Square casing and square battery

Abstract

This application relates to the field of battery technology and provides a prismatic housing and a prismatic battery. The prismatic housing of this application includes a main body and a core disposed within the main body, the core supporting a wound battery cell. The core includes a main body portion connected to the main body and a telescopic portion disposed at at least one end of the main body portion along the length direction of the main body, and the telescopic portion is capable of telescoping relative to the main body portion along the length direction of the main body. By adjusting the length of the core, the prismatic housing of this application can not only accommodate different types of wound battery cells, improving the applicability of the prismatic housing, but also reduce battery manufacturing time, thereby improving battery production efficiency.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a square housing and a square battery. Background Technology

[0002] In related technologies, prismatic batteries typically include a casing, a wound cell housed within the casing, a cover plate disposed on the casing and sealing the wound cell, and an electrolyte injected into the casing. However, existing prismatic batteries often employ methods such as adjusting and controlling the winding tension, adding a buffer layer between the electrode and the separator, or pre-forming treatment to reduce the R-value of the electrode roll. These methods are cumbersome, time-consuming, and detrimental to improving battery production efficiency. Utility Model Content

[0003] In view of this, this application aims to provide a square housing that can improve battery production efficiency.

[0004] To achieve the above objectives, the technical solution of this application is implemented as follows: A square shell housing includes a shell body and a core disposed in the shell body, the core being used to support wound battery cells; The core includes a main body portion connected to the shell body, and a telescopic portion disposed at at least one end of the main body portion along the length direction of the shell body, and the telescopic portion is capable of telescopically extending or retracting relative to the main body portion along the length direction of the shell body.

[0005] Furthermore, the main body includes an inner tube connected to the shell body and an outer tube covering the inner tube, and the telescopic part is telescopically disposed in the inner tube; a cavity is formed between the inner tube and the outer tube, the cavity is filled with flame retardant, and the outer tube can rupture when a preset temperature is reached to release the flame retardant in the cavity.

[0006] Furthermore, the telescopic part includes a telescopic tube that is telescopically disposed in the inner tube. The telescopic tube is filled with flame retardant, and a cap is provided at the end of the telescopic tube away from the inner tube along the length direction of the shell body. The cap can be broken when a preset temperature is reached to release the flame retardant in the telescopic tube.

[0007] Furthermore, the outer tube and / or the cap are made of thermoplastic or thermosetting polymer materials to undergo heat melting at 100°C-400°C.

[0008] Furthermore, the telescopic tube is slidably disposed in the inner tube along the length direction of the shell body, and a locking component is provided between the telescopic tube and the inner tube.

[0009] Furthermore, the locking assembly includes a plurality of grooves provided on the telescopic tube and a locking protrusion provided on the inner tube; when the telescopic tube is subjected to external operation, the locking protrusion can be disengaged from each of the grooves to slide relative to the inner tube, and the locking protrusion can be engaged in a predetermined groove.

[0010] Furthermore, along the length direction of the shell body, the length L1 of the core and the length L2 of the shell body satisfy: 0.5≤L1 / L2≤0.8.

[0011] Furthermore, along the height direction of the shell body, the height H1 of the core and the height H2 of the shell body satisfy: 0.3≤H1 / H2≤0.6.

[0012] Furthermore, the telescopic length S of the telescopic portion relative to the main body portion satisfies: 40mm≤S≤80mm.

[0013] Compared with related technologies, this application has the following advantages: (1) The square shell described in this application, by setting a telescopic part, and the telescopic part can extend and retract relative to the main body along the length direction of the shell body, can realize the length adjustment of the core. It can not only adapt to different types of wound cells and improve the applicability of the square shell, but also the length adjustment operation of the core is simple and convenient, which can also reduce the battery preparation time, thereby improving the battery production efficiency.

[0014] (2) The main body includes an inner tube and an outer tube, and the cavity formed between the inner tube and the outer tube is filled with flame retardant. The outer tube can break when the preset temperature is reached to release the flame retardant in the cavity, which can prevent thermal runaway in time and reduce battery safety risks.

[0015] (3) The telescopic tube is filled with flame retardant, and the cap of the telescopic tube can break when the preset temperature is reached, so as to release the flame retardant in the telescopic tube, which can prevent thermal runaway in time and thus improve the battery safety performance.

[0016] (4) The outer tube and the cap are made of thermoplastic or thermosetting polymer materials so that they can melt at 100℃-400℃. This allows the flame retardant to be released automatically when the internal temperature of the battery is abnormal, thus avoiding thermal runaway.

[0017] (5) By providing a locking component between the telescopic tube and the inner tube, the telescopic tube can be stabilized at a preset length, thereby improving the structural stability of the core.

[0018] (6) The locking assembly is mainly composed of several grooves and locking protrusions. It has a simple structure and can help improve the convenience of adjusting the length of the core.

[0019] (7) Along the length of the shell body, the length L1 of the core and the length L2 of the shell body satisfy: 0.5≤L1 / L2≤0.8. This can avoid the internal structure of the wound cell being too loose due to L1 being too small, and the electrode adhesion being reduced as the battery expands during cycling. At the same time, it can also avoid L1 being too large, resulting in low utilization of the internal space of the battery and affecting the improvement of the battery energy density.

[0020] (8) Along the height direction of the shell body, the height H1 of the core and the height H2 of the shell body satisfy: 0.3≤H1 / H2≤0.6. This can avoid H1 being too small, which would cause the R value at the top of the wound cell to be too large. At the same time, it can also avoid H1 being too large, which would exceed the width of the electrode in the wound cell, which would be of little significance and increase the cost, affecting the improvement of battery energy density.

[0021] (9) The telescopic length S of the telescopic part relative to the main body satisfies: 40mm≤S≤80mm, which can have a wider range of applications, so as to meet the needs of different types of wound cells at present.

[0022] This application also proposes a prismatic battery, which includes a prismatic housing as described above.

[0023] The prismatic battery described in this application has the aforementioned prismatic casing, which has the same beneficial effects as conventional technology, and will not be elaborated further here. Attached Figure Description

[0024] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a schematic diagram of the overall structure of the square shell described in the embodiments of this application; Figure 2 This is a partial structural schematic diagram of the square shell described in the embodiments of this application; Figure 3 for Figure 2 Enlarged view of point A in the middle; Figure 4 This is a schematic diagram of the main body described in the embodiments of this application; Figure 5 for Figure 1 Top view of the structure shown; Figure 6 for Figure 5 Sectional view along the BB direction; Figure 7 for Figure 6 Enlarged view of point C in the middle; Explanation of reference numerals in the attached figures: 100. Shell body; 101. Bottom wall; 102. First side wall; 103. Second side wall; 200. Core; 201. Main body; 2011. Inner tube; 20111. Locking protrusion; 2012. Outer tube; 2013. Cavity; 202. Telescopic part; 2021. Telescopic tube; 20211. Groove; 2022. Cover. Detailed Implementation

[0025] To make the technical solution and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0027] Furthermore, it should be noted that in the description of this application, if terms such as "upper," "lower," "inner," or "outer" appear, indicating orientation or positional relationship, these are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this application and simplifying the description, 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, and therefore should not be construed as a limitation on this application. In addition, if terms such as "first" or "second" appear, they are also used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] Furthermore, in the description of this application, unless otherwise expressly defined, the terms "installation," "connection," "joining," and "connector" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; 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; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application in light of the specific circumstances.

[0029] In this application, the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to a specific feature, structure, material, or characteristic described in connection with that embodiment or example, which is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0030] The present application will now be described in detail through exemplary embodiments. However, it should be understood that, without further description, elements, structures, and features in one embodiment may be advantageously incorporated into other embodiments.

[0031] An embodiment of the first aspect of this application provides a square housing that can not only adapt to different types of wound cells, improving applicability, but also reduce battery manufacturing time, thereby improving battery production efficiency.

[0032] In related technologies, prismatic batteries typically include a casing, wound cells housed within the casing, a cover plate disposed on the casing and sealing the wound cells, and electrolyte injected into the casing. However, existing prismatic batteries often employ methods such as adjusting and controlling the winding tension, adding a buffer layer between the electrode and the separator, or pre-forming treatment to reduce the R-value of the electrode roll. These methods are cumbersome, time-consuming, and detrimental to improving battery production efficiency.

[0033] In view of this, in order to overcome the shortcomings of related technologies, the square shell of this embodiment combines... Figures 1 to 7 As shown, the overall design includes a housing body 100 and a core 200 disposed within the housing body 100. The core 200 is used to support the wound battery cell and includes a main body portion 201 connected to the housing body 100, and a telescopic portion 202 disposed at at least one end of the main body portion 201 along the length direction of the housing body 100, and the telescopic portion 202 is capable of telescoping relative to the main body portion 201 along the length direction of the housing body 100.

[0034] Therefore, by setting the telescopic part 202, which can extend and retract relative to the main body 201 along the length direction of the shell body 100, the length of the core 200 can be adjusted. This not only adapts to different models of wound cells, improving the applicability of the square shell, but also makes the length adjustment of the core 200 simple and convenient, reducing battery manufacturing time and thus improving battery production efficiency. At the same time, the adjustable length of the core 200 can also help improve the radius of curvature of the inner electrode in the wound cell, reduce the bending stress of the electrode during winding, reduce the risk of wrinkles and active material shedding, make the electrode fit more tightly and the structure flatter, and thus allow the current to be conducted more evenly in the wound cell, avoiding the generation of local high resistance areas, thereby obtaining a suitable R value for the wound cell, thereby improving the battery's range, charging speed, power performance, safety performance and service life.

[0035] Based on the above overview, specifically, the R-value of the electrode roll, also known as the equivalent series resistance of the wound electrode roll, refers to the total resistance encountered by the current when conducting inside the electrode roll after the battery is wound (in the "electrode roll" state before encapsulation). It directly determines the battery's range, charging speed, power performance, safety level, and service life by affecting "energy loss, power output, thermal safety, and cycle stability".

[0036] Furthermore, when necessary, the electrode roll R-value can also be understood as follows: In the winding process, the wound cell (or the core of the cell) is formed by stacking and winding positive electrode sheets, negative electrode sheets, and separators to form a cylindrical or flat cylindrical structure similar to a "layer cake". The electrode roll R-value represents the ratio between the winding radii of different layers (positive electrode, negative electrode, separator), such as the ratio of the winding radius of the negative electrode sheet to the winding radius of the positive electrode sheet, or the ratio of the innermost winding radius to the outermost winding radius. In this embodiment, the wound cell refers to the wound electrode assembly, which can also be called a wound electrode roll. Therefore, the aforementioned electrode roll R-value can also be called the wound electrode assembly R-value or the wound cell R-value.

[0037] In some exemplary embodiments, improving the length of the core 200 can help improve the radius of curvature of the inner electrode in the wound cell to adapt to different types of wound cells, reduce the bending stress of the electrode during winding, reduce the risk of wrinkles and active material shedding, make the electrode fit more tightly and the structure flatter, and thus enable the current to be conducted more evenly in the wound cell, avoid the generation of local high resistance areas, and obtain a suitable R value for the wound cell. This ensures that the wound cell is at a suitable winding angle during long battery cycles, thereby improving the battery's range, charging speed, power performance, safety performance and service life.

[0038] Furthermore, continue to combine Figure 1 and Figure 2 As shown, in some exemplary embodiments, the shell body 100 of this embodiment includes a bottom wall 101, and a first side wall 102 and a second side wall 103 disposed on the bottom wall 101. Along the length direction of the shell body 100, the bottom wall 101 is provided with a second side wall 103 at both ends. Along the width direction of the shell body 100, the bottom wall 101 is provided with a first side wall 102 on both sides. The bottom wall 101, each first side wall 102 and each second side wall 103 form a receiving cavity for accommodating the wound battery core. Meanwhile, the main body portion 201 of the core 200 is specifically connected to the bottom wall 101.

[0039] Furthermore, the prismatic housing of this embodiment is particularly suitable for prismatic batteries, such as sodium-ion prismatic batteries and lithium-ion prismatic batteries. In specific implementations of the prismatic housing of this embodiment, in some exemplary embodiments, the two ends of the main body 201 along the length direction of the housing body 100 are respectively provided with telescopic portions 202, so that the length of both ends of the main body 201 can be adjusted.

[0040] Furthermore, in some exemplary embodiments, in order to adapt to a square housing that accommodates multiple wound cells, there are multiple cores 200 corresponding one-to-one with each wound cell, and depending on the specific spatial arrangement requirements within the square housing, the cores 200 may be arranged sequentially at intervals along the width direction of the housing body or sequentially at intervals along the length direction of the housing body, etc.

[0041] Continue to combine Figures 2 to 4 As shown, in some exemplary embodiments, the main body 201 includes an inner tube 2011 connected to the shell body 100, and an outer tube 2012 covering the inner tube 2011. A telescopic portion 202 is telescopically disposed within the inner tube 2011. Furthermore, a cavity 2013 is formed between the inner tube 2011 and the outer tube 2012, the cavity 2013 is filled with a flame retardant, and the outer tube 2012 is capable of rupturing upon reaching a preset temperature to release the flame retardant in the cavity 2013.

[0042] It is understood that the main body 201 includes an inner tube 2011 and an outer tube 2012, and a flame retardant is filled in the cavity 2013 formed between the inner tube 2011 and the outer tube 2012. The outer tube 2012 can rupture when a preset temperature is reached to release the flame retardant in the cavity 2013. The flame retardant can prevent thermal runaway in a timely manner, reduce battery safety risks, and thus improve battery safety performance.

[0043] At the same time, continue to combine Figure 3 As shown, in some exemplary embodiments, the telescopic portion 202 includes a telescopic tube 2021 telescopically disposed in the inner tube 2011, the telescopic tube 2021 being filled with a flame retardant, and a cap 2022 being provided at one end of the telescopic tube 2021 away from the inner tube 2011 along the length direction of the shell body 100. The cap 2022 is capable of rupturing when a preset temperature is reached to release the flame retardant in the telescopic tube 2021.

[0044] Here, by filling the telescopic tube 2021 with flame retardant and making the cap 2022 of the telescopic tube 2021 able to rupture when a preset temperature is reached to release the flame retardant in the telescopic tube 2021, thermal runaway can be prevented in time when the temperature is abnormal by releasing the flame retardant, thereby improving the battery safety performance.

[0045] In practice, the flame retardant can be selected according to the characteristics of the wound battery cell. It can be a flame retardant agent or material commonly used by those skilled in the art. For example, when the wound battery cell is a lithium-ion battery cell, a phosphorus-based organic flame retardant can be used. When the wound battery cell is a sodium-ion battery cell, a phosphorus-nitrogen synergistic flame retardant can be used.

[0046] Continue to combine Figures 1 to 3 As shown, in some exemplary embodiments, both the outer tube 2012 and the cap 2022 are made of thermoplastic or thermosetting polymer materials to undergo thermal melting at 100°C-400°C. This configuration allows for the automatic release of the flame retardant in the event of abnormal internal battery temperatures, preventing thermal runaway.

[0047] Specifically, the heat fusion temperature of the outer tube 2012 and the cap 2022 in this embodiment can be specifically set to 100°C, 200°C, 300°C or 400°C, etc. That is, the above-mentioned preset temperature can be specifically set to 100°C, 200°C, 300°C or 400°C, etc. Meanwhile, the so-called rupture refers to the crack formed in the outer tube 2012 and the cap 2022 due to heat fusion, which can release flame retardant.

[0048] In addition, continue to combine Figures 5 to 7 As shown, in some exemplary embodiments, the telescopic tube 2021 is slidably disposed in the inner tube 2011 along the length direction of the shell body 100, and a locking assembly is provided between the telescopic tube 2021 and the inner tube 2011.

[0049] By setting a locking component, it is possible to lock and fix the telescopic tube 2021 after it has been extended or retracted, that is, to stabilize the telescopic tube 2021 at a preset length, thereby improving the structural stability of the core 200.

[0050] In specific implementations, in some exemplary embodiments, the locking assembly includes a plurality of grooves 20211 provided on the telescopic tube 2021 and locking protrusions 20111 provided on the inner tube 2011. Furthermore, when the telescopic tube 2021 is subjected to external operation, the locking protrusions 20111 can disengage from each groove 20211 to slide relative to the inner tube 2011, and the locking protrusions 20111 can engage in the predetermined grooves 20211.

[0051] The term "accessible to external operation" here means that the operator can pull the telescopic tube 2021 to disengage the locking protrusion 20111 from the groove 20211. To lock the telescopic tube 2021, simply drag it to the preset position, and then insert the locking protrusion 20111 into the groove 20211 corresponding to the preset position. The locking assembly is mainly composed of several grooves 20211 and locking protrusions 20111, which has a simple structure and can also improve the convenience of adjusting the length of the core 200.

[0052] In addition, continue to combine Figure 6 As shown, in some exemplary embodiments, along the length direction of the shell body 100, the length L1 of the core 200 and the length L2 of the shell body 100 satisfy: 0.5 ≤ L1 / L2 ≤ 0.8, and can specifically take values ​​of 0.5, 0.6, 0.7, or 0.8, etc. This avoids L1 being too small, resulting in a loose internal structure of the wound cell, causing a decrease in electrode adhesion due to volume expansion during battery cycling. At the same time, it also avoids L1 being too large, leading to low utilization of the battery's internal space and affecting the improvement of battery energy density.

[0053] Meanwhile, in some exemplary embodiments, along the height direction of the shell body 100, the height H1 of the core 200 and the height H2 of the shell body 100 satisfy: 0.3 ≤ H1 / H2 ≤ 0.6, and can specifically take values ​​of 0.3, 0.4, 0.5, or 0.6. The main advantage of this setting is that it avoids H1 being too small, which would lead to an excessively large R value at the top of the wound cell; at the same time, it also avoids H1 being too large, exceeding the width of the electrode in the wound cell, which would be meaningless, increase costs, and affect the improvement of battery energy density.

[0054] In addition, in some exemplary embodiments, the telescopic length S of the telescopic portion 202 relative to the main body portion 201 satisfies: 40mm≤S≤80mm, and may specifically take the values ​​of 40mm, 60mm, 70mm or 80mm.

[0055] It is understandable that by ensuring that the telescopic length S of the telescopic part 202 relative to the main body 201 satisfies 40mm≤S≤80mm, it can have a wider range of applications, which is conducive to meeting the needs of different types of wound battery cells at present.

[0056] Furthermore, to adapt to the wound battery cell, in some exemplary embodiments, the thickness t of the main body portion 201 along the width direction of the housing body 100 satisfies: 5mm≤t≤7mm, and can specifically be 5mm, 6mm or 7mm, for example. Meanwhile, the adjustable radius of curvature of the core body 200 is between 6-10mm, and can specifically be 6mm, 8mm or 10mm, for example, to facilitate the wound battery cell having a reasonable R value.

[0057] It is worth noting that, regarding the square shell casing of this embodiment, based on the above exemplary embodiments, in specific implementation, as a preferred embodiment, it is still composed of... Figures 1 to 7 As shown, it includes a shell body 100 and a core 200 disposed in the shell body 100.

[0058] The core 200 is used to support the wound battery cell. The core 200 includes a main body portion 201 connected to the shell body 100, and a telescopic portion 202 disposed at at least one end of the main body portion 201 along the length direction of the shell body 100. The telescopic portion 202 is capable of telescopically extending or retracting relative to the main body portion 201 along the length direction of the shell body 100.

[0059] The main body 201 includes an inner tube 2011 connected to the shell body 100, and an outer tube 2012 covering the inner tube 2011. A telescopic part 202 is telescopically disposed in the inner tube 2011. A cavity 2013 is formed between the inner tube 2011 and the outer tube 2012. The cavity 2013 is filled with a flame retardant, and the outer tube 2012 can rupture when a preset temperature is reached to release the flame retardant in the cavity 2013.

[0060] The telescopic part 202 includes a telescopic tube 2021 that is telescopically disposed in the inner tube 2011. The telescopic tube 2021 is filled with flame retardant, and a cap 2022 is provided at the end of the telescopic tube 2021 away from the inner tube 2011 along the length direction of the shell body 100. The cap 2022 can rupture when a preset temperature is reached to release the flame retardant in the telescopic tube 2021.

[0061] The outer tube 2012 and the cap 2022 are both made of thermoplastic or thermosetting polymer materials so that they can melt at 100℃-400℃.

[0062] The telescopic tube 2021 is slidably disposed in the inner tube 2011 along the length of the shell body 100, and a locking component is provided between the telescopic tube 2021 and the inner tube 2011.

[0063] The locking assembly includes several grooves 20211 on the telescopic tube 2021 and locking protrusions 20111 on the inner tube 2011. When the telescopic tube 2021 is subjected to external operation, the locking protrusions 20111 can disengage from each groove 20211 to slide relative to the inner tube 2011 and engage with the predetermined grooves 20211.

[0064] Among them, along the length direction of the shell body 100, the length L1 of the core 200 and the length L2 of the shell body 100 satisfy: 0.5≤L1 / L2≤0.8.

[0065] Among them, along the height direction of the shell body 100, the height H1 of the core 200 and the height H2 of the shell body 100 satisfy: 0.3≤H1 / H2≤0.6.

[0066] The telescopic length S of the telescopic part 202 relative to the main body 201 satisfies: 40mm≤S≤80mm.

[0067] In the preferred embodiment of the shell, the specific configuration and arrangement of the shell body 100, core 200, inner tube 2011, outer tube 2012, telescopic tube 2021, cover 2022, locking components, etc., can still be referred to the descriptions in the above exemplary embodiments. Furthermore, in this preferred embodiment, the beneficial effects brought about by the design of the shell body 100, core 200, inner tube 2011, outer tube 2012, telescopic tube 2021, cover 2022, locking components, etc., can also be referred to the descriptions in the above exemplary embodiments.

[0068] The square shell housing of this embodiment, with the above design, allows for length adjustment of the core 200. This not only adapts to different models of wound cells, improving the applicability of the square shell housing, but also simplifies and facilitates the length adjustment operation of the core 200, reducing battery manufacturing time and thus improving battery production efficiency. Simultaneously, the adjustable length of the core 200 also helps to improve the radius of curvature of the inner electrode sheets in the wound cell, reducing the bending stress of the electrode sheets during winding. This reduces the risk of wrinkles and active material shedding, resulting in tighter electrode adhesion and a flatter structure. Consequently, current can be conducted more evenly within the wound cell, avoiding the formation of localized high-resistance areas, and achieving a suitable R-value for the wound cell. This, in turn, improves the battery's range, charging speed, power performance, safety performance, and lifespan.

[0069] An embodiment of the second aspect of this application provides a prismatic battery, which includes the prismatic housing described in the above embodiments.

[0070] Specifically, in some exemplary embodiments, the prismatic battery of this embodiment includes a wound cell disposed in a cavity of the prismatic housing, a cover plate disposed on the prismatic housing to seal the wound cell 2022 in the cavity, and an electrolyte filling the cavity.

[0071] The square-shell battery of this embodiment, by setting the square shell as described in the above embodiment, has the same beneficial effects as the traditional technology, and will not be described in detail here.

[0072] The above descriptions are merely some embodiments of this application and are not intended to limit this application. The technical features or structures in the foregoing different embodiments can be arbitrarily combined to form other specific technical solutions as needed. For those skilled in the art, this application can have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of the claims of this application.

Claims

1. A square shell, characterized in that: It includes a shell body and a core disposed in the shell body, the core being used to support the wound battery cell; The core includes a main body portion connected to the shell body, and a telescopic portion disposed at at least one end of the main body portion along the length direction of the shell body, and the telescopic portion is capable of telescopically extending or retracting relative to the main body portion along the length direction of the shell body.

2. The square shell according to claim 1, characterized in that: The main body includes an inner tube connected to the shell body and an outer tube covering the inner tube, and the telescopic part is telescopically disposed in the inner tube; A cavity is formed between the inner tube and the outer tube, the cavity is filled with flame retardant, and the outer tube can rupture when a preset temperature is reached to release the flame retardant in the cavity.

3. The square shell according to claim 2, characterized in that: The telescopic part includes a telescopic tube that is telescopically disposed in the inner tube. The telescopic tube is filled with flame retardant, and a cap is provided at the end of the telescopic tube away from the inner tube along the length direction of the shell body. The cap can be broken when a preset temperature is reached to release the flame retardant in the telescopic tube.

4. The square shell according to claim 3, characterized in that: The outer tube and / or the cap are made of thermoplastic or thermosetting polymer materials to undergo heat melting at 100°C-400°C.

5. The square shell according to claim 3, characterized in that: The telescopic tube is slidably disposed in the inner tube along the length direction of the shell body, and a locking component is provided between the telescopic tube and the inner tube.

6. The square shell according to claim 5, characterized in that: The locking assembly includes several grooves on the telescopic tube and locking protrusions on the inner tube; When the telescopic tube is used for external operation, it can disengage the locking protrusion from each of the grooves to slide relative to the inner tube, and engage the locking protrusion in the predetermined groove.

7. The square shell according to claim 1, characterized in that: Along the length of the shell body, the length L1 of the core and the length L2 of the shell body satisfy: 0.5≤L1 / L2≤0.

8.

8. The square shell according to claim 1, characterized in that: Along the height direction of the shell body, the height H1 of the core and the height H2 of the shell body satisfy: 0.3≤H1 / H2≤0.

6.

9. The square shell according to any one of claims 1 to 8, characterized in that: The telescopic length S of the telescopic part relative to the main body satisfies: 40mm≤S≤80mm.

10. A prismatic battery, characterized in that: The square shell as described in any one of claims 1 to 9.

Images