Battery pack lower shell and battery pack

Abstract

The utility model provides a battery pack lower shell and a battery pack. The utility model relates to a lower shell of a battery pack, which is used for accommodating a battery monomer of a double-layer module and comprises a main body frame, a first exhaust channel and a second exhaust channel, the cross beam is connected to the main body frame and provided with a second exhaust channel in the length direction of the cross beam, and the second exhaust channel communicates with an independent first exhaust channel; the cross beams are arranged in pairs corresponding to the upper and lower layers of battery monomers and are communicated with the anti-explosion valves of the corresponding layers of battery monomers; and when the battery monomers are in thermal runaway, the second exhaust channel and the first exhaust channel jointly form exhaust of smoke of the battery pack. According to the lower shell of the battery pack, electric heating separation in the battery pack can be realized, and meanwhile, the upper-layer battery monomers and the lower-layer battery monomers have different flue gas emission paths, so that heat diffusion can be reduced, the adjacent-layer battery monomers are unlikely to be affected, and the use safety of the battery pack is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a lower shell of a battery pack. The utility model also relates to a battery pack provided with the lower shell of the battery pack. Background Art

[0002] As global resource issues, such as energy shortages, environmental pollution and climate change, become increasingly prominent, the global society's demand for sustainable development is becoming more urgent. Against this backdrop, the new energy industry, with its clean, renewable and low-carbon characteristics, has become one of the key industries to address global resource issues and has ushered in vigorous development opportunities. In the field of new energy, battery packs, as the core product of energy storage devices, play a vital role. More and more companies are continuously improving the performance and quality of battery packs through technological innovation, promoting the rapid development of the new energy industry.

[0003] The energy density of the battery pack is the key factor affecting the performance of the battery pack, and the explosion-proof ability of the battery pack during thermal runaway is the key to the safety performance of the battery pack. Nowadays, a type of double-layer module structure battery pack with double-layer arranged cells has appeared on the market. This type of battery pack can improve the space utilization inside the battery pack, so that the battery pack can accommodate more battery cells. The explosion-proof method of this type of battery pack usually adopts internal exhaust of the battery pack, that is, the high-temperature flue gas generated by the thermal runaway battery cell is discharged from the battery pack through the internal space of the battery pack through the explosion-proof valve of the battery pack. This exhaust method will cause the flue gas to contact the internal electrical parts, and it is impossible to achieve thermal and electrical separation.

[0004] In some relevant documents, a new exhaust method is disclosed, in which an exhaust channel is set in the lower shell of the battery pack, and the exhaust channel is connected to the explosion-proof valves of all battery cells. After the battery cell has thermal runaway, the exhaust gas will enter the exhaust channel and then be uniformly discharged from the explosion-proof valve at one end of the battery pack. The high-temperature flue gas will not directly contact the electrical parts in the battery pack, thus achieving thermal and electrical separation. However, using this exhaust method, the heat diffusion area of ​​the flue gas generated by the battery cell after thermal runaway is large, which affects the safety of the battery pack. Utility Model Content

[0005] In view of this, the utility model aims to propose a battery pack lower shell to reduce the heat diffusion area of ​​smoke generated by thermal runaway of battery cells in a double-layer module battery pack and improve the safety of battery pack use.

[0006] In order to achieve the above object, the technical solution of the utility model is implemented as follows:

[0007] A battery pack lower shell, used for accommodating a battery cell of a double-layer module, comprising:

[0008] The main frame is provided with a first exhaust passage communicating with the outside of the battery pack;

[0009] A crossbeam, connected to the main frame, and provided with a second exhaust channel along its length, wherein the second exhaust channel is connected to an independent first exhaust channel;

[0010] The crossbeams are arranged in pairs corresponding to the upper and lower layers of battery cells and are connected to the explosion-proof valves of the battery cells of the corresponding layers; when the battery cells are in thermal runaway, the second exhaust channel and the first exhaust channel together constitute the exhaust of smoke from the battery pack.

[0011] Furthermore, the main frame includes side beams, and the first exhaust passages are arranged along the height direction in the side beams.

[0012] Furthermore, a pair of cross beams are provided on each side of the main frame in the length direction.

[0013] Furthermore, the air inlet and the air outlet of the first exhaust passage are respectively arranged at two ends of the side beam along its own length direction.

[0014] Furthermore, longitudinal beams are connected between the two pairs of transverse beams.

[0015] Furthermore, the side beam is respectively provided with one at two opposite ends in the width direction of the main frame; the cross beam is connected between the two side beams, and is respectively provided with one of the second exhaust channels on both sides in its own length direction, and each of the second exhaust channels is connected to the first exhaust channel of the adjacent side beam.

[0016] Furthermore, the battery cell is a blade battery cell.

[0017] Furthermore, an explosion-proof device is provided at the outlet of the first exhaust passage.

[0018] Furthermore, a cold plate assembly is sandwiched between the two cross beams arranged in pairs, and the cold plate assembly contacts the side walls of the upper and lower layers of the battery cells at the same time.

[0019] Compared with the prior art, the utility model has the following advantages:

[0020] The lower shell of the battery pack described in the utility model forms a smoke exhaust path when the battery cell is in thermal runaway by arranging a first exhaust channel in the main frame and a second exhaust channel in the crossbeam, so as to realize the electric and thermal separation inside the battery pack, that is, the separation of the smoke generated by the thermal runaway of the electrical components in the battery pack and the battery cells, and the high-temperature smoke will not directly contact the electrical components, so as to protect the electrical components from the influence of the high-temperature smoke; the crossbeams are arranged in pairs corresponding to the upper and lower layers of battery cells, so that the upper battery cells and the lower battery cells have different smoke exhaust paths, and the high-temperature smoke generated by the upper battery cells or the lower battery cells in thermal runaway will be discharged from the battery pack from the corresponding smoke exhaust path, and the smoke passes through fewer areas, which can reduce heat diffusion. At the same time, the smoke does not contact the battery cells of the adjacent layers during movement, which can reduce the influence on the battery cells of the adjacent layers, making the battery cells of the adjacent layers less susceptible to influence, thereby improving the safety of the battery pack.

[0021] The first exhaust channels are arranged along the height direction in the side beam, which can make more effective use of the internal space of the side beam and reasonably separate the first exhaust channels. At the same time, the part of the side beam used to separate the first exhaust channels can form ribs to strengthen the structural strength of the side beam. Even if the side beam is a hollow structure, it can still have good lateral supporting strength to better protect internal parts.

[0022] The two pairs of cross beams can cool the battery cells on both sides of the lower shell of the battery pack along the length direction, so more battery cells can be cooled, thereby increasing the battery cell capacity of the lower shell of the battery pack.

[0023] By arranging the air inlet and outlet of the first exhaust channel at the two ends of the side beam along its own length direction, the internal space of the side beam can be reasonably utilized, so that when the battery cell is in thermal runaway, the smoke generated has a certain buffer in the first exhaust channel and is then discharged from the battery pack. It is not easy to cause instantaneous air pressure damage inside the battery pack, thereby improving the safety performance of the battery pack.

[0024] The longitudinal beam and the cross beam together form an "I"-shaped structure, which can effectively improve the structural retention ability of the cross beam when impacted by high-temperature smoke, and improve the overall stiffness of the lower shell of the battery pack.

[0025] By setting two side beams and two second exhaust channels in the cross beam, the battery cells in the same layer can discharge smoke on both sides of the width direction of the main frame, shortening the distance required for the smoke to move before entering the first exhaust channel, reducing heat diffusion, and improving the safety performance of the battery pack.

[0026] The blade cell is a long rectangular block with explosion-proof valves set at the ends in the length direction to facilitate unified thermal runaway management.

[0027] The explosion-proof device is used to generate a passage through changes in its own structure after the air pressure in the first exhaust passage rises rapidly, so that the smoke in the first exhaust passage can be discharged quickly.

[0028] Placing the cold plate assembly between the upper battery cells and the lower battery cells can cool the bottom end of the upper battery cells and the top end of the lower battery cells at the same time, and can also quickly absorb part of the heat energy when the battery cells thermally run away, thereby reducing production costs and achieving a lightweight design of the battery pack.

[0029] Another object of the present invention is to provide a battery pack having the battery pack lower shell as described above.

[0030] The battery pack described in the utility model can achieve electric and thermal separation inside the battery pack when thermal runaway occurs in the battery cells inside, that is, separation of the electrical components in the battery pack and the smoke generated by the thermal runaway of the battery cells. The high-temperature smoke will not directly contact the electrical components, and the electrical components can be protected from the influence of the high-temperature smoke. Each layer of battery cells has a different independent smoke emission path. When the battery cells are in thermal runaway, the high-temperature smoke generated will be discharged from the battery pack from the corresponding smoke emission path. The area through which the smoke passes is smaller, which can reduce heat diffusion. At the same time, the smoke will not contact the battery cells of adjacent layers during movement, which can reduce the influence on the battery cells of adjacent layers, making the battery cells of adjacent layers less susceptible to influence, thereby improving the safety of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0032] Figure 1 This is a schematic diagram of the overall structure of the lower housing of the battery pack of the first embodiment of the utility model;

[0033] Figure 2 This is a schematic diagram of the positional relationship between the battery cells and the cold plate assembly in the lower shell of the battery pack according to the first embodiment of the utility model;

[0034] Figure 3 It is a top view of the overall structure of the lower shell of the battery pack of the first embodiment of the utility model;

[0035] Figure 4 for Figure 3 Sectional view in the AA direction;

[0036] Figure 5 This is a schematic structural diagram of a crossbeam according to an embodiment of the present utility model.

[0037] Description of reference numerals:

[0038] 1. Battery cell; 101. Explosion-proof valve;

[0039] 2. Main frame;

[0040] 201, side beam; 202, front beam; 203, rear beam; 204, longitudinal beam; 205, partition beam;

[0041] 3. beam; 301. air inlet;

[0042] 4. Explosion-proof device;

[0043] 5. Cold plate assembly;

[0044] a. First exhaust channel; b. Second exhaust channel. DETAILED DESCRIPTION

[0045] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0046] In the description of the present invention, it should be noted that if there are terms such as "upper", "lower", "inner", "outer" and the like indicating orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, if there are terms such as "first" and "second", they are also used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0047] In addition, in the description of the present invention, unless otherwise clearly defined, the terms "installation", "connection", "connection" and "connector" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood in combination with specific circumstances.

[0048] The present invention will be described in detail below with reference to the accompanying drawings and in combination with embodiments.

[0049] Embodiment 1

[0050] The present embodiment relates to a battery pack lower shell to optimize the exhaust channel structure inside a battery pack using a double-layer module to reduce the thermal diffusion of high-temperature smoke in the battery pack when a battery cell has thermal runaway, thereby improving the safety of the battery pack.

[0051] In terms of overall structure, a battery pack lower shell in this embodiment is used to accommodate a battery cell 1 of a double-layer module, and includes:

[0052] The main frame 2 is provided with a first exhaust passage a communicating with the outside of the battery pack;

[0053] The crossbeam 3 is connected to the main frame 2 and is provided with a second exhaust channel b along its length direction, and the second exhaust channel b is connected to an independent first exhaust channel a;

[0054] The crossbeams 3 are arranged in pairs corresponding to the upper and lower layers of battery cells 1 and are connected to the explosion-proof valves 101 of the corresponding layers of battery cells 1; when the battery cells 1 are in thermal runaway, the second exhaust channel b and the first exhaust channel a together constitute the exhaust of smoke from the battery pack.

[0055] As set above, by setting the first exhaust channel a in the main frame 2 and the second exhaust channel b in the crossbeam 3, a smoke exhaust path is formed when the battery cell 1 is in thermal runaway, which can realize the electric and thermal separation inside the battery pack, that is, the separation of the smoke generated by the thermal runaway of the electrical components in the battery pack and the battery cell 1, and the high-temperature smoke will not directly contact the electrical components, which can protect the electrical components from the influence of the high-temperature smoke. The crossbeam 3 is arranged in pairs corresponding to the upper and lower layers of battery cells 1, which can make the upper battery cell 1 and the lower battery cell 1 have different smoke exhaust paths. When the upper battery cell 1 or the lower battery cell 1 is in thermal runaway, the high-temperature smoke generated will be discharged from the battery pack from the corresponding smoke exhaust path. The area through which the smoke passes is small, which can reduce heat diffusion. At the same time, during the movement of the smoke, it does not contact the battery cell 1 of the adjacent layer, which can reduce the influence on the battery cell 1 of the adjacent layer, so that the battery cell 1 of the adjacent layer is not easily affected, thereby improving the safety of the battery pack.

[0056] Based on the above overall introduction, refer to Figure 1-Figure 5 Specifically, the end of the main frame 2 where the electrical components are set is taken as the front end, the direction pointed by the front end is the length direction, and the battery cells 1 of the same group in the double-layer module are arranged in sequence along the width direction of the main frame 2. The explosion-proof valves 101 of the same group of battery cells 1 face the same direction of the length direction of the main frame 2, which is convenient for connection with the crossbeam 3.

[0057] In order to obtain better structural layout effect, refer to Figure 1 , Figure 2 and Figure 5As shown, the battery cell 1 of this embodiment adopts a blade cell, which is a long rectangular parallelepiped, and its explosion-proof valve 101 is set at the end in the length direction, which is convenient for unified thermal runaway management. It should be noted that other types of battery cells 1 can also be used, such as cylindrical cells, square cells, etc., and when in use, the explosion-proof valve 101 can be connected to the second exhaust passage in the crossbeam 3 by a connecting pipeline. The explosion-proof valve 101 of the blade cell can adopt an oblong explosion-proof disc, and the crossbeam 3 is provided with an air inlet 301 corresponding to the explosion-proof disc. Of course, other forms of explosion-proof valves 101 can also be used, such as circular explosion-proof discs, rectangular explosion-proof discs, and ejector-type explosion-proof valves 101, as long as they can play the function of timely exhaust when subjected to high pressure.

[0058] For the purpose of better heat management inside the battery pack, a cold plate assembly 5 is sandwiched between the two crossbeams 3 arranged in pairs, and the cold plate assembly 5 contacts the side walls of the upper and lower layers of battery cells 1 at the same time. Specifically, because the battery cells 1 generate heat when in use, the heat accumulation will cause the performance of the battery cells 1 to deteriorate, and the cold plate assembly 5 is used to cool the battery cells 1 so that the battery cells 1 can better perform charging and discharging operations. The cold plate assembly 5 is arranged between the upper battery cells 1 and the lower battery cells 1, which can cool the bottom end of the upper battery cells 1 and the top end of the lower battery cells 1 at the same time, and can also quickly absorb part of the heat energy when the battery cells 1 are thermally runaway, thereby reducing production costs and also realizing a lightweight design of the battery pack.

[0059] For the specific structure of the main frame 2, refer to Figure 3 and Figure 4 As shown, the main frame 2 of this embodiment includes a side beam 201, and the first exhaust channels a are arranged in the height direction in the side beam 201. The longitudinal section of the side beam 201 is usually a vertically arranged long rectangular strip, and the first exhaust channels a are arranged in the height direction in the side beam 201, which can make fuller use of the internal space of the side beam 201 and reasonably separate the first exhaust channels a. At the same time, the part of the side beam 201 used to separate the first exhaust channels a can form ribs to strengthen the structural strength of the side beam 201. Even if the side beam 201 is a hollow structure, it can have a good lateral support strength to better protect the internal parts.

[0060] In order to increase the capacity of the battery cells 1 in the lower shell of the battery pack, a pair of cross beams 3 are provided on both sides in the length direction of the main frame 2. The two pairs of cross beams 3 can cool the battery cells 1 in the lower shell of the battery pack and on both sides in the length direction, so that more battery cells 1 can be cooled, thereby increasing the capacity of the battery cells 1 in the lower shell of the battery pack.

[0061] As a further optimization of the first exhaust channel a, refer to Figure 1 and Figure 4As shown, the air inlet and the air outlet of the first exhaust channel a are respectively arranged at the two ends of the side beam 201 along its own length direction. By arranging the air inlet and the air outlet of the first exhaust channel a at the two ends of the side beam 201 along its own length direction, the internal space of the side beam 201 can be reasonably utilized, so that when the battery cell 1 is in thermal runaway, the smoke generated has a certain buffer in the first exhaust channel a, and then is discharged from the battery pack, which is not easy to cause instantaneous air pressure damage inside the battery pack, thereby improving the safety performance of the battery pack. Secondly, it can also make the upper battery cell 1 and the lower battery cell 1 have the same exhaust path distance, which also improves the safety performance of the battery pack.

[0062] In order to make more full use of the side beams 201, one side beam 201 is provided at each opposite end in the width direction of the main frame 2. The front ends of the side beams 201 on both sides are connected to the front side beams 202, and the rear ends are connected to the rear side beams 203, forming a rectangular frame. The crossbeam 3 is connected between the side beams 201 on both sides, and is provided with a second exhaust channel b on each side in its own length direction, and each second exhaust channel b is connected to the first exhaust channel a of the adjacent side beams 201. By setting two side beams 201 and setting two second exhaust channels b in the crossbeam 3 at the same time, the same layer of battery cells 1 can discharge smoke nearby on both sides in the width direction of the main frame 2, shortening the distance required for the smoke to move before entering the first exhaust channel a, reducing heat diffusion, and improving the safety performance of the battery pack.

[0063] As a preferred arrangement of the battery cells 1, refer to Figure 2 and Figure 3 As shown, this embodiment is provided with eight groups of battery cells 1, four groups are provided in the upper layer and four groups are provided in the lower layer, and the cross beams 3 of each layer are connected to two different groups of battery cells 1, which can effectively utilize the exhaust path in the lower shell of the battery pack. Specifically, four first exhaust paths are provided from top to bottom in each side beam 201, the two first exhaust paths in the upper layer correspond to the battery cells 1 in the upper layer, and the two first exhaust paths in the lower layer correspond to the battery cells 1 in the lower layer. The positions of the air inlets and air outlets of adjacent first exhaust paths are staggered.

[0064] In order to strengthen the overall structural strength of the lower shell of the battery pack, a longitudinal beam 204 is connected between the two pairs of cross beams 3. The longitudinal beam 204 and the cross beam 3 together form an "I" structure, which can effectively improve the structural retention ability of the cross beam 3 when it is impacted by high-temperature smoke and improve the overall rigidity of the lower shell of the battery pack. Furthermore, a partition beam 205 is also connected between the two side beams 201 to separate the battery cells 1 on both sides in the width direction and enhance the overall structural strength of the lower shell of the battery pack.

[0065] For the specific exhaust structure of the first exhaust passage, refer to Figure 1 and Figure 3As shown, an explosion-proof device 4 is provided at the outlet of the first exhaust passage a. The explosion-proof device 4 is used to generate a passage by changing its own structure after the air pressure in the first exhaust passage increases rapidly, so that the smoke in the first exhaust passage can be quickly discharged. The explosion-proof device 4 can adopt a piston-type explosion-proof valve 101, or other structures such as a pin-type explosion-proof valve 101, an expanded polytetrafluoroethylene (expanded PTFE) explosion-proof valve 101, etc., as long as it can meet the explosion-proof function.

[0066] When thermal runaway occurs in the battery cell 1, a large amount of smoke is rapidly generated inside it. The smoke will break through the explosion-proof valve 101, enter the second exhaust channel b in the cross beam 3 through the air inlet 301, and then enter the first exhaust channel a in the side beam 201 from the second exhaust channel b, and finally be discharged from the battery pack through the explosion-proof device 4. Different groups of battery cells 1 have independent smoke exhaust channels when thermal runaway occurs, which reduces heat diffusion during the smoke exhaust process and improves the safety of the battery pack.

[0067] Embodiment 2

[0068] This embodiment relates to a battery pack, which is provided with the battery pack lower shell in the first embodiment.

[0069] By setting the lower shell of the battery pack of the first embodiment, the battery pack of this embodiment can achieve electrical and thermal separation inside the battery pack when the internal battery cell has thermal runaway, that is, the separation of the electrical components in the battery pack and the smoke generated by the thermal runaway of the battery cell, and the high-temperature smoke will not directly contact the electrical components, which can protect the electrical components from the influence of the high-temperature smoke. Each group of battery cells has a different independent smoke emission path. When the battery cell is in thermal runaway, the high-temperature smoke generated will be discharged from the battery pack from the corresponding smoke emission path. The smoke passes through fewer areas, which can reduce heat diffusion. At the same time, the smoke does not contact the battery cells of the adjacent layers during the movement process, which can reduce the influence on the battery cells of the adjacent layers, making the battery cells of the adjacent layers less susceptible to influence, thereby improving the safety of the battery pack.

[0070] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A battery pack lower shell for accommodating a battery cell of a double-layer module, characterized in that: include: The main frame is provided with a first exhaust passage communicating with the outside of the battery pack; A crossbeam, connected to the main frame, and provided with a second exhaust channel along its length, wherein the second exhaust channel is connected to an independent first exhaust channel; The crossbeams are arranged in pairs corresponding to the upper and lower layers of battery cells and are connected to the explosion-proof valves of the battery cells of the corresponding layers; when the battery cells are in thermal runaway, the second exhaust channel and the first exhaust channel together constitute the exhaust of smoke from the battery pack.

2. The battery pack lower shell according to claim 1, characterized in that: The main body frame includes a side beam, and the first exhaust passage is arranged in the side beam along the height direction.

3. The battery pack lower shell according to claim 2, characterized in that: The cross beams are each provided with a pair on both sides of the main frame in the length direction.

4. The battery pack lower shell according to claim 3, characterized in that: The air inlet and the air outlet of the first exhaust passage are respectively arranged at two ends of the side beam along its own length direction.

5. The battery pack lower shell according to claim 3, characterized in that: A longitudinal beam is connected between the two pairs of cross beams.

6. The battery pack lower shell according to claim 2, characterized in that: The side beams are each provided with one at two opposite ends in the width direction of the main frame; the cross beam is connected between the two side beams, and is each provided with a second exhaust channel on both sides in its own length direction, and each second exhaust channel is connected to the first exhaust channel of the adjacent side beams.

7. The battery pack lower housing according to claim 1, characterized in that: The battery cell is a blade battery cell.

8. The battery pack lower shell according to claim 1, characterized in that: An explosion-proof device is provided at the outlet of the first exhaust passage.

9. The battery pack lower casing according to any one of claims 1 to 8, characterized in that: A cold plate assembly is sandwiched between the two cross beams arranged in pairs, and the cold plate assembly contacts the side walls of the upper and lower layers of the battery cells at the same time.

10. A battery pack, characterized in that: A battery pack lower shell as claimed in any one of claims 1 to 9 is provided.

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