Battery case and battery

Abstract

The application belongs to the technical field of batteries, and discloses a battery shell and a battery. The battery shell comprises a shell assembly, an explosion-proof valve and a protective support. The shell assembly comprises a shell body, a first wall surface and a second wall surface, a cover plate body, and / or an installation through hole for installing the explosion-proof valve is arranged on the second wall surface. The protective support is arranged in the accommodating cavity and abuts against the side of the pole group facing the explosion-proof valve. The welding area of each protective support and the first wall surface is S, and satisfies δ×S>1.3F. When thermal runaway occurs and the insulating part is heated and melted, the protective support supports and fixes the pole group, avoids the pole group from moving and blocking the explosion-proof valve, and the welding area S of the protective support and the first wall surface is limited, so that the connection strength between the protective support and the first wall surface is sufficient to resist the impact of the pole group on the protective support under the pushing of high-temperature and high-pressure gas.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more particularly to a battery casing and a battery. Background Technology

[0002] Traditional blade batteries are typically designed with tabs on both sides. Their structure includes a cover plate (integrating terminals, explosion-proof valves, and electrolyte filling holes), a casing, electrode assembly, and electrolyte. The cover plate and casing are welded together to form a sealed space with sufficient mechanical strength to protect the electrode assembly. The electrode assembly is electrically connected to the cover plate's terminal base via laser welding through the tabs on both sides. The length of the cell is primarily secured by an insulating component beneath the cover plate pressing against the electrode assembly. The cover plate integrates an explosion-proof valve structure, mainly used for the directional release of high-temperature, high-pressure gases inside the battery in the event of thermal runaway due to an internal short circuit, thus improving battery safety.

[0003] The insulating components inside the battery, besides providing insulation, also come into contact with the electrode assembly, effectively securing it. However, these insulating components are typically made of PP material, which has limited strength and high-temperature resistance. When the temperature reaches around 150 degrees Celsius, the insulating components securing the electrode assembly will melt due to the high temperature, thus losing their securing effect. However, the temperature at which the battery cell experiences thermal runaway is usually much higher than the melting point of these insulating components. Therefore, once thermal runaway occurs, because the insulating components cannot effectively secure the electrode assembly, the electrode assembly will move around inside the casing, causing it to block the venting passage of the explosion-proof valve. This greatly reduces the venting effect of the explosion-proof valve during thermal runaway, potentially leading to explosions and other adverse problems, resulting in poor safety in use. Summary of the Invention

[0004] The purpose of this invention is to provide a battery casing and battery that improves the situation of electrode blockage and explosion-proof valve, and has a higher safety in use.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] On one hand, a battery housing is provided, the battery housing comprising:

[0007] A housing assembly, the housing assembly including an outer shell body and at least one cover plate body, the outer shell body including a plurality of first walls and at most one second wall, the plurality of first walls being used to form a hollow shell structure with double-sided openings, at least one cover plate body and at most one second wall being disposed at the two-sided openings to form a receiving cavity for receiving an electrode assembly, the cover plate body and / or the second wall being provided with mounting through holes;

[0008] An explosion-proof valve is provided at the mounting through hole;

[0009] A protective bracket, at least one of the protective brackets is disposed in the receiving cavity and connected to the side of the first wall facing the mounting through hole. The protective bracket abuts against the side of the electrode assembly facing the explosion-proof valve. The welding area of ​​each protective bracket to the first wall is S, and satisfies that δ×S>1.3F, where δ is the shear force coefficient per unit area of ​​the protective bracket along the first direction, and F is the impact force of the electrode assembly on the high temperature and high pressure gas.

[0010] Optionally, in a ternary nickel-cobalt-manganese lithium battery system, the height dimension of the protective bracket along the first direction is H1, and satisfies 1.5mm≤H1<2mm.

[0011] Optionally, the inner height dimension of the receiving cavity along the first direction is H, and satisfies 3.5% ≤ H1 / H ≤ 5%.

[0012] Optionally, in a lithium iron phosphate battery system, the height dimension of the protective bracket along the first direction is H2, and satisfies 1mm≤H2<1.5mm.

[0013] Optionally, the inner height dimension of the receiving cavity along the first direction is H, and satisfies 2% ≤ H2 / H ≤ 3.5%.

[0014] Optionally, the protective bracket includes a connecting part, which is connected to the first wall surface and has a plurality of welding through holes for welding to the first wall surface. The welding area S of each protective bracket to the first wall surface is the total area of ​​the plurality of welding through holes.

[0015] Optionally, the protective bracket further includes a limiting portion that abuts against the electrode assembly, the limiting portion being disposed between each pair of adjacent welding through holes and protruding in a direction away from the connecting portion.

[0016] Optionally, the battery casing further includes an insulating member, which is disposed on the side of the cover plate body and the second wall facing the electrode assembly, and has clearance grooves corresponding to the limiting portions.

[0017] Optionally, the cover plate body includes a closing part and a plug-in part. The plug-in part is inserted into the opening of the outer shell body and abuts against the side of the protective bracket away from the pole group. The closing part is used to close the opening of the outer shell body.

[0018] On the other hand, a battery is provided, the battery including an electrode assembly and a battery housing as described in any of the preceding claims, the electrode assembly being disposed within the battery housing.

[0019] The beneficial effects of this invention are:

[0020] This invention provides a battery casing with at least one protective bracket within a receiving cavity. The protective bracket is connected to the side of a first wall facing the mounting through hole and abuts against the electrode assembly. In the event of thermal runaway, even if the insulating components melt due to heat, the protective bracket can still support and fix the electrode assembly, preventing the electrode assembly from blocking the explosion-proof valve's exhaust passage due to free movement. Furthermore, by limiting the welding area S between each protective bracket and the first wall to satisfy δ×S>1.3F, sufficient connection strength between the protective bracket and the first wall is ensured to resist the impact of the electrode assembly on the protective bracket under high-temperature and high-pressure gas, thereby ensuring the fixing strength of the protective bracket for the electrode assembly and preventing the electrode assembly from blocking the explosion-proof valve's exhaust passage during thermal runaway, ensuring the exhaust effect of the explosion-proof valve, and thus providing high safety performance.

[0021] The present invention also provides a battery that, by applying the above-mentioned battery casing, ensures a relatively high venting efficiency in the event of thermal runaway, allowing the pressurized gas to be released rapidly during thermal runaway, reducing the risk factor during thermal runaway, and improving the safety performance of the product. Attached Figure Description

[0022] Figure 1 This is an exploded view of the battery casing provided by the present invention;

[0023] Figure 2 This is a schematic diagram of the connection between the outer casing body and the protective bracket in the battery casing provided by the present invention;

[0024] Figure 3 This is a schematic diagram of the structure of the protective bracket in the battery casing provided by the present invention.

[0025] In the picture:

[0026] 1. Housing assembly; 11. Housing body; 111. First wall surface; 12. Cover plate body;

[0027] 2. Explosion-proof valve;

[0028] 3. Protective bracket; 31. Connecting part; 32. Welding through hole; 33. Limiting part;

[0029] 4. Insulating components; 41. Clearance groove. Detailed Implementation

[0030] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0031] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0033] In the description of this embodiment, the terms "upper," "lower," "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0034] In the event of thermal runaway, the insulating components used to fix the electrode assembly will melt due to high temperature, thus failing to effectively fix the electrode assembly. This causes the electrode assembly to move inside the housing during thermal runaway, which in turn blocks the exhaust passage of the explosion-proof valve, resulting in a significant reduction in exhaust effect, inability to achieve rapid pressure reduction, and reduced safety during use.

[0035] Therefore, in order to prevent the electrode assembly from blocking the exhaust passage of the explosion-proof valve due to free movement in the event of thermal runaway, and to ensure the exhaust effect and improve the safety of use, this embodiment provides a battery casing.

[0036] like Figures 1 to 3As shown, the battery casing includes a casing assembly 1, an explosion-proof valve 2, and a protective bracket 3. The casing assembly 1 includes a casing body 11 and at least one cover plate body 12. The casing body 11 includes multiple first walls 111 and at most one second wall. The multiple first walls 111 are used to form a hollow casing structure with double-sided openings. At least one cover plate body 12 and at most one second wall are located at the two side openings to form a receiving cavity for accommodating the electrode assembly. The cover plate body 12 and / or the second wall are provided with mounting through holes. The explosion-proof valve 2 is located at the mounting through holes. At least one protective bracket 3 is located in the receiving cavity and connected to the side of the first wall 111 facing the mounting through holes. The protective bracket 3 abuts against the side of the electrode assembly facing the explosion-proof valve 2. The welding area of ​​each protective bracket 3 to the first wall 111 is S, and satisfies that δ×S>1.3F, where δ is the shear force coefficient per unit area of ​​the protective bracket 3 along the first direction, and F is the impact force of the electrode assembly on the high-temperature and high-pressure gas.

[0037] The battery casing incorporates at least one protective bracket 3 within the receiving cavity. The protective bracket 3 is connected to the side of the first wall surface 111 facing the mounting through-hole and abuts against the electrode assembly. In the event of thermal runaway, even if the insulating components melt, the protective bracket 3 can still support and fix the electrode assembly, preventing it from blocking the exhaust passage of the explosion-proof valve 2 due to free movement. Furthermore, by limiting the welding area S between each protective bracket 3 and the first wall surface 111 to satisfy δ×S>1.3F, sufficient connection strength between the protective bracket 3 and the first wall surface 111 is ensured to withstand the impact of the electrode assembly on the protective bracket 3 under high-temperature, high-pressure gas. This guarantees the fixing strength of the protective bracket 3 to the electrode assembly, preventing the electrode assembly from blocking the exhaust passage of the explosion-proof valve 2 during thermal runaway, thus ensuring the exhaust effect of the explosion-proof valve 2 and providing high safety performance.

[0038] The shear force coefficient δ per unit area of ​​the protective bracket 3 along the first direction is typically 8 N / mm. 2 Up to 15 N / mm 2 During thermal runaway, the electrode assembly is subjected to an impact force F from high-temperature and high-pressure gas, typically between 120N and 350N.

[0039] The battery casing can be adapted to different types of batteries, such as blade batteries or prismatic batteries. In addition, the battery casing can be configured into various structures of blade batteries or prismatic batteries by setting the number of openings in the casing body 11 and the number of cover bodies 12. For example, a blade battery with a casing body 11 and double cover bodies 12 with openings on both sides, or a blade battery with a casing body 11 and single cover body 12 with openings on one side, or a prismatic battery with a casing body 11 and single cover body 12 with openings on one side, etc. The mounting through holes can be set separately on the second wall of the casing body 11, or separately on the cover body 12, or mounting through holes can be set on both the second wall of the cover body 12 and the second wall of the casing body 11. In this embodiment, the specific structure of the battery casing is a blade battery casing consisting of a casing body 11 with double-sided openings and a double cover plate body 12. The mounting through holes are opened on the cover plate body 12, while the casing body 11 does not have mounting through holes. The multiple first walls 111 used to form the hollow casing structure are divided into two narrow sides and two wide sides according to their area. Each narrow side facing the mounting through hole is connected to a protective bracket 3, thereby fixing the two sides of the electrode assembly, ensuring the fixing strength of the protective bracket 3 for the electrode assembly, and preventing the electrode assembly from moving during thermal runaway.

[0040] Optionally, such as Figure 3 As shown, in the ternary nickel-cobalt-manganese lithium battery system, the height dimension of the protective bracket 3 along the first direction is H1, and it satisfies 1.5mm≤H1<2mm. By limiting the height dimension H1 of the protective bracket 3 along the first direction to satisfy 1.5mm≤H1<2mm, the protective bracket 3 is guaranteed to have sufficient structural strength, thus preventing deformation of the protective bracket 3 when the electrode assembly impacts it, which would cause the electrode assembly to shift.

[0041] In this embodiment, the height dimension H1 of the protective bracket 3 along the first direction can be any value between 1.5mm and 2mm or a range between any two values, such as 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm, etc.

[0042] Furthermore, the inner height dimension of the receiving cavity along the first direction is H, and it satisfies 3.5% ≤ H1 / H ≤ 5%. By setting the inner height dimension of the receiving cavity along the first direction to H, and limiting the ratio between the height dimension H1 of the protective bracket 3 along the first direction and the inner height dimension H of the receiving cavity along the first direction, the ratio of the two satisfies 3.5% ≤ H1 / H ≤ 5%, thereby ensuring that the height of the protective bracket 3 is compatible with the electrode assembly after it is installed in the housing, so that the electrode assembly abuts against the protective bracket 3 after it is installed in the housing.

[0043] Optionally, such as Figure 3As shown, in the lithium iron phosphate battery system, the height dimension of the protective bracket 3 along the first direction is H2, and it satisfies 1mm≤H2<1.5mm. By limiting the height dimension H2 of the protective bracket 3 along the first direction to satisfy 1mm≤H2<1.5mm, the protective bracket 3 is guaranteed to have sufficient structural strength, preventing deformation of the protective bracket 3 when the electrode assembly impacts it, thus avoiding displacement of the electrode assembly.

[0044] In this embodiment, the height dimension H2 of the protective bracket 3 along the first direction can be any value between 1mm and 1.5mm or a range between any two values, such as 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, etc.

[0045] Furthermore, the inner height dimension of the receiving cavity along the first direction is H, and it satisfies 2% ≤ H2 / H ≤ 3.5%. By setting the inner height dimension of the receiving cavity along the first direction to H, and limiting the ratio between the height dimension H2 of the protective bracket 3 along the first direction and the inner height dimension H of the receiving cavity along the first direction, the ratio of the two satisfies 2% ≤ H2 / H ≤ 3.5%, thereby ensuring that the height of the protective bracket 3 is compatible with the electrode assembly after it is installed in the housing, so that the electrode assembly abuts against the protective bracket 3 after it is installed in the housing.

[0046] In this embodiment, the reason for separately defining the ternary nickel-cobalt-manganese lithium battery system and the lithium iron phosphate battery system is that the chemical reaction is more intense during thermal runaway in the ternary nickel-cobalt-manganese lithium battery system, with a large amount of gas produced and a high gas production rate, resulting in a greater impact force of the electrode assembly on the protective support 3. In contrast, the chemical reaction during thermal runaway in the lithium iron phosphate battery system is more moderate, with a smaller amount of gas produced and a slower gas production rate, resulting in a smaller impact force of the electrode assembly on the protective support 3. Therefore, the impact force of the electrode assembly on the protective support 3 differs between the two systems. Thus, by limiting the height dimension of the protective support 3 along the first direction to different ranges in different systems, it is possible to ensure that the protective support 3 has sufficient structural strength while avoiding dimensional redundancy and material waste.

[0047] In this embodiment, to verify the influence of the height dimension H1 of the protective bracket 3 along the first direction, the ratio of the height dimension H1 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction, and the welding area S of each protective bracket 3 to the first wall surface 111 during thermal runaway in the ternary nickel-cobalt-manganese lithium battery system, as shown in Table 1, two sets of embodiments and six sets of comparative examples are provided for verification. In this experiment, the impact force F of the high-temperature and high-pressure gas on the electrode group during thermal runaway is set to be 350N, and the shear force coefficient δ per unit area of ​​the protective bracket 3 along the first direction is 9.5N / mm. 2 .

[0048] Table 1

[0049]

[0050] In Embodiment 1, the height dimension H1 of the protective bracket 3 along the first direction is set to 1.5 mm, the ratio of the height dimension H1 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 4%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 48 mm². 2 At this point, the thermal runaway safety test result is qualified, the explosion-proof valve 2 exhausts smoothly, and the exhaust effect is not affected.

[0051] In embodiment 2, the height dimension H1 of the protective bracket 3 along the first direction is set to 1.5 mm, the ratio of the height dimension H1 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 4%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 50 mm². 2 At this point, the thermal runaway safety test result is qualified, the explosion-proof valve 2 exhausts smoothly, and the exhaust effect is not affected.

[0052] As can be seen from Examples 1 and 2, when the height dimension H1 of the protective bracket 3 along the first direction is within the range of 1.5mm ≤ H1 < 2mm, the protective bracket 3 has sufficient structural strength and will not deform when fixing the electrode assembly. When the ratio of the height dimension H1 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is within the range of 3.5% ≤ H1 / H ≤ 5%, the assembled electrode assembly is exactly in contact with the protective bracket 3, with no gap between them, so the electrode assembly will not move. When the welding area S between each protective bracket 3 and the first wall surface 111 is within the range of δ×S > 1.3F, the protective bracket 3 and the first wall surface 111 have sufficient connection strength and will not fall off under the impact of the electrode assembly during thermal runaway, thus avoiding the electrode assembly from blocking the exhaust passage of the explosion-proof valve 2. The explosion-proof valve 2 exhausts smoothly, and the exhaust effect is not affected, thereby passing the thermal runaway safety test.

[0053] In Comparative Example 1, the height dimension H1 of the protective bracket 3 along the first direction is set to 1.5 mm, the ratio of the height dimension H1 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 4%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 30 mm². 2 At this point, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 is not venting smoothly, and the venting effect is weakened.

[0054] In Comparative Example 2, the height dimension H1 of the protective bracket 3 along the first direction is set to 1.5 mm, the ratio of the height dimension H1 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 4%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 35 mm². 2 At this point, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 is not venting smoothly, and the venting effect is weakened.

[0055] As can be seen from Comparative Examples 1 and 2, when the welding area S between each protective bracket 3 and the first wall surface 111 does not meet the range of δ×S>1.3F, the connection strength between the protective bracket 3 and the first wall surface 111 is insufficient to resist the impact force of the electrode group on the protective bracket 3, causing the protective bracket 3 to fall off, thereby causing the electrode group to move and block the explosion-proof valve 2. As a result, during thermal runaway, the exhaust is obstructed, the exhaust of the explosion-proof valve 2 is not smooth, and the exhaust effect is affected to a certain extent, thus failing the thermal runaway safety test.

[0056] In Comparative Example 3, the height dimension H1 of the protective bracket 3 along the first direction is set to 1.2 mm, the ratio of the height dimension H1 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 4%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 50 mm². 2 At this point, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 is not venting smoothly, and the venting effect is weakened.

[0057] In Comparative Example 4, the height dimension H1 of the protective bracket 3 along the first direction is set to 1 mm, the ratio of the height dimension H1 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 4%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 50 mm². 2 At this point, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 is not venting smoothly, and the venting effect is weakened.

[0058] As can be seen from Comparative Examples 3 and 4, when the height dimension H1 of the protective bracket 3 along the first direction does not meet the range of 1.5mm≤H1<2mm, the structural strength of the protective bracket 3 itself is insufficient to withstand the impact of the electrode assembly on the protective bracket 3, causing the protective bracket 3 to deform. This results in a gap between the protective bracket 3 and the electrode assembly, causing the electrode assembly to move during thermal runaway, which in turn blocks the explosion-proof valve 2. Consequently, during thermal runaway, the exhaust is obstructed, the exhaust of the explosion-proof valve 2 is not smooth, and the exhaust effect is affected to a certain extent, thus failing the thermal runaway safety test.

[0059] In Comparative Example 5, the height dimension H1 of the protective bracket 3 along the first direction is set to 1.5 mm, the ratio of the height dimension H1 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 3.2%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 50 mm². 2 At this point, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 is not venting smoothly, and the venting effect is weakened.

[0060] In Comparative Example 6, the height dimension H1 of the protective bracket 3 along the first direction is set to 1.5 mm, the ratio of the height dimension H1 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 3%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 50 mm². 2 At this point, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 is not venting smoothly, and the venting effect is weakened.

[0061] As can be seen from Comparative Examples 5 and 6, when the ratio of the height dimension H1 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction does not meet the range of 3.5% ≤ H1 / H ≤ 5%, there is a gap between the assembled electrode assembly and the protective bracket 3, which makes it impossible to effectively fix the electrode assembly. This causes the electrode assembly to move during thermal runaway, thereby blocking the explosion-proof valve 2. As a result, during thermal runaway, the exhaust is obstructed, the exhaust of the explosion-proof valve 2 is not smooth, and the exhaust effect is affected to a certain extent, thus failing the thermal runaway safety test.

[0062] In this embodiment, to verify the influence of the height dimension H2 of the protective bracket 3 along the first direction, the ratio of the height dimension H2 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction, and the welding area S of each protective bracket 3 to the first wall surface 111 during thermal runaway in the lithium iron phosphate battery system, as shown in Table 2, two sets of embodiments and six sets of comparative examples are provided for verification. In this experiment, the impact force F of the high temperature and high pressure gas on the electrode group during thermal runaway is set to be 250N, and the shear force coefficient δ per unit area of ​​the protective bracket 3 along the first direction is 9.5N / mm. 2 .

[0063] Table 2

[0064]

[0065] In embodiment 3, the height dimension H2 of the protective bracket 3 along the first direction is set to 1 mm, the ratio of the height dimension H2 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 2%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 35 mm². 2At this point, the thermal runaway safety test result is qualified, the explosion-proof valve 2 exhausts smoothly, and the exhaust effect is not affected.

[0066] In embodiment 4, the height dimension H2 of the protective bracket 3 along the first direction is set to 1 mm, the ratio of the height dimension H2 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 2%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 40 mm². 2 At this point, the thermal runaway safety test result is qualified, the explosion-proof valve 2 exhausts smoothly, and the exhaust effect is not affected.

[0067] As can be seen from Examples 3 and 4, when the height dimension H2 of the protective bracket 3 along the first direction is within the range of 1mm≤H2<1.5mm, the protective bracket 3 has sufficient structural strength and will not deform when fixing the electrode assembly. When the ratio of the height dimension H2 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is within the range of 2%≤H2 / H≤3.5%, the assembled electrode assembly is exactly in contact with the protective bracket 3, with no gap between them, so the electrode assembly will not move. When the welding area S between each protective bracket 3 and the first wall surface 111 is within the range of δ×S>1.3F, the protective bracket 3 and the first wall surface 111 have sufficient connection strength and will not fall off under the impact of the electrode assembly during thermal runaway, thus avoiding the electrode assembly from blocking the exhaust passage of the explosion-proof valve 2. The explosion-proof valve 2 exhausts smoothly, and the exhaust effect is not affected, thereby passing the thermal runaway safety test.

[0068] In Comparative Example 7, the height dimension H2 of the protective bracket 3 along the first direction is set to 1.2 mm, the ratio of the height dimension H2 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 2.5%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 20 mm². 2 At this point, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 is not venting smoothly, and the venting effect is weakened.

[0069] In Comparative Example 8, the height dimension H2 of the protective bracket 3 along the first direction is set to 1.2 mm, the ratio of the height dimension H2 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 2.5%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 25 mm². 2 At this point, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 is not venting smoothly, and the venting effect is weakened.

[0070] As can be seen from Comparative Examples 7 and 8, when the welding area S between each protective bracket 3 and the first wall surface 111 does not meet the range of δ×S>1.3F, the connection strength between the protective bracket 3 and the first wall surface 111 is insufficient to resist the impact force of the electrode group on the protective bracket 3, causing the protective bracket 3 to fall off, thereby causing the electrode group to move and block the explosion-proof valve 2. As a result, during thermal runaway, the exhaust is obstructed, the exhaust of the explosion-proof valve 2 is not smooth, and the exhaust effect is affected to a certain extent, thus failing the thermal runaway safety test.

[0071] In Comparative Example 9, the height dimension H2 of the protective bracket 3 along the first direction is set to 0.8 mm, the ratio of the height dimension H2 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 2.5%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 35 mm². 2 At this point, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 is not venting smoothly, and the venting effect is weakened.

[0072] In Comparative Example 10, the height dimension H2 of the protective bracket 3 along the first direction is set to 0.6 mm, the ratio of the height dimension H2 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 2.5%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 35 mm². 2 At this point, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 is not venting smoothly, and the venting effect is weakened.

[0073] As can be seen from Comparative Examples 9 and 10, when the height dimension H2 of the protective bracket 3 along the first direction does not meet the range of 1mm≤H2<1.5mm, the structural strength of the protective bracket 3 itself is insufficient to withstand the impact of the electrode assembly on the protective bracket 3, causing the protective bracket 3 to deform. This results in a gap between the protective bracket 3 and the electrode assembly, causing the electrode assembly to move during thermal runaway, which in turn blocks the explosion-proof valve 2. As a result, during thermal runaway, the exhaust is obstructed, the exhaust of the explosion-proof valve 2 is not smooth, and the exhaust effect is affected to a certain extent, thus failing the thermal runaway safety test.

[0074] In Comparative Example 11, the height dimension H2 of the protective bracket 3 along the first direction is set to 1.2 mm, the ratio of the height dimension H2 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 1.8%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 35 mm². 2 At this point, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 is not venting smoothly, and the venting effect is weakened.

[0075] In Comparative Example 12, the height dimension H2 of the protective bracket 3 along the first direction is set to 1.2 mm, the ratio of the height dimension H2 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction is set to 1.6%, and the welding area S between each protective bracket 3 and the first wall surface 111 is set to 35 mm². 2 At this point, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 is not venting smoothly, and the venting effect is weakened.

[0076] As can be seen from Comparative Examples 11 and 12, when the ratio of the height dimension H2 of the protective bracket 3 along the first direction to the inner height dimension H of the receiving cavity along the first direction does not meet the range of 2% ≤ H2 / H ≤ 3.5%, there is a gap between the assembled electrode assembly and the protective bracket 3, which makes it impossible to effectively fix the electrode assembly. This causes the electrode assembly to move during thermal runaway, thereby blocking the explosion-proof valve 2. As a result, during thermal runaway, the exhaust is obstructed, the exhaust of the explosion-proof valve 2 is not smooth, and the exhaust effect is affected to a certain extent, thus failing the thermal runaway safety test.

[0077] Optionally, such as Figure 3 As shown, the protective bracket 3 includes a connecting part 31, which is connected to the first wall surface 111 and has multiple welding through holes 32 for welding to the first wall surface 111. The welding area S of each protective bracket 3 to the first wall surface 111 is the total area of ​​the multiple welding through holes 32. By opening multiple welding through holes 32 in the connecting part 31 of the protective bracket 3, it is convenient to perform welding operations between the protective bracket 3 and the first wall surface 111 of the outer shell body 11.

[0078] The number and shape of the welding through holes 32 on the connecting part 31 can be freely set according to requirements. In this embodiment, three circular welding through holes 32 are provided on the connecting part 31 at intervals. The radius of the welding through holes 32 is R. Therefore, the welding area S between each protective bracket 3 and the first wall surface 111 is S = 3 × πR. 2 .

[0079] Optionally, such as Figure 3 As shown, the protective bracket 3 also includes a limiting portion 33 that abuts against the electrode assembly. The limiting portion 33 is disposed between every two adjacent welding through holes 32 and protrudes in a direction away from the connecting portion 31. By protruding in a direction away from the connecting portion 31, the protective bracket 3 forms the limiting portion 33, thereby fixing the electrode assembly using the limiting portion 33. Furthermore, by placing the limiting portion 33 between two adjacent welding through holes 32, both sides of the limiting portion 33 have welding points with the first wall surface 111, resulting in better stress distribution. In this embodiment, since the connecting portion 31 is provided with three welding through holes 32, the protective bracket 3 forms two limiting portions 33 for abutting against the electrode assembly.

[0080] Optionally, such as Figure 1 , Figure 3 As shown, the battery casing also includes an insulating member 4, which is located on the side of the cover plate body 12 and the second wall facing the electrode assembly, and has clearance grooves 41 corresponding to the limiting portions 33. By providing clearance grooves 41 on the insulating member 4 that correspond to the limiting portions 33, a large coverage area of ​​the insulating member 4 on the cover plate body 12 and the second wall is retained, while avoiding interference with the protective bracket 3 during assembly.

[0081] In this embodiment, since there are two limiting parts 33 on each protective bracket 3 and one protective bracket 3 is provided on each narrow side, two clearance grooves 41 are provided on both sides of the insulating member 4 opposite to the narrow side.

[0082] Optionally, the cover plate body 12 includes a closing part and a plug-in part. The plug-in part is inserted into the opening of the outer shell body 11 and abuts against the side of the protective bracket 3 opposite to the pole group. The closing part is used to close the opening of the outer shell body 11. By providing a plug-in part on the cover plate body 12, the contact area between the cover plate body 12 and the outer shell body 11 is increased, ensuring the connection strength and sealing performance after the two are connected.

[0083] In this embodiment, a space is left between the side of the protective bracket 3 away from the pole group and the edge of the open opening of the outer shell body 11, so as to avoid interference between the insertion part of the cover plate body 12 and the protective bracket 3 when the cover plate body 12 is inserted into the outer shell body 11.

[0084] In this embodiment, a battery is also provided, comprising an electrode assembly and the aforementioned battery casing, with the electrode assembly disposed within the battery casing. By utilizing the aforementioned battery casing, this battery ensures a relatively high venting efficiency in the event of thermal runaway, allowing the pressurized gas to be released rapidly during thermal runaway, reducing the risk factor during thermal runaway, and improving the safety performance of the product.

[0085] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art will be able to make various obvious changes, readjustments, and substitutions without departing from the scope of protection of the present invention. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A battery casing, characterized in that, The battery casing includes: A housing assembly, the housing assembly including an outer shell body and at least one cover plate body, the outer shell body including a plurality of first walls and at most one second wall, the plurality of first walls being used to form a hollow shell structure with double-sided openings, at least one cover plate body and at most one second wall being disposed at the two-sided openings to form a receiving cavity for receiving an electrode assembly, the cover plate body and / or the second wall being provided with mounting through holes; An explosion-proof valve is provided at the mounting through hole; At least one of the protective brackets is disposed within the receiving cavity and connected to the side of the first wall facing the mounting through hole. The protective bracket abuts against the side of the electrode assembly facing the explosion-proof valve. The welding area of ​​each protective bracket to the first wall is S, in mm. 2 And satisfying δ×S>1.3F, where δ is the shear force coefficient per unit area of ​​the protective bracket along the first direction, in N / mm². 2 F represents the impact force exerted on the electrode assembly by the high-temperature, high-pressure gas, in N. In a ternary nickel-cobalt-manganese lithium battery system, the height dimension of the protective bracket along the first direction is H1, and it satisfies 1.5mm≤H1<2mm; The inner height dimension of the receiving cavity along the first direction is H, and satisfies 3.5%≤H1 / H≤5%; In the lithium iron phosphate battery system, the height dimension of the protective bracket along the first direction is H2, and satisfies 1mm≤H2<1.5mm; The inner height dimension of the receiving cavity along the first direction is H, and it satisfies 2%≤H2 / H≤3.5%.

2. The battery casing according to claim 1, characterized in that, The protective bracket includes a connecting part, which is connected to the first wall surface and has multiple welding through holes for welding to the first wall surface. The welding area S of each protective bracket to the first wall surface is the total area of ​​the multiple welding through holes.

3. The battery casing according to claim 2, characterized in that, The protective bracket also includes a limiting part that abuts against the electrode assembly. The limiting part is located between every two adjacent welding through holes and protrudes in a direction away from the connecting part.

4. The battery casing according to claim 3, characterized in that, The battery casing also includes an insulating component, which is disposed on the side of the cover plate body and the second wall facing the electrode assembly, and has a relief groove corresponding to the limiting part.

5. The battery casing according to claim 1, characterized in that, The cover plate body includes a sealing part and a plug-in part. The plug-in part is inserted into the opening of the outer shell body and abuts against the side of the protective bracket away from the pole group. The sealing part is used to close the opening of the outer shell body.

6. A battery, characterized in that, The battery includes an electrode assembly and a battery casing as described in any one of claims 1-5, wherein the electrode assembly is disposed within the battery casing.

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