High safety battery module and preparation method thereof

Abstract

This invention discloses a high-safety battery module, comprising several interconnected high-safety single-cell soft-pack batteries. Each high-safety single-cell soft-pack battery includes a single cell. A directional pressure relief port is formed on one side of the cell's side seal and connected to a heat sink. A micro-carbon fiber-aluminum element is connected to the other end of the heat sink. The surface of the single cell is covered with a heat-insulating material. The manufacturing method of this invention is as follows: 1. Overcharge-induced thermal runaway operation; 2. Fabrication of the directional pressure relief port; 3. Connection of the heat sink and the micro-carbon fiber-aluminum element and covering with heat-insulating material; 4. Assembly. This invention reduces the risk of thermal runaway of the battery module by creating a directional pressure relief port on the cell's side seal and connecting it to the heat sink for directional pressure relief and heat dissipation of high-temperature, high-pressure gases. This invention also improves the efficiency of pressure relief and heat dissipation through multi-sample overcharge-induced thermal runaway operation, accurately determining the specific location and direction of the directional pressure relief port in the single cell.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery thermal runaway technology, specifically relating to a high-safety battery module and its preparation method. Background Technology

[0002] Lithium-ion batteries are characterized by high voltage, high specific energy, high power, and long cycle life. However, due to their unique battery structure and the characteristics of the materials used, the safety performance of lithium-ion batteries cannot be ignored. In particular, improper operation during use can lead to mechanical damage, thermal abuse, overcharging, short circuits, etc., which can directly cause the battery temperature to rise rapidly and eventually lead to thermal runaway. The thermal runaway of a single cell can then transfer heat to the entire battery module through thermal diffusion, thus causing even greater danger.

[0003] Currently, many batteries utilize safety valves to release the high-temperature, high-pressure gases generated during thermal runaway. These batteries are typically prismatic (square-shell) batteries, which generally have larger capacities. During thermal runaway, the instantaneous internal gas pressure and temperature are higher, increasing the risk. Furthermore, their fixed cell dimensions make it difficult to meet flexible customer needs. In contrast, pouch batteries offer flexible dimensions. During thermal runaway, the cell expands when high-temperature, high-pressure gases are generated, reducing the excessive internal pressure and mitigating the risk to some extent. However, research on pressure relief methods for pouch lithium-ion batteries is currently limited. Summary of the Invention

[0004] The technical problem to be solved by this invention is to provide a high-safety battery module that addresses the shortcomings of the prior art. This high-safety battery module utilizes a directional pressure relief port on the cell-side seal of the basic unit, a high-safety single-cell soft-pack battery, connected to a heat sink. This allows the high-temperature, high-pressure gas generated during thermal runaway of the high-safety single-cell soft-pack battery to be directionally discharged, relieved, and dissipated. This reduces the surface temperature of the battery during thermal runaway, thereby reducing the risk of open flames inside the high-safety battery module and significantly lowering the risk of thermal runaway.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: a high-safety battery module, characterized in that the high-safety battery module includes a plurality of high-safety single-cell soft-pack batteries connected in combination, the high-safety single-cell soft-pack battery includes a single cell, a directional pressure relief port is opened on one side of the cell side seal, and the cell side seal is connected to a heat sink, the directional pressure relief port is sealed in the heat sink, a micro carbon fiber-aluminum is connected to the other end of the heat sink, and the surface of the single cell is covered with a heat insulation material.

[0006] The aforementioned high-safety battery module is characterized in that the heat sink is an L-shaped finned heat sink, and the wide end of the L-shaped finned heat sink is connected to the side sealing edge of the battery cell, while the narrow end is connected to micro carbon fiber-aluminum.

[0007] The aforementioned high-safety battery module is characterized in that the directional pressure relief port is a serrated notch, and the distance between the serrated notch and the unsealed area in the single cell is 1mm to 2mm.

[0008] The aforementioned high-safety battery module is characterized in that the heat insulation material is polytetrafluoroethylene glass fiber cloth.

[0009] In addition, the present invention also discloses a method for preparing the high-safety battery module as described above, characterized in that the method includes the following steps:

[0010] Step 1: Select several soft-pack lithium-ion batteries and perform an overcharge-induced thermal runaway operation on each soft-pack lithium-ion battery to ensure that each soft-pack lithium-ion battery triggers thermal runaway. Then, count the location of the pressure relief port on the cell side seal after each soft-pack lithium-ion battery triggers thermal runaway, and record the location of the pressure relief port that appears the most times.

[0011] Step 2: Select a soft-pack lithium-ion battery of the same model and capacity as in Step 1 as a single cell. Then, based on the location of the pressure relief port that appears most frequently as recorded in Step 1, make a directional pressure relief port on the cell side seal of the single cell.

[0012] Step 3: Connect the side of the single cell with the directional pressure relief port in Step 2 to one end of the heat sink, then connect the other end of the heat sink to the micro carbon fiber-aluminum, and then cover the surface of the single cell with heat insulation material to obtain a high-safety single soft-pack battery.

[0013] Step 4: Combine the high-safety single-cell pouch batteries obtained in Step 3 according to the design method to form a high-safety battery module.

[0014] The above method is characterized in that the soft-pack lithium-ion battery in step one is a 2000mAh capacity, Ni83 system soft-pack lithium-ion battery, and the overcharge conditions are: 1C, 50V.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] 1. The high-safety battery module of the present invention provides a directional pressure relief port on the cell-side seal of the high-safety single-cell soft-pack battery, and the cell-side seal is connected to the heat sink. This allows the high-temperature and high-pressure gas generated during thermal runaway of the high-safety single-cell soft-pack battery to be directionally discharged, relieved and dissipated, thereby reducing the temperature of the battery surface during thermal runaway and thus reducing the risk of open flame inside the high-safety battery module. This greatly reduces the risk of thermal runaway of the battery module.

[0017] 2. The high-safety battery module of the present invention provides directional pressure relief ports and connects heat sinks to the high-safety single soft-pack batteries of the basic unit, so that each high-safety single soft-pack battery can perform directional pressure relief and heat dissipation, which increases the pressure relief and heat dissipation path, significantly improves the efficiency of pressure relief and heat dissipation, and further reduces the risk of thermal runaway of the battery module.

[0018] 3. The high-safety battery module of the present invention has the advantages of rapid cooling, safety, environmental friendliness, and recyclability in preventing thermal runaway of soft-pack lithium-ion batteries.

[0019] 4. The preparation method of the present invention first performs a multi-sample overcharge-induced thermal runaway operation to accurately determine the specific location and direction of the directional pressure relief port in the single cell, thereby improving the efficiency of pressure relief and heat dissipation in the directional pressure relief port and significantly reducing the surface temperature of the high-safety single cell soft pack battery during thermal runaway.

[0020] 5. This invention effectively reduces the risk of thermal runaway of the battery module by adding an external heat sink, and because no flame retardants or other materials are added inside the battery cell, it effectively ensures the electrical performance of the individual battery cell, thereby ensuring the electrical performance of the battery module.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of the high-safety battery module of the present invention.

[0023] Figure 2 This is a schematic diagram of the structure of the high-safety single-cell soft-pack battery in the high-safety battery module of the present invention.

[0024] Figure 3 This is a schematic diagram of the structure of a single cell in the high-safety single-cell soft-pack battery of the present invention.

[0025] Explanation of reference numerals in the attached figures

[0026] 1—Single battery cell; 2—Side seal of battery cell; 3—Directional pressure relief port;

[0027] 4—Radiator; 5—Miniature carbon fiber-aluminum; 6—Insulation material;

[0028] 7—High-safety single-cell soft-pack battery; 8—High-safety battery module. Detailed Implementation

[0029] The high-safety battery module of the present invention is described in detail through Example 1.

[0030] Example 1

[0031] like Figures 1-3 As shown, the high-safety battery module 8 of this embodiment includes several high-safety single-cell soft-pack batteries 7 connected in combination. Each high-safety single-cell soft-pack battery 7 includes a single cell 1. A directional pressure relief port 3 is provided on one side of the cell side seal 2 of the single cell 1, and the cell side seal 2 is connected to a heat sink 4. The directional pressure relief port 3 is sealed in the heat sink 4. A micro carbon fiber-aluminum 5 is connected to the other end of the heat sink 4. The surface of the single cell 1 is covered with a heat insulation material 6.

[0032] The high-safety battery module 8 in this embodiment includes several interconnected high-safety single-cell pouch batteries 7. Specifically, the high-safety single-cell pouch batteries 7 serve as the basic unit of the high-safety battery module 8. By opening a directional pressure relief port 3 on one side of the cell-side seal 2 of the main cell 1 of the high-safety single-cell pouch battery 7, the high-temperature, high-pressure gas generated inside the main cell 1 during thermal runaway is directionally discharged through the cell-side seal 2 and the directional pressure relief port 3. Simultaneously, by connecting the cell-side seal 2 to a heat sink 4, and sealing the directional pressure relief port 3 within the heat sink 4, the high-temperature, high-pressure gas discharged through the directional pressure relief port 3 is dissipated by the heat sink 4. Through the directional pressure relief and heat dissipation of each high-safety single-cell pouch battery 7 within the high-safety battery module 8, the surface temperature of the high-safety single-cell pouch battery 7 during thermal runaway is effectively reduced, thereby reducing the risk of open flame inside the high-safety battery module 8 and significantly lowering the risk of thermal runaway in the module battery. In addition, in this embodiment, a micro carbon fiber-aluminum 5 is connected to the other end of the heat sink 4. The micro carbon fiber has the characteristics of high temperature resistance and strong thermal conductivity, which further cools the high temperature gas after it has been cooled by the heat sink 4. By covering the surface of the single cell 1 with heat insulation material 6, especially at the connection between the cell side seal 2 and the heat sink 4 on one side of the single cell 1, the sealing of the single cell 1 and the heat insulation performance of the high safety single soft pack battery 7 are ensured, and the damage to other high safety single soft pack batteries 7 in the high safety battery module 8 is avoided.

[0033] In summary, when the battery experiences thermal runaway due to overcharging, the high-safety single-cell soft-pack battery 7 releases the high-temperature, high-pressure gas in advance through the pressure relief port 3, reducing the gas's temperature and pressure to a certain extent. The high-temperature, high-pressure gas then enters the heat sink 4 through the pressure relief port 3 for secondary cooling and pressure reduction. Finally, the gas undergoes triple cooling through the micro carbon fiber-aluminum 5. After this triple cooling process, the temperature of the flammable and explosive gas is greatly reduced, significantly decreasing the possibility and danger of open flame. In addition, the heat-insulating material covering the surface of the single-cell battery 1 further reduces the battery surface temperature, ensuring the safety of the battery module.

[0034] In this embodiment, the micro carbon fiber-aluminum 5 is a micro carbon fiber (CFC) bonded to metallic aluminum.

[0035] Furthermore, the heat sink 4 is an L-shaped finned heat sink, with the wide end of the L-shaped finned heat sink connected to the cell side sealing edge 2, and the narrow end connected to the micro carbon fiber-aluminum 5. This embodiment ensures cooling efficiency and sealing by using an L-shaped finned heat sink, while reducing the volume ratio of the heat sink fins in the heat sink 4, thus avoiding an excessively large battery module that could affect its functionality.

[0036] Furthermore, the directional pressure relief port 3 is a serrated notch, and the distance between the serrated notch and the unsealed area in the single cell 1 is 1mm to 2mm. In this embodiment, by setting the directional pressure relief port 3 to a serrated notch and controlling its distance from the single cell 1, the high-safety single soft-pack battery 7 is ensured, while facilitating early pressure relief when high-temperature and high-pressure gas appears inside the single cell 1.

[0037] Furthermore, the heat insulation material 6 is polytetrafluoroethylene (PTFE) fiberglass cloth. PTFE fiberglass cloth has excellent heat insulation properties, effectively reducing the surface temperature of the high-safety single-cell soft-pack battery 7, further ensuring the safety of the battery module.

[0038] The preparation method of the high-safety battery module of the present invention is described in detail through Example 2 and Comparative Examples 1 to 3.

[0039] Example 2

[0040] The manufacturing process of the high-safety battery module in this embodiment is as follows:

[0041] Step 1: Select 10 pouch lithium-ion batteries with a capacity of 2000mAh and Ni83 system, number them 1# to 10# in sequence, and perform an overcharge operation to induce thermal runaway on each pouch lithium-ion battery. The overcharge conditions are: 1C, 50V. Ensure that thermal runaway is triggered in each pouch lithium-ion battery. Then, count the location of the pressure relief port on the side seal of the cell after the thermal runaway is triggered for each pouch lithium-ion battery, and record the location of the pressure relief port that appears the most times.

[0042] Step 2: Select a soft-pack lithium-ion battery of the same model and capacity as in Step 1 as a single cell 1. Then, based on the location of the pressure relief port that appears most frequently as recorded in Step 1, make a directional pressure relief port 3 with a serrated notch on the cell side seal 2 of the single cell 1. The distance between the serrated notch and the unsealed area in the single cell 1 is 1mm to 2mm.

[0043] Step 3: Connect the side of the single cell 1 with the directional pressure relief port 3 in Step 2 to the wide end of the L-shaped heat sink 4, then connect the narrow end of the L-shaped heat sink 4 to the micro carbon fiber-aluminum 5, and then cover the surface of the single cell 1 with heat insulation material 6 to obtain a high-safety single soft-pack battery 7; the heat insulation material 6 is polytetrafluoroethylene glass fiber cloth.

[0044] Step 4: Combine the four high-safety single-cell soft-pack batteries 7 obtained in Step 3 in a 4S1P configuration to form a high-safety battery module 8.

[0045] Comparative Example 1

[0046] This comparative example directly uses four 2000mAh Ni83 system soft-pack lithium-ion batteries, the same as those in Example 1, combined in a 4S1P manner to form a battery module.

[0047] Comparative Example 2

[0048] The difference between this comparative example and Example 1 is that the heat insulation material 6 was not coated on the surface of the individual cell 1 in step three.

[0049] Comparative Example 3

[0050] The difference between this comparative example and Example 1 is that step three is not performed, that is, the individual cell 1 is not connected to the L-shaped heat sink 4, the L-shaped heat sink 4 is not connected to the micro carbon fiber-aluminum 5, and the surface of the individual cell 1 is not covered with heat insulation material 6.

[0051] Overcharge-induced thermal runaway tests were conducted on the high-safety battery module prepared in Example 1 of the present invention and the battery modules prepared in Comparative Examples 1 to 3. The specific process was as follows: one battery in the middle of the 4S1P of each battery module was selected and subjected to a 1C, 5OV overcharge test. The temperature change of the surface of the adjacent battery was monitored using a thermocouple thermometer. The test results are shown in Table 1.

[0052] Table 1

[0053] Experimental group Overcharge result highest temperature Description of overcharge phenomenon Overcharge maximum voltage Comparative Example 1 Not approved 613.2℃ Fire after smoke 30.4V Example 1 pass 102.3℃ Smoke but no fire 48.9V Comparative Example 2 pass 119.2℃ Smoke but no fire 50.2V Comparative Example 3 Not approved 625.2℃ Fire after smoke 47.5V

[0054] As shown in Table 1, compared with the battery module prepared by conventional methods in Comparative Example 1, the high-safety battery module prepared in Example 1 of this invention and the battery module without thermal insulation material in Comparative Example 2 can significantly reduce the surface temperature of the adjacent battery when thermal runaway occurs, thereby reducing the degree of danger during thermal runaway and improving the safety performance of the battery module. Although Comparative Example 3 cannot avoid the high temperature phenomenon caused by the eventual fire, it effectively improves the limiting voltage when thermal runaway is caused by overcharging, and improves the overall safety performance of the battery module to a certain extent.

[0055] In summary, compared with conventional battery modules, the high-safety battery module prepared using this invention effectively enhances the overall safety performance of the battery module without changing the internal structure of individual cells or ensuring the electrical performance of the original individual cells.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Any simple modifications, alterations, and equivalent changes made to the above embodiments based on the inventive essence shall still fall within the protection scope of the present invention.

Claims

1. A high-safety battery module, characterized in that, The high-safety battery module (8) includes several high-safety single soft-pack batteries (7) connected in combination. The high-safety single soft-pack battery (7) includes a single cell (1). A directional pressure relief port (3) is provided on one side of the cell side seal (2) of the single cell (1), and the cell side seal (2) is connected to the heat sink (4). The directional pressure relief port (3) is sealed in the heat sink (4). A micro carbon fiber-aluminum (5) is connected to the other end of the heat sink (4). The surface of the single cell (1) is covered with heat insulation material (6). The directional pressure relief port (3) is a serrated notch. The distance between the serrated notch and the unsealed area in the single cell (1) is 1mm~2mm. The heat sink (4) is an L-shaped finned heat sink. The wide end of the L-shaped finned heat sink is connected to the cell side seal (2), and the narrow end is connected to the micro carbon fiber-aluminum (5).

2. The high-safety battery module according to claim 1, characterized in that, The heat insulation material (6) is polytetrafluoroethylene glass fiber cloth.

3. A method for preparing a high-safety battery module as described in claim 1 or 2, characterized in that, The method includes the following steps: Step 1: Select several soft-pack lithium-ion batteries and perform an overcharge-induced thermal runaway operation on each soft-pack lithium-ion battery to ensure that each soft-pack lithium-ion battery triggers thermal runaway. Then, count the location of the pressure relief port on the cell side seal after each soft-pack lithium-ion battery triggers thermal runaway, and record the location of the pressure relief port that appears the most times. Step 2: Select a soft-pack lithium-ion battery of the same model and capacity as in Step 1 as a single cell (1). Then, according to the location of the pressure relief port that appears most frequently recorded in Step 1, make a directional pressure relief port (3) on the cell side seal (2) of the single cell (1). Step 3: Connect one side of the single cell (1) with the directional pressure relief port (3) in Step 2 to one end of the heat sink (4), then connect the other end of the heat sink (4) to the micro carbon fiber-aluminum (5), and then cover the surface of the single cell (1) with heat insulation material (6) to obtain a high-safety single soft pack battery (7). Step 4: Combine the high-safety single-cell soft-pack batteries (7) obtained in Step 3 according to the design method to form a high-safety battery module (8).

4. The method according to claim 3, characterized in that, The soft-pack lithium-ion battery mentioned in step one is a 2000mAh capacity, Ni83 system soft-pack lithium-ion battery, and the overcharge conditions are: 1C, 50V.

Images