Batteries, battery packs and electrical devices

Abstract

This invention relates to the field of battery technology and discloses a battery, a battery pack, and an electrical device, comprising: a casing; an explosion-proof valve disposed on the bottom wall, the explosion-proof valve having grooves and forming a thinning area, the explosion-proof valve including an opening portion; an electrode assembly disposed on the top wall; a battery cell, with its tab portion welded to the electrode assembly to form a first solder mark area; and a bottom support plate disposed between the battery cell and the bottom wall, the bottom support plate having openings; the ratio of the sum of the orthographic projection areas of the openings to the area of ​​the region enclosed by the outer contour of the orthographic projection of the bottom support plate is 'a', and the welding area of ​​the first solder mark area is 's' mm. 2 The ratio c of the thickness of the thinned region to the thickness of the opening portion satisfies 1.76 × 10⁻⁶. ‑5 ≤(a×c) / s≤6.65×10 ‑3 This invention ensures that the explosion-proof valve can open in a timely manner to relieve pressure, thereby guaranteeing the safety of battery use, while preventing the explosion-proof valve from opening abnormally during the normal charging and discharging process of the battery, thus ensuring the normal use of the battery.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically to batteries, battery packs, and electrical devices. Background Technology

[0002] When existing battery explosion-proof valves open to release pressure, the resulting explosive material can easily enter the passenger compartment, threatening the safety of vehicle occupants. To mitigate this risk, current technology typically places the explosion-proof valve at the bottom of the battery. However, this arrangement has significant drawbacks: when the battery experiences thermal runaway, the bottom-mounted explosion-proof valve cannot open quickly and reliably to release pressure, causing internal pressure and heat to continuously accumulate. This leads to a worsening and significantly increased severity of the thermal runaway reaction, ultimately exacerbating the overall battery safety hazard and significantly increasing the safety risks during battery use. Summary of the Invention

[0003] This invention provides a battery, a battery pack, and an electrical device to solve the problem in the prior art where, when a battery experiences thermal runaway, the explosion-proof valve installed at the bottom cannot open quickly and reliably to release pressure, causing the thermal runaway reaction to continuously worsen and become more severe, exacerbating the overall safety hazard of the battery and increasing the safety risks during battery use.

[0004] In a first aspect, the present invention provides a battery comprising: The housing includes a bottom wall and a top wall that are spaced apart from each other along the height direction of the battery; An explosion-proof valve is disposed on the bottom wall. The explosion-proof valve has a groove recessed along the height direction of the battery. The explosion-proof valve includes a body area and a remaining portion at the groove forming a thinned area. The thickness of the thinned area is less than the thickness of the body area. The explosion-proof valve includes an opening portion formed by the groove. The pole assembly is disposed on the top wall; A battery cell is disposed within the housing. The battery cell includes a battery cell body and a tab extending from at least one end of the battery cell body. The tab is welded to the terminal assembly to form a first solder area. A bottom support plate is disposed between the battery cell and the bottom wall. The bottom support plate has an opening that extends through the height direction of the battery. The opening and the opening portion are at least partially opposite to each other along the height direction of the battery. Wherein, the welding area of ​​the first solder mark region is s mm. 2 On a projection plane perpendicular to the height direction of the battery, the ratio of the sum of the projected areas of the openings to the area enclosed by the outer contour of the projected bottom plate is 'a'. Along the height direction of the battery, the ratio of the thickness of the thinned area to the thickness of the opening is 'c', satisfying 1.76 × 10⁻⁶. -5≤(a×c) / s≤6.65×10 -3 .

[0005] Beneficial effects: By placing the explosion-proof valve on the bottom wall of the battery, when thermal runaway occurs, the high-temperature, high-pressure gas inside the battery breaks through the explosion-proof valve and sprays downwards, preventing the high-temperature, high-pressure gas from spraying upwards towards the passenger compartment during thermal runaway, thus reducing the safety risk to the occupants. Furthermore, by placing the terminal assembly and the explosion-proof valve on two opposing walls along the battery's height, when thermal runaway occurs, the high-temperature, high-pressure gas and other explosive materials inside the battery break through the explosion-proof valve and are ejected, preventing the explosive materials from impacting the terminal assembly of adjacent batteries. This achieves thermal-electric separation of the batteries, preventing the thermal runaway of one battery from affecting surrounding batteries and causing thermal propagation problems, thus improving battery safety. Simultaneously, by limiting the value of (a×c) / s, the explosion-proof valve can be opened in a timely manner to release pressure, reducing the severity of battery thermal runaway and ensuring battery safety. At the same time, it prevents the explosion-proof valve from abnormally opening during normal charging and discharging processes, ensuring normal battery operation. Specifically, if the value of (a×c) / s is too large, meaning that in (a×c) / s, the proportion of a is too large, or the proportion of c is too large, or the proportion of s is too small, it can easily lead to insufficient structural strength of the base plate. The base plate is prone to melting under high temperature, failing to provide reliable support for the battery cell. In addition, the connection effect of the terminal assembly to the battery cell through the first soldering area is poor, causing the battery cell to easily move towards the bottom wall of the battery under gravity, drastically increasing the risk of the battery cell blocking the explosion-proof valve. At the same time, the high structural strength of the thinned area itself makes it difficult to open for pressure relief, making it difficult to open the explosion-proof valve in the event of battery thermal runaway, which is not conducive to battery pressure relief and further aggravates the degree of battery thermal runaway, increasing the safety risk of the battery. If the value of (a×c) / s is too small, meaning that in (a×c) / s... If the proportion of 'a', 'c', or 's' is too small, the internal gas storage space of the battery may be too small. During normal charging and discharging, this can lead to excessive internal gas pressure, increasing the risk of abnormal opening of the explosion-proof valve. In addition, it can also result in insufficient redundant length of the tab between the cell body and the first solder area, increasing the risk of tearing of some tab layers. This, in turn, increases the internal resistance of the battery, leading to increased heat and gas generation during charging and discharging, and a sharp increase in internal gas pressure. This further increases the risk of abnormal opening of the explosion-proof valve. At the same time, insufficient structural strength of the thinning area itself also increases the risk of abnormal opening of the explosion-proof valve, affecting the normal use of the battery.

[0006] Secondly, the present invention also provides a battery pack including the battery described above.

[0007] Thirdly, the present invention also provides an electrical device including the aforementioned battery pack. Attached Figure Description

[0008] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0009] Figure 1 This is a schematic diagram of the structure of a battery according to an embodiment of the present invention; Figure 2 for Figure 1 A schematic diagram of the battery from another angle is shown; Figure 3 for Figure 1 A top view of the battery shown; Figure 4 for Figure 1 The battery shown is viewed from below. Figure 5 This is a schematic diagram of the first solder area according to an embodiment of the present invention; Figure 6 for Figure 3 The battery shown is a cross-sectional view along the AA direction; Figure 7 for Figure 6 A magnified view of part B in the diagram; Figure 8 for Figure 6 A magnified view of part of C; Figure 9 for Figure 3 Another cross-sectional view of the battery shown along the AA direction; Figure 10 for Figure 9 A magnified view of part of D; Figure 11 This is a schematic diagram of the structure of a base plate according to an embodiment of the present invention; Figure 12 for Figure 11 A schematic diagram of the base plate from another angle; Figure 13 for Figure 11 The bottom view of the base plate shown; Figure 14 This is a schematic diagram of the orthographic projection of the base plate and opening on a projection plane perpendicular to the height direction of the battery, according to an embodiment of the present invention. Figure 15 This is a schematic diagram of the orthographic projection of the first protrusion and the opening in an embodiment of the present invention onto a projection plane perpendicular to the height direction of the battery. Figure 16 This is a schematic diagram of the orthographic projection of the thinning area and openings in an embodiment of the present invention onto a projection plane perpendicular to the height direction of the battery. Figure 17 This is a schematic diagram of the structure in which the base plate and the explosion-proof valve abut against each other in an embodiment of the present invention.

[0010] Explanation of reference numerals in the attached figures: 1. Outer shell; 11. Bottom wall; 12. Top wall; 13. Side wall; 2. Explosion-proof valve; 21. Score; 22. Thinning area; 23. Opening part; 3. Terminal assembly; 31. Terminal body; 32. Adapter piece; 4. Battery cell; 41. Battery cell body; 411. First end; 412. Second end; 413. Second edge; 42. Terminal lug; 5. First soldering area; 6. Base plate; 61. Opening; 62. Plate body; 63. First protrusion; 64. Opening area; 65. First opening; 66. Second opening; 67. First edge; 68. Reinforcing rib. Detailed Implementation

[0011] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0012] To improve the safety of occupants, some technologies arrange the battery with an explosion-proof valve that is positioned downwards (the valve is located on the bottom wall of the battery). However, this arrangement has a drawback: the explosion-proof valve may not rupture in time during a battery thermal runaway, thus exacerbating the thermal runaway.

[0013] Research has found that the main reason why the explosion-proof valve cannot burst in time during battery thermal runaway is that the battery cells inside the battery casing are supported by a base plate on the bottom wall of the casing. The base plate has openings to allow gas inside the battery to flow to the vicinity of the explosion-proof valve. However, the battery generates heat during charging and discharging, resulting in a high internal temperature. The base plate is prone to melting under high temperature, especially at the openings. This melting can cause insufficient support for the battery cells, causing them to move towards the bottom wall under gravity. This can block the explosion-proof valve, preventing the high-temperature, high-pressure gas from breaking through the valve and releasing pressure during thermal runaway. This leads to the continued escalation of the thermal runaway and can cause more serious safety accidents such as battery explosions.

[0014] The following is combined Figures 1 to 17 The following describes embodiments of the present invention.

[0015] According to an embodiment of the present invention, in one aspect, a battery is provided, comprising: The outer casing 1 includes a bottom wall 11 and a top wall 12 that are spaced apart from each other along the height direction of the battery; An explosion-proof valve 2 is disposed on the bottom wall 11. The explosion-proof valve 2 has a groove 21 recessed along the height direction of the battery. The explosion-proof valve 2 includes a body area and a thinning area 22 formed by the remaining portion at the groove 21. The thickness of the thinning area is less than the thickness of the body area. The explosion-proof valve 2 includes an opening portion 23 enclosed by the groove 21. The pole assembly 3 is disposed on the top wall 12; The battery cell 4 is disposed inside the housing 1. The battery cell 4 includes a battery cell body 41 and a tab 42 extending from at least one end of the battery cell body 41. The tab 42 is welded to the terminal assembly 3 to form a first solder area 5. The bottom support plate 6 is disposed between the battery cell 4 and the bottom wall 11. The bottom support plate 6 has an opening 61 that extends through the height direction of the battery. The opening 61 and the opening part 23 are at least partially opposite to each other along the height direction of the battery. The welding area of ​​the first solder mark region 5 is s mm. 2 On the projection plane perpendicular to the height direction of the battery, the ratio of the sum of the projected areas of the opening 61 to the area of ​​the region enclosed by the outer contour of the projected area of ​​the base plate 6 is 'a'. Along the height direction of the battery, the ratio of the thickness of the thinned region 22 to the thickness of the opening 23 is 'c', satisfying 1.76 × 10⁻⁶. -5 ≤(a×c) / s≤6.65×10 -3 .

[0016] In the battery of this embodiment, the explosion-proof valve 2 is installed on the bottom wall 11 of the battery. When the battery experiences thermal runaway, the high-temperature and high-pressure gas inside the battery breaks through the explosion-proof valve 2 and sprays downwards, preventing the high-temperature and high-pressure gas from spraying upwards towards the passenger compartment during thermal runaway, thus reducing the safety risk to the occupants. Furthermore, by placing the terminal assembly 3 and the explosion-proof valve 2 on two opposing walls along the height of the battery, when the battery experiences thermal runaway, the high-temperature and high-pressure gas and other explosive materials inside the battery break through the explosion-proof valve 2 and are sprayed out, preventing the explosive materials from impacting the terminal assembly 3 of adjacent batteries. This achieves thermal-electric separation of the batteries, preventing the thermal runaway of one battery from affecting surrounding batteries and causing thermal propagation problems, thereby improving battery safety. At the same time, by limiting the value of (a×c) / s, the explosion-proof valve 2 can be opened in time to release pressure, reducing the severity of battery thermal runaway and ensuring battery safety. At the same time, the normal charging and discharging process of the battery can prevent the explosion-proof valve 2 from opening abnormally, ensuring normal battery use.

[0017] Specifically, if the value of (a×c) / s is too large, that is, if the proportion of a, c, or s in (a×c) / s is too large, the structural strength of the base plate 6 is insufficient, and the base plate 6 is prone to melting under high temperature, failing to provide reliable support for the battery cell 4. In addition, the connection effect of the electrode assembly 3 to the battery cell 4 through the first soldering area 5 is poor, causing the battery cell 4 to easily move towards the bottom wall 11 of the battery under gravity, which greatly increases the risk of the battery cell 4 blocking the explosion-proof valve 2. At the same time, the high structural strength of the thinning area 22 itself makes it difficult to open for pressure relief, making it difficult to open the explosion-proof valve 2 when the battery is in thermal runaway, which is not conducive to battery pressure relief, further aggravating the degree of battery thermal runaway and increasing the safety risk of the battery. If the value of (a×c) / s is too small, that is, if the value of (a×c) / s is too small, that is, if the proportion of a, c, or s in (a×c) / s is too large, the structural strength of the base plate 6 is insufficient, and ... If the proportion of a, c, or s is too small, the internal gas storage space of the battery may be too small. During normal charging and discharging, the internal gas pressure of the battery may be too high, increasing the risk of abnormal opening of the explosion-proof valve 2. In addition, the redundant length of the tab 42 between the cell body 41 and the first solder area 5 may be too small, increasing the risk of tearing of some tab layers in the tab 42. This leads to an increase in the internal resistance of the battery, resulting in increased heat and gas generation during charging and discharging, and a sharp increase in the internal gas pressure of the battery. This further increases the risk of abnormal opening of the explosion-proof valve 2. At the same time, the insufficient structural strength of the thinning area 22 itself also increases the risk of abnormal opening of the explosion-proof valve 2, affecting the normal use of the battery.

[0018] Therefore, in the battery of this embodiment, the bottom plate 6 has an opening 61 corresponding to the opening 23. The gas inside the battery can flow to the explosion-proof valve 2 through the opening 61, ensuring that the battery can be depressurized in time through the explosion-proof valve 2. By reducing the value of 'a', the structural strength of the bottom plate 6 can be improved, reducing the risk of melting of the bottom plate 6 under the influence of high temperature and the pressure of the battery cell 4. This avoids the battery cell 4 from moving towards the bottom wall 11 under gravity due to insufficient support after the bottom plate 6 melts, thus preventing the battery cell 4 from blocking the explosion-proof valve 2 and causing the explosion-proof valve 2 to fail to open in time to depressurize. However, the gas generated inside the battery can be partially stored in the opening of the bottom plate. If the value of 'a' is reduced, the opening range is reduced, which will reduce the gas storage space inside the battery. When the battery is charging and discharging normally and generating gas, it will cause the gas pressure inside the battery to be too high, causing the explosion-proof valve 2 to open abnormally. In order to avoid explosion-proof... If valve 2 opens abnormally, the value of c can be increased to improve the structural strength of the thinning zone 22. However, if the value of c is too large, the explosion-proof valve 2 will be difficult to open during battery thermal runaway, leading to an aggravation of battery thermal runaway and increasing the safety risk of the battery. In addition, the battery cell 4 is connected to the terminal assembly 3 through the first solder area 5. Increasing the value of s can improve the connection effect between the terminal assembly 3 and the battery cell 4, reducing the risk of the battery cell 4 moving towards the bottom wall 11 due to gravity and preventing the battery cell 4 from blocking the explosion-proof valve 2. However, if the value of s is too large, the redundant length of the tab 42 located between the battery cell body 41 and the first solder area 5 will be too small, causing some tab layers in the tab 42 to tear, resulting in an increase in the internal resistance of the battery. This leads to an increase in heat and gas generation during battery charging and discharging, which in turn leads to a sharp increase in the gas pressure inside the battery, causing the explosion-proof valve 2 to open abnormally. Therefore, when the value of 'a' is small, it will reduce the gas storage space inside the battery, making the explosion-proof valve prone to abnormal opening. In this case, the value of 'c' needs to be increased appropriately to avoid abnormal opening of the explosion-proof valve. At the same time, since the bottom support plate has good structural strength to support the battery cell, the value of 's' can be relatively reduced. When the value of 'a' is large, the bottom support plate has weak support for the battery cell. The value of 's' can be increased appropriately to improve the connection effect between the terminal and the battery cell. At the same time, since there is a large gas storage space inside the battery, the value of 'c' can be reduced appropriately to ensure timely valve opening.

[0019] In summary, in this embodiment, by controlling the value of (a×c) / s, the normal use of the battery is ensured while also taking into account the safety of the occupants and the safety of the battery itself.

[0020] Optionally, (a×c) / s can be 1.76×10 -5 1.78×10 -5 2×10 -5 3×10 -5 5×10 -5 5.99×10-5 8×10 -5 1×10 -4 1.11×10 -4 1.2×10 -4 2.49×10 -4 3.16×10 -4 4.25×10 -4 5×10 -4 7.38×10 -4 8×10 -4 9.08×10 -4 1×10 -3 1.26×10 -3 1.39×10 -3 1.5×10 -3 1.51×10 -3 3.49×10 -3 5×10 -3 5.22×10 -3 5.37×10 -3 6.65×10 -3 It can be any value in the range or the value between any two values.

[0021] Preferably, the value of (a×c) / s satisfies 1.2×10 -4 ≤(a×c) / s≤1.5×10 -3 This ensures both the normal operation of the battery and the safety of the occupants, as well as the safety of the battery itself. The value of (a×c) / s is 1.2×10⁻⁶. -4 2.49×10 -4 3.16×10 -4 4.25×10 -4 5×10 -4 7.38×10 -4 8×10 -4 9.08×10 -4 1×10 -3 1.26×10 -3 1.39×10 -3 1.5×10 -3 It can be any value in the range or the value between any two values.

[0022] It is worth noting that the phrase "the opening 61 and the opening portion 23 are at least partially arranged opposite each other along the height direction of the battery" means that at least a portion of the opening 61 and at least a portion of the opening portion 23 are arranged opposite each other along the height direction of the battery. Specifically, only a portion of the opening 61 and a portion of the opening portion 23 may be arranged opposite each other along the height direction of the battery, or all of the opening 61 and a portion of the opening portion 23 may be arranged opposite each other along the height direction of the battery, or a portion of the opening 61 and all of the opening portions 23 may be arranged opposite each other along the height direction of the battery.

[0023] It is understood that a containment space is formed inside the outer casing 1, and the battery cell 4 is placed in the containment space. The containment space is suitable for being connected to the external space through the explosion-proof valve 2. Specifically, when the battery experiences thermal runaway, the high-temperature and high-pressure gas in the containment space passes through the opening 61 to reach the explosion-proof valve 2, and breaks through the thinned area 22 at the groove 21, causing the opening part 23 to open and form an opening. The high-temperature and high-pressure gas is discharged to the external space through the opening, thereby depressurizing the battery.

[0024] It is worth noting that, in one embodiment, grooves 21 are formed on a metal substrate of uniform thickness to thin the metal substrate at the grooves 21, thereby creating an explosion-proof valve 2 with a thinned region 22 and an unthinned body region. That is, the thickness of the thinned region 22 is less than the thickness of the body region. When the battery experiences thermal runaway, the high-temperature and high-pressure gas can rupture the explosion-proof valve 2 in the thinned region 22, achieving pressure relief.

[0025] It should be further explained that, along the height direction of the battery, the explosion-proof valve 2 has an inner surface close to the battery cell 4 and an outer surface away from the battery cell 4. The groove 21 can be formed on the inner surface or on the outer surface. Of course, the groove 21 can be formed on both the inner and outer surfaces (setting grooves on both sides can avoid the single groove being too deep, resulting in uneven thickness in different areas of the groove, affecting the bursting consistency of the explosion-proof valve, and causing the explosion-proof valve to burst abnormally).

[0026] For further details, please refer to Figure 7 Along the height direction of the battery, the thickness c1 mm of the thinning region 22 is the residual thickness at the notch 21 after machining on the metal substrate, and the thickness c2 mm of the opening portion 23 is the original thickness of the metal substrate, which is also the thickness of the body region. Therefore, c = c1 / c2 is satisfied.

[0027] Specifically, the thickness c1 mm of the thinning zone 22 satisfies 0.02≤c1≤0.1, and the thickness c2 mm of the opening portion 23 satisfies 0.1≤c2≤0.5.

[0028] Optionally, c1 can take any value from 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, or a value between any two values.

[0029] Optionally, c2 can take any value from 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, or a value between any two values.

[0030] It should be noted that you should refer to [link / reference]. Figure 14 On the projection plane perpendicular to the height of the battery, the sum of the projected areas of the opening 61 is a1 mm. 2 The area enclosed by the outer contour of the orthographic projection of the base plate 6 is a2 mm. 2 Therefore, a = a1 / a2 is satisfied.

[0031] It should be further explained that the number of openings 61 can be one or several; when opening 61 is set to one, the value of a1 is the area of ​​the orthographic projection of one opening 61 on the projection plane perpendicular to the height direction of the battery; when opening 61 is set to several, the value of a1 is the total area of ​​the orthographic projection of several openings 61 on the projection plane perpendicular to the height direction of the battery.

[0032] In addition, for example, the base plate 6 is usually a rectangular plate, that is, the orthographic projection of the base plate 6 on the projection plane perpendicular to the height direction of the battery is a rectangle. Therefore, the value of a2 is the area of ​​the rectangle.

[0033] It is worth noting that the tab portion 42 includes several stacked tab layers, which are welded to the terminal assembly 3 via the first solder area 5, thereby achieving electrical connection between the cell 4 and the terminal assembly 3. Furthermore, in the battery, the tab portion is typically bent and then welded to the terminal assembly. The value of 's' refers to the orthogonal projection area of ​​the first solder area 5 on the projection plane perpendicular to the stacking direction of the tab layers when the tab portion is flattened along the lead-out direction.

[0034] In one embodiment, such as Figure 8 and Figure 12As shown, the base plate 6 includes a main body 62 and a first protrusion 63. An opening 61 is formed in the main body 62, and the first protrusion 63 is disposed on the side of the main body 62 facing the bottom wall 11, abutting against the bottom wall 11. This arrangement allows the main body 62 to support the battery cell 4, and the opening 61 allows the gas inside the battery to flow through the opening 61 to the explosion-proof valve 2. Furthermore, by providing the first protrusion 63 between the main body 62 and the bottom wall 11, the main body 62 and the bottom wall 11 are spaced apart, allowing the high-temperature, high-pressure gas inside the battery to flow through the gap between them to the explosion-proof valve 2, improving gas flow smoothness, venting efficiency, and thus enhancing battery safety. Additionally, the first protrusion 63 provides support between the main body 62 and the bottom wall 11, ensuring the base plate 6's support performance for the battery cell 4.

[0035] Furthermore, in one embodiment, such as Figure 15 As shown, the first protrusion 63 and the opening 61 are spaced apart. On the projection plane perpendicular to the height direction of the battery, the minimum distance between the orthographic projection of the first protrusion 63 and the orthographic projection of the opening 61 is d1 mm, satisfying 2≤d1≤20. By spaced apart the first protrusion 63 and the opening 61, a certain gap is created between them, allowing gas to flow through the gap and reach the opening 61, and finally reach the explosion-proof valve 2. This improves the smoothness of gas flow, increases exhaust efficiency, and prevents the explosion-proof valve 2 from opening abnormally due to excessive internal pressure in the battery. Furthermore, by limiting the value of d1, the smoothness of gas flow is effectively improved while ensuring the supporting performance of the base plate 6.

[0036] It is worth noting that if the value of d1 is too large, it may cause the distance between the first protrusion 63 and the opening 61 to be too far, or the supporting area of ​​the first protrusion 63 to be too small. The first protrusion 63 may not be able to provide effective support for the area near the opening 61. When the base plate 6 melts under the influence of high temperature and the gravity of the battery cell 4, the battery cell 4 may collapse in the area near the opening 61, increasing the risk of the battery cell 4 blocking the explosion-proof valve 2, increasing the risk of battery thermal runaway, and affecting the safety of battery use. If the value of d1 is too small, it may cause the distance between the first protrusion 63 and the opening 61 to be too close, resulting in a small gap between the first protrusion 63 and the opening 61. During the process of gas flowing from inside the battery to the opening 61, the resistance exerted by the first protrusion 63 may be too great, affecting the smoothness of gas flow. This may cause a sharp increase in the internal pressure of the battery, leading to abnormal opening of the explosion-proof valve 2 and affecting the normal use of the battery.

[0037] Optionally, d1 can take any value from 2, 4, 6, 8, 10, 12, 14, 15, 18, 20, or a value between any two values.

[0038] Furthermore, in one embodiment, such as Figure 13 and Figure 15 As shown, along the length of the battery, a first protrusion 63 is provided on both sides of the opening 61. With this arrangement, the first protrusion 63 can provide effective support to the battery cell 4 on both sides of the opening 61 along the length direction, effectively improving the support performance of the base plate 6 for the battery cell 4.

[0039] It is worth noting that, on the projection plane perpendicular to the height direction of the battery, the area occupied by the orthographic projection of the opening 61 on the orthographic projection of the base plate 6 is the opening area 64, and the orthographic projection of the first protrusion 63 is located on opposite sides of the opening area 64 along the length direction of the battery.

[0040] It is understandable that the opening area 64 may have only one orthographic projection of the opening 61, or the opening area 64 may have several orthographic projections of the opening 61.

[0041] Therefore, in this embodiment, the value of d1 is: the distance between the orthographic projection of the first protrusion 63 closest to the opening area 64 and the opening area 64 on the projection plane perpendicular to the height direction of the battery, along the length direction of the battery.

[0042] Specifically, in one embodiment, such as Figure 15 As shown, on the projection plane perpendicular to the height direction of the battery, the total projected area of ​​the first protrusion 63 is S1 mm. 2 The condition is satisfied that 150≤S1≤2600. This setting ensures that the bottom support plate 6 supports the battery cell 4 while also ensuring the gas storage space inside the battery.

[0043] It is worth noting that if the value of S1 is too small, the first protrusion 63 may not provide adequate support for the battery cell 4. When the base plate 6 melts under the influence of high temperature and the gravity of the battery cell 4, the battery cell 4 may block the explosion-proof valve 2, increasing the risk of further thermal runaway and affecting battery safety. If the value of S1 is too large, the first protrusion 63 may occupy too much internal space, compressing the internal gas storage space. During normal charging and discharging, this may cause excessive internal gas pressure, increasing the risk of abnormal opening of the explosion-proof valve 2 and affecting normal battery use.

[0044] Optionally, S1 can be any value from 150, 200, 500, 800, 1000, 1200, 1500, 1800, 2000, 2300, 2500, 2600, or a value between any two values.

[0045] It should be noted that the number of first protrusions 63 can be one or several. When there is only one first protrusion 63, the value of S1 is the area of ​​the orthographic projection of the first protrusion 63 onto the projection plane perpendicular to the height direction of the battery; when there are several first protrusions 63, the value of S1 is the total area of ​​the orthographic projection of the several first protrusions 63 onto the projection plane perpendicular to the height direction of the battery.

[0046] Furthermore, in one embodiment, such as Figure 15 As shown, several first protrusions 63 are spaced apart. On the projection plane perpendicular to the height direction of the battery, the minimum distance between the orthographic projections of any two first protrusions 63 is d2mm, satisfying 3≤d2≤20. This arrangement ensures the supporting performance of the base plate 6 while improving the smoothness of gas flow.

[0047] It is worth noting that if the value of d2 is too small, the two first protrusions 63 may be too close together, which could severely obstruct the gas inside the battery, affecting the flow of gas between the two first protrusions 63 and the smoothness of gas flow. This could cause a sharp increase in the internal pressure of the battery, leading to the abnormal opening of the explosion-proof valve 2 and affecting the normal use of the battery. If the value of d2 is too large, the first protrusions 63 may not provide adequate support for the battery cell 4. When the base plate 6 melts under the influence of high temperature and the gravity of the battery cell 4, the battery cell 4 may block the explosion-proof valve 2, increasing the risk of further thermal runaway and affecting the safety of battery use.

[0048] Optionally, d2 can take any value from 3, 5, 7, 9, 10, 12, 15, 16, 18, 20, or a value between any two values.

[0049] In one embodiment, such as Figure 16 As shown, on the projection plane perpendicular to the height of the battery, the area occupied by the orthographic projection of the opening 61 onto the orthographic projection of the base plate 6 is the opening area 64, and the orthographic projection of the thinning area 22 falls within the opening area 64. That is, the edge of the opening area 64 extends beyond the edge of the thinning area 22. This arrangement can further increase the opening range, thereby further increasing the gas storage space inside the battery, avoiding excessive internal gas pressure during normal charging and discharging, and reducing the risk of abnormal opening of the explosion-proof valve 2.

[0050] Furthermore, in one embodiment, such as Figure 16As shown, on the projection plane perpendicular to the height direction of the battery, along the length direction of the battery, the distance between the edge of the opening region 64 and the edge of the orthographic projection of the thinning region 22 is b1 mm, and along the width direction of the battery, the distance between the edge of the opening region 64 and the edge of the orthographic projection of the thinning region 22 is b2 mm, satisfying b1 < b2. This setting can avoid the opening 61 on the base plate 6 along the length direction of the battery being too large, reducing the impact on the structural strength of the base plate 6.

[0051] It is worth noting that since the base plate 6 is more prone to deformation along the length of the battery than along the width of the battery, in this embodiment, by controlling the range of the openings 61 along the length of the battery on the base plate 6, the structural strength of the base plate 6 in the length direction is ensured, thereby ensuring the support performance of the base plate 6 for the battery cell 4.

[0052] Specifically, in one embodiment, on the projection plane perpendicular to the height direction of the battery, along the length direction of the battery, the distance b1 mm between the edge of the opening region 64 and the edge of the orthogonal projection of the thinning region 22, and along the width direction of the battery, the distance b2 mm between the edge of the opening region 64 and the edge of the orthogonal projection of the thinning region 22, satisfy 1 ≤ b2 - b1 ≤ 20. This arrangement ensures both the support performance of the base plate 6 for the battery cell 4 and the gas storage space inside the battery.

[0053] It is worth noting that if the values ​​of b2-b1 are too small, the opening 61 along the length of the battery on the base plate 6 may be too large, which could affect the structural strength of the base plate 6 along the length of the battery and thus its support performance. If the values ​​of b2-b1 are too large, the opening 61 along the length of the battery on the base plate 6 may be insufficient, reducing the gas storage space inside the battery. During normal charging and discharging of the battery, this could lead to excessive internal gas pressure, increasing the risk of abnormal opening of the explosion-proof valve 2.

[0054] Optionally, b2-b1 can be any value from 1, 2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, 20 or a value between any two values.

[0055] Specifically, in one embodiment, on the projection plane perpendicular to the height direction of the battery, along the length direction of the battery, the distance b1 mm between the edge of the opening region 64 and the edge of the orthographic projection of the thinning region 22 satisfies 1≤b1≤20.

[0056] Optionally, b1 can be any value from 1, 2, 4, 5, 6, 8, 10, 12, 14, 15, 16, 18, 20, or a value between any two values.

[0057] Specifically, in one embodiment, on the projection plane perpendicular to the height direction of the battery, along the width direction of the battery, the distance b2 mm between the edge of the opening region 64 and the edge of the orthographic projection of the thinning region 22 satisfies 2≤b2≤25.

[0058] Optionally, b2 can be any value from 2, 5, 8, 10, 12, 15, 18, 20, 22, 25 or a value between any two values.

[0059] In one embodiment, such as Figure 16 As shown, several openings 61 are spaced apart. On the projection plane perpendicular to the height of the battery, the minimum distance between the orthographic projections of any two openings 61 is d3 mm, satisfying 0.5≤d3≤5. This arrangement ensures the supporting performance of the base plate 6 while improving the smoothness of gas flow.

[0060] It is worth noting that if the value of d3 is too small, the remaining portion of the base plate 6 between the two openings 61 may be insufficient. When the base plate 6 melts under the influence of high temperature and the gravity of the battery cell 4, it is prone to collapse. The battery cell 4 may then block the explosion-proof valve 2, increasing the risk of further thermal runaway and affecting battery safety. If the value of d3 is too large, the remaining portion of the base plate 6 between the two openings 61 will obstruct the flow of gas from inside the battery to the explosion-proof valve 2, affecting the smoothness of gas flow. This can cause a sharp increase in internal battery pressure, leading to abnormal opening of the explosion-proof valve 2 and affecting normal battery use.

[0061] Optionally, d3 can take any value from 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, or a value between any two values.

[0062] In one embodiment, such as Figure 13 and Figure 16 As shown, several openings 61 are spaced apart. These openings 61 include a first opening 65 and a second opening 66. Along the length of the battery, the first opening 65 is positioned closer to the center of the base plate 6 than the second opening 66. On the projection plane perpendicular to the height of the battery, the projected area of ​​a single first opening 65 is S² mm. 2 The projected area of ​​a single second opening 66 is S3 mm. 2 This satisfies S2 < S3. This configuration further ensures the structural strength of the base plate 6 in the central region along the length of the battery and improves the support performance of the base plate 6 for the battery cell 4.

[0063] It is worth noting that the expansion degree of the central region of the side of the battery cell 4 facing the bottom wall 11 is greater than that of the edge region along the length of the battery. Therefore, the opening area of ​​the first opening 65 near the central region is smaller than the opening area of ​​the second opening 66 near the edge region, which ensures the structural strength of the bottom support plate 6 in the central region along the length of the battery and improves the support performance of the bottom support plate 6 for the battery cell 4.

[0064] In one embodiment, such as Figure 7 As shown, the thinning area and the base plate 6 are spaced apart along the height direction of the battery, with a spacing of h1 mm, satisfying 0.5 ≤ h1 ≤ 4. This arrangement, by spacing the thinning area and the base plate 6, avoids the base plate 6 being subjected to double-sided compression from the battery cell 4 and the bottom wall 11, reducing the risk of the base plate 6 melting under high-temperature conditions and preventing the battery cell 4 from blocking the explosion-proof valve 2, thus ensuring the timely opening of the explosion-proof valve 2 to release pressure and guaranteeing the battery's safety performance. Furthermore, by limiting the value of h1, the volumetric energy density of the battery is guaranteed while ensuring timely pressure release.

[0065] It is worth noting that if the value of h1 is too small, the distance between the main body of the plate and the bottom wall 11 may be too close, still posing a risk of contact between them. This increases the risk of melting of the base plate 6 under high-temperature conditions. Furthermore, if the base plate is too close to the explosion-proof valve, deformation of the base plate could cause the battery cell 4 to block the explosion-proof valve 2, preventing it from opening in time to release pressure and affecting the battery's safety performance. If the value of h1 is too large, the gap between the bottom wall 11 and the base plate 6 may be too large, compressing the space for the battery cell 4 and affecting the battery's volumetric energy density.

[0066] Optionally, h1 can take any value from 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.5, 3, 3.2, 3.5, 3.8, 4, or a value between any two values.

[0067] As an alternative implementation, in another embodiment, such as Figure 17 As shown, the explosion-proof valve 2 and the base plate 6 are abutted together along the height direction of the battery. At this time, the base plate 6 is subjected to double-sided compression from the battery cell 4 and the bottom wall 11, making it more prone to melting under high-temperature conditions, increasing the risk of the battery cell 4 blocking the explosion-proof valve 2. Therefore, on the projection plane perpendicular to the height direction of the battery, the ratio 'a' of the sum of the projected areas of the opening 61 to the area enclosed by the outer contour of the projected area of ​​the base plate 6 satisfies 0.05 ≤ a ≤ 0.32. By further limiting the value of 'a', the opening range of the opening 61 is further reduced, the structural strength of the base plate 6 is improved, the support performance of the base plate 6 for the battery cell 4 is guaranteed, and the battery cell 4 is prevented from blocking the explosion-proof valve 2, thus preventing the explosion-proof valve 2 from failing to open and release pressure in time, ensuring the safety performance of the battery.

[0068] In one embodiment, such as Figure 6 As shown, the battery cell body 41 has a first end 411 facing the top wall 12, and a tab 42 extends from the first end 411. At this time, the tab 42 pulls the battery cell body 41 at its top end, and the tab 42 has a certain length of redundant portion. Therefore, the pulling force of the tab 42 on the battery cell body 41 is relatively small, increasing the risk of the battery cell 4 blocking the explosion-proof valve 2. Therefore, the welding area s mm of the first soldering area 5 is... 2 The condition 25 ≤ s ≤ 150 is satisfied. By further limiting the value of s, the connection effect between the tab 42 and the terminal assembly 3 is further enhanced, the risk of the cell 4 moving towards the bottom wall 11 is reduced, the risk of the cell 4 blocking the explosion-proof valve 2 is reduced, the timely opening and pressure relief of the explosion-proof valve 2 is ensured, and the safety performance of the battery is guaranteed.

[0069] It is worth noting that in this embodiment, the electrode assembly 3 includes an electrode body 31, and the electrode tab 42 is directly welded to the electrode body 31 to form a first solder mark area 5; or, the electrode assembly 3 includes an electrode body 31 and an adapter piece 32, the electrode body 31 and the adapter piece 32 are welded together, and the electrode tab 42 and the adapter piece 32 are welded together to form a first solder mark area 5.

[0070] As an alternative implementation, in another embodiment, such as Figure 9 and Figure 10 As shown, the outer casing 1 also has a side wall 13 connected between the bottom wall 11 and the top wall 12. The cell body 41 has a second end 412 facing the side wall 13, and the tab 42 extends from the second end 412. At this time, the tab 42 extends to the side, and the position of the tab 42 pulling the cell body 41 is closer to the center of gravity of the cell body 41. Therefore, a greater pulling force can be applied to the cell body 41, reducing the risk of the cell 4 moving towards the bottom wall 11, reducing the risk of the cell 4 blocking the explosion-proof valve 2, ensuring the timely opening and pressure relief of the explosion-proof valve 2, and ensuring the safety performance of the battery.

[0071] Specifically, in the above alternative implementations, such as Figure 10 As shown, the pole assembly 3 includes a pole body 31 and an adapter plate 32. The pole body 31 is disposed on the top wall 12, and the adapter plate 32 has an L-shaped structure. Both the pole body 31 and the pole ear 42 are welded to the adapter plate 32.

[0072] It is understandable that the side wall 13 is set perpendicular to the bottom wall 11 and the top wall 12.

[0073] Specifically, in one embodiment, on the projection plane perpendicular to the height direction of the battery, the ratio 'a' of the sum of the projected areas of the openings 61 and the area enclosed by the outer contour of the projected bottom plate 6 satisfies 0.05 ≤ a ≤ 0.35. This configuration ensures that the explosion-proof valve 2 can open in a timely manner to release pressure, reducing the severity of battery thermal runaway and thus guaranteeing battery safety. Simultaneously, it prevents the explosion-proof valve 2 from abnormally opening during normal charging and discharging gas generation, ensuring normal battery operation.

[0074] It is worth noting that if the value of 'a' is too large, the structural strength of the base plate 6 may be insufficient, making it prone to melting under high temperatures. This would prevent the base plate 6 from providing reliable support for the battery cell 4, increasing the risk of the battery cell 4 blocking the explosion-proof valve 2. Consequently, the explosion-proof valve 2 would be difficult to open during battery thermal runaway, hindering battery pressure relief and further exacerbating the battery's thermal runaway, thus increasing the battery's safety risks. If the value of 'a' is too small, the internal gas storage space of the battery may be too small. During normal charging and discharging, the internal gas pressure of the battery may become too high, increasing the risk of abnormal opening of the explosion-proof valve 2 and affecting the normal use of the battery.

[0075] Optionally, the value of 'a' can be any one of the following: 0.05, 0.06, 0.08, 0.09, 0.1, 0.12, 0.14, 0.15, 0.18, 0.2, 0.21, 0.22, 0.25, 0.26, 0.27, 0.28, 0.3, 0.32, 0.33, 0.35, or a value between any two values.

[0076] Preferably, the value of 'a' satisfies 0.1 ≤ a ≤ 0.26. This further ensures that the explosion-proof valve 2 can open in a timely manner to relieve pressure, reducing the severity of battery thermal runaway and thus ensuring battery safety. Simultaneously, it prevents the explosion-proof valve 2 from abnormally opening during normal charging and discharging gas generation, ensuring normal battery operation. The value of 'a' is any one of 0.1, 0.12, 0.14, 0.15, 0.18, 0.2, 0.21, 0.22, 0.25, and 0.26, or a value between any two of these two values.

[0077] Specifically, in one embodiment, the welding area s mm of the first solder mark region 5 2 The setting satisfies 20≤s≤150. This configuration ensures that the explosion-proof valve 2 can open in time to release pressure, reducing the severity of battery thermal runaway and thus ensuring battery safety. At the same time, it prevents the explosion-proof valve 2 from opening abnormally during the normal charging and discharging process of the battery, thus ensuring normal battery use.

[0078] It is worth noting that if the value of s is too small, the connection between the terminal assembly 3 and the cell 4 through the first solder area 5 will be poor. This will cause the cell 4 to easily move towards the bottom wall 11 of the battery under the influence of gravity, increasing the risk of the cell 4 blocking the explosion-proof valve 2. This will make it difficult for the explosion-proof valve 2 to open in the event of battery thermal runaway, hindering battery pressure relief and further exacerbating the degree of battery thermal runaway, thus increasing the safety risk of the battery. If the value of s is too large, the redundant length of the tab 42 between the cell body 41 and the first solder area 5 may be too small, increasing the risk of tearing of some tab layers in the tab 42. This will increase the internal resistance of the battery, leading to increased heat and gas generation during battery charging and discharging, and increased internal gas pressure. This will increase the risk of abnormal opening of the explosion-proof valve 2, affecting the normal use of the battery.

[0079] Optionally, s can take any value from 20, 20.1, 24.5, 25, 27.5, 30, 34, 40, 50, 50.1, 50.3, 60, 62, 63, 70, 72, 80, 83.3, 89.8, 90, 90.2, 92, 100, 110, 120, 130, 140, 140.1, 149.2, 149.8, 150, or a value between any two values.

[0080] Preferably, the value of s satisfies 50≤s≤90. This further ensures that the explosion-proof valve 2 can open in a timely manner to relieve pressure, reducing the severity of battery thermal runaway and thus ensuring battery safety. Simultaneously, it prevents the explosion-proof valve 2 from opening abnormally during the normal charging and discharging gas generation process, ensuring normal battery operation. The value of s is any one of 50, 50.1, 50.3, 60, 62, 63, 70, 72, 80, 83.3, 89.8, or 90, or a value between any two of these.

[0081] Specifically, in one embodiment, the ratio c of the thickness of the thinned region 22 to the thickness of the opening portion 23 along the height direction of the battery satisfies 0.05≤c≤0.4. This configuration ensures that the explosion-proof valve 2 can open in a timely manner to release pressure, reducing the severity of battery thermal runaway and thus guaranteeing battery safety. Simultaneously, it prevents the explosion-proof valve 2 from abnormally opening during normal charging and discharging gas generation, ensuring normal battery operation.

[0082] It is worth noting that if the value of c is too large, the thinning region 22 itself may have high structural strength, making it difficult to open for pressure relief. This would make it difficult for the explosion-proof valve 2 to open in the event of battery thermal runaway, hindering battery pressure relief and further exacerbating the degree of battery thermal runaway, thus increasing the battery's safety risks. If the value of c is too small, the thinning region 22 itself may have insufficient structural strength, increasing the risk of abnormal opening of the explosion-proof valve 2 and affecting the normal use of the battery.

[0083] Optionally, c can take any value from 0.05, 0.1, 0.15, 0.16, 0.17, 0.19, 0.2, 0.25, 0.26, 0.27, 0.29, 0.3, 0.32, 0.35, 0.36, 0.38, 0.39, 0.4, or a value between any two values.

[0084] Preferably, the value of c satisfies 0.1 ≤ c ≤ 0.3. This further ensures that the explosion-proof valve 2 can open in a timely manner to relieve pressure, reducing the severity of battery thermal runaway and thus ensuring battery safety. Simultaneously, it prevents the explosion-proof valve 2 from abnormally opening during normal charging and discharging gas generation, ensuring normal battery operation. Specifically, the value of c can be any value from 0.1, 0.15, 0.16, 0.17, 0.19, 0.2, 0.25, 0.26, 0.27, 0.29, and 0.3, or a value between any two of these values.

[0085] In one embodiment, such as Figure 8 As shown, along the length of the battery, the base plate 6 has two first edges 67 spaced apart, and the cell body 41 has two second edges 413 spaced apart, with the first edges 67 extending beyond the second edges 413. This arrangement allows the base plate 6 to fully support the bottom of the cell 4 along the length of the battery, thereby improving the support performance of the base plate 6 for the cell 4. This prevents the cell 4 from blocking the explosion-proof valve 2, which could prevent the explosion-proof valve 2 from opening in time to release pressure, thus ensuring the safety performance of the battery.

[0086] Furthermore, in one embodiment, such as Figure 8 As shown, the base plate 6 includes a main body 62 and a first protrusion 63. An opening 61 is formed in the main body 62, and the first protrusion 63 is disposed on the side of the main body 62 facing the bottom wall 11, abutting against the bottom wall 11. On a projection plane perpendicular to the height of the battery, at least a portion of the orthographic projection of the second edge 413 falls on the orthographic projection of the first protrusion 63. This arrangement allows the first protrusion 63 to support the edge of the battery cell 4 along its length, further enhancing the support effect of the base plate 6 on the battery cell 4. This prevents the battery cell 4 from blocking the explosion-proof valve 2, thus ensuring the battery's safety performance.

[0087] It is worth noting that the first protrusion 63 may support only a portion of the second edge 413, or the first protrusion 63 may support the entire second edge 413.

[0088] Specifically, in one embodiment, such as Figure 8As shown, along the length of the battery, the distance by which the first edge 67 extends beyond the second edge 413 is b3 mm, satisfying 0.1≤b3≤8. This configuration ensures both the support performance of the base plate 6 for the battery cell 4 and the volumetric energy density of the battery.

[0089] It is worth noting that when the battery is subjected to vibration in the operating environment, the cell and the base plate will experience relative displacement. If the value of b3 is too small, the support effect of the base plate 6 on the cell 4 cannot be effectively improved. There is a risk that the cell 4 will block the explosion-proof valve 2, preventing the explosion-proof valve 2 from opening in time to release pressure, thus affecting the safety performance of the battery. If the value of b3 is too large, it may result in the cell 4 being too small, affecting the volumetric energy density of the battery.

[0090] Optionally, b3 can be any value from 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, or a value between any two values.

[0091] It should be noted that the two first edges 67 can extend beyond the corresponding second edge 413 by the same or different dimensions.

[0092] In one embodiment, such as Figure 12 and Figure 13 As shown, the base plate 6 includes a main body 62 and reinforcing ribs 68. An opening 61 is formed in the main body 62, and the reinforcing ribs 68 are located on the side of the main body 62 facing the bottom wall 11 and protrude towards the bottom wall 11. By providing reinforcing ribs 68 on the main body 62, the structural strength of the base plate 6 can be improved, ensuring the support performance of the base plate 6 for the battery cell 4, preventing the battery cell 4 from blocking the explosion-proof valve 2 and causing the explosion-proof valve 2 to fail to open and release pressure in time, thus ensuring the safety performance of the battery.

[0093] Furthermore, in one embodiment, such as Figure 12 and Figure 13 As shown, the base plate 6 also includes a first protrusion 63, which is disposed on the side of the plate body 62 facing the bottom wall 11. The first protrusion 63 abuts against the bottom wall 11, and the reinforcing rib 68 is spaced apart from the first protrusion 63. This arrangement allows the gas inside the battery to flow between the first protrusion 63 and the reinforcing rib 68, ensuring smooth gas flow, improving exhaust efficiency, and preventing excessive internal pressure in the battery from causing abnormal opening of the explosion-proof valve 2.

[0094] In one embodiment, the base plate 6 is an insulating component. This configuration allows the base plate 6 to act as an insulator between the battery cell 4 and the bottom wall 11, ensuring the battery's insulation performance.

[0095] As an alternative implementation, in another embodiment, the base plate 6 includes a metal element, with the metal element accounting for 0.002% to 0.02% of its mass. This configuration, by incorporating a metal element into the base plate 6, improves its high-temperature resistance, reduces the risk of melting in high-temperature environments, ensures the base plate 6's support for the battery cell 4, prevents the battery cell 4 from blocking the explosion-proof valve 2, thus preventing the explosion-proof valve 2 from failing to open and release pressure in time, and ensuring the battery's safety performance.

[0096] It should be noted that the metallic element can be copper, aluminum, molybdenum, tungsten, etc.

[0097] In one embodiment, the melting temperature of the base plate 6 is between 80°C and 300°C. This setting ensures the high-temperature resistance of the base plate 6, reduces the risk of melting of the base plate 6 in high-temperature environments, ensures the support performance of the base plate 6 for the battery cell 4, and prevents the battery cell 4 from blocking the explosion-proof valve 2, which would prevent the explosion-proof valve 2 from opening in time to release pressure, thus ensuring the safety performance of the battery.

[0098] In one embodiment, such as Figure 8 As shown, the thickness of the base plate 6 along the height direction of the battery is t mm, satisfying 0.5≤t≤3. This setting ensures the reliability of the base plate 6 in supporting the battery cell 4 while also guaranteeing the volumetric energy density of the battery.

[0099] It is worth noting that if the value of t is too small, the structural strength of the base plate 6 may be insufficient. Especially under high temperature conditions, if the base plate 6 melts and deforms, it may fail to provide effective support for the battery cell 4. This could cause the battery cell 4 to block the explosion-proof valve 2, preventing the explosion-proof valve 2 from exploding in time during battery thermal runaway. This would lead to a more severe degree of battery thermal runaway and increase the safety risks of battery use. If the value of t is too large, the base plate 6 may become too thick, occupying too much internal space in the battery and encroaching on the arrangement space of the battery cell 4, thus affecting the volumetric energy density of the battery.

[0100] Optionally, t can take any value from 0.5, 0.8, 1, 1.2, 1.5, 1.8, 2, 2.2, 2.5, 2.8, 3, or a value between any two values.

[0101] Preferably, the thickness t mm of the base plate 6 satisfies 1≤t≤2, which can further ensure the reliability of the base plate 6 in supporting the battery cell 4 while ensuring the volumetric energy density of the battery. Here, t can take any value from 1, 1.2, 1.5, 1.8, 2, or a value between any two values.

[0102] According to an embodiment of the present invention, in another aspect, a battery pack is also provided, including the battery described above.

[0103] According to an embodiment of the present invention, in another aspect, an electrical device is also provided, including the battery pack described above.

[0104] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0105] The preparation of the example battery and the comparative battery includes the following steps: (1) Preparation of the positive electrode: The prepared positive electrode active material, conductive agent (e.g., acetylene black), and binder (e.g., PVDF) are mixed, and solvent NMP is added. The mixture is stirred under vacuum until the system is homogeneous to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated on both surfaces of the positive electrode current collector foil, dried at room temperature, and then transferred to an oven for further drying. The positive electrode sheet is then obtained by rolling and slitting.

[0106] Specifically, the mass ratio of positive electrode active material: conductive agent: binder satisfies (92~98): (4~1): (4~1).

[0107] (2) Preparation of negative electrode: The negative electrode active material, conductive agent (e.g., acetylene black), thickener (e.g., carboxymethyl cellulose (CMC)), and binder (e.g., styrene-butadiene rubber (SBR)) are mixed, and deionized water is added as a solvent. The mixture is stirred under vacuum until the system is homogeneous to obtain a negative electrode slurry. The negative electrode slurry is uniformly coated on both surfaces of the negative electrode current collector foil, air-dried at room temperature, and then transferred to an oven for further drying. Finally, the negative electrode sheet is obtained by rolling and slitting.

[0108] Specifically, the ratio of negative electrode active material: conductive agent: thickener: binder satisfies (90~96): (4~2): (2~1): (4~1).

[0109] (3) Preparation of electrolyte: Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1 to obtain an organic solvent. Then, fully dried lithium salt LiPF6 was dissolved in the mixed organic solvent to prepare an electrolyte with a concentration of 1 mol / L.

[0110] (4) Preparation of the diaphragm: Polyethylene film is selected as the diaphragm.

[0111] (5) Preparation of lithium-ion batteries: An explosion-proof valve is installed on the bottom wall of the casing, and a bottom support plate is placed inside the casing and supported on the bottom wall. The positive electrode, separator, and negative electrode are stacked in sequence and wound to form a battery cell. The tabs of the battery cell are welded to the terminal assembly, placed in the battery casing, and the cover plate is welded to the casing. The battery is dried, injected with electrolyte, and then packaged, left to stand, formed, and volume-adjusted to obtain a lithium-ion battery.

[0112] In the selection of materials for the aforementioned battery, this application may also select other materials, not limited to those limited by the above preparation method. The positive electrode active material may be selected from one or more lithium-containing positive electrode active materials, including lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate. The conductive agent in the positive electrode sheet may also be selected from one or more of graphite, superconducting carbon, Ketjen black, Super P, carbon nanotubes, graphene, and carbon nanofibers. The binder in the positive electrode sheet may also be selected from one or more of polytetrafluoroethylene (PTFE), vinylidene fluoride-tetrafluoroethylene-propylene ternary copolymer, vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene ternary copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, fluorinated acrylate resin, styrene-butadiene rubber, polyacrylic acid, sodium polyacrylate, polyacrylamide, polyvinyl alcohol, sodium alginate, polymethacrylic acid, and carboxymethyl chitosan. The positive electrode current collector may also be selected from one or more of stainless steel with surface silver plating, stainless steel, aluminum, nickel, carbon electrode, carbon, nickel, and titanium. The positive electrode current collector may also include a composite current collector, which may include a polymer material base layer and a metal layer. Composite current collectors can be formed by forming metallic materials (aluminum, aluminum alloys, copper, nickel, nickel alloys, titanium, titanium alloys, silver and silver alloys, etc.) on a polymer substrate (such as a substrate of polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc.).

[0113] The negative electrode active material can be selected from one or more of the following negative electrode active main materials: artificial graphite, natural graphite, silicon carbide, silicon oxide, lithium titanate, etc.; the conductive agent in the negative electrode sheet can be selected from one or more of the following: conductive carbon black, conductive graphite, carbon nanotubes, graphene, carbon fiber, etc.; the binder in the negative electrode sheet can be selected from one or more of the following: styrene-butadiene rubber, polyacrylic acid and its salts, sodium alginate, etc.; the thickener in the negative electrode sheet can be selected from one or more of the following: sodium carboxymethyl cellulose, polyacrylonitrile multi-component copolymer, etc.; the negative electrode current collector can also be selected from one or more of the following: stainless steel with silver plating, stainless steel, copper, nickel, carbon electrode, carbon, nickel, titanium, etc.; the negative electrode current collector can also include composite current collectors, which can include a polymer material base layer and a metal layer. The composite current collector can be formed by forming a metal material (aluminum, aluminum alloy, copper, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polyethylene, polyethylene terephthalate, polybutylene terephthalate, polyethylene, etc.). The negative electrode active layer includes the negative electrode active material, conductive components, adhesives, etc.

[0114] The difference between the batteries in each embodiment and the comparative battery lies in the values ​​of a, c, and s, as shown in Table 1.

[0115] Specifically, the test method for the ratio 'a' of the projected area of ​​the opening to the projected area of ​​the base plate on the projection plane perpendicular to the height direction of the battery is as follows: Place the battery in a CT (computed tomography) scanner and measure the area enclosed by the edge of the support plate, denoted as a1 mm. 2 Measure the sum of the areas of all openings along the edge of the support plate, and record it as a² mm. 2 Calculate a2 / a1, which is the ratio of the sum of the opening areas on the support plate to the area of ​​the support plate.

[0116] Specifically, the test method for the welding area s of the first solder mark region is as follows: place the battery in a CT device, measure the area of ​​the first solder mark region formed by welding the tab and the terminal assembly, and record it as s mm. 2 .

[0117] Specifically, the test method for the ratio c of the thickness of the thinned area to the thickness of the opening part along the height direction of the battery is as follows: along the direction perpendicular to the large surface of the cover plate, use a micrometer (accuracy 0.01mm) to measure the maximum thickness of the explosion-proof sheet, measure 3 times, take the average value and record it as c2 mm. Use a micrometer to measure the thickness of the thinned area of ​​the explosion-proof sheet, measure 3 times, take the average value and record it as c1 mm. Calculate c1 / c2 as the residual thickness ratio c of the explosion-proof valve.

[0118] The relevant performance of the batteries in the above embodiments and comparative examples was tested, and the test results are recorded in Table 1. The test methods are as follows: Performance Test 1: Battery Abnormal Explosion Test Following the battery preparation method described above, 200 batteries were prepared for each of the embodiments and comparative examples. The a, s, and c values ​​of the batteries in each embodiment are shown in Table 1 below. Apart from this, the other structures are the same. The lithium-ion batteries prepared in the examples and comparative examples were subjected to cycle tests at 25°C according to the following procedure.

[0119] (1) Charge at a constant current of 1C to the upper limit voltage, and charge at a constant voltage until the current drops to 0.05C; (2) Let stand for 10 minutes; (3) Discharge the battery at a 1C rate to the lower limit voltage; (4) Let stand for 10 minutes; Perform 400 charge-discharge cycles according to steps (1)-(4).

[0120] Observe whether the explosion-proof valve explodes. If the explosion-proof valve explodes, record the number of exploded batteries as N. The abnormal explosion rate of the explosion-proof valve is calculated as (N / 200) × 100%. If the abnormal explosion rate of the explosion-proof valve is less than or equal to 1%, it is considered good. If the abnormal explosion rate of the explosion-proof valve is greater than 1% and less than or equal to 2%, it is considered qualified. If the abnormal explosion rate of the explosion-proof valve is greater than 2%, it is considered unqualified.

[0121] Different battery systems require corresponding adjustments to their upper and lower voltage limits: For cathode active materials including LFP (LiFePO4, lithium iron phosphate) – upper limit voltage 3.65V, lower limit voltage 2.5V; for cathode active materials including NCM (lithium nickel cobalt manganese oxide) – upper limit voltage 4.25V, lower limit voltage 2.5V; for cathode active materials including LFMP (lithium manganese iron phosphate) – upper limit voltage 4.25V, lower limit voltage 2.5V; for cathode active materials including lithium nickel manganese oxide – upper limit voltage 4.8V, lower limit voltage 3.5V.

[0122] The positive electrode active material used in this test was selected from LiNi. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, other positive electrode active materials all meet the above test requirements, and the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and other negative electrode active materials all meet the above test requirements, and the mass ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0123] Performance Test 2: Battery Thermal Runaway Explosion Test Following the battery preparation method described above, 200 batteries were prepared for each of the embodiments and comparative examples. The a, s, and c values ​​of the batteries in each embodiment are shown in Table 1 below. Apart from this, the remaining structures are the same. The batteries were charged at 1C to the upper limit voltage at 25°C, and then charged at a constant voltage until the cutoff current was 0.05C. A heating wire was placed on the periphery of the battery, and the battery was continuously heated for 10 minutes. Then the heating was stopped, and it was observed whether the explosion-proof valve exploded. If the explosion-proof valve exploded, the number of batteries that exploded was recorded as N. The explosion-proof valve explosion rate = (N / 200) × 100%. If the explosion-proof valve explosion rate is greater than or equal to 98%, it is considered good. If the explosion-proof valve explosion rate is less than 98% but greater than or equal to 95%, it is considered qualified. If the explosion-proof valve explosion rate is less than 95%, it is considered unqualified.

[0124] Different battery systems require corresponding adjustments to their upper and lower voltage limits: For cathode active materials including LFP (LiFePO4, lithium iron phosphate) – upper limit voltage 3.65V, lower limit voltage 2.5V; for cathode active materials including NCM (lithium nickel cobalt manganese oxide) – upper limit voltage 4.25V, lower limit voltage 2.5V; for cathode active materials including LFMP (lithium manganese iron phosphate) – upper limit voltage 4.25V, lower limit voltage 2.5V; for cathode active materials including lithium nickel manganese oxide – upper limit voltage 4.8V, lower limit voltage 3.5V.

[0125] The positive electrode active material used in this test was selected from LiNi. 0.6 Co 0.2 Mn 0.2 Taking O2 as an example, other positive electrode active materials all meet the above test requirements, and the mass ratio of positive electrode active material: conductive agent: binder meets 96:2:2; the negative electrode active material is selected from artificial graphite, and other negative electrode active materials all meet the above test requirements, and the mass ratio of negative electrode active material: conductive agent: thickener: binder meets 95:2:1:2.

[0126] Table 1:

[0127] As can be seen from Table 1, in Examples 1 to 18, the value of (a×c) / s is all within 1.76×10. -5 Up to 6.65×10 -3 Within the scope, therefore, for the batteries of Examples 1 to 18, the test results of the abnormal explosion test of the explosion-proof valve are all qualified or above, and the test results of the explosion-proof valve explosion test when the battery is thermally runaway are all qualified or above.

[0128] Furthermore, in Examples 5 to 8, 12, 13, and 16 to 18, the value of (a×c) / s is all within 1.2×10⁻⁶. -4 Up to 1.5×10-3 Within the scope of the test, the test results of the abnormal explosion test of the explosion-proof valve for the batteries of Examples 5 to 8, Examples 12, Examples 13 and Examples 16 to 18 are all good, and the test results of the explosion-proof valve explosion test during battery thermal runaway are all good.

[0129] Furthermore, in Examples 1, 2, 11, and 14, the value of (a×c) / s is all within 1.76×10. -5 Up to 6.65×10 -3 Within the range, but not within 1.2×10 -4 Up to 1.5×10 -3 Within the range and less than 1.2 × 10 -4 Therefore, in the abnormal explosion test of the batteries in Examples 1, 2, 11 and 14, the abnormal explosion rate of the explosion-proof valve is greater than 1% and less than or equal to 2%, and the test result is qualified.

[0130] Furthermore, in Examples 3, 4, 9, 10, and 15, the value of (a×c) / s is always within 1.76×10. -5 Up to 6.65×10 -3 Within the range, but not within 1.2×10 -4 Up to 1.5×10 -3 Within the range and greater than 1.5 × 10 -3 Therefore, in the battery tests of Examples 3, 4, 9, 10 and 15, the explosion-proof valve burst rate during battery thermal runaway was less than 98% and greater than or equal to 95%, and the test results were qualified.

[0131] As can be seen from Table 1, in Comparative Example 1 and Comparative Example 3, the value of (a×c) / s is not greater than 1.76×10. -5 Up to 6.65×10 -3 Within the range and less than 1.76 × 10 -5 This resulted in the batteries in Comparative Example 1 and Comparative Example 3 exhibiting an abnormal explosion rate of over 2% in the battery explosion test, leading to unqualified test results.

[0132] As can be seen from Table 1, in Comparative Examples 2 and 4, the value of (a×c) / s is not greater than 1.76×10. -5 Up to 6.65×10 -3 Within the range and greater than 6.65×10 -3 As a result, in the battery tests of Comparative Example 2 and Comparative Example 4, the explosion rate of the explosion-proof valve was less than 95% during battery thermal runaway, and the test results were unqualified.

[0133] The following is an explanation of the terms used in this application.

[0134] Battery packs can serve as the operating power source for electrical devices, or as the driving power source for electrical devices, replacing or partially replacing fuel or natural gas to provide driving power for vehicles. Electrical devices include: energy storage devices, electric ships, aircraft, laptops, power tools, electric bicycles, electric motorcycles, electric cars, military equipment, aerospace, and many other technological fields.

[0135] A battery pack consists of multiple batteries, which can be connected in series, parallel, or a combination thereof. A combination thereof means that multiple batteries are connected in both series and parallel.

[0136] The battery pack is a cluster-level battery structure formed by multiple batteries connected in series, where the number of batteries in each cluster is strictly configured according to voltage and capacity requirements. Specifically, the battery cells of the battery pack include multiple batteries with similar capacity and internal resistance. Some of the batteries are connected in series to form a cluster that meets the preset power supply voltage requirements, and at least one spare battery among the multiple batteries is bypassed.

[0137] The battery pack may include battery cells and a switching control unit.

[0138] A battery can store chemical energy and controllably convert it into electrical energy. In a recyclable battery, the active materials can be reactivated by charging after discharge, allowing it to continue to be used. A battery pack includes a casing and battery cells housed within the casing. The casing includes a housing and a cover.

[0139] A housing is a component used to provide a space to house electrode assemblies and other parts and isolate them from the external environment. A housing generally includes a body with an opening at at least one end and a receiving cavity. The opening of the housing can be closed by a cover plate, sealing and isolating the internal environment of the battery cell from the external environment. Housing materials include, but are not limited to, copper, iron, aluminum, stainless steel, and aluminum alloys.

[0140] A cover is a component that seals the opening of the battery cell to isolate the internal environment of the battery cell from the external environment. Covers can be made of materials including, but not limited to, copper, iron, aluminum, stainless steel, and aluminum alloys.

[0141] A battery cell is the component in a battery where electrochemical reactions occur; it is the smallest unit in a battery capable of carrying out electrochemical reactions such as charging and discharging. A battery cell is the basic unit of a battery, typically consisting of a positive electrode, a negative electrode, and a separator. Lithium-ion cells primarily function by the movement of lithium ions between the positive and negative electrodes. In cylindrical cells, a three-layer thin-film structure is wound into a cylindrical electrode assembly, while in cuboid cells, the thin-film structure is wound or stacked into an electrode assembly with a roughly cuboid shape.

[0142] A laminated battery cell is a battery cell made by laminating positive electrode plates, negative electrode plates, and separators. The positive and negative electrode plates are separated by a separator. The adjacent positive and / or negative electrode plates in the cell are discontinuous. The lamination process includes stacking or Z-shaped folding.

[0143] The positive electrode sheet includes a positive current collector and a positive active material. The positive current collector can be made of metal materials such as aluminum foil, nickel foil, and stainless steel, or a composite foil formed by combining metals and insulating materials. The positive active material includes the main positive active material, conductive agent, and binder. The main positive active material includes one or more of the following lithium-containing positive active materials: lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate. Similarly, the negative electrode sheet includes a negative current collector and a negative active material. The negative current collector can be made of metal materials such as copper foil, aluminum foil, and stainless steel, or a composite foil formed by combining metals and insulating materials. The negative active material includes the main negative active material, conductive agent, and binder. The main negative active material includes one or more of the following negative active materials: artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate.

[0144] A separator is positioned between the positive and negative electrode plates to separate them and prevent short circuits. The separator's dimensions extend beyond the positive and negative electrode plates. The separator can be at least one of glass fiber, non-woven fabric, polyethylene (PE), polypropylene (PP), and polyvinylidene fluoride (PVDF). A coating can also be applied to the separator surface. This coating can be inorganic or organic, wherein the inorganic coating material includes at least one of alumina, silicon dioxide, titanium dioxide, magnesium oxide, zirconium oxide, and boehmite; and the organic coating includes at least one of aramid coating and polyvinylidene fluoride (PVDF) coating.

[0145] Terminals are used to electrically connect the battery cell located inside the casing to external devices (adjacent batteries or other electrical equipment) located outside the casing. The battery can discharge to external devices through the cell output terminals (tabs) and the external device output terminals (terminals), and an external power source can charge the battery through the terminals and tabs. Terminals can be directly electrically connected to the cell tabs, or they can be electrically connected to the tabs through metal adapters.

[0146] The electrode post is made of metal materials including but not limited to copper, aluminum, aluminum alloy, and copper-aluminum alloy.

[0147] As a key component of a battery, the tab is used to transmit the current inside the cell and draw the current out. The material of the tab can be the same as that of the current collector. For example, the tab can be made of at least one of the following: silver-plated aluminum, silver-plated stainless steel, stainless steel, copper, aluminum, nickel, carbon, nickel, or titanium. Furthermore, the tab can be cut from the current collector or it can be a separately formed metal part. It can be understood that the positive tab is electrically connected to the positive electrode plate in the cell body, and the negative tab is electrically connected to the negative electrode plate in the cell body.

[0148] An explosion-proof valve is a component or part that can be actuated to release internal pressure or temperature when the internal pressure or temperature of a battery cell reaches a predetermined threshold.

[0149] During battery use, explosion-proof valves are mainly used to prevent excessive pressure buildup inside the battery, which could cause deformation or explosion, by allowing gas to escape and reducing the internal pressure of the battery in the event of thermal runaway or other situations.

[0150] The materials used for explosion-proof valves are not limited, including but not limited to copper, iron, aluminum, steel, alloys, etc. The shapes of explosion-proof valves are not limited, such as square, oblong, elliptical, racetrack-shaped, etc. The types of explosion-proof valves are not limited, such as scored explosion-proof valves, which can be formed by stamping or laser etching.

[0151] The explosion-proof valve and the housing can be separate structures, that is, the housing and the explosion-proof valve plate are manufactured separately and then fixed (welded) together; or an integrated explosion-proof valve can be used, that is, a thinning zone is made on the first surface of the housing, which can be formed by mechanical cutting, laser etching or other methods.

[0152] The explosion-proof valve (pressure relief mechanism) achieves pressure relief by reducing the thickness of the pressure relief plate to form a weak part. The thinned weak part forms a groove, which can be formed on the side close to the battery cell, the side away from the battery cell, or both sides. The groove can be a V-shaped groove, a U-shaped groove, or a trapezoidal groove, etc. The groove can be set around the entire circumference of the explosion-proof valve surface, that is, to form a closed ring structure, or it can be an open ring structure.

[0153] The base plate is positioned between the battery cell casing and the electrode assembly to support the electrode assembly inside the battery cell. The base plate can be made of at least one of polytetrafluoroethylene, metal, carbon fiber, mica, and ceramic.

[0154] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A battery, characterized in that, include: The outer casing (1) includes a bottom wall (11) and a top wall (12) that are spaced apart from each other along the height direction of the battery. An explosion-proof valve (2) is disposed on the bottom wall (11). The explosion-proof valve (2) has a groove (21) recessed along the height direction of the battery. The explosion-proof valve (2) includes a body area and a remaining portion at the groove (21) forming a thinning area (22). The thickness of the thinning area is less than the thickness of the body area. The explosion-proof valve (2) includes an opening portion (23) enclosed by the groove (21). The pole assembly (3) is disposed on the top wall (12); The battery cell (4) is disposed inside the housing (1). The battery cell (4) includes a battery cell body (41) and a tab (42) extending from at least one end of the battery cell body (41). The tab (42) is welded to the terminal assembly (3) to form a first solder area (5). A bottom support plate (6) is disposed between the battery cell (4) and the bottom wall (11). The bottom support plate (6) has an opening (61) that extends through the height of the battery. The opening (61) and the opening part (23) are at least partially opposite to each other along the height of the battery. The welding area of ​​the first solder mark area (5) is s mm. 2 On the projection plane perpendicular to the height direction of the battery, the ratio of the sum of the projected areas of the opening (61) to the area of ​​the region enclosed by the outer contour of the projected area of ​​the base plate (6) is a; and along the height direction of the battery, the ratio of the thickness of the thinning area (22) to the thickness of the opening (23) is c, satisfying 1.76 × 10⁻⁶. -5 ≤(a×c) / s≤6.65×10 -3 .

2. The battery according to claim 1, characterized in that, The base plate (6) includes a plate body (62) and a first protrusion (63). The opening (61) is formed in the plate body (62). The first protrusion (63) is disposed on the side of the plate body (62) facing the bottom wall (11). The first protrusion (63) abuts against the bottom wall (11).

3. The battery according to claim 2, characterized in that, The first protrusion (63) and the opening (61) are spaced apart. On the projection plane perpendicular to the height direction of the battery, the minimum distance between the orthographic projection of the first protrusion (63) and the orthographic projection of the opening (61) is d1 mm, which satisfies 2≤d1≤20.

4. The battery according to claim 2, characterized in that, Along the length of the battery, the first protrusion (63) is provided on both sides of the opening (61).

5. The battery according to claim 2, characterized in that, On the projection plane perpendicular to the height direction of the battery, the total projected area of ​​the first protrusion (63) is S1 mm. 2 The condition is satisfied that 150≤S1≤2600.

6. The battery according to claim 2, characterized in that, The first protrusion (63) is provided at intervals of several. On the projection plane perpendicular to the height direction of the battery, the minimum distance between the orthographic projections of any two first protrusions (63) is d2 mm, which satisfies 3≤d2≤20.

7. The battery according to claim 1, characterized in that, On the projection plane perpendicular to the height direction of the battery, the area occupied by the orthographic projection of the opening (61) on the orthographic projection of the base plate (6) is the opening area (64), and the orthographic projection of the thinning area (22) falls within the opening area (64).

8. The battery according to claim 7, characterized in that, On the projection plane perpendicular to the height direction of the battery, along the length direction of the battery, the distance between the edge of the opening area (64) and the edge of the orthographic projection of the thinning area (22) is b1 mm, and along the width direction of the battery, the distance between the edge of the opening area (64) and the edge of the orthographic projection of the thinning area (22) is b2 mm, satisfying b1 < b2.

9. The battery according to claim 8, characterized in that, On the projection plane perpendicular to the height direction of the battery, along the length direction of the battery, the distance b1 mm between the edge of the opening area (64) and the edge of the orthographic projection of the thinning area (22), and along the width direction of the battery, the distance b2 mm between the edge of the opening area (64) and the edge of the orthographic projection of the thinning area (22), satisfy 1≤b2-b1≤20.

10. The battery according to claim 1, characterized in that, The openings (61) are spaced out in several places. On the projection plane perpendicular to the height direction of the battery, the minimum distance between the orthographic projections of any two openings (61) is d3 mm, which satisfies 0.5≤d3≤5.

11. The battery according to claim 1, characterized in that, The openings (61) are spaced out in a plurality of increments, including a first opening (65) and a second opening (66). Along the length of the battery, the first opening (65) is positioned closer to the center of the base plate (6) than the second opening (66). On a projection plane perpendicular to the height of the battery, the projected area of ​​a single first opening (65) is S² mm. 2 The projected area of ​​a single second opening (66) is S3 mm. 2 The condition is that S2 < S3.

12. The battery according to any one of claims 1 to 11, characterized in that, Along the height direction of the battery, the thinning area and the bottom support plate (6) are spaced apart, and the spacing is h1 mm, satisfying 0.5≤h1≤4.

13. The battery according to any one of claims 1 to 11, characterized in that, Along the height direction of the battery, the explosion-proof valve (2) and the base plate (6) are abutted together. On the projection plane perpendicular to the height direction of the battery, the ratio a of the sum of the orthographic projection areas of the opening (61) and the area of ​​the region enclosed by the outer contour of the orthographic projection of the base plate (6) satisfies 0.05≤a≤0.

32.

14. The battery according to any one of claims 1 to 11, characterized in that, The cell body (41) has a first end (411) facing the top wall (12), the tab (42) extends from the first end (411), and the welding area of ​​the first solder area (5) is s mm. 2 The condition 25 ≤ s ≤ 150 is satisfied.

15. The battery according to any one of claims 1 to 11, characterized in that, The outer casing (1) also has a side wall (13) connected between the bottom wall (11) and the top wall (12), the battery cell body (41) has a second end (412) facing the side wall (13), and the tab (42) extends from the second end (412).

16. The battery according to any one of claims 1 to 11, characterized in that, On the projection plane perpendicular to the height direction of the battery, the ratio 'a' of the sum of the projected areas of the openings (61) to the area of ​​the region enclosed by the outer contour of the projected area of ​​the base plate (6) satisfies 0.05 ≤ a ≤ 0.35; and / or, The welding area s mm of the first solder mark area (5) 2 Satisfying 20 ≤ s ≤ 150; and / or, Along the height direction of the battery, the ratio c of the thickness of the thinning region (22) to the thickness of the opening (23) satisfies 0.05≤c≤0.

4.

17. The battery according to any one of claims 1 to 11, characterized in that, Along the length of the battery, the base plate (6) has two first edges (67) arranged at relative intervals, and the cell body (41) has two second edges (413) arranged at relative intervals, with the first edges (67) extending beyond the second edges (413).

18. The battery according to claim 17, characterized in that, The base plate (6) includes a plate body (62) and a first protrusion (63). The opening (61) is formed in the plate body (62). The first protrusion (63) is disposed on the side of the plate body (62) facing the bottom wall (11). The first protrusion (63) abuts against the bottom wall (11). On a projection plane perpendicular to the height direction of the battery, at least a portion of the orthographic projection of the second edge (413) falls on the orthographic projection of the first protrusion (63).

19. The battery according to claim 17, characterized in that, Along the length direction of the battery, the distance by which the first edge (67) extends beyond the second edge (413) is b3 mm, satisfying 0.1≤b3≤8.

20. The battery according to any one of claims 1 to 11, characterized in that, The base plate (6) includes a plate body (62) and a reinforcing rib (68). The opening (61) is formed in the plate body (62). The reinforcing rib (68) is disposed on the side of the plate body (62) facing the bottom wall (11) and protrudes towards the bottom wall (11).

21. The battery according to claim 20, characterized in that, The base plate (6) further includes a first protrusion (63), which is disposed on the side of the plate body (62) facing the bottom wall (11). The first protrusion (63) abuts against the bottom wall (11), and the reinforcing rib (68) and the first protrusion (63) are spaced apart.

22. The battery according to any one of claims 1 to 11, characterized in that, The base plate (6) is an insulating component.

23. The battery according to any one of claims 1 to 11, characterized in that, The base plate (6) includes a metal element, and the mass percentage of the metal element is 0.002% to 0.02%.

24. The battery according to any one of claims 1 to 11, characterized in that, The melting temperature of the base plate (6) is 80°C to 300°C.

25. A battery pack, characterized in that, The battery includes any one of claims 1 to 24.

26. An electrical appliance, characterized in that, Includes the battery pack as described in claim 25.

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