Battery casing and battery

Abstract

This invention belongs to the field of battery technology and discloses a battery casing and a battery. The battery casing includes a casing assembly, an explosion-proof valve, and a protective bracket. The casing assembly includes a casing body and a cover plate body. The casing body and / or the cover plate body have mounting holes for accommodating the explosion-proof valve. The protective bracket is disposed in the receiving cavity and includes a connecting seat and a support plate. The connecting seat is connected to the casing body and / or the cover plate body with the mounting holes. The support plate is connected to the connecting seat and abuts against the electrode assembly. The projected area of ​​the support plate on the casing body or the cover plate body is S1, and the cross-sectional area of ​​the electrode assembly is S, satisfying 25% ≤ S1 / S < 40%. The protective bracket provides support and fixation for the electrode assembly during thermal runaway, preventing the electrode assembly from blocking the explosion-proof valve's exhaust channel due to free movement. Furthermore, by ensuring sufficient contact area between the support plate and the electrode assembly, the fixing effect of the support plate on the electrode assembly is guaranteed.

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 insulating components 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 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, comprising an outer shell body and a cover plate body, the outer shell body having at least one opening, the cover plate body corresponding one-to-one with the opening of the outer shell body and closing the opening of the outer shell body to form a receiving cavity for accommodating an electrode assembly, the outer shell body and / or the cover plate body having a mounting through hole communicating with the receiving cavity;

[0008] An explosion-proof valve is disposed in the mounting through hole and is used to release the pressurized gas inside the receiving cavity;

[0009] A protective bracket is disposed within the receiving cavity and includes a connecting seat and a support plate. The connecting seat is connected to the outer shell body with the mounting through hole and / or the cover plate body. The support plate is connected to the connecting seat and abuts against the electrode assembly. The projected area of ​​the support plate along a first direction on the outer shell body or the cover plate body is S1, and the cross-sectional area of ​​the electrode assembly is S, satisfying 25% ≤ S1 / S < 40%.

[0010] Optionally, the support plate is also provided with a plurality of exhaust holes, the total effective area of ​​the plurality of exhaust holes for gas flow is S2, and satisfies 40% ≤ S2 / S1 < 60%.

[0011] 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 4.5mm≤H1<6mm.

[0012] Optionally, in the lithium iron phosphate battery system, the height dimension of the protective bracket along the first direction is H2, and satisfies 3mm≤H2<4.5mm.

[0013] Optionally, the protective bracket is mounted on the outer shell body, and / or the cover plate body has the mounting through hole, the mounting through hole being located within the projection of the support plate on the outer shell body or the cover plate body.

[0014] Optionally, the battery casing includes a plurality of the protective brackets, and the mounting through holes are symmetrically distributed with a plurality of spaced-apart protective brackets on both sides of the second direction.

[0015] Optionally, the vent hole is a circular hole, a polygonal hole, or an elliptical hole.

[0016] Optionally, multiple connecting seats are provided, and multiple connecting seats are symmetrically distributed on both sides of the support plate along the second direction and spaced apart along the third direction. One end of the multiple connecting seats is connected to the cover plate body and / or the outer shell body, and the support plate is connected to the other end of the multiple connecting seats to form an exhaust passage between the support plate and the outer shell body and / or the cover plate body.

[0017] Optionally, the connecting seat includes a connecting part and a fixing part, the connecting part being vertically connected to the support plate, and the fixing part being connected to the other end of the connecting part and parallel to the support plate.

[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 that utilizes a protective bracket within a housing cavity to connect to a cover plate body with mounting through holes, and / or, the protective bracket of the casing body abuts against the electrode assembly. This protective bracket protects the explosion-proof valve. In the event of thermal runaway, even if the insulating components melt, 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, the ratio of the projected area S1 of the support plate along a first direction on the casing body or cover plate body to the cross-sectional area S of the electrode assembly is limited to 25% ≤ S1 / S < 40%. This avoids both excessively small contact areas between the support plate and the electrode assembly, which would cause excessive pressure and deformation of the support plate under impact from the electrode assembly, and excessively large contact areas, which would increase structural weight and violate lightweight design principles.

[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 a three-dimensional isometric view of the battery casing after the cover plate body, explosion-proof valve and protective bracket are assembled according to the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of the protective bracket in the battery casing provided by the present invention;

[0024] Figure 3 This is a schematic diagram showing the relative positions of the protective bracket and the explosion-proof valve in the battery casing provided by the present invention;

[0025] Figure 4 This is a schematic diagram showing the position of the protective bracket in the battery casing provided by the present invention located on both sides of the explosion-proof valve.

[0026] In the picture:

[0027] 1. Cover plate body;

[0028] 2. Explosion-proof valve;

[0029] 3. Protective bracket; 31. Connecting seat; 311. Connecting part; 312. Fixing part; 32. Support plate; 33. Vent hole; 34. Vent passage. 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 4As shown, the battery casing includes a casing assembly, an explosion-proof valve 2, and a protective bracket 3. The casing assembly includes a casing body and a cover plate body 1. The casing body has at least one opening. The cover plate body 1 corresponds one-to-one with the opening of the casing body and closes the opening of the casing body to form a receiving cavity for accommodating the electrode assembly. The casing body and / or the cover plate body 1 have mounting through holes communicating with the receiving cavity. The explosion-proof valve 2 is located in the mounting through hole and is used to release the pressurized gas inside the receiving cavity. The protective bracket 3 is located in the receiving cavity and includes a connecting seat 31 and a support plate 32. The connecting seat 31 is connected to the casing body and / or the cover plate body 1 with mounting through holes. The support plate 32 is connected to the connecting seat 31 and abuts against the electrode assembly. The projected area of ​​the support plate 32 along the first direction on the casing body or the cover plate body 1 is S1, and the cross-sectional area of ​​the electrode assembly is S, satisfying 25% ≤ S1 / S < 40%.

[0037] The battery casing protects the explosion-proof valve 2 by providing a protective bracket 3 within the housing cavity and connecting it to the cover plate body 1 with mounting through holes, and / or by having the protective bracket 3 of the casing body abut against the electrode assembly. In the event of thermal runaway, even if the insulating components melt due to heat, the protective bracket 3 can still support and fix the electrode assembly, preventing the electrode assembly from blocking the exhaust passage of the explosion-proof valve 2 due to free movement. Furthermore, the ratio of the projected area S1 of the support plate 32 along the first direction on the casing body or cover plate body 1 and the cross-sectional area S of the electrode assembly is limited to 25% ≤ S1 / S < 40%. This avoids both excessively small contact area between the support plate 32 and the electrode assembly, which would cause excessive pressure on the support plate 32 when subjected to the impact of the electrode assembly, leading to deformation, and excessively large contact area, which would increase the structural weight and fail to meet the lightweight design principle.

[0038] The battery casing can be adapted to different types of batteries, such as blade batteries or prismatic batteries. Furthermore, the battery casing can be configured with various blade battery or prismatic battery structures by setting the number of openings in the casing body and the number of cover plates 1. For example, a blade battery with a casing body and two cover plates 1 having openings on both sides, a blade battery with a casing body and a single cover plate 1 having an opening on one side, or a prismatic battery with a casing body and a single cover plate 1 having an opening on one side. The mounting through holes can be provided separately on the casing body, separately on the cover plate 1, or on both the cover plate 1 and the casing body. In this embodiment, the specific structure of the battery casing is a blade battery casing with a casing body and two cover plates 1 having openings on both sides. The mounting through holes are provided on the cover plate 1, while the casing body does not have mounting through holes. Therefore, the protective bracket 3 is provided on the cover plate 1. The protective bracket 3 and the cover plate 1 can be separately molded and then connected, or the cover plate 1 with the protective bracket 3 can be manufactured using an integrated molding process. In this embodiment, the protective bracket 3 and the cover plate body 1 are manufactured separately. After the manufacturing is completed, the protective bracket 3 and the cover plate body 1 are welded together.

[0039] Optionally, such as Figure 2 As shown, the support plate 32 is also provided with multiple vent holes 33. The total effective area of ​​the multiple vent holes 33 for gas flow is S2, and satisfies 40% ≤ S2 / S1 < 60%. By providing multiple vent holes 33 on the support plate 32, pressurized gas can flow freely through the vent holes 33 during thermal runaway, avoiding obstruction of the pressurized gas by the support plate 32 and slowing down the flow speed of the pressurized gas when passing through the protective bracket 3. Furthermore, by limiting the ratio of the total effective area S2 of the multiple vent holes 33 for gas flow to the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1, the ratio is made to satisfy 40% ≤ S2 / S1 < 60%. This avoids the total effective area S2 of the multiple vent holes 33 on the protective bracket 3 being too small, which would weaken the venting effect. On the other hand, it avoids the proportion of the multiple vent holes 33 being too large, which would reduce the structural strength of the protective bracket 3 and cause the protective bracket 3 to deform under the impact of the electrode assembly, making it impossible for the protective bracket 3 to effectively fix the electrode assembly.

[0040] Specifically, such as Figure 2 As shown, the vent 33 can be a circular hole, a polygonal hole, or an elliptical hole. The shape and number of vent 33 can be freely set according to design requirements. In this embodiment, each protective bracket 3 has three elliptical vent 33 on its support plate 32.

[0041] Optionally, such as Figure 2As 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 4.5mm≤H1<6mm. By limiting the height dimension H1 of the protective bracket 3 along the first direction in the ternary nickel-cobalt-manganese lithium battery system to satisfy 4.5mm≤H1<6mm, on the one hand, it avoids the protective bracket 3 being too small along the first direction, resulting in a gap between the protective bracket 3 and the electrode assembly after assembly, so that the electrode assembly will still have a small amount of movement during thermal runaway. On the other hand, it avoids the protective bracket 3 being too large along the first direction, resulting in the protective bracket 3 occupying too much space in the cavity, thus restricting and compressing the volume of the electrode assembly, leading to a decrease in energy density.

[0042] In the ternary nickel-cobalt-manganese lithium battery system, the height dimension H1 of the protective bracket 3 along the first direction can be any value between 4.5mm and 6mm or any range between two values, such as 4.5mm, 5mm, 5.5mm, 6mm, etc.

[0043] Optionally, such as Figure 2 As 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 3mm ≤ H2 < 4.5mm. By limiting the height dimension H2 of the protective bracket 3 along the first direction in the lithium iron phosphate battery system to satisfy 3mm ≤ H2 < 4.5mm, on the one hand, it avoids the protective bracket 3 being too small along the first direction, resulting in a gap between the protective bracket 3 and the electrode assembly after assembly, so that the electrode assembly will still have a small amount of movement during thermal runaway. On the other hand, it avoids the protective bracket 3 being too large along the first direction, resulting in the protective bracket 3 occupying too much space in the cavity, thus restricting and compressing the volume of the electrode assembly, leading to a decrease in energy density.

[0044] In the lithium iron phosphate battery system, the height dimension H2 of the protective bracket 3 along the first direction can be any value between 3mm and 4.5mm or any range between two values, such as 3mm, 3.5mm, 4mm, 4.5mm, etc.

[0045] In this embodiment, the ternary nickel-cobalt-manganese lithium battery system and the lithium iron phosphate battery system are defined separately because the chemical reaction during thermal runaway is more intense in the ternary nickel-cobalt-manganese lithium battery system, resulting in a large amount of gas production and a high gas production rate, and the electrode assembly exerts a greater impact on the protective support 3. In contrast, the chemical reaction during thermal runaway is more moderate in the lithium iron phosphate battery system, resulting in a smaller amount of gas production and a slower gas production rate, and the electrode assembly exerts a smaller impact on the protective support 3. Therefore, due to the different impact forces exerted by the electrode assembly on the protective support 3 in the two systems, the fixing strength of the electrode assembly on the protective support 3 also differs to a certain extent. By defining different ranges for the height dimension of the protective support 3 along the first direction in different systems, it is possible to ensure that the protective support 3 has sufficient fixing strength on the electrode assembly under the current system, thereby avoiding dimensional redundancy and material waste.

[0046] In this embodiment, to verify the ratio between the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 and the cross-sectional area S of the electrode group, the ratio between the total effective area S2 of the multiple exhaust holes 33 for gas flow and the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1, and the height dimension H1 of the protective bracket 3 along the first direction during thermal runaway in the ternary nickel-cobalt-manganese lithium battery system, as shown in Table 1, two sets of embodiments and eight sets of comparative examples are provided for verification.

[0047] Table 1

[0048]

[0049] In Example 1, the cross-sectional area S of the electrode assembly is set to 5700 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 1500 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 600 mm. 2 The height dimension H1 of the protective bracket 3 along the first direction is set to 4.5mm. At this time, the thermal runaway safety test result is qualified, the explosion-proof valve 2 exhausts smoothly, and the exhaust effect is not affected.

[0050] In Example 2, the cross-sectional area S of the electrode assembly is set to 5700 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 1500 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 650 mm. 2 The height dimension H1 of the protective bracket 3 along the first direction is set to 4.5mm. At this time, the thermal runaway safety test result is qualified, the explosion-proof valve 2 exhausts smoothly, and the exhaust effect is not affected.

[0051] As can be seen from Examples 1 and 2, when the ratio between the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 and the cross-sectional area S of the pole group satisfies the range of 25% ≤ S1 / S < 40%, there is sufficient contact area between the support plate 32 and the pole group. This not only provides a good fixing effect on the pole group but also reduces the pressure applied to the support plate 32, preventing deformation of the support plate 32 due to excessive pressure. When the ratio between the total effective area S2 of the multiple exhaust holes 33 used for gas flow and the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 satisfies the range of 40% ≤ S2 / S1 < 60%, the exhaust holes 33 are both... This ensures the flow rate of pressurized gas through the protective bracket 3 while also guaranteeing that the protective bracket 3 has sufficient structural strength to withstand the impact of the electrode assembly on the protective bracket 3, preventing deformation of the protective bracket 3 due to its weak structural strength. When the height dimension H1 of the protective bracket 3 along the first direction meets the range of 4.5mm≤H1<6mm, there is no gap between the assembled protective bracket 3 and the electrode assembly. In the ternary nickel-cobalt-manganese lithium battery system where the chemical reaction is relatively violent, the protective bracket 3 has sufficient fixing strength to the electrode assembly, so that the electrode assembly is prevented from blocking the exhaust passage of the explosion-proof valve 2 during thermal runaway. The explosion-proof valve 2 exhausts smoothly, and the exhaust effect is not affected, thus passing the thermal runaway safety test.

[0052] In Comparative Example 1, the cross-sectional area S of the electrode assembly is set to 5700 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 1300 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 530 mm. 2 The height dimension H1 of the protective bracket 3 along the first direction is set to 4.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0053] In Comparative Example 2, the cross-sectional area S of the electrode assembly is set to 5700 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 1400 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 580 mm. 2 The height dimension H1 of the protective bracket 3 along the first direction is set to 4.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0054] As can be seen from Comparative Examples 1 and 2, when the ratio between the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 and the cross-sectional area S of the electrode group does not meet the range of 25% ≤ S1 / S < 40%, the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is too small, resulting in a small contact area between the support plate 32 and the electrode group. As a result, when the thermal runaway electrode group impacts the protective bracket 3, the pressure borne by the support plate 32 is too large, causing the support plate 32 to deform. This results in a gap between the protective bracket 3 and the electrode group, causing the electrode group to move during thermal runaway, which in turn blocks the explosion-proof valve 2, obstructs the exhaust, and makes the exhaust effect of the explosion-proof valve 2 unsmooth. This affects the exhaust effect to a certain extent, thus failing the thermal runaway safety test.

[0055] In Comparative Example 3, the cross-sectional area S of the electrode assembly is set to 5700 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 1500 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 930 mm. 2 The height dimension H1 of the protective bracket 3 along the first direction is set to 4.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0056] In Comparative Example 4, the cross-sectional area S of the electrode assembly is set to 5700 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 1500 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 950 mm. 2 The height dimension H1 of the protective bracket 3 along the first direction is set to 4.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0057] As can be seen from Comparative Examples 3 and 4, when the ratio between the total effective area S2 of the multiple vent holes 33 used for gas flow and the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is greater than the maximum value of 40% ≤ S2 / S1 < 60%, the total effective area S2 of the multiple vent holes 33 used for gas flow is too large, which significantly reduces the structural strength of the protective bracket 3. As a result, during thermal runaway, the protective bracket 3 cannot withstand the impact force of the electrode group on the protective bracket 3 and deforms, thus creating a gap between the protective bracket 3 and the electrode group. This causes the electrode group to move during thermal runaway, thereby blocking the explosion-proof valve 2, obstructing the exhaust, and making the exhaust effect of the explosion-proof valve 2 not smooth. As a result, the exhaust effect is affected to a certain extent, and the thermal runaway safety test cannot be passed.

[0058] In Comparative Example 5, the cross-sectional area S of the electrode assembly is set to 5700 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 1500 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 550 mm. 2 The height dimension H1 of the protective bracket 3 along the first direction is set to 4.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0059] In Comparative Example 6, the cross-sectional area S of the electrode assembly is set to 5700 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 1500 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 500 mm. 2 The height dimension H1 of the protective bracket 3 along the first direction is set to 4.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0060] As can be seen from Comparative Examples 5 and 6, when the ratio between the total effective area S2 of the multiple vent holes 33 for gas flow and the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is less than the minimum value of 40% ≤ S2 / S1 < 60%, the total effective area S2 of the multiple vent holes 33 for gas flow is too small, causing the pressurized gas to be blocked by the protective bracket 3 when passing through the protective bracket 3, thereby slowing down the flow speed of the pressurized gas. As a result, during thermal runaway, the exhaust is obstructed, the explosion-proof valve 2 does not exhaust smoothly, and the exhaust effect is affected to a certain extent, thus failing the thermal runaway safety test.

[0061] In Comparative Example 7, the cross-sectional area S of the electrode assembly is set to 5700 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 1500 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 600 mm. 2 The height dimension H1 of the protective bracket 3 along the first direction is set to 4.0mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0062] In Comparative Example 8, the cross-sectional area S of the electrode assembly is set to 5700 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 1600 mm. 2The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 600 mm. 2 The height dimension H1 of the protective bracket 3 along the first direction is set to 3.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0063] As can be seen from Comparative Examples 7 and 8, when the height dimension H1 of the protective bracket 3 along the first direction does not meet the range of 4.5mm≤H1<6mm, there is a gap between the assembled protective bracket 3 and the electrode assembly. In the ternary nickel-cobalt-manganese lithium battery system where the chemical reaction is relatively intense, the protective bracket 3 has a poor fixing effect on the electrode assembly, thus failing to effectively fix the electrode assembly. This causes the electrode assembly to move during thermal runaway, which in turn blocks the explosion-proof valve 2, obstructs the exhaust, and makes the exhaust of the explosion-proof valve 2 unsmooth, affecting the exhaust effect to a certain extent, thus failing the thermal runaway safety test.

[0064] In this embodiment, to verify the ratio between the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 and the cross-sectional area S of the electrode group, the ratio between the total effective area S2 of the multiple exhaust holes 33 for gas flow and the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1, and the height dimension H2 of the protective bracket 3 along the first direction during thermal runaway in the lithium iron phosphate battery system, as shown in Table 2, two sets of embodiments and eight sets of comparative examples are provided for verification.

[0065] Table 2

[0066]

[0067] In Example 3, the cross-sectional area S of the electrode assembly is set to 2500 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 700 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 300 mm. 2 The height dimension H2 of the protective bracket 3 along the first direction is set to 3.5mm. At this time, the thermal runaway safety test result is qualified, the explosion-proof valve 2 exhausts smoothly, and the exhaust effect is not affected.

[0068] In Example 4, the cross-sectional area S of the electrode assembly is set to 2500 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 700 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 350 mm. 2The height dimension H2 of the protective bracket 3 along the first direction is set to 3.5mm. At this time, the thermal runaway safety test result is qualified, the explosion-proof valve 2 exhausts smoothly, and the exhaust effect is not affected.

[0069] As can be seen from Examples 3 and 4, when the ratio between the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 and the cross-sectional area S of the pole group satisfies the range of 25% ≤ S1 / S < 40%, there is sufficient contact area between the support plate 32 and the pole group. This not only provides a good fixing effect on the pole group but also reduces the pressure applied to the support plate 32, preventing deformation of the support plate 32 due to excessive pressure. When the ratio between the total effective area S2 of the multiple exhaust holes 33 used for gas flow and the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 satisfies the range of 40% ≤ S2 / S1 < 60%, the exhaust holes 33... This design ensures both the flow rate of pressurized gas through the protective bracket 3 and sufficient structural strength to withstand the impact of the electrode assembly on the protective bracket 3, preventing deformation due to weak structural strength. When the height dimension H2 of the protective bracket 3 along the first direction meets the range of 3mm≤H2<4.5mm, there is no gap between the assembled protective bracket 3 and the electrode assembly. In the relatively mild chemical reaction of lithium iron phosphate battery system, the protective bracket 3 has sufficient fixing strength to the electrode assembly, preventing the electrode assembly from blocking the exhaust passage of the explosion-proof valve 2 during thermal runaway. The explosion-proof valve 2 can exhaust smoothly without affecting the exhaust effect, thus passing the thermal runaway safety test.

[0070] In Comparative Example 9, the cross-sectional area S of the electrode assembly is set to 2500 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 500 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 200 mm. 2 The height dimension H2 of the protective bracket 3 along the first direction is set to 3.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0071] In Comparative Example 10, the cross-sectional area S of the electrode assembly is set to 2500 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 600 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 250 mm. 2 The height dimension H2 of the protective bracket 3 along the first direction is set to 3.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0072] As can be seen from Comparative Examples 9 and 10, when the ratio between the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 and the cross-sectional area S of the pole group does not meet the range of 25% ≤ S1 / S < 40%, the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is too small, resulting in a small contact area between the support plate 32 and the pole group. As a result, when the thermal runaway pole group impacts the protective bracket 3, the pressure borne by the support plate 32 is too large, causing the support plate 32 to deform. This results in a gap between the protective bracket 3 and the pole group, causing the pole group to move during thermal runaway, which in turn blocks the explosion-proof valve 2, obstructs the exhaust, and makes the exhaust effect of the explosion-proof valve 2 unsmooth. This affects the exhaust effect to a certain extent, thus failing the thermal runaway safety test.

[0073] In Comparative Example 11, the cross-sectional area S of the electrode assembly is set to 2500 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 700 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 440 mm. 2 The height dimension H2 of the protective bracket 3 along the first direction is set to 3.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0074] In Comparative Example 12, the cross-sectional area S of the electrode assembly is set to 2500 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 700 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 450 mm. 2 The height dimension H2 of the protective bracket 3 along the first direction is set to 3.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0075] As can be seen from Comparative Examples 11 and 12, when the ratio between the total effective area S2 of the multiple vent holes 33 for gas flow and the projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is greater than the maximum value of 40% ≤ S2 / S1 < 60%, the total effective area S2 of the multiple vent holes 33 for gas flow is too large, which significantly reduces the structural strength of the protective bracket 3. As a result, during thermal runaway, the protective bracket 3 cannot withstand the impact force of the electrode group on the protective bracket 3 and deforms, thus creating a gap between the protective bracket 3 and the electrode group. This causes the electrode group to move during thermal runaway, thereby blocking the explosion-proof valve 2. As a result, during thermal runaway, the exhaust is obstructed, the explosion-proof valve 2 does not exhaust smoothly, and the exhaust effect is affected to a certain extent, thus failing the thermal runaway safety test.

[0076] In Comparative Example 13, the cross-sectional area S of the electrode assembly is set to 2500 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 700 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 270 mm. 2 The height dimension H2 of the protective bracket 3 along the first direction is set to 3.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0077] In Comparative Example 14, the cross-sectional area S of the electrode assembly is set to 2500 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 700 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 260 mm. 2 The height dimension H2 of the protective bracket 3 along the first direction is set to 3.0mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0078] As can be seen from Comparative Examples 13 and 14, when the ratio between the total effective area S2 of the multiple vent holes 33 for gas flow and the projected area S1 of the support plate 32 on the outer shell body or cover plate body 1 along the first direction is less than the minimum value of 40% ≤ S2 / S1 < 60%, the total effective area S2 of the multiple vent holes 33 for gas flow is too small, causing the pressurized gas to be blocked by the protective bracket 3 when passing through the protective bracket 3, thereby slowing down the flow speed of the pressurized gas. As a result, during thermal runaway, the exhaust is obstructed, the explosion-proof valve 2 does not exhaust smoothly, and the exhaust effect is affected to a certain extent, thus failing the thermal runaway safety test.

[0079] In Comparative Example 15, the cross-sectional area S of the electrode assembly is set to 2500 mm.2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 700 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 300 mm. 2 The height dimension H2 of the protective bracket 3 along the first direction is set to 2.5mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0080] In Comparative Example 16, the cross-sectional area S of the electrode assembly is set to 2500 mm. 2 The projected area S1 of the support plate 32 along the first direction on the outer shell body or cover plate body 1 is set to 700 mm. 2 The total effective area S2 of multiple exhaust holes 33 for gas flow is set to 300 mm. 2 The height dimension H2 of the protective bracket 3 along the first direction is set to 2.0mm. At this time, the thermal runaway safety test result is unqualified, the explosion-proof valve 2 exhaust is not smooth, and the exhaust effect is affected.

[0081] As can be seen from Comparative Examples 15 and 16, when the height dimension H2 of the protective bracket 3 along the first direction does not meet the range of 3mm≤H2<4.5mm, there is a gap between the assembled protective bracket 3 and the electrode assembly. In the lithium iron phosphate battery system where the chemical reaction is relatively mild, the protective bracket 3 has a poor fixing effect on the electrode assembly, thus failing to effectively fix the electrode assembly. This causes the electrode assembly to move around 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.

[0082] Optionally, such as Figure 3 As shown, the protective bracket 3 is mounted on the outer shell body, and / or the cover plate body 1 has a mounting through hole, which is located within the projection of the support plate 32 onto the outer shell body or the cover plate body 1. By setting the protective bracket 3 on the outer shell body, and / or the cover plate body 1 having a mounting through hole, and making the mounting through hole located within the projection of the support plate 32 onto the outer shell body or the cover plate body 1, the protective bracket 3 not only fixes the electrode assembly, but also protects the inside of the explosion-proof valve 2 facing the receiving cavity, preventing internal components from damaging the explosion-proof valve 2 and thus affecting the opening pressure of the explosion-proof valve 2.

[0083] Optionally, such as Figure 4As shown, the battery casing includes multiple protective supports 3, with multiple protective supports 3 symmetrically distributed at intervals on both sides of the mounting through-hole along the second direction. By symmetrically arranging multiple protective supports 3 on both sides of the mounting through-hole along the second direction, the impact force on the protective supports 3 during thermal runaway is distributed among multiple protective supports 3, thereby preventing a single protective support 3 from being unable to withstand the impact force of the electrode group during thermal runaway, which would cause the protective support 3 to deform and reduce the fixing effect of the protective support 3 on the electrode group.

[0084] The number of protective brackets 3 can be freely set according to actual needs. In this embodiment, the battery casing includes two protective brackets 3, which are respectively set on both sides of the mounting through hole along the second direction.

[0085] Optionally, such as Figure 2 As shown, multiple connecting seats 31 are provided, and multiple connecting seats 31 are symmetrically distributed on both sides of the support plate 32 along the second direction and spaced apart along the third direction. One end of the multiple connecting seats 31 is connected to the cover plate body 1 and / or the outer shell body, and the support plate 32 is connected to the other end of the multiple connecting seats 31 to form an exhaust passage 34 between the support plate 32 and the outer shell body and / or the cover plate body 1. By connecting the support plate 32 to the other end of the connecting seats 31, the electrode assembly is fixed by the support plate 32, and the support plate 32 is also raised, so that an exhaust passage 34 for gas flow is formed between the support plate 32 and the cover plate body 1 or the outer shell body. It cooperates with the exhaust hole 33 opened on the support plate 32. In the event of thermal runaway, the pressurized gas can pass through the protective bracket 3 from different directions, avoiding the protective bracket 3 from obstructing the flow of pressurized gas, slowing down the flow speed of pressurized gas during discharge, and ensuring the efficiency and effect of exhaust.

[0086] Optionally, such as Figure 2 As shown, the connecting seat 31 includes a connecting part 311 and a fixing part 312. The connecting part 311 is vertically connected to the support plate 32, and the fixing part 312 is connected to the other end of the connecting part 311 and is parallel to the support plate 32. By providing the fixing part 312 parallel to the support plate 32, the contact area between the connecting seat 31 and the cover plate body 1 or the outer shell body is increased. This not only provides ample welding space for welding operations of the connecting seat 31, but also ensures sufficient connection strength between the connecting seat 31 and the cover plate body 1 or the outer shell body after connection.

[0087] 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.

[0088] 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, comprising an outer shell body and a cover plate body, the outer shell body having at least one opening, the cover plate body corresponding one-to-one with the opening of the outer shell body and closing the opening of the outer shell body to form a receiving cavity for accommodating an electrode assembly, the outer shell body and / or the cover plate body having a mounting through hole communicating with the receiving cavity; An explosion-proof valve is disposed in the mounting through hole and is used to release the pressurized gas inside the receiving cavity; A protective bracket is disposed within the receiving cavity and includes a connecting seat and a support plate. The connecting seat is connected to the outer shell body with the mounting through hole and / or the cover plate body. The support plate is connected to the connecting seat and abuts against the electrode assembly. The projected area of ​​the support plate on the outer shell body or the cover plate body along a first direction is S1, and the cross-sectional area of ​​the electrode assembly is S, satisfying 25%≤S1 / S<40%. The first direction is the height direction of the protective bracket. The support plate is also provided with multiple exhaust holes, and the total effective area of ​​the multiple exhaust holes for gas flow is S2, which satisfies 40%≤S2 / S1<60%.

2. The battery casing according to claim 1, characterized in that, 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 4.5mm≤H1<6mm.

3. The battery casing according to claim 1, characterized in that, In the lithium iron phosphate battery system, the height dimension of the protective bracket along the first direction is H2, and it satisfies 3mm≤H2<4.5mm.

4. The battery casing according to claim 1, characterized in that, The protective bracket is mounted on the outer shell body, and / or the cover plate body has the mounting through hole, the mounting through hole being located within the projection of the support plate on the outer shell body or the cover plate body.

5. The battery casing according to claim 1, characterized in that, The battery casing includes a plurality of protective brackets, and the mounting through holes are symmetrically distributed with a plurality of spaced protective brackets on both sides of a second direction, the second direction being the width direction of the protective brackets.

6. The battery casing according to claim 1, characterized in that, The vent hole can be a circular hole, a polygonal hole, or an elliptical hole.

7. The battery casing according to claim 1, characterized in that, The connecting seat is provided in multiple ways. The support plate has multiple connecting seats symmetrically distributed on both sides along the second direction and spaced apart along the third direction. One end of the multiple connecting seats is connected to the cover plate body and / or the outer shell body. The support plate is connected to the other end of the multiple connecting seats to form an exhaust passage between the support plate and the outer shell body and / or the cover plate body. The third direction is the length direction of the protective bracket.

8. The battery casing according to claim 1, characterized in that, The connecting seat includes a connecting part and a fixing part. The connecting part is vertically connected to the support plate, and the fixing part is connected to the other end of the connecting part and is parallel to the support plate.

9. A battery, characterized in that, The battery includes an electrode assembly and a battery casing as described in any one of claims 1-8, wherein the electrode assembly is disposed within the battery casing.

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