Power battery module and battery pack

Abstract

A power battery module, comprising a plastic support (1) and a sealing cover plate (2), the sealing cover plate (2) covering the plastic support (1), the plastic support (1) cooperating with the sealing cover plate (2) to form a pressure relief chamber (3), and a pressure relief protective layer (4) made of a heat insulation material being formed on an inner chamber wall of the pressure relief chamber (3).

Description

A power battery module and battery pack

[0001] This application claims priority to Chinese Patent Application No. 2024214246152, filed on June 20, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of batteries, and more particularly to a power battery module and battery pack. Background Technology

[0003] A power battery is a storage battery that provides power to electric vehicles, electric trains, and other similar vehicles. Power batteries are a core component of new energy vehicles and a crucial direction for future energy transition.

[0004] In the battery pack of the related technology, the cell support, the second part of the casing, and the inner wall form a pressure relief chamber, which is connected to the outside. A barrier membrane is provided on the side of the cell support facing the second part of the casing to block the expansion foam, so that there is no expansion foam in the pressure relief chamber. By providing a barrier membrane on the side of the cell support facing the second part of the casing, expansion foam can be prevented from entering the pressure relief chamber under the action of gravity. Thus, when the cell experiences thermal runaway, high-temperature and high-pressure ejected material is released from the cell explosion-proof valve at the bottom of the cell. The pressure of the high-temperature and high-pressure ejected material acting on the expansion foam and barrier membrane in the vent hole is greater than the compressive strength of the barrier membrane and the adhesive in the vent hole, so as to rupture the barrier membrane and the expansion foam in the vent hole. The cell explosion-proof valve opens, and the high-temperature and high-pressure ejected material enters the pressure relief chamber through the vent hole, and is finally discharged to the outside of the battery pack through the casing explosion-proof valve connected to the pressure relief chamber. Technical issues

[0005] In the above structural design, since the depth dimension of the pressure relief chamber along the central axis of the battery cell is not very large, the high-temperature and high-pressure ejected material will inevitably generate thermal shock after entering the pressure relief chamber, causing damage to the pressure relief chamber and thus rendering the pressure relief function and the function of guiding the ejected material out of the chamber ineffective. Technical solutions

[0006] In a first aspect, this application provides a power battery module, including:

[0007] Plastic bracket;

[0008] A sealing cover is provided on the plastic bracket, and the plastic bracket is formed with the sealing cover to form a pressure relief chamber, the inner wall of the pressure relief chamber being formed with a pressure relief protective layer made of heat insulation material.

[0009] Secondly, a battery pack, including the aforementioned power battery module. Beneficial effects

[0010] A cleverly designed pressure relief protective layer is formed within the pressure relief chamber, effectively protecting the plastic support and sealing cover from damage caused by high-pressure thermal shock. This ensures the effectiveness of the pressure relief chamber, allowing for the stable discharge of high-temperature, high-pressure ejected material away from the power battery module. This effectively reduces the risk of thermal propagation within the power battery module and solves the problem of existing pressure relief chambers being easily damaged or failing due to thermal shock from high-temperature, high-pressure ejected material. Furthermore, the fitted design of the plastic support and sealing cover facilitates the formation of the pressure relief protective layer on the inner wall of the pressure relief chamber, reducing processing difficulty and costs. Attached Figure Description

[0011] Figure 1 is an exploded view of the overall structure of a power battery module according to this application;

[0012] Figure 2 is a partial exploded view of a power battery module according to this application;

[0013] Figure 3 is a top view of the assembly of a power battery module according to this application;

[0014] Figure 4 is a cross-sectional view of section AA in Figure 2;

[0015] Figure 5 is a magnified view of part B in Figure 3;

[0016] Figure 6 is a magnified view of part C in Figure 3.

[0017] Icons: 1-Plastic bracket, 11-Vent hole, 12-Inner side of bracket, 13-Outer side of bracket, 14-Circumferential side of bracket, 2-Sealing cover plate, 21-Inner side of cover plate, 22-Outer side of cover plate, 23-Circumferential side of cover plate, 3-Pressure relief chamber, 4-Pressure relief protection layer, 41-Cover plate protection layer, 42-Bracket protection layer, 43-Transition protection layer, 5-Snap-on protrusion, 6-Sealing connector, 7-Foaming colloid, 8-Battery cell unit, 9-Pressure relief connecting pipe. Embodiments of the present invention

[0018] In the description of this application, it should be noted that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0019] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of this application.

[0020] Referring specifically to Figures 1 to 5, this application discloses a power battery module, including a plastic bracket 1, a sealing cover 2, and one or more battery cell units 8 connected in series and parallel. The shape and size of the sealing cover 2 are adapted to the shape and size of the plastic bracket 1. The sealing cover 2 has an inner side 21, an outer side 22, and a peripheral side 23 that are oppositely arranged. The two opposite sides of the peripheral side 23 are respectively connected to the inner side 21 and the outer side 22.

[0021] In some embodiments, the plastic bracket 1 has an inner side 12, an outer side 13, and a peripheral side 14. The inner side 12 and the outer side 13 are arranged opposite to each other. The two opposite sides of the peripheral side 14 are respectively connected to the inner side 12 and the outer side 13. The outer side 13 is the side of the plastic bracket 1 used to approach the battery cell unit 8. The sealing cover 2 is placed on the plastic bracket 1. The inner side 12 of the plastic bracket 1 and the inner side 21 of the sealing cover 2 cooperate to form a pressure relief chamber 3. The vertical distance between the inner side 12 of the bracket and the inner side 21 of the cover is the depth dimension of the pressure relief chamber 3.

[0022] In some embodiments, the inner wall of the pressure relief chamber 3 is formed with a pressure relief protective layer 4 made of heat-insulating material, such as mica material with high-temperature resistance. The pressure relief protective layer 4 is formed by spraying. Of course, it can also be connected by snap-fit ​​or adhesive. In this way, when high-temperature and high-pressure ejected material is injected into the interior of the pressure relief chamber 3, it will impact the pressure relief protective layer 4, so that the high-temperature and high-pressure ejected material generated by the thermal runaway state of the battery cell unit 8 will not directly impact the pressure relief chamber wall, thus preventing a large amount of heat and impact force from damaging the plastic bracket 1 and / or sealing cover 2, reducing the risk of failure of the plastic bracket 1 and / or sealing cover 2, and ensuring that the high-temperature and high-pressure material can be discharged under the guidance of the pressure relief chamber 3 and away from the battery module / battery pack.

[0023] In some embodiments, as specifically shown in Figures 1 to 5, the aforementioned pressure relief protection layer 4 includes a cover plate protection layer 41, which is disposed on the sealing cover plate 2. Specifically, the cover plate protection layer 41 is disposed on the inner side 21 of the sealing cover plate 2, and the cover plate protection layer 41 covers each battery cell unit 8 at least in the orthographic projection direction. Thus, when any battery cell unit 8 experiences thermal runaway, it can ensure that the high-temperature and high-pressure jets released by the battery cell unit 8 impact the inner side 21 of the cover plate.

[0024] In some embodiments, specifically as shown in Figures 1 to 5, the pressure relief protection layer 4 further includes a support protection layer 42, which is disposed on the plastic support 1. Specifically, the support protection layer 42 is disposed on the inner side 12 of the support of the plastic support 1, and the support protection layer 42 covers each cell unit 8 at least in the orthographic projection direction. In some embodiments, the support protection layer 42 covers the entire inner side 12 of the support.

[0025] Thus, when a high-temperature, high-pressure substance impacts the cover plate protective layer 41 and rebounds towards the plastic bracket 1, the high-temperature, high-pressure substance will not directly cause thermal shock to the plastic bracket 1 under the action of the bracket protective layer 42, thus protecting the plastic bracket 1 from damage.

[0026] It should be noted that the power battery module also includes a foaming colloid 7, which is a polyurethane or silicone-based adhesive, without specific limitations. The foaming colloid 7 wraps around the periphery of the battery cell unit 8 and the cell explosion-proof valve of the battery cell unit 8, and each battery cell unit 8 is mounted on a plastic bracket 1. The plastic bracket 1 is equipped with vent holes 11 or weak points that are aligned with the cell explosion-proof valve.

[0027] In some embodiments, the foamed colloid 7 can be injected into the battery box of the battery pack, and then the battery pack formed by connecting one or more cell units 8 can be placed in the battery box, so that each cell unit 8 of the battery pack is completely wrapped by the foamed colloid 7. This not only utilizes the good flame-retardant and heat-insulating capabilities of the foamed colloid 7 to prevent the heat, substances, flames, etc. of any cell unit 8 from being transferred to adjacent cell units 8 after thermal runaway, but also eliminates the need to set injection holes on the battery box. This solves the problem of designing glue flow channels at the bottom of the cell unit 8 and additional openings in the CCS module caused by the existing process of filling the foamed colloid 7 from the side or top.

[0028] In some embodiments, the foamed colloid 7 is filled between the plastic support 1 and the battery cell unit 8 to seal the assembly gap between the plastic support 1 and the battery cell unit 8 and to cover the battery cell explosion-proof valve of the battery cell unit 8, thus avoiding the problem of the battery cell explosion-proof valve being exposed. An unexpected effect is that, supported by the support protective layer 42, the foamed colloid 7 can be prevented from entering the pressure relief chamber 3 from the vent hole 11 or weak points under the action of gravity.

[0029] When a thermal runaway occurs in the cell unit 8, the cell unit 8 compresses and ruptures the foam colloid 7 and the support protective layer 42 near the cell explosion-proof valve, causing the high-temperature, high-pressure ejected material to be released from the cell explosion-proof valve of the cell unit 8 and enter the pressure relief chamber 3. Meanwhile, the support protective layer 42 seals and blocks the corresponding vent holes 11 or weak points of other cell units 8, thus protecting adjacent or nearby cell units 8 from the effects of the high-temperature, high-pressure ejected material.

[0030] In some embodiments, as shown in Figures 1 to 5, the pressure relief protection layer 4 further includes a transition protection layer 43, with the two opposite sides of the transition protection layer 43 connected to the cover plate protection layer 41 and the bracket protection layer 42, respectively.

[0031] In some embodiments, the transition protective layer 43 is disposed on the plastic bracket 1, or alternatively on the sealing cover 2, or both the plastic bracket 1 and the sealing cover 2 may be provided with the transition protective layer 43. Thus, through the cooperation of the cover protection layer 41, the cover protection layer 41, and the transition protective layer 43, the large amount of heat carried by the high-temperature, high-pressure jet during its flow along the extension direction of the pressure relief chamber 3 is completely blocked by the pressure relief protective layer 4, reducing the risk of heat deformation or melting of the plastic bracket 1 and the sealing cover 2, thereby effectively ensuring the effectiveness of the plastic bracket 1 and the sealing cover 2 during use.

[0032] In some embodiments, the power battery module also includes a pressure relief connecting pipe 9, through which the interior of the pressure relief cavity is connected to the exterior of the pressure relief cavity, so that the high-temperature and high-pressure jet flowing inside the pressure relief wall can be discharged into the pressure relief cavity, that is, the high-temperature and high-pressure jet can be guided away from the power battery module, avoiding the impact of a large amount of heat on the function and status of the battery pack.

[0033] In some embodiments, as specifically shown in Figures 1, 2, 4, and 6, the plastic bracket 1 is provided with a snap-fit ​​protrusion 5 extending along the circumferential direction of the inner side surface 12 of the plastic bracket 1. The sealing cover plate 2 is provided with a snap-fit ​​groove corresponding to the snap-fit ​​protrusion 5, and the snap-fit ​​protrusion 5 engages with the snap-fit ​​groove. This not only achieves the purpose of detachable connection between the plastic bracket 1 and the sealing cover plate 2, ensuring that the pressure relief protective layer 4 is formed inside the pressure relief chamber 3, reducing the processing difficulty and cost of forming the pressure relief protective layer 4, but also achieves rapid positioning and stable installation during the assembly process of the plastic bracket 1 and the sealing cover plate 2.

[0034] In some embodiments, the sealing cover plate 2 may also be provided with a buckle protrusion 5, and the plastic bracket 1 may be provided with a buckle groove corresponding to the buckle protrusion 5, and the buckle protrusion 5 may be engaged with the buckle groove.

[0035] In some embodiments, as shown in Figures 1, 2, 4 and 6, a sealing connector 6 is provided between the snap-fit ​​protrusion 5 and the snap-fit ​​groove. The sealing connector 6 extends along the groove length of the snap-fit ​​groove, thereby sealing the assembly gap between the snap-fit ​​protrusion 5 and the snap-fit ​​groove, thus improving the sealing performance of the pressure relief chamber 3.

[0036] It should be noted that the aforementioned sealing cover 2 may be made of plastic or metal. In some embodiments, the aforementioned cell unit 8 is a cylindrical battery; of course, it may also be a prismatic battery. Taking a cylindrical battery as an example, the cell unit 8 has a positive terminal and a negative terminal arranged opposite to each other. The cell explosion-proof valve of the cell unit 8 may be located near the positive terminal of the cell unit 8, while in other designs, the cell explosion-proof valve of the cell unit 8 may also be located at the negative terminal of the cell unit 8.

[0037] It should also be noted that, when one or more battery cell units 8 arranged along the short side of the plastic support 1 are defined as battery pack modules, then the array direction of the battery pack modules is the direction along the long side of the plastic support 1. In each battery cell unit 8 within the battery pack module, the positive terminal of the cell is located on the same side. In some embodiments, the positive terminals of the cell units 8 in adjacent battery pack modules are staggered.

[0038] In some embodiments, specifically as shown in Figure 1, plastic supports 1 are provided on both sides of the battery pack, and each plastic support 1 is equipped with a sealing cover 2, thus forming a pressure relief chamber 3 on both sides of the battery pack. In addition, each plastic support 1 is equipped with an exhaust hole 11 or a weak part that is aligned with the cell explosion-proof valve.

[0039] With this configuration, regardless of whether the cell explosion-proof valve of cell unit 8 is located near the positive terminal of cell unit 8 or near the negative terminal of cell unit 8, and regardless of whether the positive terminals of the cell units 8 of two adjacent battery pack modules are staggered or side-by-side, in the event of thermal runaway, any cell unit can release the high-temperature, high-pressure ejected material into the pressure relief chamber 3, improving the flexibility of battery design. Simultaneously, the pressure relief chamber 3 is formed with a pressure relief protection layer 4, which stably guides and discharges the high-temperature, high-pressure ejected material out of the pressure relief chamber 3, effectively improving the safety and stability of the battery module.

[0040] Based on the structure and connection relationship of the power battery module described above, the inventors also provide a battery pack that includes the aforementioned power battery module.

Claims

1. A power battery module, comprising: a plastic support (1); a sealing cover plate (2) covering the plastic support (1), and the plastic support (1) being matched with the sealing cover plate (2) to form a pressure relief chamber (3), and an inner cavity wall of the pressure relief chamber (3) being formed with a pressure relief protection layer (4) made of a heat insulation material.

2. The power battery module of claim 1, wherein: The pressure relief protection layer (4) comprises a cover plate protection layer (41) arranged on the sealing cover plate (2).

3. The power battery module of claim 2, wherein: The pressure relief protection layer (4) further comprises a support protection layer (42) arranged on the plastic support (1).

4. The power battery module of claim 3, wherein: The pressure relief protection layer (4) further comprises a transition protection layer (43) connected to the cover plate protection layer (41) and the support protection layer (42) at two opposite sides thereof.

5. The power battery module according to any one of claims 1 to 4, wherein: One of the plastic support (1) and the sealing cover plate (2) is provided with a buckle protrusion (5), and the other of the plastic support (1) and the sealing cover plate (2) is provided with a buckle groove, and the buckle protrusion (5) is buckled in the buckle groove.

6. The power battery module of claim 5, wherein: A sealing connector (6) is arranged between the buckle protrusion (5) and the buckle groove, and the sealing connector (6) is arranged along a groove length direction of the buckle groove.

7. The power battery module according to claim 1, further comprising a foamed colloid (7) and one or more electric cell units (8) connected in series and / or in parallel, the foamed colloid (7) wrapping a peripheral side of the electric cell unit (8) and an electric cell explosion-proof valve of the electric cell unit (8), and each of the electric cell units (8) is arranged on the plastic support (1), and the plastic support (1) is arranged with an exhaust hole (11) or a weak part arranged in position with the electric cell explosion-proof valve.

8. The power battery module according to claim 7, further comprising a pressure relief communication pipe (9), and an inside of the pressure relief cavity is communicated with an outside of the pressure relief cavity through the pressure relief communication pipe (9).

9. The power battery module according to claim 7 or 8, wherein: One or more of the electric cell units (8) are connected to form a battery pack, two sides of the battery pack are provided with the plastic supports (1), and each of the plastic supports (1) is arranged with the sealing cover plate (2), and each of the plastic supports (1) is arranged with the exhaust hole (11) or the weak part arranged in position with the electric cell explosion-proof valve.

10. A battery pack comprising the power battery module according to any one of claims 1 to 9.

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