Battery pack

Abstract

The battery pack comprises a box body and a box cover, an opening is formed in one side of the box body, and the box cover covers the opening to form a close seam; the battery pack further comprises a plurality of battery cells, a limiting pressing plate and a protection assembly; an anti-explosion valve is arranged at one end of the battery cell; the battery cells are arranged side by side to form a battery unit, the battery unit forms at least one layer of battery module and is placed in the box body, and the limiting pressing plate and the end plate are fixedly arranged relative to the box body and are used for pressing and limiting the battery unit. And when a thermal runaway phenomenon occurs, gas in the battery cell rushes out from the battery cell explosion-proof valve to the greatest extent, so that the risks of thermal runaway diffusion and even fire and explosion caused by explosion of the battery cell from the side edge are avoided. Especially for a high-capacity'short-knife laminated 'battery system, the occurrence of safety accidents caused by chamber explosion due to thermal runaway of the battery is one of industrial'pain points', the risk of chamber explosion due to thermal runaway of the short-knife laminated battery is effectively solved, and one of'pain points' in the lithium battery industry is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium batteries, and more specifically, to a battery pack of a short-knife laminated battery cell. Background Art

[0002] Lithium batteries are widely used in the field of new energy power, and according to the user demand orientation, lithium batteries are developing towards a higher energy density direction, especially large-capacity battery pack systems. With the increase in the capacity of the battery pack, there are also increasingly high safety risks, especially the thermal safety risk of the battery.

[0003] There are various forms of thermal runaway in the battery system. For a CTP battery system with large-capacity side-out electrode plates and side-out explosion-proof valves, the voltage difference between modules is large. Especially the voltage difference between the total positive and total negative of the system can often reach several hundred to thousands of volts. When the battery undergoes thermal runaway, the electrolyte inside the battery cell sprays out and flows onto the electrode plate, which is extremely easy to form a short circuit. In addition to the electrolyte, the particulate matter ejected during the thermal runaway of the battery cell will also conduct the positive and negative electrodes, causing a short circuit in the system. This is the first point.

[0004] For a CTP battery system with large-capacity side-out explosion-proof valves, when the battery cell undergoes thermal runaway, high-temperature gas and electrolyte are ejected, which is extremely easy to damage the sealing of the system box, resulting in the system catching fire and explosion, dangerous events occurring, and the insulating paint catching fire, resulting in the failure of the system thermal runaway test and other results, posing a very high challenge to the safety of the system.

[0005] Especially for a large-capacity "short-knife laminated" battery system, due to the long battery cell, when the battery cell undergoes thermal runaway, the exhaust and pressure relief inside the battery cell are not timely, and it is extremely easy for the battery cell to explode. After the "short-knife laminated" battery cell explodes, it is extremely easy to cause the surrounding battery cells to undergo thermal runaway, spreading from the occurrence of thermal runaway. When large-scale diffusion occurs in the system, the battery system will inevitably catch fire and explode violently, triggering safety accidents; the easy explosion of the "short-knife laminated" battery cell is a pain point in the industry.

[0006] The existing publication number is CN220692129U, which discloses a battery cell heat exchange system and a power battery. In this solution, a fluid channel is added on the pole column side of each battery cell housing to achieve the purpose of improving the heat exchange efficiency and the heat exchange effect. The heat exchange channels of each battery cell are independently arranged, which can better maintain the thermal balance between the battery cells and improve the safety and thermal stability of the power battery. However, the thermal safety protection of the battery is still not sufficient. Summary of the Invention

[0007] Aiming at the problems in the prior art, the present invention provides a battery pack, which solves the industry problem that it is difficult to prevent and control the thermal runaway explosion of the short-knife laminated battery while improving the energy density of the battery.

[0008] To achieve the above object, the technical solution provided by the present invention is as follows:

[0009] A battery pack, comprising a box body and a box cover, wherein one side of the box body has an opening, and the box cover covers the opening to form a joint seam;

[0010] It further includes a plurality of battery cells, a limiting pressing plate and a protection component; an explosion-proof valve is arranged at one end of the battery cell; the battery cells are arranged side by side to form a battery unit, and at least one layer of battery modules formed by the battery units are placed in the box body, and the explosion-proof valve parts of the battery cells in at least one layer of battery modules face or are close to the joint seam between the box body and the box cover; the protection component is arranged close to the explosion-proof valve, and the explosion-proof valve is arranged facing or close to the joint seam between the box body and the box cover; the limiting pressing plate is located on the side of the battery unit close to the box cover and is used to press the battery unit.

[0011] In this solution, the front explosion-proof valve is arranged facing or close to the joint seam between the box body and the box cover. Once a thermal runaway occurs, the gas ejected from the front explosion-proof valve faces the joint seam between the box body and the box cover, which easily leads to the sealing failure of the battery pack and causes a greater safety accident. In this solution, a protection component is arranged, and the protection component is arranged close to the front explosion-proof valve. The gas ejected from the front explosion-proof valve mainly faces the protection component, and the protection component bears the gas ejected from the front explosion-proof valve to prevent the sealing failure and fire of the battery pack.

[0012] As a further improvement, the protection component includes a first protection part and a second protection part; the first protection part is arranged at the joint seam between the box body and the box cover; the second protection part is arranged on the box cover. The edge of the box body opening towards or close to which the explosion-proof valve is located is the box body sealing surface; the first protection part includes a boss arranged on the box body sealing surface and a sealing gasket located at the joint seam between the box body and the box cover. The second protection part includes a heat insulation plate, and the heat insulation plate is located at one end of the box cover close to the explosion-proof valve. In this solution, the boss and the sealing gasket in the first protection part are combined with each other to effectively control the spread of thermal runaway. The boss blocks the gas ejected from the explosion-proof valve, and the sealing gasket effectively seals the airtightness of the battery pack system. The second protection part effectively reduces the occurrence of fire. By combining and using the first protection part and the second protection part, the thermal runaway is further controlled.

[0013] As a preferred implementation manner, when the box body and the box cover are closed, the sealing gasket is pressed; and the height of the pressed sealing gasket is higher than the height of the boss, so that a gap is formed between the top surface of the boss and the box cover, avoiding that after the box body and the box cover are closed, the box cover abuts against the boss, and the required pre-tightening force for closing between the box body and the box cover cannot be achieved, and the pressing degree of the sealing gasket is poor, resulting in a reduction in the sealing effect.

[0014] Further, the height difference between the compressed gasket and the boss is 0-1 mm. If the gap is too large, the gas ejected from the explosion-proof valve passing through the gap will ablate and damage the structure of the gasket, increasing the risk of seal failure.

[0015] Preferably, the gasket is made of foamed silica gel. Using foamed silica gel material makes the gasket have good elasticity and improves the sealing effect.

[0016] In a preferred embodiment, the heat insulation plate is L-shaped, including a first side plate and a second side plate, and one side edge of the first side plate is connected to one side edge of the second side plate; the box cover includes a box cover top surface and a box cover side surface surrounding the periphery of the box cover top surface; the second side plate abuts against the box cover top surface of the box cover; the first side plate abuts against the box cover side surface of the box cover. The heat insulation plate has a simple structure and can be quickly installed with the box cover.

[0017] Preferably, the first side plate extends towards the box body and exceeds the joint between the box body and the box cover, so that the first side plate can cooperate with the boss to block the gas ejected from the explosion-proof valve together, further reducing the ablation damage of the gas ejected from the explosion-proof valve to the gasket.

[0018] As a further improvement, a plurality of connecting grooves are further provided on the side edge of the first side plate away from the second side plate, and bumps are provided at corresponding positions on the inner side of the box body; the connecting grooves are used for snap connection with the bumps. After the battery pack is installed, the connecting grooves are snapped onto the bumps, thereby further fixing the heat insulation plate, making the installation of the heat insulation plate more firm and avoiding loosening, thereby improving the impact resistance stability of the heat insulation plate. Moreover, the snap connection between the connecting grooves and the bumps also facilitates the disassembly of the heat insulation plate and the box cover.

[0019] As a further improvement, the side-out cell explosion-proof valve battery pack further includes an end plate, and the limiting pressure plate and the end plate are respectively located on different sides of the battery unit. The limiting pressure plate and the end plate are both fixedly arranged relative to the box body and are used for pressing and limiting the battery unit. The limiting pressure plate and the end plate press and limit the battery cells at different positions to prevent the battery cells from exploding. When a thermal runaway occurs, the limiting pressure plate and the end plate press and limit the battery cells at different positions, so that the gas in the battery cells can be ejected from the explosion-proof valve to the greatest extent, avoiding the explosion of the battery cells and the spread of thermal runaway, and even the phenomenon of fire and explosion.

[0020] As a further improvement, a liquid cooling plate is arranged between adjacent two layers of the battery modules. Coolant is injected into the liquid cooling plate for simultaneous liquid cooling and liquid heating of the upper and lower layers of battery modules.

[0021] As a further improvement, an integrated cover plate is further provided at one end of the battery cell, and a plurality of connecting pieces are arranged on the integrated cover plate for corresponding connection with the battery cells to realize the connection between the battery cells.

[0022] As a preferred embodiment, the integrated cover plate includes a tray, a surrounding plate and / or side protection plates, and the connecting piece is located on the tray; both ends of the surrounding plate are respectively connected to both ends of the tray, so that an accommodation cavity with openings at the top and bottom is formed between the surrounding plate and the tray. The integrated cover plate is also connected to the liquid cooling plate, and one opening of the accommodation cavity is close to the liquid cooling plate. The accommodation cavity is filled with heat-conducting insulating glue fillers such as heat-conducting glue or foaming glue, and the filler is in contact connection with the liquid cooling plate, and can conduct the heat of the connecting piece and the ear to the liquid cooling plate 4, so that the liquid cooling plate cools it.

[0023] Further, the height of the accommodation cavity is higher than the top of the connecting piece, so that the filler completely covers the connecting piece, which can not only balance the temperature of the battery cell system, but also prevent the electrolyte and particulate matter from falling on or near the cell ear or the connecting piece after the thermal runaway of the cell, causing local or system short circuit and triggering the spread of thermal runaway of the battery system.

[0024] As a further improvement, the height difference between the height of the accommodation cavity and the top of the connecting piece is 1-10 mm. The setting of this range avoids that the high-temperature electrolyte and particulate matter will ablate and burn through the filler, and the electrolyte will conduct electricity between the pole pieces of the cells, resulting in local short circuit and thermal runaway spread; at the same time, it avoids the filler from blocking the explosion-proof valve of the cell.

[0025] Preferably, the side protection plate covers the side of the integrated cover plate away from the cell, and a heat insulation layer is pasted at the position corresponding to the explosion-proof valve on the side protection plate. The side protection plate is provided to block the gas ejected from the battery unit opposite to it.

[0026] Other technical problems that the side-out cell explosion-proof valve battery pack of the present invention can solve, other technical features included in the technical solution, and the advantages brought by these technical features will be further described in detail in conjunction with the accompanying drawings. Description of the Drawings

[0027] Figure 1 It is an explosion schematic diagram of the overall structure of the battery pack;

[0028] Figure 2 It is an enlarged schematic diagram of the end part of the overall structure of the battery pack;

[0029] Figure 3 It is a schematic diagram of the structure of the battery unit;

[0030] Figure 4 It is a schematic diagram of the installation structure of the liquid cooling plate, the limit pressing plate and the end plate;

[0031] Figure 5 It is a schematic diagram of the structure of the limit pressing plate;

[0032] Figure 6 It is a schematic diagram of the structure of the heat insulation plate;

[0033] Figure 7 Schematic diagram of the integrated cover plate structure;

[0034] Figure 8 Schematic diagram of the internal structure of the integrated cover plate.

[0035] Description of reference numerals:

[0036] 1. Box body; 11. Boss; 101. Sealing surface of the box body; 102. Protrusion; 12. Sealing gasket; 2. Box cover; 201. Side surface of the box cover; 202. Top surface of the box cover; 21. Heat insulation board; 211. First side plate; 212. Second side plate; 213. Connection groove; 3. Battery cell; 31. Explosion-proof valve; 32. Integrated cover plate; 321. Tray; 322. Enclosure; 323. FPC circuit board; 324. Connection piece; 325. Limit convex plate; 326. Side protection plate; 33. Limit pressure plate; 34. Colloid layer; 35. Tab; 36. End plate; 4. Liquid cooling plate. Specific embodiments

[0037] To further understand the content of the present invention, the present invention will be described in detail in combination with the drawings and embodiments.

[0038] The structures, proportions, sizes, etc. shown in the drawings of this specification are only used to cooperate with the content disclosed in the specification for those skilled in this technology to understand and read, and are not used to limit the limiting conditions under which the present invention can be implemented. Therefore, they do not have technical essence. Any modification of the structure, change of the proportional relationship or adjustment of the size, without affecting the effects that the present invention can produce and the purposes that can be achieved, should still fall within the scope that the technical content disclosed by the present invention can cover.

[0039] It should be noted that the terms "first", "second", etc. in the specification, claims and above-mentioned drawings of this application are used to distinguish similar objects, and do not have to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances for the embodiments of the present application described here.

[0040] In this application, the orientation or positional relationship indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal", etc. is based on the orientation or positional relationship shown in the drawings. These terms are mainly used to better describe this application and its embodiments, and are not used to limit that the indicated devices, elements or components must have a specific orientation, or be constructed and operated in a specific orientation. Moreover, in addition to being used to represent the orientation or positional relationship, some of the above terms may also be used to represent other meanings. For example, the term "upper" may also be used to represent a certain attachment relationship or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0041] As Figure 1 shown, this embodiment provides a battery pack, which is a short blade laminated battery pack with a side-out cell explosion-proof valve, including a box body 1 and a box cover 2. One side of the box body 1 has an opening, and the box cover 2 covers the opening of the box body 1 and forms a joint seam.

[0042] Combined Figure 1 with the view orientation in [reference], where the Z direction is the up-down direction, the X direction is the left-right direction, and the Y direction is the front-back direction.

[0043] Combined Figure 3 shown, this side-out cell explosion-proof valve battery pack further includes a plurality of cells 3, and the cells 3 are arranged side by side. When the cells 3 are placed, their length directions are placed along the X direction, and the explosion-proof valves 31 of the cells 3 are arranged at one end in their length directions. After a plurality of cells 3 are arranged, the explosion-proof valves 31 of adjacent cells 3 are arranged staggered with each other.

[0044] Positive tabs and negative tabs are respectively arranged at both ends of the cell 3, and the directions of adjacent cells 3 are opposite, so that it is convenient to connect the cells 3 in series. A plurality of cells 3 are connected in series to form a module-free battery unit, and a plurality of battery units form at least one layer of battery module. In this embodiment, two layers of battery modules are formed, and each layer of battery module includes four battery units. Among them, some explosion-proof valves 31 face the side of the box body 1, and for the convenience of description, this part of the explosion-proof valve 31 is called the front explosion-proof valve; some explosion-proof valves 31 face the other battery unit opposite to it, and for the convenience of description, this part of the explosion-proof valve 31 is called the rear explosion-proof valve. However, in other embodiments, the number of layers of the battery module and the number of battery units can also be set to other values.

[0045] In this embodiment, two layers of battery modules are placed in the box body 1. Among them, the front explosion-proof valve of the battery cell 3 in the upper-layer battery module faces or is close to the joint between the box body 1 and the box cover 2. It should be noted that since the directions of adjacent battery cells 3 are opposite, the explosion-proof valves of adjacent battery cells 3 are staggeredly arranged, and the explosion-proof valves 31 of the battery cells 3 with one end spaced from each other are in the same direction. For example, the explosion-proof valves 31 in the same direction at this end face the side of the box body 1 and are the front explosion-proof valves. Among them, the front explosion-proof valve of the battery cell 3 in the upper-layer battery module faces or is close to the joint between the box body 1 and the box cover 2.

[0046] The battery pack in this embodiment is a module-free double-layer battery with a large capacity. Therefore, higher requirements are placed on the safety of the battery. To improve the battery safety performance, the side-out battery cell explosion-proof valve battery pack in this embodiment further includes a protection component, and the protection component is arranged close to the front explosion-proof valve.

[0047] Combined with Figure 1 and Figure 3 As shown, the two ends of the battery cell 3 in the length direction are respectively the pole ears 35, and the explosion-proof valve 31 is offset from the center of the length direction of the battery cell 3. In this solution, after the box body 1 and the box cover 2 are closed, a joint is formed at the closing position. The front explosion-proof valve in the upper-layer battery module faces or is close to the joint between the box body 1 and the box cover 2. Once a thermal runaway occurs, the front explosion-proof valve ejects gas towards the joint between the box body 1 and the box cover 2, which is likely to cause the sealing failure of the battery pack and lead to a greater safety accident. In this solution, a protection component is provided, and the protection component is arranged close to the front explosion-proof valve. The gas ejected by the front explosion-proof valve mainly faces the protection component, and the protection component bears the gas ejected by the front explosion-proof valve to prevent the sealing failure and fire of the battery pack.

[0048] As a further improvement, combined with Figure 2 As shown, the protection component includes a first protection piece and a second protection piece. The first protection piece is arranged at the joint between the box body 1 and the box cover 2 for sealing protection; the second protection piece is arranged on the box cover 2 for impact resistance and heat insulation protection.

[0049] Specifically, the edge of the opening of the box body 1 towards or close to which the front explosion-proof valve faces is the box body sealing surface 101; here, the box body sealing surface 101 only includes the two side surfaces at the opening of the box body 1 near the front explosion-proof valve. The first protection piece includes a boss 11 arranged on the box body sealing surface 101 and a sealing gasket 12 located at the joint between the box body 1 and the box cover 2.

[0050] It should be noted that the boss 11 in this embodiment is arranged on the two box body sealing surfaces 101 at the opening of the box body 1, while the sealing gasket 12 is arranged in a ring at the joint between the box body 1 and the box cover 2. The boss 11 is arranged adjacent to the front explosion-proof valve for blocking the gas ejected by the explosion-proof valve. The sealing gasket 12 needs to completely seal the joint between the box body 1 and the box cover 2.

[0051] The gasket 12 needs to be elastic. After the box body 1 and the box cover 2 are closed, the box cover 2 is locked and installed on the box body 1. After the two are closed and installed, the gasket 12 will be compressed between them. Using an elastic gasket 12 can produce a better sealing effect after being compressed. In this solution, the gasket 12 is made of foamed silica gel, which is a foamed silica gel gasket. On the one hand, the gasket made of silica gel material has better heat resistance. On the other hand, foamed silica gel has better elasticity and can achieve a better sealing effect.

[0052] As a further improvement, in this solution, when the box body 1 and the box cover 2 are closed, the gasket 12 is compressed; and the height of the compressed gasket 12 is higher than the height of the boss 11. The height of the boss 11 is the distance between the top surface of the boss 11 and the box body sealing surface 101 protruding. The height of the compressed gasket 12 being higher than the height of the boss 11 means that after the box body 1 and the box cover 2 are closed, there is still a certain gap between the top surface of the boss 11 and the box cover 2. Further, the height difference between the compressed gasket 12 and the boss 11 is 0 - 1 mm. This height difference forms a gap between the top surface of the boss 11 and the box cover 2. On the one hand, forming this gap can prevent the box cover 2 from abutting against the boss 11 after the box body 1 and the box cover 2 are closed, so that the required pre-tightening force for the closing of the box body 1 and the box cover 2 cannot be achieved, and the compression degree of the gasket 12 is poor, resulting in a reduction in the sealing effect. On the other hand, the size of this gap does not exceed 1 mm. If the gap is too large, the gas ejected by the explosion-proof valve passing through this gap will damage the structure of the gasket 12 and increase the risk of sealing failure. In this solution, the first protective part protects the gasket 12 by blocking the gas ejected by the explosion-proof valve through the setting of the boss 11, so that the gasket 12 can still effectively seal between the box body 1 and the box cover 2 during thermal runaway, effectively avoiding the sealing failure of the battery pack and preventing the spread of thermal runaway.

[0053] Further, the second protective part combines with the first protective part to further control thermal runaway. The second protective part includes a heat insulation plate 21, and the heat insulation plate 21 is located at one end of the box cover 2 close to the front explosion-proof valve.

[0054] Combine Figure 6As shown, the heat insulation plate 21 is L-shaped, including a first side plate 211 and a second side plate 212. One side edge of the first side plate 211 is connected to one side edge of the second side plate 212. The lid 2 includes a lid top surface 202 and a lid side surface 201 provided around the lid top surface 202. The second side plate 212 is attached to the lid top surface 202 of the lid 2; the first side plate 211 is attached to the lid side surface 201 of the lid 2. The heat insulation plate 21 and the lid 2 can be adhesively connected through a colloid. In addition, the other side edge of the first side plate 211 away from the second side plate 212 is not shorter than the lid side surface 201 it abuts against. Specifically, the first side plate 211 extends beyond the joint between the box body 1 and the lid 2, so that the first side plate 211 can cooperate with the boss 11 to block the gas ejected by the explosion-proof valve, further reducing the ablation damage of the gas ejected by the explosion-proof valve to the gasket 12. Moreover, since insulating paint is usually sprayed on the lid 2, the gas ejected by the explosion-proof valve is likely to cause the insulating paint to catch fire. The heat insulation plate 21 is provided for protection to prevent the insulating paint from catching fire. The heat insulation plate 21 is formed of a high-temperature resistant and impact-resistant material, such as mica plate or mica coil. Preferably, the thickness of the heat insulation plate 21 is 1-3 mm.

[0055] As a further improvement, a plurality of connecting grooves 213 are also provided on the side edge of the first side plate 211 away from the second side plate 212, and bumps 102 are provided at corresponding positions on the inner side of the box body 1. After the battery pack is installed, the connecting grooves 213 are snapped onto the bumps 102, thereby further fixing the heat insulation plate 21, making the installation of the heat insulation plate 21 more firm and avoiding loosening, thereby improving the impact resistance stability of the heat insulation plate 21. Moreover, the snap connection between the connecting grooves 213 and the bumps 102 also facilitates the disassembly of the heat insulation plate 21 and the lid 2.

[0056] Combined with Figure 4 and Figure 5 As shown, the side-out battery cell explosion-proof valve battery pack further includes a limit pressing plate 33 and an end plate 36, and the limit pressing plate 33 and the end plate 36 are respectively located on different sides of the battery unit. Combined with Figure 1As shown, a battery cell, especially the one located in the upper layer, can have its XZ side limited by the battery cores approaching each other, but the battery cores at the outermost edges need to be limited by the end plate 36. In this solution, both the limiting pressure plate 33 and the end plate 36 are fixedly arranged relative to the box body 1. Specifically, the limiting pressure plate 33 is connected to the XY upper side of each battery core 3 through the colloid layer 34. Both ends and the middle of the limiting pressure plate 33 are fixedly connected to the box body 1 and the battery core through rivets. The limiting pressure plate 33 presses the battery core 3 to tightly limit the XY upper side of the battery core. The end plate 36 is fixedly connected to the box body 1 through a pull rod. The limiting pressure plate 33 and the end plate 36 tightly limit the battery core at different positions to prevent the battery core 3 from experiencing a "blown chamber" phenomenon. When a thermal runaway phenomenon occurs, the limiting pressure plate 33 and the end plate 36 press the battery core 3, enabling the gas in the battery core 3 to rush out of the explosion-proof valve 31 to the greatest extent, avoiding an explosion caused by the "blown chamber" of the battery core. The surface of the limiting pressure plate 33 is sprayed with electrophoretic paint for insulation protection. The limiting pressure plate 33 is made of aluminum plate, epoxy board, or steel plate. In other embodiments, the limiting pressure plate 33 is not limited to the listed materials.

[0057] In this embodiment, a liquid cooling plate 4 is arranged between adjacent two layers of battery modules. A coolant is injected into the liquid cooling plate 4 for simultaneously liquid cooling and liquid heating of the upper and lower layer battery modules.

[0058] Combined with Figure 4 As shown, the pull rod connecting the end plate 36 passes through the liquid cooling plate 4 and is connected to the box body 1. The limiting pressure plate 33 is connected to the end plate 36 through rivets. The liquid cooling plate 4, the limiting pressure plate 33, and the end plate 36 enclose a limiting cavity for accommodating the battery cell. The limiting cavity tightly limits the four sides of the battery core, enabling the gas in the battery core 3 to rush out of the explosion-proof valve 31 to the greatest extent, avoiding an explosion caused by the "blown chamber" of the battery core.

[0059] Combined with Figure 2 、 Figure 7 and Figure 8 As shown, integrated covers 32 are respectively arranged at both ends of the battery core 3. A plurality of connecting pieces 324 are arranged on the integrated cover 32 for correspondingly connecting with the tabs 35 of the battery core 3 to connect the battery cores in the battery cell in series. Specifically, the integrated cover 32 includes a tray 321. The connecting pieces 324 are located on the tray 321. An FPC circuit board 323 is also arranged on the tray 321. The connecting pieces 324 are connected to the tabs 35 and are also connected to the FPC circuit board 323. Limiting convex plates 325 are arranged on the tray 321 and between adjacent connecting pieces 324. ， The limiting convex plates 325 are used to limit and fix the connecting pieces 324.

[0060] The integrated cover plate 32 further includes a surrounding plate 322. The two ends of the surrounding plate 322 are respectively connected to the two ends of the tray 321, so as to form a receiving cavity with openings at the upper and lower parts between the surrounding plate 322 and the tray 321. The integrated cover plate 32 is also connected to the liquid cooling plate 4, and one opening of the receiving cavity is close to the liquid cooling plate 4. The receiving cavity is filled with heat-conducting insulating glue fillers such as heat-conducting glue or foaming glue, which can conduct the heat of the connecting piece 324 and the pole ear 35 to the liquid cooling plate 4, so that the liquid cooling plate 4 cools it. The height of the receiving cavity is higher than the top of the connecting piece 324, so that the filler completely covers the connecting piece 324, which can not only balance the temperature of the battery cell system, but also prevent the electrolyte and particulate matter from falling on or near the battery cell pole ear or the connecting piece after the thermal runaway of the battery cell, causing local or system short circuit and triggering the spread of thermal runaway of the battery system.

[0061] The limiting convex plate 325 can also increase the contact area between the filler and the tray 321, so that the filler is filled more firmly.

[0062] Further, the height difference between the height of the receiving cavity and the top of the connecting piece 324 is 1-10 mm. If the height difference is less than 1 mm, the electrolyte and particulate matter ejected after the thermal runaway of the battery cell will fall on the filler, and the high-temperature electrolyte and particulate matter will ablate and burn through the filler, and the electrolyte will conduct the pole pieces between the battery cells, resulting in local short circuit and the spread of thermal runaway; if the height difference is higher than 10 mm, it is easy to block the explosion-proof valve of the battery cell, and it will also waste space and materials.

[0063] In addition, it should be noted that the integrated cover plate 32 arranged near the rear explosion-proof valve further includes a side protection plate 326. The side protection plate 326 covers the side of the integrated cover plate away from the battery cell, and a heat insulation layer is pasted at the position corresponding to the explosion-proof valve. The heat insulation layer is made of mica and other materials. The side protection plate 326 is arranged to block the gas ejected from the battery unit opposite to it.

[0064] In the side-out battery cell explosion-proof valve battery pack in this solution, by arranging the protection components to block the gas, particulate matter, electrolyte, etc. ejected from the explosion-proof valve, through the combination of the first protection component and the second protection component, it is possible to prevent the gas, particulate matter and electrolyte from damaging the sealing performance of the battery pack, and at the same time prevent the insulating paint from catching fire. In addition, a limiting pressure plate 33 and an end plate 36 are arranged to press and limit the battery cell 3, so as to avoid the phenomenon of the battery cell bursting, and enable the gas in the battery cell to be relieved through the explosion-proof valve to the greatest extent. A liquid cooling plate 4 is also arranged between the upper and lower battery modules to further improve the safety of the battery pack.

[0065] In this solution, the electrodes of the battery cell extend out from both ends in the X direction. Connecting pieces are used to connect the battery cells to form a battery unit, and several battery units form a layer of battery module. The battery module is placed in the box 1 to form a battery pack system. The limiting pressure plate 33 and the end plate 36 jointly compress and limit the battery cell 3, inhibiting the explosion of the battery cell due to thermal runaway and thus preventing the spread of thermal runaway. The combination of the first protection component and the second protection component prevents the destruction of the system airtightness caused by the thermal runaway of the battery cell, thereby preventing the system from catching fire and exploding. The liquid cooling plate 4 and the integrated cover plate 32 further improve the safety of the battery pack. This battery pack provides comprehensive thermal safety protection for the battery pack system from the protection of the battery cell to the protection of the battery module and then to the protection of the system.

[0066] This solution is especially applicable to the short blade stacked battery pack system. Since the battery cell is relatively long, when thermal runaway occurs in the battery cell, the exhaust and pressure relief inside the battery cell are not timely, and it is extremely easy for the battery cell to explode. After the "short blade stacked" battery system battery cell explodes, it is very easy to cause thermal runaway of the surrounding battery cells, resulting in the spread of thermal runaway. When large-scale spread occurs in the system, the battery system will inevitably catch fire and explode violently, causing safety accidents. The explosion of the "short blade stacked" battery due to thermal runaway and the resulting safety accidents are one of the "pain points" in the industry. The present invention effectively solves the risk of explosion of the "short blade stacked" battery due to thermal runaway and solves one of the "pain points" of the lithium battery industry. Specifically, on the one hand, the limiting pressure plate 33, the end plate 36 and the bottom liquid cooling plate 4 are used to limit the battery cell on all sides, so that the ejecta of the battery thermal runaway can only be ejected from the explosion-proof valve of the battery cell, eliminating the risk of explosion of the "short blade stacked" battery cell and solving the thermal safety of the "short blade stacked" battery system. On the other hand, the protection component is used to provide impact resistance and heat insulation protection for the battery system, and effectively prevent and control the fire and explosion of the battery system.

[0067] Some of the terms referred to here, such as "installed", "set", "provided with", "connected", should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, or there can be internal communication between two devices, components or parts. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0068] The above has schematically described the present invention and its implementation manners. This description is not restrictive, and what is shown in the drawings is only one of the implementation manners of the present invention. The actual structure is not limited thereto. Therefore, if those of ordinary skill in the art are inspired by it and design similar structural manners and embodiments without creative work without departing from the purpose of the present invention, they should fall within the protection scope of the present invention.

Claims

1. A battery pack, comprising: A box body (1) and a box cover (2), wherein one side of the box body (1) has an opening, and the box cover (2) covers the opening to form a joint; It is characterized by further comprising: A plurality of battery cells (3), one end of each battery cell (3) being provided with an explosion-proof valve (31); the battery cells (3) being arranged side by side to form a battery unit, the battery unit forming at least one layer of battery modules being placed in a box body (1), and the explosion-proof valve (31) portions of the battery cells (3) in at least one layer of the battery modules being oriented toward or close to a joint between the box body (1) and the box cover (2); The protection component is arranged close to the explosion-proof valve (31), and the explosion-proof valve (31) is arranged toward or close to the joint between the box body (1) and the box cover (2). The limiting pressure plate (33) is located on a side of the battery unit close to the box cover (2) and is used to press the battery unit.

2. The side-outlet explosion-proof valve battery pack according to claim 1, characterized in that: The protection component comprises a first protection member and a second protection member; the first protection member is arranged at the joint between the box body (1) and the box cover (2); and the second protection member is arranged on the box cover (2).

3. The battery pack according to claim 2, characterized in that: The edge of the opening of the box body (1) toward or close to which the explosion-proof valve (31) is directed is the box body sealing surface (101); The first protective member comprises a boss (11) arranged on the sealing surface (101) of the box body and a sealing gasket (12) located at the joint between the box body (1) and the box cover (2).

4. The battery pack according to claim 2, characterized in that: The second protective member comprises a heat insulation board (21), and the heat insulation board (21) is located at one end of the box cover (2) close to the explosion-proof valve (31).

5. The battery pack according to claim 3, characterized in that: When the box body (1) and the box cover (2) are closed, the sealing gasket (12) is compressed; and the height of the compressed sealing gasket (12) is higher than the height of the boss (11).

6. The battery pack according to claim 5, characterized in that: The height difference between the sealing gasket (12) and the boss (11) after being pressed is 0-1 mm.

7. The battery pack according to claim 5 or 6, characterized in that: The sealing pad (12) is made of foamed silica gel.

8. The battery pack according to claim 4, characterized in that: The heat insulation board (21) is L-shaped, and comprises a first side board (211) and a second side board (212), and one side edge of the first side board (211) is connected to one side edge of the second side board (212); The box cover (2) comprises a box cover top surface (202) and a box cover side surface (201) arranged around the box cover top surface (202); The second side plate (212) is in contact with the top surface (202) of the box cover (2); The side plate 1 (211) is in contact with the box cover side surface (201) of the box cover (2).

9. The battery pack according to claim 8, characterized in that: The side panel 1 (211) extends toward the box body (1) and exceeds the joint between the box body (1) and the box cover (2).

10. The battery pack according to claim 9, characterized in that: A plurality of connection grooves (213) are also provided on the side of the first side panel (211) away from the second side panel (212), and a protrusion (102) is provided at a corresponding position on the inner side of the box body (1); the connection groove (213) is used for being snap-connected with the protrusion (102).

11. The battery pack according to any one of claims 1 to 6 or 8 to 10, characterized in that: It also includes end plates (36), and the end plates (36) are respectively located on one side of the large surface in the length direction of the battery unit.

12. The battery pack according to claim 11, characterized in that: The limiting pressure plate (33) and the end plate (36) are both fixedly arranged relative to the box body (1) and are used to press and limit the battery unit.

13. The battery pack according to claim 11, characterized in that: A liquid cooling plate (4) is arranged between two adjacent layers of battery modules.

14. The battery pack according to claim 13, characterized in that: An integrated cover plate (32) is also provided at one end of the battery cell (3), and a plurality of connecting plates (324) are provided on the integrated cover plate (32) for corresponding connection with the battery cell (3).

15. The battery pack according to claim 14, characterized in that: The integrated cover plate (32) comprises a tray (321), a surrounding plate (322) and / or a side protection plate (326), and the connecting piece (324) is located on the tray (321); The two ends of the enclosure (322) are respectively connected to the two ends of the tray (321), so that a receiving cavity with upper and lower openings is formed between the enclosure (322) and the tray (321).

16. The battery pack according to claim 15, characterized in that: The integrated cover plate (32) is also connected to the liquid cooling plate (4), and an opening of the accommodating cavity is close to the liquid cooling plate (4).

17. The battery pack according to claim 15, characterized in that: The height of the accommodating cavity is higher than the top of the connecting piece (324).

18. The battery pack according to claim 17, characterized in that: The height difference between the accommodating cavity and the top of the connecting piece (324) is 1-10 mm.

19. The battery pack according to claim 15, characterized in that: The side protection plate (326) covers a side of the integrated cover plate away from the battery core, and a heat insulation layer is pasted to a position of the side protection plate (326) corresponding to the explosion-proof valve.

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