Battery and electric equipment

Abstract

The utility model discloses a battery and electric equipment. The battery comprises a shell, a top cover and a battery cell, the shell comprises a bottom plate; the battery cell comprises a first pole piece, a second pole piece and a diaphragm which are laminated; a through mounting hole is formed in the bottom plate, and an anti-explosion valve is arranged in the mounting hole; on one side close to the top cover, the length of the diaphragm exceeding the second pole piece is L1; and on one side close to the bottom plate, the length of the diaphragm exceeding the second pole piece is L2, and L2 is less than L1. The explosion-proof valve is arranged on the bottom plate of the shell, and the part, exceeding the pole piece, of the diaphragm covers the end part of the pole piece on the side close to the explosion-proof valve (namely the side close to the bottom plate), so that the size L2, exceeding the second pole piece, of the diaphragm is controlled, L2 is ensured to be less than L1, and the length, exceeding the pole piece, of the diaphragm on the side close to the explosion-proof valve is not too long; and electrolyte and gas in the battery cell are more easily discharged from the bottom plate of the battery cell, so that the normal explosion of the explosion-proof valve and the pressure relief smoothness after explosion are ensured, and the explosion of the battery is avoided.

Description

Technical Field

[0001] The present application relates to the technical field of lithium-ion batteries, and more specifically to a battery, and also to an electrical device including the battery. Background Art

[0002] When the battery fails abnormally and the pressure inside the battery increases to a certain level, the explosion-proof valve will rupture to discharge gas and liquid, thereby preventing the battery from exploding. If the rate of gas and liquid discharge is low after the explosion-proof valve ruptures, the battery still has the risk of explosion. Utility Model Content

[0003] In view of this, the present application provides a battery and also provides an electrical device including the battery, which solves the problem of low exhaust and liquid discharge rates causing battery explosion.

[0004] In order to achieve the above objectives, this application provides the following technical solutions:

[0005] A battery comprises a shell, a top cover, and a battery cell arranged in a closed space enclosed by the shell and the top cover; the shell comprises a bottom plate opposite to the top cover;

[0006] The battery cell comprises a first pole piece and a second pole piece which are stacked and a diaphragm arranged between the first pole piece and the second pole piece; wherein:

[0007] The bottom plate is provided with a through installation hole, and an explosion-proof valve is arranged in the installation hole;

[0008] On a side close to the top cover, the second pole piece exceeds the first pole piece, and the length of the diaphragm exceeding the second pole piece is L1;

[0009] On the side close to the bottom plate, the second pole piece exceeds the first pole piece, the length of the diaphragm exceeding the second pole piece is L2, and L1 and L2 satisfy: L2<L1.

[0010] Optionally, in the above battery, along a first direction, the length of the battery cell is L, the first direction is parallel to a direction from the top cover to the bottom plate, and in the first direction:

[0011] 0.5mm≤L1≤5mm;

[0012] and / or,

[0013] 0.5mm≤L2≤5mm;

[0014] and / or,

[0015] 0.2%L≤L2≤5%L.

[0016] Optionally, in the above battery, the outer surface of the battery cell is covered with a Mylar film;

[0017] The inner surface of the bottom plate is provided with a bottom support plate;

[0018] The bottom support plate is provided with a first through hole, and the side surface of the Mylar film opposite to the bottom support plate is provided with a second through hole, and the first through hole is connected to the second through hole.

[0019] Optionally, in the above battery, an extension length of the first through hole and an extension length of the second through hole are both parallel to the first direction;

[0020] The explosion-proof valve has a first area; in a cross section perpendicular to the first direction, the projection area of ​​the first area is S1, the mounting hole has a first projection, and the sum of the projection areas of the plurality of first through holes located in the first projection is S2, and S1 and S2 satisfy:

[0021] 2≤S1 / S2≤5.

[0022] Optionally, in the above battery, the mounting hole is a stepped hole, the stepped hole includes a plurality of hole segments, wherein the first hole segment close to the outer surface of the bottom plate has the largest hole diameter, and a stepped surface is formed at the junction of the first hole segment and its adjacent hole segment;

[0023] The explosion-proof valve is fixedly arranged on the step surface.

[0024] Optionally, in the above battery, the explosion-proof valve includes a middle area and an edge area arranged around the middle area, and the edge area is at least partially fixedly arranged on the step surface;

[0025] Along the first direction, the depth of the first hole segment is D, the thickness of the edge region is B, and D and B satisfy:

[0026] D≥B.

[0027] Optionally, in the above battery, along the first direction, the thickness of the bottom plate is H, the thickness from the step surface to the inner surface of the bottom plate is A, and H, D, and A satisfy:

[0028] A=HD;

[0029] A≥0.5mm.

[0030] Optionally, in the above battery, along the first direction, the thickness dimension of the middle area is smaller than the thickness dimension of the edge area.

[0031] Optionally, in the above battery, the first electrode sheet is a positive electrode sheet; the positive electrode sheet includes:

[0032] A composite current collector, comprising an intermediate support layer and two conductive layers arranged on both side surfaces of the intermediate support layer;

[0033] The first pole tab and the second pole tab are connected to the two conductive layers respectively, and the first pole tab is connected to the second pole tab.

[0034] An electrical device comprises the battery described above.

[0035] In the battery and electrical equipment provided by the present application, an explosion-proof valve is arranged on the bottom plate of the shell. Since the part of the diaphragm that exceeds the pole piece on the side close to the explosion-proof valve (i.e., the side close to the bottom plate) will cover the end of the pole piece, the dimension L2 of the diaphragm that exceeds the second pole piece is controlled, and L2 < L1 is ensured, so that the length of the diaphragm that exceeds the pole piece on the side close to the explosion-proof valve is not too long, so that the electrolyte and gas inside the battery cell can be more easily discharged from the bottom plate of the battery cell, thereby ensuring the normal explosion of the explosion-proof valve and the smoothness of the pressure relief after the explosion, thereby avoiding the explosion of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0037] Figure 1 A three-dimensional diagram of a battery in this application;

[0038] Figure 2 An exploded view of the battery in this application from another angle;

[0039] Figure 3 An exploded view of the battery in this application;

[0040] Figure 4 It is a schematic diagram of the structure of the battery cell in this application;

[0041] Figure 5 It is a cross-sectional view of the explosion-proof valve and the base plate assembly in this application;

[0042] Figure 6 This is a schematic diagram of the structure of the first pole piece in this application.

[0043] Figure 1-Figure 6 middle:

[0044] 1. First pole piece; 2. Second pole piece; 3. Diaphragm; 4. Top cover; 5. Bottom plate; 6. Explosion-proof valve; 7. Mylar film; 8. Bottom support plate; 9. First through hole; 10. Liquid injection hole;

[0045] 501, mounting hole;

[0046] 601, middle area; 602, edge area;

[0047] 101, composite current collector; 102, first pole ear; 103, second pole ear;

[0048] 1011, middle supporting layer; 1012, first conductive layer; 1013, second conductive layer. DETAILED DESCRIPTION

[0049] The present application provides a battery and also provides an electrical device including the battery.

[0050] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0051] like Figure 1-5 As shown, a battery comprises a shell, a top cover 4, and a battery cell. The shell and the top cover 4 enclose a closed space, and the battery cell is placed in the closed space. The battery cell comprises a first pole piece 1 and a second pole piece 2 which are stacked and a diaphragm 3 arranged between the first pole piece 1 and the second pole piece 2. The shell comprises a bottom plate 5 opposite to the top cover 4. The bottom plate 5 is provided with a through mounting hole 501, and an explosion-proof valve 6 is arranged in the mounting hole 501.

[0052] On the side close to the top cover 4 , the second pole piece 2 exceeds the first pole piece 1 , the diaphragm 3 exceeds the second pole piece 2 , and the length of the diaphragm 3 exceeding the second pole piece 2 is L1 .

[0053] On the side close to the bottom plate 5, the second pole piece 2 exceeds the first pole piece 1, the diaphragm 3 exceeds the second pole piece 2, and the length of the diaphragm 3 exceeding the second pole piece 2 is L2. L1 and L2 satisfy: L1>L2.

[0054] It should be noted that the housing is a three-dimensional structure with an opening at the top, and the top cover 4 covers the top opening of the housing. The first pole piece 1 is a positive pole piece, and the second pole piece 2 is a negative pole piece.

[0055] Along the direction from the top cover 4 to the bottom plate 5, the length of the second pole piece 2 is greater than the length of the first pole piece 1, and the two side edges of the second pole piece 2 respectively have excess areas exceeding the two side edges of the first pole piece 1. Along the direction from the top cover 4 to the bottom plate 5, the length of the diaphragm 3 is greater than the length of the second pole piece 2, and the two side edges of the diaphragm 3 respectively have excess areas exceeding the two side edges of the second pole piece 2.

[0056] On the side close to the top cover 4, the length of the diaphragm 3 beyond the second pole piece 2 is L1, that is, on the side close to the top cover 4, the length of the excess area of ​​the diaphragm 3 beyond the second pole piece 2 is L1. On the side close to the bottom plate 5, the length of the excess area of ​​the diaphragm 3 beyond the second pole piece 2 is L2.

[0057] The present application sets the explosion-proof valve 6 on the bottom plate 5 of the shell. Since the excess area of ​​the diaphragm 3 exceeding the second pole piece 2 on the side close to the explosion-proof valve 6 (i.e., the side close to the bottom plate 5) will cover the end of the pole piece, the length dimension L2 of the excess area of ​​the diaphragm 3 exceeding the second pole piece 2 is controlled to ensure that L2 is less than L1, so that the length of the excess area of ​​the diaphragm 3 exceeding the second pole piece 2 on the side close to the explosion-proof valve 6 is not too long, so that the electrolyte and gas inside the battery cell can more easily break through the diaphragm 3 covering the end of the pole piece, and then flow to the explosion-proof valve 6 set on the bottom plate 5, thereby ensuring the normal explosion of the explosion-proof valve 6 and the smoothness of the pressure relief after the explosion of the explosion-proof valve 6, thereby avoiding the explosion of the battery.

[0058] Please refer to the attached Figure 4 In some embodiments of the present application, in the first direction: 0.5 mm ≤ L1 ≤ 5 mm, for example, L1 can be any one of 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm.

[0059] The first direction is parallel to the direction from the top cover 4 to the bottom plate 5. Figure 4 , the first direction is attached Figure 4 Direction indicated by the arrow.

[0060] On the side close to the top cover 4, the length dimension of the excess area of ​​the diaphragm 3 beyond the second pole piece 2 is limited to the range of 0.5mm-5mm. On the one hand, it ensures that the length dimension of the excess area is not too small to avoid the risk of short circuit caused by direct contact between the first pole piece 1 and the second pole piece 2. On the other hand, it ensures that the length dimension of the excess area is not too large to avoid affecting the energy density of the battery.

[0061] Please refer to the attached Figure 4 In some embodiments, in the first direction: 0.5 mm ≤ L2 ≤ 5 mm, for example, L2 can be any one of 0.5 mm, 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3.5 mm, 4 mm, 4.5 mm, and 5 mm.

[0062] On the side close to the bottom plate 5, the length of the excess area of ​​the diaphragm 3 beyond the second pole piece 2 is limited to the range of 0.5mm-5mm. On the one hand, the length of the excess area is ensured not to be too small, thereby avoiding the risk of short circuit caused by direct contact between the first pole piece 1 and the second pole piece 2. On the other hand, the length of the excess area is ensured not to be too large, thereby avoiding the difficulty of discharging the electrolyte and gas from the diaphragm 3 covering the end of the pole piece, thereby ensuring the smoothness of the pressure relief after the explosion-proof valve 6 explodes.

[0063] In some embodiments, along the first direction, the length of the battery cell is L. Figure 3-4 , in the first direction: 0.2%L≤L2≤5%L, for example, L2 can be 0.2%L, 0.5%L, 1%L, 1.5%L, 2%L, 2.5%L, 3%L, 3.5%L, 4%L, 4.5%L, 5%L.

[0064] On the side close to the bottom plate 5, the length of the excess area where the diaphragm 3 exceeds the second pole piece 2 and the length of the battery cell are limited to the range of 0.2%L-5%L. On the one hand, the length of the excess area is ensured not to be too small to avoid the risk of short circuit caused by direct contact between the first pole piece 1 and the second pole piece 2. On the other hand, the length of the excess area is ensured not to be too large to avoid the difficulty of electrolyte and gas to be discharged from the diaphragm 3 covering the end of the pole piece, thereby ensuring the normal explosion of the explosion-proof valve 6 and the smoothness of the pressure relief after the explosion.

[0065] Please refer to the attached Figure 3 In some embodiments of the present application, the outer surface of the battery cell is covered with a Mylar film 7. The inner surface of the bottom plate 5 is provided with a bottom support plate 8. The bottom support plate 8 is provided with a first through hole 9, and the side of the Mylar film 7 opposite to the bottom support plate 8 is provided with a second through hole, and the first through hole 9 is connected to the second through hole.

[0066] Further, a plurality of first through holes 9 are provided; a plurality of second through holes are provided; the plurality of first through holes 9 are connected with the plurality of second through holes. Preferably, the plurality of first through holes 9 are connected with the plurality of second through holes one by one.

[0067] In addition to arranging the multiple first through holes 9 and the multiple second through holes in a one-to-one connected setting, other forms of settings can also be used, that is, the multiple first through holes 9 and the multiple second through holes are staggered to ensure that each first through hole 9 has a second through hole connected to it, so as to ensure normal pressure relief and exhaust effects.

[0068] The bottom support plate 8 is provided with a plurality of first through holes 9 , and the side of the Mylar film 7 opposite to the bottom support plate 8 is provided with a plurality of second through holes , and the plurality of first through holes 9 are connected to the plurality of second through holes in a one-to-one manner.

[0069] It should be noted that the bottom support plate 8 and the Mylar film 7 are connected together by hot melt; the first through hole 9 and the second through hole which are positioned opposite to each other are spliced ​​into a through communication channel, so the bottom support plate 8 and the Mylar film 7 form a total of multiple through communication channels, and the multiple communication channels are arranged at intervals.

[0070] On the side close to the explosion-proof valve 6, the size L2 of the excess area of ​​the diaphragm 3 beyond the second pole piece 2 is controlled to avoid the excess area being too large to cover the connecting channel, resulting in poor pressure relief after the explosion-proof valve 6 explodes.

[0071] A plurality of through-going communication channels are provided on the Mylar film 7 and the bottom support plate 8, so as to facilitate the electrolyte to flow in the shell and better infiltrate the battery core; when the battery is abnormal, the explosion-proof valve 6 can better explode and release pressure.

[0072] In some embodiments of the present application, the extension length of the first through hole 9 and the extension length of the second through hole are parallel to the first direction. The explosion-proof valve 6 has a first region; in a cross section perpendicular to the first direction, the projection area of ​​the first region is S1, the mounting hole 501 has a first projection, and the sum of the projection areas of the first through hole 9 located in the first projection is S2, and S1 and S2 satisfy: 2≤S1 / S2≤5, for example, S1 / S2 can be any one of 2, 2.5, 3, 3.5, 4, 4.5, and 5.

[0073] It should be noted that the first area is at least a part of the explosion-proof valve 6; in some embodiments, the first area may be the valve opening area of ​​the explosion-proof valve 6; the valve opening area refers to the area of ​​the explosion opening of the explosion-proof valve 6 after the explosion of the explosion-proof valve 6, that is, the actual pressure relief area of ​​the explosion-proof valve 6; the projection area of ​​the valve opening area in the cross section perpendicular to the first direction, that is, the area of ​​the valve opening area, is also the area of ​​the actual pressure relief area.

[0074] The ratio of the area S1 of the first region to the area of ​​all the first through holes 9 under the corresponding area of ​​the mounting hole 501 and S2 is limited to a range of 2-5, so as to ensure that the bottom support plate 8 has sufficient supporting strength and at the same time ensure the discharge speed of the electrolyte and the gas, so that when the battery is abnormal, the explosion-proof valve 6 can better explode and release pressure.

[0075] Please refer to the attached Figure 5 In some embodiments of the present application, the mounting hole 501 is a stepped hole, which includes a plurality of hole segments, wherein the first hole segment close to the outer surface of the bottom plate 5 has the largest hole diameter, and a stepped surface is formed at the junction of the first hole segment and the adjacent hole segment. The explosion-proof valve 6 is fixedly arranged on the stepped surface.

[0076] It should be noted that the step hole may have two hole sections or more than two hole sections. The explosion-proof valve 6 is welded to the step surface.

[0077] The step surface of the step hole provides a welding area for welding the explosion-proof valve 6, and the first hole section provides an accommodating space for accommodating the explosion-proof valve 6, thereby preventing the explosion-proof valve 6 from increasing the volume of the battery too much.

[0078] Please refer to the attached Figure 5 In some embodiments of the present application, the explosion-proof valve 6 includes a middle area 601 and an edge area 602 arranged around the middle area 601, and the edge area 602 is at least partially fixedly arranged on the step surface. Along the first direction, the depth of the first hole section is D, the thickness of the edge area 602 is B, and A and B satisfy: D≥B.

[0079] It should be noted that, in the cross section perpendicular to the first direction, the projection of the edge region 602 completely covers the projection of the step surface. The shape of the edge region 602 is adapted to the shape of the step surface, both are annular, and the area of ​​the edge region 602 is larger than the area of ​​the step surface, which can ensure the contact area between the edge region 602 and the step surface, and ensure the welding and fixing effect of the explosion-proof valve 6 on the step surface.

[0080] As described above, the explosion-proof valve 6 is prevented from protruding from the outer surface of the bottom plate 5, thereby ensuring the energy density of the battery and preventing collision damage to the explosion-proof valve 6 caused by external factors.

[0081] Please refer to the attached Figure 5 In certain embodiments of the present application, along the first direction, the thickness of the bottom plate 5 is H, the thickness from the step surface to the inner surface of the bottom plate 5 is A, and H, D, and A satisfy: A=HD; A≥0.5mm.

[0082] When the stepped mounting hole 501 is formed, the hole depth of the first hole section is controlled to avoid the thickness A from the step surface to the inner surface of the bottom plate 5 being too small, and A≥0.5mm is sufficient. If A<0.5mm, the strength of the bottom plate 5 where the mounting hole 501 is formed is low, and the bottom support plate 8 above the explosion-proof valve 6 will be deformed under the pressure of the electrolyte and the battery cell, reducing the gap between the bottom support plate 8 and the explosion-proof valve 6, causing the bottom support plate 8 to contact the explosion-proof valve 6, affecting the explosion value of the explosion-proof valve 6, and not conducive to pressure relief.

[0083] Please refer to the attached Figure 5 In some embodiments of the present application, along the first direction, the thickness dimension of the middle region 601 is smaller than the thickness dimension of the edge region 602 .

[0084] It should be noted that the opening area of ​​the explosion-proof valve 6 is located in the middle area 601. The thickness of the edge area 602 is relatively large, which can ensure the welding effect of the explosion-proof valve on the step surface of the mounting hole 501 and avoid the risk of accidental detachment of the battery during normal use; the size of the middle area 601 is reduced, and when the battery is abnormal, the normal explosion of the explosion-proof valve 6 can be ensured to avoid battery explosion.

[0085] Please refer to the attached Figure 6 In some embodiments of the present application, the first pole piece 1 is a positive pole piece; the second pole piece 2 is a negative pole piece. The positive pole piece includes a composite current collector 101, a first pole ear 102, and a second pole ear 103. The composite current collector 101 includes an intermediate support layer 1011 and two conductive layers arranged on both side surfaces of the intermediate support layer 1011. The two conductive layers are a first conductive layer 1012 and a second conductive layer 1013. The first pole ear 102 and the second pole ear 103 are respectively connected to the two conductive layers; on the side close to the top cover 4, the first pole ear 102 is located at one end of the first conductive layer 1012 and extends out of the first conductive layer 1012, and the second pole ear 103 is located at one end of the second conductive layer 1013 and extends out of the second conductive layer 1013. The extension length of the first pole tab 102 is greater than that of the second pole tab 103 , and the second pole tab 103 is connected to the first pole tab 102 , thereby achieving electrical connection between the two conductive layers of the composite current collector 101 and conducting electrical energy out of the battery cell through the second pole tab 103 .

[0086] It should be noted that after the composite current collector 101, the first pole tab 102, and the second pole tab 103 are stacked, they are electrically welded together by roller welding. The positive electrode sheet is a composite positive electrode sheet with a composite current collector 101, which has higher safety, energy density, and lower manufacturing cost.

[0087] In summary, the present application also provides an electrical device, which includes the battery described above.

[0088] Since the electrical device has the battery as described above, the beneficial effects of the battery on the electrical device can be found above and will not be described in detail here.

[0089] The components and devices involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the drawings. As will be appreciated by those skilled in the art, these components and devices can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, meaning "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The word "such as" used here refers to the phrase "such as but not limited to", and can be used interchangeably with it.

[0090] It should also be noted that in the device of the present application, each component can be decomposed and / or reassembled, and these decompositions and / or reassemblies should be regarded as equivalent solutions of the present application.

[0091] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0092] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

[0093] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A battery, characterized in that: It comprises a shell, a top cover (4), and a battery cell arranged in a closed space enclosed by the shell and the top cover (4); the shell comprises a bottom plate (5) opposite to the top cover (4); The battery cell comprises a first pole piece (1), a second pole piece (2) which are stacked, and a diaphragm (3) arranged between the first pole piece (1) and the second pole piece (2); wherein: The bottom plate (5) is provided with a through installation hole, and an explosion-proof valve (6) is arranged in the installation hole; On a side close to the top cover (4), the second pole piece (2) extends beyond the first pole piece (1), and the length of the diaphragm (3) extending beyond the second pole piece (2) is L1; On the side close to the bottom plate (5), the second pole piece (2) extends beyond the first pole piece (1), the length of the diaphragm (3) extending beyond the second pole piece (2) is L2, and L1 and L2 satisfy: L2<L1.

2. The battery according to claim 1, characterized in that Along a first direction, the length of the battery cell is L, the first direction is parallel to a direction from the top cover (4) to the bottom plate (5), and in the first direction: 0.5mm≤L1≤5mm; and / or, 0.5mm≤L2≤5mm; and / or, 0.2%L≤L2≤5%L.

3. The battery according to claim 1, characterized in that The outer surface of the battery core is covered with a Mylar film (7); The inner surface of the bottom plate (5) is provided with a bottom support plate (8); The bottom support plate (8) is provided with a first through hole (9), and the side surface of the Mylar film (7) opposite to the bottom support plate (8) is provided with a second through hole, and the first through hole (9) is connected to the second through hole.

4. The battery according to claim 3, characterized in that The extension length of the first through hole (9) and the extension length of the second through hole are both parallel to the first direction; The explosion-proof valve (6) has a first area; in a cross section perpendicular to a first direction, a projection area of ​​the first area is S1, the mounting hole has a first projection, and a sum of projection areas of a plurality of the first through holes (9) located in the first projection is S2, and S1 and S2 satisfy: 2≤S1 / S2≤5.

5. The battery according to claim 1, characterized in that The mounting hole is a stepped hole, and the stepped hole comprises a plurality of hole segments, wherein the first hole segment close to the outer surface of the bottom plate (5) has the largest hole diameter, and a stepped surface is formed at the junction of the first hole segment and its adjacent hole segment; The explosion-proof valve (6) is fixedly arranged on the step surface.

6. The battery according to claim 5, characterized in that The explosion-proof valve (6) comprises a middle area (601) and an edge area (602) arranged around the middle area (601), and the edge area (602) is at least partially fixedly arranged on the step surface; Along the first direction, the depth of the first hole segment is D, the thickness of the edge region (602) is B, and D and B satisfy: D≥B.

7. The battery according to claim 6, characterized in that Along the first direction, the thickness of the bottom plate (5) is H, the thickness from the step surface to the inner surface of the bottom plate (5) is A, and H, D, and A satisfy: A=HD; A≥0.5mm.

8. The battery according to claim 6, characterized in that Along the first direction, the thickness dimension of the middle region (601) is smaller than the thickness dimension of the edge region (602).

9. The battery according to any one of claims 1 to 8, characterized in that The first electrode sheet (1) is a positive electrode sheet; the positive electrode sheet comprises: A composite current collector, comprising an intermediate support layer and two conductive layers arranged on both side surfaces of the intermediate support layer; The first pole tab and the second pole tab are connected to the two conductive layers respectively, and the first pole tab is connected to the second pole tab.

10. An electrical device, characterized in that: A battery comprising the battery according to any one of claims 1 to 9.

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