Battery cover plate assembly, battery and battery pack

Abstract

The utility model relates to the technical field of batteries, and discloses a battery cover plate assembly, a battery and a battery pack, the battery cover plate assembly comprises a cover plate body, a lower insulating part and at least one stopping part, and the cover plate body is provided with an explosion-proof mechanism; the lower insulating part is connected with the cover plate body and is provided with a mounting groove with an opening facing the cover plate body; the stop piece is arranged in the mounting groove, the stop piece is formed by high-temperature-resistant and electrolyte-resistant colloid, and the projection plane of the stop piece on the cover plate body is not completely overlapped with the explosion-proof mechanism in the thickness direction of the cover plate body. According to the utility model, the backstop piece is arranged and is formed by adopting the high-temperature-resistant and electrolyte-resistant colloid, so that the backstop piece is still intact when the battery is subjected to thermal runaway and the lower insulating piece is melted, the backstop piece is propped between the cover plate body and the pole group to prevent the pole group from shielding the explosion-proof mechanism, and the backstop piece enables an exhaust channel to be formed between the cover plate body and the pole group; therefore, normal exhaust and pressure relief of the explosion-proof mechanism are facilitated, and the safety performance of the battery is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a battery cover assembly, a battery and a battery pack. Background Art

[0002] At present, the battery cell includes a shell, an electrode group and a cover plate assembly. The shell has an inner cavity for accommodating the electrode group. One end of the shell is open. The cover plate is arranged at the open end of the shell to encapsulate the electrode group in the shell.

[0003] The cover assembly includes an explosion-proof valve and an insulating protection structure, which can well protect the electrode group during the battery cell manufacturing process and normal use, and avoid abnormal lap short circuit inside the battery cell.

[0004] The current battery cells use plastic materials such as PP for their insulating protection structures. When the battery cell experiences thermal runaway, the internal temperature can reach over 600°C in a short period of time. The plastic materials of the insulating protection structure will quickly melt and fail. At this time, only the electrode group is left inside the shell. Under the action of the internal high-temperature and high-pressure gas, the electrode group loses balance. Since the pressure at the cover explosion-proof valve is relatively low, the electrode group can easily move toward the explosion-proof valve, thereby blocking the explosion-proof valve and causing the battery to fail to release pressure in time, resulting in fire and explosion. Utility Model Content

[0005] In view of this, the utility model provides a battery cover assembly, a battery and a battery pack to solve the problem that the explosion-proof valve is easily blocked by the pole group when thermal runaway occurs in the battery cell.

[0006] In the first aspect, the utility model provides a battery cover assembly, including a cover body, a lower insulating member and at least one stopper, the cover body is provided with an explosion-proof mechanism; the lower insulating member is connected to the cover body, and the lower insulating member is provided with a mounting groove with an opening toward the cover body; the stopper is arranged in the mounting groove, the stopper is formed of a colloid that is resistant to high temperature and electrolyte, and along the thickness direction of the cover body, the projection surface of the stopper on the cover body does not completely overlap with the explosion-proof mechanism.

[0007] Beneficial effect: The battery cover assembly provided by the utility model is provided with a stopper, and the stopper is located between the cover body and the lower insulating member. When thermal runaway occurs in the battery, the temperature rises. Since the lower insulating member is usually made of plastic materials such as PP, the lower insulating member melts at high temperature. Under the action of the internal high-temperature and high-pressure gas, the pole group loses balance. Since the pressure at the explosion-proof mechanism of the cover is relatively low, the pole group is easy to move toward the explosion-proof mechanism. Since the stopper is provided and the stopper is formed of a colloid that is resistant to high temperature and electrolyte, the stopper is intact at high temperature. Since the projection of the stopper on the cover body does not completely overlap with the explosion-proof mechanism, the stopper abuts between the cover body and the pole group. The stopper will not block the explosion-proof valve. At the same time, it can prevent the pole group from blocking the explosion-proof mechanism. The stopper forms an exhaust channel between the cover body and the pole group, thereby facilitating normal exhaust and pressure relief of the explosion-proof mechanism and improving the safety performance of the battery.

[0008] In an optional embodiment, the stopper can withstand a temperature of not less than 600°C.

[0009] Beneficial effect: With such arrangement, the stopper formed of colloid can remain intact and not melt when thermal runaway occurs inside the battery cell, thereby supporting the exhaust channel between the electrode group and the cover plate body.

[0010] In an optional embodiment, the volume resistivity of the stopper is P, where P≥10 9 Ω·m.

[0011] Beneficial effect: With this arrangement, the stopper made of colloid is insulated. Because when thermal runaway occurs, the lower insulating member melts at high temperature, and the stopper abuts between the cover body and the pole group, the stopper has a large volume resistivity, good insulation performance, and high safety.

[0012] In an optional implementation, the thermal conductivity of the stopper is λ, λ≤0.02-8 W / mK.

[0013] Beneficial effect: With this arrangement, the stopper made of colloid has good heat resistance, and when thermal runaway occurs in the battery, it will not cause the spread of heat, thereby further improving the safety performance of the battery.

[0014] In an optional embodiment, the stopper is independently molded and is interference fit with the mounting groove; or, a glue injection hole connected to the inner cavity of the mounting groove is provided at the bottom of the mounting groove, and the stopper is molded by injecting colloid into the mounting groove through the glue injection hole, and the stopper, the lower insulating member and the cover plate body are bonded and fixed.

[0015] Beneficial effects: Both methods can form the stopper, and the processing or assembly of the stopper is easy.

[0016] In an optional embodiment, at least one positioning rib is provided in the installation groove, and along the thickness direction of the cover body, the length of the positioning rib is no greater than the depth of the installation groove, and the stopper is provided with a positioning slot that cooperates with the positioning rib.

[0017] Beneficial effect: By arranging the positioning ribs in the installation groove and the stopper being provided with the positioning slots matched with the positioning ribs, the assembly positioning accuracy between the stopper and the installation groove is high. This structure is applicable to both the stopper formed by colloid independently and the stopper formed by injection molding.

[0018] In addition, after the stopper and the mounting groove of the lower insulating member are assembled, the positioning dowel is located inside the stopper, and the stopper is resistant to high temperatures. When other parts of the lower insulating member melt, the positioning dowel is not easy to melt because it is wrapped in insulation by the stopper. The positioning dowel remains in the stopper and can also strengthen the stopper, ensuring the support function of the stopper between the cover plate body and the pole group.

[0019] In an optional embodiment, the stopper is formed by glue injection through the glue injection hole, a fixing rib is provided in the installation groove, and a plurality of barbs are provided on the surface of the fixing rib.

[0020] Beneficial effect: Since a fixing rib is provided in the installation groove and a plurality of barbs are provided on the surface of the fixing rib, glue is injected into the installation groove through the glue injection hole, and the molded stopper follows the shape of the installation slot and the fixing rib. After the colloid is formed, grooves are formed on the stopper at corresponding positions of the barbs of the fixing rib. The barbs on the fixing rib are used to achieve a firm connection between the stopper and the lower insulating member, preventing the stopper from being displaced or moved in the installation groove, thereby ensuring that the performance of the battery is not affected.

[0021] In addition, since the stopper and the lower insulating member are connected by glue injection, the fixing ribs are located inside the stopper, and the stopper is resistant to high temperatures. When other parts of the lower insulating member melt, the fixing ribs are not easy to melt because they are wrapped in insulation by the stopper. The fixing ribs remain inside the stopper and can also strengthen the stopper, ensuring the support function of the stopper between the cover plate body and the pole group.

[0022] In an optional embodiment, the explosion-proof mechanism includes an explosion-proof valve, and when the stopper is arranged between the explosion-proof valve and the lower insulating member, the size of the explosion-proof valve is smaller than the size of the stopper along the width direction or the length direction of the cover body.

[0023] Beneficial effect: This arrangement can ensure that the stopper will not fly out of the explosion-proof valve when the battery cell experiences thermal runaway and the lower insulating member melts and is impacted by the pole group.

[0024] In the second aspect, the utility model also provides a battery, comprising a shell, a pole group and a battery cover assembly of any one of the above technical solutions, the shell is provided with an open end; the pole group is arranged in the shell; the battery cover assembly is arranged at the open end of the shell, and the pole group is encapsulated in the shell, and the stopper of the battery cover assembly is suitable for abutting between the pole group and the cover body after the lower insulating member melts due to thermal runaway inside the battery, so as to form an exhaust channel connected to the explosion-proof mechanism.

[0025] Beneficial effect: Since the battery includes the battery cover assembly of the above-mentioned Su embodiment, and since a stopper is provided, the stopper is located between the cover body and the lower insulating member. When thermal runaway occurs in the battery, the temperature rises. Since the lower insulating member is usually made of plastic materials such as PP, the lower insulating member melts at high temperatures. Under the action of the internal high-temperature and high-pressure gas, the pole group loses balance. Since the pressure at the explosion-proof mechanism of the cover is relatively low, the pole group is easy to move toward the explosion-proof mechanism. Since a stopper is provided and the stopper is formed of a colloid that is resistant to high temperatures and electrolytes, the stopper is intact at high temperatures. Since the projection of the stopper on the cover body does not completely overlap with the explosion-proof mechanism, the stopper abuts between the cover body and the pole group. The stopper will not block the explosion-proof valve. At the same time, it can prevent the pole group from blocking the explosion-proof mechanism. The stopper forms an exhaust channel between the cover body and the pole group, thereby facilitating normal exhaust and pressure relief of the explosion-proof mechanism, and the safety performance of the battery is improved.

[0026] In addition, since the battery includes the above-mentioned battery cover assembly, it has all the beneficial effects of the battery cover assembly.

[0027] In a third aspect, the utility model further provides a battery pack, characterized in that it includes the battery cover assembly in the above technical solution.

[0028] Beneficial effect: Since the battery pack includes the above-mentioned battery, it has the same effect as the battery and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A top view of a battery cover assembly according to an embodiment of the utility model;

[0031] Figure 2 For along Figure 1 Sectional view of AA in the middle;

[0032] Figure 3 for Figure 1 An exploded view of the battery cover assembly shown;

[0033] Figure 4 For Figure 1 A three-dimensional view of the battery cover assembly from a reverse perspective;

[0034] Figure 5 for Figure 2 A partial enlarged view of point B in the middle;

[0035] Figure 6 A partial enlarged view of another embodiment of the utility model;

[0036] Figure 7 A partial enlarged view of another embodiment of the utility model;

[0037] Figure 8 for Figure 7 A partial enlarged view of point C in the middle.

[0038] Description of reference numerals:

[0039] 1. Cover plate body; 2. Lower insulating part; 21. Mounting groove; 22. Glue injection hole; 23. Positioning rib; 24. Fixing rib; 241. Barb; 3. Stopper; 4. Explosion-proof mechanism; 5. Pole; 6. End plate. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the embodiment of the utility model clearer, the technical solution in the embodiment of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiment of the utility model. Obviously, the described embodiment is a part of the embodiment of the utility model, not all the embodiments. Based on the embodiment of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0041] Combine the following Figures 1 to 8 , describing an embodiment of the utility model.

[0042] According to an embodiment of the utility model, in a first aspect, a battery cover assembly is provided, comprising a cover body 1, a lower insulating member 2 and at least one stop member 3, the cover body 1 being provided with an explosion-proof mechanism 4; the lower insulating member 2 being connected to the cover body 1, and the lower insulating member 2 being provided with a mounting groove 21 with an opening toward the cover body 1; the stop member 3 being arranged in the mounting groove 21, the stop member 3 being formed of a colloid that is resistant to high temperature and electrolyte, and along the thickness direction of the cover body 1, the projection surface of the stop member 3 on the cover body 1 does not completely overlap with the explosion-proof mechanism 4.

[0043] The battery cover assembly provided by the utility model is provided with a stopper 3, and the stopper 3 is located between the cover body 1 and the lower insulating member 2. When thermal runaway occurs in the battery, the temperature rises. Since the lower insulating member 2 is usually made of plastic materials such as PP, the lower insulating member 2 melts at high temperature. Under the action of the internal high-temperature and high-pressure gas, the pole group loses balance. Since the pressure at the explosion-proof mechanism 4 of the cover is relatively low, the pole group is easy to move toward the explosion-proof mechanism 4. Since the stopper 3 is provided and the stopper 3 is formed of a colloid that is resistant to high temperature and electrolyte, the stopper 3 is intact at high temperature. Since the projection of the stopper 3 on the cover body 1 does not completely overlap with the explosion-proof mechanism 4, the stopper 3 abuts between the cover body 1 and the pole group, and the stopper 3 will not block the explosion-proof valve. At the same time, it can prevent the pole group from blocking the explosion-proof mechanism 4. The stopper 3 forms an exhaust channel between the cover body 1 and the pole group, thereby facilitating normal exhaust and pressure relief of the explosion-proof mechanism 4, thereby improving the safety performance of the battery.

[0044] In one embodiment, the temperature resistance of the stopper 3 is not less than 600°C.

[0045] Since the colloid can withstand a temperature of not less than 600° C., the stopper 3 formed of the colloid can remain intact and not melt when thermal runaway occurs inside the battery cell, thereby supporting the exhaust channel between the electrode group and the cover body 1 .

[0046] In one embodiment, the volume resistivity of the stopper 3 is P, P ≥ 10 9 Ω·m.

[0047] Since the volume resistivity of the colloid is P≥10 9 Ω·m, therefore, the stopper 3 made of colloid is insulated, because when thermal runaway occurs, the lower insulating member 2 melts at high temperature, and the stopper 3 abuts between the cover body 1 and the pole group, and the stopper 3 has a large volume resistivity, good insulation performance, and high safety. Specifically, the lower insulating member 2 includes a lower plastic.

[0048] In one embodiment, the thermal conductivity of the stopper 3 is λ, λ≤0.02-8 W / mK.

[0049] Since the thermal conductivity of the colloid is λ≤0.02-8W / mK, the stopper 3 made of the colloid has good heat resistance and will not cause heat spread when thermal runaway occurs in the battery, thereby further improving the safety performance of the battery.

[0050] Specifically, the main component of the colloid making the stopper 3 is an inorganic crystal material, including aluminum oxide and silicon nitride.

[0051] In one embodiment, the stop member 3 is independently molded, and the stop member 3 is interference fit with the mounting groove 21; or, a glue injection hole 22 connected to the inner cavity of the mounting groove 21 is provided at the bottom of the mounting groove 21, and the stop member 3 is molded by injecting colloid into the mounting groove 21 through the glue injection hole 22, and the stop member 3, the lower insulating member 2 and the cover plate body 1 are bonded and fixed.

[0052] The stopper 3 is formed by colloid. Since the colloid has fluidity, the stopper 3 can be formed in the following two ways:

[0053] First, the stopper 3 is independently molded by colloid. During assembly, the stopper 3 is installed in the mounting groove 21 of the lower insulating member 2, and then the lower insulating member 2 is assembled with the cover body 1. The shape of the stopper 3 can match the mounting groove 21 of the lower insulating member 2 to prevent the stopper 3 from shifting in the mounting groove 21 and affecting the battery performance.

[0054] Second, after assembling the lower insulating member 2 and the cover body 1, glue is injected into the mounting groove 21 from the glue injection hole 22 at the bottom of the mounting groove 21 to fill the mounting groove 21 with glue, thereby achieving a fixed connection between the lower insulating member 2, the stopper 3 and the cover body 1.

[0055] Both of these methods can form the stopper 3, and the processing or assembly difficulty of the stopper 3 is small. Different forming processes of the stopper 3 can be selected according to actual conditions.

[0056] In one embodiment, at least one positioning rib 23 is provided in the installation groove 21 , and along the thickness direction of the cover body 1 , the length of the positioning rib 23 is no greater than the depth of the installation groove 21 , and the stopper 3 is provided with a positioning slot that cooperates with the positioning rib 23 .

[0057] By providing the positioning rib 23 in the installation groove 21 and providing the positioning slot matched with the positioning rib 23 in the stopper 3, the assembly positioning accuracy between the stopper 3 and the installation groove 21 is high. This structure is applicable to both the stopper 3 formed by colloid independently and the stopper 3 formed by injection molding.

[0058] In addition, after the stopper 3 and the mounting groove 21 of the lower insulating member 2 are assembled, the positioning dowel 23 is located inside the stopper 3, and the stopper 3 is resistant to high temperatures. When other parts of the lower insulating member 2 melt, the positioning dowel 23 is not easy to melt because it is wrapped by the stopper 3 for heat insulation. The positioning dowel 23 still remains in the stopper 3 and can also play a role in strengthening the stopper 3, thereby ensuring the support role of the stopper 3 between the cover plate body 1 and the pole group.

[0059] In one embodiment, the stopper 3 is formed by glue injection through the glue injection hole 22 , a fixing rib 24 is provided in the installation groove 21 , and a plurality of barbs 241 are provided on the surface of the fixing rib 24 .

[0060] This structure is suitable for the stopper 3 formed by injection molding. Since the mounting groove 21 is provided with a fixing rib 24, and a plurality of barbs 241 are provided on the surface of the fixing rib 24, the stopper 3 is formed by injecting glue into the mounting groove 21 through the injection hole 22, and the stopper 3 is formed to conform to the mounting slot and the fixing rib 24. After the colloid is formed, a groove is formed at the corresponding position of the barb 241 of the fixing rib 24 on the stopper 3. The barb 241 on the fixing rib 24 realizes a firm connection between the stopper 3 and the lower insulating member 2, preventing the stopper 3 from being displaced or moved in the mounting groove 21, and ensuring that the performance of the battery is not affected.

[0061] In addition, since the stopper 3 and the lower insulating member 2 are connected by glue injection, the fixing rib 24 is located inside the stopper 3, and the stopper 3 is resistant to high temperatures. When other parts of the lower insulating member 2 melt, the fixing rib 24 is not easy to melt because it is wrapped by the stopper 3 for heat insulation. The fixing rib 24 still remains in the stopper 3 and can also play a role in strengthening the stopper 3, thereby ensuring the support role of the stopper 3 between the cover plate body 1 and the pole group.

[0062] In one embodiment, the explosion-proof mechanism 4 includes an explosion-proof valve, and when the stopper 3 is disposed between the explosion-proof valve and the lower insulating member 2, the size of the explosion-proof valve along the width direction of the cover body 1 or along the length direction of the cover body 1 is smaller than the size of the stopper 3. W1≤W2.

[0063] like Figure 3 As shown, the dimension of the explosion-proof valve along the width direction of the cover plate body 1 is the width W1 of the explosion-proof valve, and the dimension of the stopper 3 along the width direction of the cover plate body 1 is the width W2 of the stopper 3. Therefore, W1<W2, thereby ensuring that the stopper 3 will not fly out of the explosion-proof valve when the battery cell undergoes thermal runaway and the lower insulating member 2 melts and is impacted by the pole group.

[0064] Specifically, the length of the explosion-proof valve along the length direction of the cover body 1 is the length of the explosion-proof valve, and the length of the stopper 3 along the length direction of the cover body 1 is the length of the stopper 3. When the length of the stopper 3 is greater than the length of the explosion-proof valve, it can also prevent the stopper 3 from flying out of the explosion-proof valve under the impact of the pole group after the battery cell thermal runaway occurs and the lower insulating member 2 melts. This embodiment is not shown in the figure, but it can be understood that Figure 3 The stopper 3 of the embodiment shown is rotated 90 degrees in a direction parallel to the end surface of the cover body 1. The mounting groove 21 is arranged in a corresponding manner.

[0065] In addition, the cover body 1 is also provided with a pole 5 . The number and position of the stopper 3 are not limited, but the stopper 3 must be arranged away from the pole 5 .

[0066] In one embodiment, the battery cover assembly further includes an end plate 6, which is disposed on a side of the lower insulating member 2 away from the cover body 1, and a groove is disposed on the end plate 6, which matches the mounting groove 21 of the lower insulating member 2. Correspondingly, when a glue injection hole 22 is disposed at the bottom of the mounting groove 21 of the lower insulating member 2, a through hole is also disposed at a corresponding position of the end plate 6 for glue injection.

[0067] When the battery cover assembly, the battery housing and the electrode group are assembled, the end plate 6 abuts against the electrode group.

[0068] According to an embodiment of the utility model, in a second aspect, a battery is further provided, comprising a shell, a pole group and a battery cover assembly of any one of the above technical solutions, wherein the shell is provided with an open end; the pole group is arranged in the shell; the battery cover assembly is arranged at the open end of the shell, and the pole group is encapsulated in the shell, and the stopper 3 of the battery cover assembly is suitable for abutting between the pole group and the cover body 1 after the lower insulating member 2 melts due to thermal runaway inside the battery, so as to form an exhaust channel connected to the explosion-proof mechanism 4.

[0069] Since the battery includes the battery cover assembly of the above-mentioned Soviet embodiment, since the stopper 3 is provided, the stopper 3 is located between the cover body 1 and the lower insulating member 2, when the battery has thermal runaway, the temperature rises, and since the lower insulating member 2 is usually made of plastic materials such as PP, the lower insulating member 2 melts at high temperature, and the pole group loses balance under the action of the internal high-temperature and high-pressure gas. Since the pressure at the explosion-proof mechanism 4 of the cover is relatively low, the pole group is easy to move toward the explosion-proof mechanism 4. Since the stopper 3 is provided and the stopper 3 is formed of a colloid that is resistant to high temperature and electrolyte, the stopper 3 is intact at high temperature, and since the projection of the stopper 3 on the cover body 1 does not completely overlap with the explosion-proof mechanism 4, the stopper 3 abuts between the cover body 1 and the pole group, and the stopper 3 will not block the explosion-proof valve. At the same time, it can prevent the pole group from blocking the explosion-proof mechanism 4. The stopper 3 forms an exhaust channel between the cover body 1 and the pole group, thereby facilitating the normal exhaust and pressure relief of the explosion-proof mechanism 4, and the safety performance of the battery is improved.

[0070] In addition, since the battery includes the battery cover assembly of the above embodiment, it has all the beneficial effects of the battery cover assembly.

[0071] According to an embodiment of the present utility model, in a third aspect, a battery pack is further provided, characterized in that it includes the battery cover assembly in the above technical solution.

[0072] Since the battery pack includes the battery of the above embodiment and has the same effect as the battery, it will not be described in detail here.

[0073] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A battery cover assembly, characterized in that: include: A cover body, wherein the cover body is provided with an explosion-proof mechanism; A lower insulating member connected to the cover body, the lower insulating member being provided with a mounting groove opening toward the cover body; At least one stopper is disposed in the mounting groove, the stopper is formed of a colloid that is resistant to high temperatures and electrolytes, and along the thickness direction of the cover body, the projection surface of the stopper on the cover body does not completely overlap with the explosion-proof mechanism.

2. The battery cover assembly according to claim 1, characterized in that: The stopper can withstand a temperature of not less than 600°C.

3. The battery cover assembly according to claim 1 or 2, characterized in that: The volume resistivity of the stopper is P, P≥10 9 Ω·m.

4. The battery cover assembly according to claim 1 or 2, characterized in that: The thermal conductivity of the stopper is λ, λ≤0.02-8W / mK.

5. The battery cover assembly according to claim 1 or 2, characterized in that: The stopper is independently formed, and the stopper is interference fitted with the mounting groove; Alternatively, a glue injection hole communicating with the inner cavity of the mounting groove is provided at the bottom of the mounting groove, the stopper is formed by injecting colloid into the mounting groove through the glue injection hole, and the stopper, the lower insulating member and the cover plate body are bonded and fixed.

6. The battery cover assembly according to claim 5, characterized in that: At least one positioning rib is provided in the installation groove, and along the thickness direction of the cover body, the length of the positioning rib is not greater than the depth of the installation groove, and the stopper is provided with a positioning slot that cooperates with the positioning rib.

7. The battery cover assembly according to claim 5, characterized in that: The stopper is formed by glue injection through the glue injection hole, a fixing rib is arranged in the installation groove, and a plurality of barbs are arranged on the surface of the fixing rib.

8. The battery cover assembly according to claim 1 or 2, characterized in that: The explosion-proof mechanism comprises an explosion-proof valve. When the stopper is arranged between the explosion-proof valve and the lower insulating member, the size of the explosion-proof valve is smaller than the size of the stopper along the width direction of the cover body or along the length direction of the cover body.

9. A battery, characterized in that: include: a housing having an open end; A pole group, the pole group is arranged in the shell; The battery cover assembly according to any one of claims 1 to 8, wherein the battery cover assembly is arranged at the open end of the shell, and the electrode group is encapsulated in the shell, and the stopper of the battery cover assembly is suitable for abutting between the electrode group and the cover body after the lower insulating member melts due to thermal runaway inside the battery, thereby forming an exhaust channel connected to the explosion-proof mechanism.

10. A battery pack, characterized in that: Includes the battery cover assembly as described in claim 9.

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