Battery module and battery pack
By alternating low-burst-threshold and high-burst-threshold cells in the battery module, thermal runaway management is optimized, solving the problem of excessive gas pressure and temperature during thermal runaway of the battery pack, and achieving a safer and more stable battery module design.
Patent Information
- Application Number
- CN202422970865.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-03
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2034-12-03
AI Technical Summary
In the event of thermal runaway, the existing battery pack has excessively high gas pressure and temperature inside the chamber, which cannot dissipate heat in time, posing a safety hazard.
By alternating the arrangement of cells with low and high burst thresholds, and by setting different explosion-proof valve thresholds for the alternating arrangement of cells, thermal runaway management is optimized, and heat accumulation and pressure rise are reduced.
Effective management of thermal runaway events reduces the rapid increase in gas pressure and temperature inside the battery module, lowers the risk of explosion and fire, improves the safety and stability of the battery module, and extends its service life.
Smart Images
Figure CN223539816U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of module structure design technology, specifically to a battery module and battery pack. Background Technology
[0002] When lithium-ion batteries are abused, such as overcharging, over-discharging, short-circuiting, or being squeezed, they can generate gas inside, catch fire, or even explode. When the internal gas pressure of a lithium-ion battery reaches the burst pressure value of the explosion-proof valve, the valve will suddenly rupture at the notch and release pressure to reduce the internal pressure of the battery and prevent an explosion.
[0003] Generally, lithium iron phosphate batteries use a single explosion-proof valve design on the top cover, with an opening pressure typically between 0.4 and 0.8 MPa. This indicates a large tolerance range for the explosion threshold of the cell's explosion-proof valve. When a single cell experiences thermal runaway, the resulting thermal diffusion across the entire pack can vary. It is generally believed that a lower explosion threshold for the cell's explosion-proof valve is more beneficial for thermal runaway safety, as it allows for timely release of internal heat. However, lower is not always better. When the total explosion-proof valve threshold for all cells is 0.4 MPa, thermal runaway in a single cell can easily trigger the valves of adjacent cells to open. An excessive number of open valves leads to a sharp increase in exhaust gas, resulting in excessively high gas pressure and temperature inside the enclosure. This can exceed the enclosure's structural strength, causing high-temperature melting holes. Thermally diffused gases can then leak from the enclosure into the passenger compartment (where 12V battery packs are typically installed), posing a safety hazard to the driver. Conversely, if the explosion-proof valve threshold for all battery cells is 0.8 MPa, when a single battery cell experiences thermal runaway, the thermally runaway cell will be unable to release heat in time, leading to more battery cells exploding.
[0004] In summary, existing battery packs suffer from technical problems such as excessively high gas pressure and temperature inside the pack during thermal runaway, and the inability to dissipate heat in a timely manner. Utility Model Content
[0005] The purpose of this application is to overcome the above-mentioned technical deficiencies and propose a battery module and battery pack to solve the technical problems of excessively high gas pressure and temperature inside the box during thermal runaway and the inability to release heat in a timely manner.
[0006] To achieve the above-mentioned technical objectives, the present application adopts the following technical solution:
[0007] In a first aspect, this application provides a battery module, including a module housing and a battery cell assembly:
[0008] A module housing having an accommodating space;
[0009] A battery cell assembly located in the accommodating space, the battery cell assembly including a first battery cell and a second battery cell, a plurality of first battery cells and a plurality of second battery cells arranged alternately, the explosion-proof valve threshold of the second battery cell being greater than the explosion-proof valve threshold of the first battery cell.
[0010] In some embodiments of this application, the first battery cell includes a first housing, a first cover plate, and a first explosion-proof valve, and the second battery cell includes a second housing, a second cover plate, and a second explosion-proof valve. The first housing and the second housing are arranged side by side, and the first cover plate and the second cover plate respectively cover the first housing and the second housing. The first explosion-proof valve and the second explosion-proof valve are respectively disposed on the first cover plate and the second cover plate.
[0011] In some embodiments of this application, the first cover plate and the second cover plate respectively cover the same end opening of the first housing and the second housing.
[0012] In some embodiments of this application, foam is also included, which is filled between adjacent first and second cells.
[0013] In some embodiments of this application, the foam is located on the side of the first housing or the second housing.
[0014] In some embodiments of this application, the burst threshold of the first explosion-proof valve is not less than 0.4 MPa and less than 0.6 MPa, and the burst threshold of the second explosion-proof valve is not less than 0.6 MPa and not greater than 0.8 MPa.
[0015] In some embodiments of this application, the first battery cell further includes a first terminal post, and the second battery cell further includes a second terminal post, wherein the first terminal post and the second terminal post are respectively disposed on the surfaces of the first housing and the second housing facing the same direction.
[0016] In some embodiments of this application, both ends of the battery cell group are the first battery cells, and any one of the second battery cells is located between two adjacent first battery cells.
[0017] In some embodiments of this application, a plurality of first cells and a plurality of second cells are connected in series or in parallel.
[0018] Secondly, this application also provides a battery pack, including the battery module as described in any embodiment of the first aspect.
[0019] Compared with the prior art, the beneficial technical effects of the technical solution provided in this application include:
[0020] This application categorizes battery cells into a first battery cell with a low burst threshold and a second battery cell with a high burst threshold based on their burst threshold. During module assembly, the two types of cells with different burst thresholds are arranged alternately. The thermal runaway scenarios are divided into two types: 1) When the thermal runaway cell is a first battery cell with a low burst threshold, its adjacent sides are second battery cells with a high burst threshold. The second battery cells are less likely to open the cell's explosion-proof valve. Ideally, the thermal runaway cell can successfully dissipate internal heat while reducing the number of cells with open valves. 2) When the thermal runaway cell is a second battery cell with a high burst threshold, its adjacent sides are first battery cells with a low burst threshold. The first battery cells easily open the cell's explosion-proof valve. Ideally, the thermal runaway cell can successfully dissipate internal heat while reducing the number of cells with open valves. Attached Figure Description
[0021] To more clearly illustrate the technical solutions in this application, the accompanying drawings used in the embodiments will be briefly described below:
[0022] Figure 1 This is a schematic diagram of the structure of a battery module provided in an embodiment of this application;
[0023] Figure 2 This is a schematic diagram of the structure of a first battery cell provided in an embodiment of this application.
[0024] Figure label:
[0025] 1-Module housing, 2-First battery cell, 3-Second battery cell, 4-Foam;
[0026] 21-First housing, 22-First cover plate, 23-First explosion-proof valve. Detailed Implementation
[0027] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0028] Those skilled in the art will understand that, in this specification, the term "comprising" is an open-ended expression, meaning that the stated feature is present but other features are excluded. Directional terms such as "upper," "lower," "left," and "right" refer to exemplary directions based on the accompanying drawings. Features specified as "first" or "second" implicitly include one or more of that feature. Singular expressions can also be used in plural forms. "Multiple" means two or more. The terms "installed," "connected," and "linked" can refer to a fixed connection, a detachable connection, or an integral connection; it can be a direct connection or an indirect connection via an intermediate medium, and it can be a connection within two components. Furthermore, "linked" can include wireless connections.
[0029] The purpose of this application is to overcome the above-mentioned technical deficiencies and propose a battery module and battery pack to solve the technical problems of excessively high gas pressure and temperature inside the box during thermal runaway and the inability to release heat in a timely manner.
[0030] To achieve the above-mentioned technical objectives, the present application adopts the following technical solution:
[0031] Firstly, this application provides a battery module, such as Figure 1 and Figure 2 As shown, Figure 1 This is a schematic diagram of the structure of a battery module provided in an embodiment of this application;
[0032] Figure 2 This is a schematic diagram of the structure of a first battery cell 2 provided in an embodiment of this application.
[0033] A battery module includes a module housing 1 and a battery cell assembly:
[0034] Module housing 1, the module housing 1 having an accommodating space;
[0035] A battery cell assembly located in the accommodating space, the battery cell assembly including a first battery cell 2 and a second battery cell 3, with multiple first battery cells 2 and multiple second battery cells 3 arranged alternately, and the explosion-proof valve threshold of the second battery cell 3 being greater than the explosion-proof valve threshold of the first battery cell 2.
[0036] This application divides battery cells into a first battery cell 2 with a low burst threshold and a second battery cell 3 with a high burst threshold based on their burst threshold. When assembling the battery cells into a module, the two types of battery cells with different burst thresholds are arranged alternately. The thermal runaway of a battery cell can be categorized into two scenarios: 1) When the thermal runaway battery cell is the first battery cell 2 with a low burst threshold, its adjacent sides are the second battery cells 3 with a high burst threshold. The second battery cells 3 are less likely to open the cell's explosion-proof valve. Ideally, the thermal runaway battery cell can successfully dissipate the heat inside the cell while reducing the number of cells with open valves. 2) When the thermal runaway battery cell is the second battery cell 3 with a high burst threshold, its adjacent sides are the first battery cells 2 with a low burst threshold. The first battery cells 2 can easily open the cell's explosion-proof valve. Ideally, the thermal runaway battery cell can successfully dissipate the heat inside the cell while reducing the number of cells with open valves.
[0037] By alternating battery cells with different explosion-proof valve thresholds, thermal runaway events can be managed more effectively, reducing heat accumulation and pressure increases. In the event of thermal runaway, only some cell explosion-proof valves will open, reducing battery performance degradation and potential safety risks caused by the simultaneous opening of multiple valves. Effective heat release control reduces the rapid increase in internal gas pressure and temperature of the battery module, decreasing the risk of explosion and fire. Reducing unnecessary explosion-proof valve opening due to thermal runaway helps maintain cell integrity and the long-term stability of the battery module, thereby extending battery life. Optimized thermal runaway management can improve the reliability and performance of the battery module under extreme conditions.
[0038] In some embodiments of this application, the first battery cell 2 includes a first housing 21, a first cover plate 22, and a first explosion-proof valve 23, and the second battery cell 3 includes a second housing, a second cover plate, and a second explosion-proof valve. The first housing 21 and the second housing are arranged side by side, and the first cover plate 22 and the second cover plate respectively cover the first housing 21 and the second housing. The first explosion-proof valve 23 and the second explosion-proof valve are respectively disposed on the first cover plate 22 and the second cover plate.
[0039] The first housing 21 and the second housing are arranged side by side within the receiving space of the module housing 1. The first explosion-proof valve 23 is disposed on the first cover plate 22, and the second explosion-proof valve is disposed on the second cover plate. These explosion-proof valves open when the internal pressure of the battery cell exceeds a set threshold to release excess gas and heat, preventing the battery cell from exploding due to overheating.
[0040] By arranging the cell casings side-by-side and covering them with a cover plate, the overall structural stability of the battery module is improved, which helps protect the cells during transportation and use. Because the explosion-proof valve thresholds of the first cell 2 and the second cell 3 are different, heat and pressure can be selectively released when thermal runaway occurs, thus managing thermal runaway events more effectively. The explosion-proof valves can respond promptly to changes in internal cell pressure, preventing cell rupture or explosion due to excessive pressure, thereby improving the safety of the battery module.
[0041] In some embodiments of this application, the first cover plate 22 and the second cover plate respectively cover the same end opening of the first housing 21 and the second housing.
[0042] The junction between the cover and the housing is sealed with seals or other sealing methods to ensure that the chemical substances inside the cell do not leak, and also to prevent external impurities from entering the cell.
[0043] The explosion-proof valve is installed on the cover plate. When the internal pressure of the battery cell exceeds the set threshold, the explosion-proof valve will open to release the excess gas inside, thereby reducing the internal pressure of the battery cell and preventing an explosion.
[0044] Because all cell covers are located at the same opening in the casing, this facilitates unified management and control of heat release from the cells, making the handling of thermal runaway events more centralized and effective. The sealed design of the covers and casing reduces the risk of internal leakage from the cells, while the inclusion of explosion-proof valves provides an additional layer of safety, further enhancing the safety of the battery module. Since the explosion-proof valves for all cells are located at the same end, this helps to quickly and effectively release heat in the event of thermal runaway, reducing the overall temperature and stress of the battery module.
[0045] In some embodiments of this application, foam 4 is also included, which is filled between adjacent first cell 2 and second cell 3.
[0046] In some embodiments of this application, the foam 4 is located on the side of the first housing 21 or the second housing.
[0047] During battery module assembly, foam 4 is placed in the gap between the first battery cell 2 and the second battery cell 3. This reduces direct contact between the cells and avoids wear or short circuits between the cells caused by vibration or temperature changes.
[0048] Foam 4 is located on the side of the first housing 21 or the second housing, which means that foam 4 fills along the side of the cell, providing lateral support and cushioning for the cell.
[0049] Foam 4 possesses excellent elasticity and shock absorption properties, effectively absorbing vibrations and impacts that battery cells may encounter during transportation and use, protecting them from physical damage. Foam 4 filling helps maintain the fixed position of the battery cells within the module, preventing movement and thus improving the structural stability of the battery module. Foam 4 also provides some thermal insulation, isolating heat transfer between battery cells to a certain extent, helping to control the temperature distribution of the battery module and reducing the risk of thermal runaway. Foam 4 typically has electrical insulation properties, preventing short circuits between battery cells and improving the electrical safety of the battery module. The presence of foam 4 creates airflow channels between battery cells, aiding in heat dissipation and lowering the operating temperature of the cells.
[0050] In some embodiments of this application, the burst threshold of the first explosion-proof valve 23 is not less than 0.4 MPa and less than 0.6 MPa, and the burst threshold of the second explosion-proof valve is not less than 0.6 MPa and not greater than 0.8 MPa.
[0051] The burst threshold of the first explosion-proof valve 23 is set in a relatively low range, that is, not less than 0.4 MPa and less than 0.6 MPa; while the burst threshold of the second explosion-proof valve is set in a relatively high range, that is, not less than 0.6 MPa and not greater than 0.8 MPa.
[0052] When thermal runaway occurs in a cell within the battery module, the internal pressure will increase. If the thermal runaway occurs in the first cell 2, the first explosion-proof valve 23 will open first to release the pressure, thus preventing the pressure from rising further, because its explosion-proof valve has a low burst threshold.
[0053] If thermal runaway occurs in the second cell 3, the explosion-proof valve of the first cell 2 will open before the explosion-proof valve of the second cell 3 because its explosion-proof valve has a higher burst threshold. This can release the pressure more quickly and reduce the possibility of the explosion-proof valve of the second cell 3 opening, thereby preventing the pressure from spreading throughout the battery module.
[0054] By setting different burst thresholds, graded pressure release can be achieved, effectively managing thermal runaway events and reducing the impact on surrounding battery cells. The first explosion-proof valve 23, with a lower burst threshold, can respond quickly, reducing the risk of battery casing rupture or explosion due to excessive pressure. The second explosion-proof valve, with a higher burst threshold, can protect the battery cells to some extent, preventing unnecessary opening of the explosion-proof valves under less severe pressure increases, thus extending the battery cell's lifespan. Different burst thresholds help optimize the thermal management of the battery module, enabling more effective control of gas and heat release in the event of thermal runaway. Reasonable burst threshold settings can reduce unnecessary opening of explosion-proof valves, thereby reducing the maintenance cost and replacement frequency of the battery module.
[0055] In some embodiments of this application, the first battery cell 2 further includes a first terminal post, and the second battery cell 3 further includes a second terminal post. The first terminal post and the second terminal post are respectively disposed on the surfaces of the first housing 21 and the second housing that are in the same direction.
[0056] In some embodiments of this application, both ends of the battery cell group are the first battery cell 2, and any one of the second battery cells 3 is located between two adjacent first battery cells 2.
[0057] Both ends of the battery cell assembly, that is, the beginning and end positions of the battery module, are the first cell 2.
[0058] Because the explosion threshold of the first cell 2 is low (not less than 0.4 MPa and less than 0.6 MPa), when the internal pressure of the battery module increases, the explosion valve of the first cell 2 located at both ends will open first, thereby quickly releasing the internal pressure and reducing the risk of thermal runaway.
[0059] Using the first cell 2 at both ends allows for a faster response to changes in internal pressure, because in the event of thermal runaway, the explosion-proof valves of these cells will open first, thus protecting the entire battery module.
[0060] In another embodiment, both ends of the battery pack are the second battery cells 3, and any one of the first battery cells 2 is located between two adjacent second battery cells 3.
[0061] In yet another embodiment, the two ends of the battery pack are a first battery cell 2 and a second battery cell 3, respectively.
[0062] In some embodiments of this application, a plurality of first battery cells 2 and a plurality of second battery cells 3 are connected in series or in parallel.
[0063] The first terminal is disposed on one surface of the first housing 21, and the second terminal is disposed on the corresponding surface of the second housing. These terminals are the positive or negative terminals of the battery cell and are used to connect to other battery cells or external circuits.
[0064] The first and second terminals are located on the same surface of the casing, which means that when the cells are arranged side by side, all the positive or negative terminals face the same direction, forming a consistent polarity.
[0065] By aligning the cell terminals in the same direction, multiple cells can be easily connected in series or parallel to form a complete battery module, thus meeting specific voltage and capacity requirements.
[0066] Secondly, this application also provides a battery pack, including the battery module as described in any embodiment of the first aspect.
[0067] Compared with the prior art, the beneficial technical effects of the technical solution provided in this application include:
[0068] This application divides battery cells into a first battery cell 2 with a low burst threshold and a second battery cell 3 with a high burst threshold based on their burst threshold. When assembling the battery cells into a module, the two types of battery cells with different burst thresholds are arranged alternately. The thermal runaway of a battery cell can be categorized into two scenarios: 1) When the thermal runaway battery cell is the first battery cell 2 with a low burst threshold, its adjacent sides are the second battery cells 3 with a high burst threshold. The second battery cells 3 are less likely to open the cell's explosion-proof valve. Ideally, the thermal runaway battery cell can successfully dissipate the heat inside the cell while reducing the number of cells with open valves. 2) When the thermal runaway battery cell is the second battery cell 3 with a high burst threshold, its adjacent sides are the first battery cells 2 with a low burst threshold. The first battery cells 2 can easily open the cell's explosion-proof valve. Ideally, the thermal runaway battery cell can successfully dissipate the heat inside the cell while reducing the number of cells with open valves.
[0069] Those skilled in the art will understand that the steps, measures, and schemes in the various operations, methods, processes, and procedures discussed in this application can be alternated, modified, rearranged, decomposed, combined, or deleted.
[0070] The specific embodiments described above do not constitute a limitation on the scope of protection of this application. Any other corresponding changes and modifications made based on the technical concept of this application should be included within the scope of protection of the claims of this application.
Claims
1. A battery module, characterized in that, include: A module housing having an accommodating space; A battery cell assembly located in the accommodating space, the battery cell assembly including a first battery cell and a second battery cell, a plurality of first battery cells and a plurality of second battery cells arranged alternately, the explosion-proof valve threshold of the second battery cell being greater than the explosion-proof valve threshold of the first battery cell.
2. A battery module according to claim 1, characterized in that, The first battery cell includes a first housing, a first cover plate, and a first explosion-proof valve. The second battery cell includes a second housing, a second cover plate, and a second explosion-proof valve. The first housing and the second housing are arranged side by side. The first cover plate and the second cover plate respectively cover the first housing and the second housing. The first explosion-proof valve and the second explosion-proof valve are respectively disposed on the first cover plate and the second cover plate.
3. A battery module according to claim 2, characterized in that, The first cover plate and the second cover plate respectively cover the same end opening of the first housing and the second housing.
4. A battery module according to claim 2, characterized in that, It also includes foam, which is filled between adjacent first and second cells.
5. A battery module according to claim 4, characterized in that, The foam is located on the side of the first housing or the second housing.
6. A battery module according to claim 2, characterized in that, The first explosion-proof valve has a burst threshold of not less than 0.4 MPa and not less than 0.6 MPa, and the second explosion-proof valve has a burst threshold of not less than 0.6 MPa and not greater than 0.8 MPa.
7. A battery module according to claim 2, characterized in that, The first battery cell further includes a first terminal post, and the second battery cell further includes a second terminal post. The first terminal post and the second terminal post are respectively disposed on the surfaces of the first housing and the second housing facing the same direction.
8. A battery module according to claim 1, characterized in that, Both ends of the battery cell assembly are the first battery cells, and any one of the second battery cells is located between two adjacent first battery cells.
9. A battery module according to claim 1, characterized in that, Multiple first cells and multiple second cells are connected in series or in parallel.
10. A battery pack, characterized in that, Includes the battery module as described in any one of claims 1 to 9.