the plurality of lower cell pressure relief ports (21) are displaced in position.The pressure relief structure for a dual-layer battery according to claim 1, wherein the pressure relief layer (3) includes a first side surface (31) opposite to the cell upper pressure relief ports (11) and a second side surface (32) opposite to the cell lower pressure relief ports (21), a first partition wall (34) is provided in parallel to the first side surface (31) and the second side surface (32) in the pressure relief chamber (33), the first partition wall (34) partitions the pressure relief chamber (33) into a first pressure relief chamber (331) and a second pressure relief chamber (332), the first pressure relief chamber (331) communicates with the cell upper pressure relief ports (11), and the second pressure relief chamber (332) communicates with the cell lower pressure relief ports (21).The pressure relief structure for a dual-layer battery according to claim 2, wherein one or more support partition walls (35) are provided perpendicularly to the first partition wall (34) in the pressure relief chamber (33), and the support partition wall (35) and the first partition wall (34) divide the pressure relief chamber (33) into a plurality of pressure relief passages (36).The pressure relief structure for a dual-layer battery according to claim 3, wherein the pressure relief layer (3) is provided with one or more pressure relief outlets (37), and the one or more pressure relief outlets (37) communicate with the plurality of pressure relief passages (36).The pressure relief structure for a dual-layer battery according to any one of claims 2 to 4, wherein a first support (4) is attached between the upper cell module (1) and the first side surface (31) and is provided with first pressure relief through holes (41) corresponding to the upper cell pressure relief openings (11); and a second support (5) is attached between the lower cell module (2) and the second side surface (32) and is provided with second pressure relief through holes (51) corresponding to the lower cell pressure relief openings (21).The pressure relief structure for a dual-layer battery according to claim 5, wherein a fixed frame (6) is provided at each of the first pressure relief through hole (41) and the second pressure relief through hole (51), the fixed frame (6) being configured to fix cells within the upper cell module (1) or the lower cell module (2) such that each of the first pressure relief through holes (41) and each of the second pressure relief through holes (51) respectively corresponds to each of the cells.A battery pack characterized by comprising a battery case (7), an explosion-proof valve (8), an electric compartment (10), a liquid cooling system (9), and one or more pressure release structures for a dual-layer battery according to any one of claims 1-6, wherein the battery case (7) is provided with a receiving chamber (71), wherein the electric compartment (10), the liquid cooling system (9), the upper cell module (1), the lower cell module (2), and the pressure release layer (3) are all provided in the receiving chamber (71), the explosion-proof valve (8) is provided on a side wall of the battery case (7), and the explosion-proof valve (8) communicates with the pressure release chamber (33) of the pressure release layer (3).The battery pack according to claim 7, wherein a collection chamber (72) is provided in the battery case (7), the explosion-proof valve (8) is attached to an outer side wall of the battery case (7), the explosion-proof valve (8) communicates with the collection chamber (72), the pressure release layer (3) is attached to an inner side wall of the battery case (7), and the plurality of pressure release passages (36) of the pressure release chamber (33) is all of the collection chamber (72), the pressure release layer (3) is attached to an inner side wall of the battery case (7), and the plurality of pressure release passages (36) of the pressure release chamber (33) are all communicated with the collection chamber (72).The battery pack according to claim 7, wherein the liquid cooling system (9) comprises: a first liquid cooling mechanism (91) adjacent to the upper cell module (1); a second liquid cooling mechanism (92) adjacent to the lower cell module (2), wherein the first liquid cooling mechanism (91) and the second liquid cooling mechanism (92) are connected in parallel and communicate with an outlet main pipe (93) and an inlet main pipe (94).The battery pack according to claim 9, wherein one of the first liquid cooling mechanism (91) and the second liquid cooling mechanism (92) comprises: a plurality of serpentine liquid cooling plates (911); a plurality of current collectors (912) provided at one end of the plurality of serpentine liquid cooling plates (911); and a connection pipe (913) configured to connect the plurality of current collectors (912) to the outlet main pipe (93) or the inlet main pipe (94).

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