Secondary battery

Abstract

The utility model provides a secondary battery, which relates to the technical field of new energy, and comprises a battery cell shell and a top cover plate assembly, the first inner wall is provided with at least one first interval bulge, and the first interval bulge is used for abutting against the battery cell assembly, so that an ascending channel is formed between the battery cell assembly and the inner wall of the battery cell shell. According to the secondary battery provided by the utility model, the first interval bulges arranged on the battery cell shell can play a role in fixing the battery cell component, so that the battery cell component does not shake, and the first interval bulges enable the ascending channel to be formed between the battery cell component and the first inner wall of the battery cell shell, so that when the battery cell component generates a large amount of gas, the ascending channel is blocked, and the battery cell component is prevented from shaking. Gas at the lower end of the battery cell assembly can flow upwards through the ascending channel; the explosion caused by ultrahigh internal air pressure due to serious air blockage caused by the fact that gas cannot be smoothly discharged from the secondary battery is prevented; the explosion-proof capability of the high-capacity battery cell shell is improved, and the thermal runaway failure risk of the battery is effectively reduced.

Description

Technical Field

[0001] This utility model relates to the field of new energy technology, and in particular to a secondary battery. Background Technology

[0002] Global demand for high-capacity energy storage batteries is growing, particularly in the commercial and industrial energy storage market. With the widening gap between peak and off-peak electricity prices and the decreasing cost of lithium batteries, the economic viability of commercial and industrial energy storage is becoming increasingly apparent, making it the fastest-growing segment. Driven by increasing market demand and technological advancements, technological iteration in the energy storage battery field is accelerating. All cell manufacturers have achieved mass production and delivery of cells with capacities exceeding 310Ah, enabling 20-foot single-cell batteries to reach capacities of 5MWh or even 6MWh. This technological progress not only improves the integrated capacity and efficiency of energy storage systems but also meets the market's demand for highly integrated, high-efficiency, and low-cost energy storage products. However, as energy storage cell capacity increases, so do the safety risks.

[0003] Currently, lithium-ion batteries are widely used in both power and energy storage batteries. However, people still fear battery spontaneous combustion and explosions, and battery safety remains an unavoidable topic in the industry. Thermal runaway is a major focus of research on improving the safety of lithium-ion batteries. Battery thermal runaway refers to a chain reaction phenomenon triggered by various factors. It begins with the decomposition of the SEI film at the negative electrode within the battery cell, followed by the decomposition and melting of the separator, causing a reaction between the negative electrode and the electrolyte. Subsequently, the positive electrode and electrolyte decompose, leading to a large-scale internal short circuit, causing electrolyte combustion, which then spreads to other cells, resulting in severe thermal runaway and causing the entire battery pack to spontaneously combust. The exterior of a large-capacity battery cell is composed of a high-strength, corrosion-resistant aluminum shell and a cover plate with positive and negative terminals, an explosion-proof valve, and an injection hole, all tightly welded together.

[0004] The battery's aluminum casing is equipped with a special explosion-proof device (explosion-proof valve), which is crucial for ensuring the battery cell passes thermal runaway testing. In the event of excessive pressure due to a large amount of gas generated inside the cell, the explosion-proof device will automatically open to release pressure and prevent an explosion. Through extensive routine thermal runaway testing and analysis of failure causes, we have found that the internal structure of the aluminum casing also significantly affects the leakage of gas from inside the battery cell. Utility Model Content

[0005] The purpose of this invention is to provide a secondary battery to alleviate the technical problem of the battery's internal structure affecting gas leakage efficiency.

[0006] This utility model provides a secondary battery, including a cell housing, a cell assembly, and a top cover assembly; the cell housing has an upper opening, and the cell assembly is assembled into the cell housing through the upper opening;

[0007] The top cover assembly is assembled at the upper opening. The inner walls at both ends of the battery cell housing in the first direction are the first inner walls. At least one first spacer protrusion is provided on the first inner wall. The first spacer protrusion is used to abut against the battery cell assembly, so that an upward channel is formed between the battery cell assembly and the first inner wall of the battery cell housing.

[0008] The first direction is the length direction of the top cover assembly.

[0009] In an optional embodiment, the battery cell assembly includes two battery cells, and the battery cells are square battery cells.

[0010] In an optional embodiment, at least two first spacer protrusions are provided on the first inner wall of the battery cell housing, and one end of each battery cell in a first direction abuts against at least one of the first spacer protrusions.

[0011] In an optional embodiment, four first spacer protrusions are provided on the first inner wall, and one end of each of the battery cells in the first direction abuts against two of the first spacer protrusions.

[0012] In an optional embodiment, the outer side wall of the battery cell housing is provided with a stamping hole, which causes the inner side wall of the battery cell housing to form the first spacer protrusion.

[0013] In an optional embodiment, the surface of the first spacer protrusion that abuts against the cell assembly is an arc surface.

[0014] In an optional embodiment, the battery cell assembly is wrapped with an insulating sheet, the insulating sheet having a plurality of wetting holes, and the wetting holes being located at the lower end of the battery cell assembly;

[0015] A support pad is provided inside the battery cell housing, and the support pad is located at the lower end of the battery cell assembly.

[0016] In an optional embodiment, a plurality of first guide grooves are provided on the upper surface of the support pad, and the first guide grooves extend along a first direction.

[0017] In an optional embodiment, a plurality of second guide grooves are provided on the lower end surface of the support pad, and the second guide grooves are staggered with the first guide grooves.

[0018] In an optional embodiment, the inner walls at both ends of the battery cell housing in the second direction are the second inner walls, and at least one second spacer protrusion is provided on the second inner wall, the second spacer protrusion abutting against the battery cell assembly.

[0019] The second direction is the width direction of the top cover assembly.

[0020] The first spacer protrusion on the cell casing of the secondary battery provided by this utility model can fix the cell assembly, preventing it from shaking. The first spacer protrusion also forms an upward channel between the cell assembly and the first inner wall of the cell casing. When the cell assembly generates a large amount of gas, the gas at the lower end of the cell assembly can flow upward through the upward channel. This prevents the secondary battery from being severely blocked due to the inability of gas to be discharged smoothly, which could lead to excessive internal pressure and even an explosion. It also improves the explosion-proof capability of the large-capacity cell casing and effectively reduces the risk of battery thermal runaway failure. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the internal structure of a secondary battery provided in an embodiment of the present utility model;

[0023] Figure 2 for Figure 1 The diagram shows the structure of the insulating component of the secondary battery cell assembly.

[0024] Figure 3 This is a schematic diagram of the structure of the cell casing of the secondary battery provided in an embodiment of the present utility model;

[0025] Figure 4 A schematic diagram of the structure of the support pad for the secondary battery provided in an embodiment of this utility model;

[0026] Figure 5 for Figure 4 A partial enlarged view of support pad A shown.

[0027] Icons: 100-Top cover assembly; 200-Cell assembly; 201-Insulating sheet; 202-Immersion hole; 300-Support pad; 301-First guide groove; 302-Second guide groove; 400-Cell housing; 500-First spacer protrusion; 600-Punching hole. Detailed Implementation

[0028] The terms “first,” “second,” “third,” etc., are used only for distinguishing descriptions and do not indicate a sequence number, nor should they be interpreted as indicating or implying relative importance.

[0029] Furthermore, terms such as "horizontal," "vertical," and "sag" do not imply that components must be absolutely horizontal or suspended, but rather that they can be slightly tilted. For example, "horizontal" simply means that its direction is more horizontal relative to "vertical," and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0030] In the description of this application, it should be noted that the terms "inner", "outer", "left", "right", "upper", "lower", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this application is in use. They 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. Therefore, they should not be construed as limitations on this application.

[0031] In the description of this application, unless otherwise expressly specified and limited, the terms “set up,” “install,” “connect,” and “link” shall be interpreted broadly, for example, as a fixed connection, a detachable connection, or an integral connection; as a mechanical connection or an electrical connection; as a direct connection or an indirect connection through an intermediate medium; or as a connection within two components.

[0032] The technical solution of this application will now be clearly and completely described with reference to the accompanying drawings.

[0033] Example

[0034] Reference Figures 1-5 The present invention provides a secondary battery, including a cell housing 400, a cell assembly 200 and a top cover assembly 100; the cell housing 400 has an upper opening, and the cell assembly 200 is assembled into the cell housing 400 through the upper opening;

[0035] The top cover assembly 100 is assembled at the upper opening. The inner walls at both ends of the cell housing 400 in the first direction are the first inner walls. At least one first spacer protrusion 500 is provided on the first inner wall. The first spacer protrusion 500 is used to abut against the cell assembly 200, so that an upward channel is formed between the cell assembly 200 and the first inner wall of the cell housing 400.

[0036] The first direction is the length direction of the top cover assembly 100.

[0037] In some embodiments, the cell assembly 200 is assembled from the upper end of the cell housing 400 into the cell housing 400, and the top cover assembly 100 is assembled at the upper opening of the cell housing 400; when gas is generated at the lower end of the cell assembly 200, the gas cannot flow upward smoothly due to the cell assembly 200.

[0038] By providing a first spacer protrusion 500 inside the cell housing 400, a gap is formed between the inner wall of the cell housing 400 and the cell assembly 200. The first spacer protrusion 500 extends along the height direction of the cell housing 400, and the first spacer protrusion 500 forms an upward channel between the first inner wall of the cell housing 400 and the cell assembly 200. When gas is generated at the lower end of the cell assembly 200, the gas can flow upward through the upward channel, avoiding the cell assembly 200 from affecting the flow of gas, thereby effectively preventing the internal gas pressure from becoming too high due to severe gas blockage caused by the inability of gas to be discharged smoothly, which could lead to an explosion.

[0039] The first gap protrusion 500 abuts against the cell assembly 200, which can also effectively fix the cell assembly 200 and prevent the cell assembly 200 from shaking.

[0040] In an optional embodiment, the cell assembly 200 includes two cells, and the cells are square cells.

[0041] In an optional embodiment, at least two first spacer protrusions 500 are provided on the first inner wall of the cell housing 400, and one end of each cell in a first direction abuts against at least one of the first spacer protrusions 500.

[0042] In some embodiments, the cell assembly 200 includes two cells, each of which has at least two first spacer protrusions 500 on its first inner wall, that is, each cell abuts against a first spacer protrusion 500, thereby ensuring the stability of the cell assembly 200 and guaranteeing the stability of the rising channel.

[0043] Reference Figure 3 In an optional embodiment, four first spacer protrusions 500 are provided on the first inner wall, and one end of each of the battery cells in the first direction abuts against two of the first spacer protrusions 500.

[0044] To further improve the stability of the battery cell assembly 200, four first interval protrusions 500 are provided on the first inner wall, and every two first interval protrusions 500 abut against one end of a battery cell, thus ensuring that the battery cell assembly 200 is firmly fixed.

[0045] The cell housing 400 has a first spacer protrusion 500 on its first inner wall. The inner wall of the large surface of the cell housing 400 abuts against the cell assembly 200, which can effectively ensure that the cell assembly 200 will not shake inside the cell housing 400. While ensuring gas venting efficiency, it also ensures that the cell assembly 200 does not shake.

[0046] In an optional embodiment, the outer side wall of the cell housing 400 is provided with a stamping hole 600, which causes the inner side wall of the cell housing 400 to form the first spacer protrusion 500.

[0047] In an optional embodiment, the surface on which the first spacer protrusion 500 abuts against the cell assembly 200 is an arc surface.

[0048] A punching hole 600 is formed on the outside of the cell housing 400. At the same time as forming the punching hole 600, a first spacer protrusion 500 is formed inside the cell housing 400. The first spacer protrusion 500 has an arc surface, which can prevent the thermal runaway core from expanding and completely pressing against the first inner wall, thus blocking the gas discharge.

[0049] Reference Figure 2 In an optional embodiment, the battery cell assembly 200 is wrapped with an insulating sheet 201, the insulating sheet 201 is provided with a plurality of wetting holes 202, and the wetting holes 202 are located at the lower end of the battery cell assembly 200.

[0050] A support pad 300 is provided inside the cell housing 400, and the support pad 300 is located at the lower end of the cell assembly 200.

[0051] Reference Figure 4 and Figure 5 In an optional embodiment, a plurality of first guide grooves 301 are provided on the upper surface of the support pad 300, and the first guide grooves 301 extend along a first direction.

[0052] In an optional embodiment, a plurality of second guide grooves 302 are provided on the lower end surface of the support pad 300, and the second guide grooves 302 are staggered with the first guide grooves 301.

[0053] In an optional embodiment, the inner walls at both ends of the battery cell housing 400 in the second direction are the second inner walls, and at least one second spacer protrusion is provided on the second inner wall, the second spacer protrusion abutting against the battery cell assembly 200.

[0054] The second direction is the width direction of the top cover assembly 100.

[0055] In some embodiments, an insulating sheet 201 is wrapped around the cell assembly 200, causing the gas inside the cell assembly 200 to flow only upwards and downwards. The gas inside the cell assembly 200 flows from the wetting hole 202 to the lower end of the cell assembly 200. In order to allow the gas to flow to both sides, a support pad 300 is provided between the cell assembly 200 and the cell housing 400. The support pad 300 can serve as a physical isolation between the cell assembly 200 and the cell housing 400, preventing the cell assembly 200 from connecting to the cell housing 400 through the wetting hole 202.

[0056] The first guide groove 301 provided on the support pad 300 is in the same direction as the first direction. The first guide groove 301 guides the gas to the rising channel. The gas moves to the top of the cell assembly 200 through the rising channel and is discharged from the pressure relief valve, which improves the exhaust efficiency and avoids excessive pressure in the cell housing 400 and explosion.

[0057] Multiple second guide grooves 302 are provided on the lower end surface of the support pad 300. The second guide grooves 302 are staggered with the first guide grooves 301. A support protrusion is formed between two adjacent second guide grooves 302. The support protrusion and the second guide grooves 302 make the lower end of the support pad 300 form a wave-shaped structure. The wave-shaped structure not only plays a supporting role, but also has a certain elasticity. When the secondary battery vibrates or collides, it can play a certain buffering role for the cell assembly 200.

[0058] The cell housing 400 is a square housing with two large surfaces inside, which are the second inner walls. Multiple second spacer protrusions can be provided on the second inner walls to maintain a gap between the second inner walls and the cell assembly 200, thereby further improving the venting efficiency.

[0059] The first spacer protrusion 500 on the cell housing 400 of the secondary battery provided by this utility model can fix the cell assembly 200, preventing the cell assembly 200 from shaking. The first spacer protrusion 500 forms an upward channel between the cell assembly 200 and the first inner wall of the cell housing 400. When the cell assembly 200 generates a large amount of gas, the gas at the lower end of the cell assembly 200 can flow upward through the upward channel. This prevents the secondary battery from being severely blocked due to the inability of gas to be discharged smoothly, resulting in excessive internal gas pressure and thus causing an explosion. It also improves the explosion-proof capability of the large-capacity cell housing 400 and effectively reduces the risk of battery thermal runaway failure.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A secondary battery, characterized in that, It includes a cell housing (400), a cell assembly (200), and a top cover assembly (100); the cell housing (400) has an upper opening, and the cell assembly (200) is assembled into the cell housing (400) through the upper opening; The top cover assembly (100) is assembled at the upper opening. The inner walls at both ends of the cell housing (400) in the first direction are the first inner walls. At least one first spacer protrusion (500) is provided on the first inner wall. The first spacer protrusion (500) is used to abut against the cell assembly (200) so that an upward channel is formed between the cell assembly (200) and the inner wall of the cell housing (400). The first direction is the length direction of the top cover assembly (100).

2. The secondary battery according to claim 1, characterized in that, The battery cell assembly (200) includes two battery cells, and the battery cells are square battery cells.

3. The secondary battery according to claim 2, characterized in that, At least two first spacer protrusions (500) are provided on the first inner wall of the battery cell housing (400), and one end of each battery cell in a first direction abuts against at least one of the first spacer protrusions (500).

4. The secondary battery according to claim 2, characterized in that, The first inner wall is provided with four first spacer protrusions (500), and one end of each of the battery cells in the first direction abuts against two of the first spacer protrusions (500).

5. The secondary battery according to claim 1, characterized in that, The outer side wall of the cell housing (400) is provided with a stamping hole (600), and the stamping hole (600) causes the inner side wall of the cell housing (400) to form the first spacer protrusion (500).

6. The secondary battery according to claim 1, characterized in that, The surface on which the first spacer protrusion (500) abuts against the cell assembly (200) is an arc surface.

7. The secondary battery according to claim 1, characterized in that, The battery cell assembly (200) is wrapped with an insulating sheet (201), and the insulating sheet (201) is provided with a plurality of impregnation holes (202), and the impregnation holes (202) are located at the lower end of the battery cell assembly (200); A support pad (300) is provided inside the cell housing (400), and the support pad (300) is located at the lower end of the cell assembly (200).

8. The secondary battery according to claim 7, characterized in that, The upper surface of the support pad (300) is provided with a plurality of first guide grooves (301), and the first guide grooves (301) extend along a first direction.

9. The secondary battery according to claim 8, characterized in that, The lower end surface of the support pad (300) is provided with a plurality of second guide grooves (302), and the second guide grooves (302) are staggered with the first guide grooves (301).

10. The secondary battery according to claim 1, characterized in that, The inner walls at both ends of the battery cell housing (400) in the second direction are the second inner walls, and at least one second spacer protrusion is provided on the second inner wall, the second spacer protrusion abutting against the battery cell assembly (200); The second direction is the width direction of the top cover assembly (100).

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