Battery and flame-retardant explosion-proof cap thereof

Abstract

The flame-retardant explosion-proof cover cap comprises a top cover, a connecting piece, a flame-retardant piece and a flame-retardant capsule, the top cover and the flame-retardant piece are respectively connected with the connecting piece in a matched mode, one end, far away from the top cover, of the connecting piece is provided with a first containing cavity used for being connected with a battery cell, and the flame-retardant capsule is arranged in the first containing cavity. The top cover and the flame-retardant capsule are separated by the flame-retardant sheet, and a flame retardant is arranged in the flame-retardant capsule. When the temperature of the battery cell continuously rises and a large amount of gas is generated due to thermal runaway of the battery cell caused by abuse or internal short circuit of the battery cell, the internal pressure of the battery cell rises, the flame-retardant capsule is extruded and broken, and the flame retardant is released into electrolyte of the battery cell and is fully mixed with inflammable gas generated by side reaction under the action of heat, so that a flame-retardant effect is achieved.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, specifically to batteries and their flame-retardant and explosion-proof caps. Background Technology

[0002] Currently, countries around the world are vigorously developing green and efficient rechargeable battery cells. Lithium-ion batteries, as a new type of rechargeable battery cell, have advantages such as high energy density and power density, high operating voltage, light weight, small size, long cycle life, good safety, and environmental friendliness. They have broad application prospects in portable appliances, power tools, large-scale energy storage, and electric vehicle power supplies. However, under high-rate charging and discharging or abuse, various electrochemical reactions or internal short circuits can occur in lithium-ion batteries, causing a continuous increase in internal temperature and pressure, which can easily lead to thermal runaway, and even combustion and explosion. This is one of the main reasons affecting the large-scale application of lithium-ion batteries. Existing patent CN116914274A discloses a secondary battery cell that adds an explosion-proof cavity connected to the outside inside the cell. The explosion-proof cavity is equipped with an explosion-proof valve and a flame arrester. The flame arrester is a metal structure that reduces the temperature by increasing the flow rate. However, when the battery cell experiences thermal runaway, the gas ejected from it is a flammable gas. The high-speed gas that is ignited has a stronger ablation ability and poses a risk of burning the flame arrester. The uncertainty caused by this design increases the uncertainty after the battery cell experiences thermal runaway. Utility Model Content

[0003] To address the technical problem of the risk of ablation in existing flame arresters, this invention proposes a flame-retardant and explosion-proof cap. When the flame-retardant capsule is squeezed and ruptured, the flame retardant is released into the electrolyte of the battery cell and fully mixes with the flammable gas produced by the side reaction under the action of heat, thereby playing a flame-retardant role.

[0004] The technical solution adopted by this utility model is as follows: a flame-retardant and explosion-proof cap, including a top cover, a connecting piece, a flame-retardant piece, and a flame-retardant capsule. The top cover and the flame-retardant piece are respectively connected to the connecting piece. The end of the connecting piece away from the top cover is provided with a first cavity for connecting with the battery cell. At least a portion of the flame-retardant capsule is disposed in the first cavity. The flame-retardant piece separates the top cover and the flame-retardant capsule. The flame-retardant capsule contains a flame retardant.

[0005] Optionally, the flame-retardant capsule includes a capsule portion, a pressure-bearing portion, and a bursting portion connected in sequence. The flame retardant is filled in the capsule portion, the pressure-bearing portion, and the bursting portion. The capsule portion is located inside the first cavity. One end of the pressure-bearing portion is connected to the capsule portion, and the other end of the pressure-bearing portion extends into the battery cell. The thickness of the capsule wall of the flame-retardant capsule decreases sequentially from the capsule portion to the bursting portion.

[0006] Optionally, the connecting piece is provided with a first step, a second step and a third step from top to bottom. The top surface of the first step abuts against the bottom surface of the top cover, the top surface of the second step abuts against the bottom surface of the flame retardant sheet, and the top surface of the third step abuts against the bottom surface of the bladder.

[0007] Optionally, the top cover includes a top, a first connecting portion and a second connecting portion, the two ends of the first connecting portion are respectively connected at an angle to the top and the second connecting portion, the connecting piece is provided with an annular groove that mates with the second connecting portion, and a second cavity is provided between the top and the flame retardant sheet.

[0008] Optionally, the flame retardant sheet is provided with a pressure relief hole, and a pressure relief plate is provided inside the pressure relief hole, with the pressure relief plate corresponding to the second cavity.

[0009] Optionally, the first connecting portion is provided with a plurality of through holes spaced apart along the circumference, and the through holes communicate with the second cavity.

[0010] Optionally, the capsule wall is made of resin material with a melting point of 100-140℃.

[0011] Optionally, the end of the connecting piece facing away from the top cover is provided with a boss for abutting against the positive current collector of the battery cell.

[0012] This utility model also discloses a battery, including a shell, a cell and the flame-retardant and explosion-proof cap mentioned above. The connecting piece and the cell are both disposed inside the shell. The cell has a channel communicating with the first cavity. One end of the flame-retardant capsule is disposed inside the first cavity, and the other end of the flame-retardant capsule is disposed inside the channel.

[0013] Optionally, a sealing ring is provided between the outer peripheral wall of the connecting piece and the inner peripheral wall of the housing.

[0014] The beneficial effects of this invention are as follows: When the battery cell experiences thermal runaway due to misuse or internal short circuit, causing the cell temperature to rise continuously and generating a large amount of gas, the internal pressure of the cell increases. The flame-retardant capsule is then squeezed and ruptured, releasing the flame retardant into the electrolyte of the battery cell. Under the influence of heat, the flame retardant fully mixes with the flammable gas produced by the side reaction, thus achieving a flame-retardant effect. This embodiment achieves flame retardancy for thermally runaway battery cells by directly inserting a flame retardant inside the cell. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the flame-retardant and explosion-proof cap proposed in an embodiment of this utility model;

[0016] Figure 2 This is a schematic diagram of the top cover of the flame-retardant and explosion-proof cap proposed in an embodiment of this utility model;

[0017] Figure 3This is a schematic diagram of the connecting piece of the flame-retardant and explosion-proof cap proposed in an embodiment of this utility model.

[0018] The labels in the attached figures are as follows: 1. Top cover; 11. Top; 12. First connecting part; 121. Through hole; 13. Second connecting part; 14. Second cavity; 2. Connecting piece; 21. First cavity; 22. First step; 23. Second step; 24. Third step; 25. Boss; 26. Annular groove; 3. Flame retardant piece; 31. Pressure relief hole; 4. Flame retardant capsule; 41. Capsule; 42. Pressure bearing part; 43. Bursting part; 5. Shell; 6. Battery cell; 7. Sealing ring. Detailed Implementation

[0019] The present application will now be described in further detail with reference to the accompanying drawings and embodiments.

[0020] In the description of this utility model, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0021] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0022] like Figures 1 to 3As shown, this embodiment discloses a flame-retardant and explosion-proof cap, including a top cover 1, a connecting piece 2, a flame-retardant piece 3, and a flame-retardant capsule 4. The top cover 1 and the flame-retardant piece 3 are respectively connected to the connecting piece 2. The end of the connecting piece 2 away from the top cover 1 is provided with a first cavity 21 for connecting to the battery cell 6. At least a portion of the flame-retardant capsule 4 is disposed in the first cavity 21. The flame-retardant piece 3 separates the top cover 1 and the flame-retardant capsule 4. The flame-retardant capsule 4 contains a flame retardant. When the battery cell 6 experiences thermal runaway due to abuse or internal short circuit, causing the temperature of the battery cell 6 to rise continuously and a large amount of gas to be generated, the internal pressure of the battery cell 6 increases, and the flame-retardant capsule 4 is squeezed and ruptured, releasing the flame retardant into the electrolyte of the battery cell 6. Under the action of heat, the flame retardant fully mixes with the flammable gas generated by the side reaction, thereby playing a flame-retardant role. This embodiment achieves flame retardancy for the thermally runaway battery cell 6 by directly loading a flame retardant inside the battery cell 6. It provides a manufacturing method and structure for a high-safety, high-rate battery cell 6.

[0023] In this embodiment, as Figure 1 As shown, the flame-retardant capsule 4 includes a capsule portion 41, a pressure-bearing portion 42, and a bursting portion 43 connected in sequence. The flame retardant is filled in the capsule portion 41, the pressure-bearing portion 42, and the bursting portion 43. The capsule portion 41 is located inside the first cavity 21. One end of the pressure-bearing portion 42 is connected to the capsule portion 41, and the other end extends into the cell 6. The thickness of the capsule wall of the flame-retardant capsule 4 decreases sequentially from the capsule portion 41 to the bursting portion 43. The bursting portion 43 is thinner than the capsule portion 41 and the pressure-bearing portion 42. When the cell 6 experiences thermal runaway due to abuse or internal short circuit, causing the temperature of the cell 6 to rise continuously and a large amount of gas to be generated, the internal pressure of the cell 6 increases. The flame-retardant capsule 4 is squeezed and ruptures at the bursting portion 43, releasing the flame retardant into the electrolyte. When a certain pressure value is reached inside the cell 6, the pressure-bearing portion 42 is further squeezed, causing it to rupture and further releasing the flame retardant. The pressure-bearing part 42 makes it easier to experimentally control the burst value of the flame-retardant capsule 4, enabling more precise control over the release of the flame retardant. The capsule wall of the flame-retardant capsule 4 is made of resin material with a melting point of 100-140℃. In the event of thermal runaway of the battery cell 6, the low-melting-point resin material ensures that the flame-retardant capsule 4 does not block the pressure relief channel after melting.

[0024] like Figure 2 and 3As shown, the connecting piece 2 has a first step 22, a second step 23, and a third step 24 arranged sequentially from top to bottom. The top surface of the first step 22 abuts against the bottom surface of the top cover 1, the top surface of the second step 23 abuts against the bottom surface of the flame-retardant sheet 3, and the top surface of the third step 24 abuts against the bottom surface of the bladder portion 41. The top cover 1 includes a top 11, a first connecting portion 12, and a second connecting portion 13. The two ends of the first connecting portion 12 are respectively angled to the top 11 and the second connecting portion 13. The connecting piece 2 has an annular groove that mates with the second connecting portion 13. A second cavity 14 is provided between the top 11 and the flame-retardant sheet 3. The top 11 and the second connecting portion 13 are arranged parallel to each other, and the second connecting portion 13 is circumferentially snapped into the annular groove to connect the top cover 1 and the connecting piece 2.

[0025] like Figure 1 and 2 As shown, the flame-retardant sheet 3 is provided with a pressure relief hole 31, and a pressure relief plate is provided inside the pressure relief hole 31. The pressure relief plate is correspondingly arranged with the second cavity 14. The pressure relief plate engages with the pressure relief hole 31 by pressing. When the air pressure inside the first cavity 21 reaches a certain value, the air pressure pushes the pressure relief plate into the second cavity 14, achieving the purpose of pressure relief. The first connecting part 12 is provided with a plurality of through holes 121 spaced apart along the circumference, and the through holes 121 communicate with the second cavity 14. The top cover 1 is made of carbon steel, serving as the positive terminal and having a certain strength to protect the internal structure. The through holes 121 are used for pressure relief.

[0026] like Figure 1 As shown, the end of the connecting piece 2 facing away from the top cover 1 is provided with a boss 15 for abutting against the positive current collector of the battery cell 6. The connecting piece 2 realizes the electrical connection between the electrode tab and the top cover 1. During the assembly process, the boss 15 is positioned by cooperating with the center hole of the positive current collector to ensure accurate positioning and not affect the assembly of the flame-retardant capsule 4.

[0027] like Figure 1 As shown, this embodiment also discloses a battery, including a housing 5, a battery cell 6, and the flame-retardant and explosion-proof cap described above. The connecting piece 2 and the battery cell 6 are both disposed inside the housing 5. The battery cell 6 has a channel communicating with the first cavity 21. One end of the flame-retardant capsule 4 is disposed within the first cavity 21, and the other end of the flame-retardant capsule 4 is disposed within the channel. A sealing ring 7 is provided between the outer peripheral wall of the connecting piece 2 and the inner peripheral wall of the housing 5. The sealing ring 7 seals the battery cell 6 within the space formed by the housing 5 and the connecting piece 2.

[0028] It is understood that the specific embodiments described above are merely for explaining the relevant utility model and not for limiting the utility model. It should also be noted that, for ease of description, only the parts related to the utility model are shown in the accompanying drawings. Multiple technical solutions in the same embodiment, as well as multiple technical solutions in different embodiments, can be arranged and combined to form new technical solutions that do not contradict or conflict with each other. All equivalent structural transformations made based on the content of this utility model specification and drawings, directly or indirectly applied to other related technical fields, are similarly included within the protection scope of this utility model.

Claims

1. A flame-retardant and explosion-proof cap, characterized in that, The device includes a top cover (1), a connecting piece (2), a flame retardant piece (3), and a flame retardant capsule (4). The top cover (1) and the flame retardant piece (3) are respectively connected to the connecting piece (2). The end of the connecting piece (2) away from the top cover (1) is provided with a first cavity (21) for connecting to the battery cell (6). At least a part of the flame retardant capsule (4) is disposed in the first cavity (21). The flame retardant piece (3) separates the top cover (1) and the flame retardant capsule (4). The flame retardant capsule (4) contains a flame retardant inside.

2. The flame-retardant and explosion-proof cap according to claim 1, characterized in that, The flame-retardant capsule (4) includes a capsule portion (41), a pressure-bearing portion (42), and a bursting portion (43) connected in sequence. The flame retardant is filled in the capsule portion (41), the pressure-bearing portion (42), and the bursting portion (43). The capsule portion (41) is located inside the first cavity (21). One end of the pressure-bearing portion (42) is connected to the capsule portion (41), and the other end of the pressure-bearing portion (42) extends into the battery cell (6). The thickness of the capsule wall of the flame-retardant capsule (4) decreases sequentially from the capsule portion (41) to the bursting portion (43).

3. The flame-retardant and explosion-proof cap according to claim 2, characterized in that, The connecting piece (2) is provided with a first step (22), a second step (23) and a third step (24) from top to bottom. The top surface of the first step (22) abuts against the bottom surface of the top cover (1), the top surface of the second step (23) abuts against the bottom surface of the flame retardant sheet (3), and the top surface of the third step (24) abuts against the bottom surface of the bladder (41).

4. The flame-retardant and explosion-proof cap according to claim 1, characterized in that, The top cover (1) includes a top (11), a first connecting part (12) and a second connecting part (13). The two ends of the first connecting part (12) are respectively connected at an angle to the top (11) and the second connecting part (13). The connecting piece (2) is provided with an annular groove that mates with the second connecting part (13). A second cavity (14) is provided between the top (11) and the flame retardant piece (3).

5. The flame-retardant and explosion-proof cap according to claim 4, characterized in that, The flame retardant sheet (3) is provided with a pressure relief hole (31), and a pressure relief plate is provided inside the pressure relief hole (31). The pressure relief plate is correspondingly arranged with the second cavity (14).

6. The flame-retardant and explosion-proof cap according to claim 4, characterized in that, The first connecting part (12) is provided with a plurality of through holes (121) spaced apart along the circumference, and the through holes (121) are connected to the second cavity (14).

7. The flame-retardant and explosion-proof cap according to claim 1, characterized in that, The flame-retardant capsule (4) has a capsule wall made of resin with a melting point of 100-140℃.

8. The flame-retardant and explosion-proof cap according to claim 1, characterized in that, The connecting piece (2) has a boss (15) at one end away from the top cover (1) for abutting against the positive current collector of the battery cell (6).

9. A battery, characterized in that, The device includes a housing (5), a battery cell (6), and a flame-retardant and explosion-proof cap as described in any one of claims 1 to 8. The connecting piece (2) and the battery cell (6) are both located inside the housing (5). The battery cell (6) has a channel communicating with the first cavity (21). One end of the flame-retardant capsule (4) is located inside the first cavity (21), and the other end of the flame-retardant capsule (4) is located inside the channel.

10. The battery according to claim 9, characterized in that, A sealing ring (7) is provided between the outer peripheral wall of the connecting piece (2) and the inner peripheral wall of the shell (5).

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