A new type of double-layered battery case

Abstract

The utility model discloses a novel structure battery shell of double -deck relates to battery structure technical field, including shell portion, be provided with the inner shell portion at the inboard of shell portion, the sealed gap that shell portion is formed with inner shell portion fills with the cooling filler in, set up the inner shell thin portion on the position of inner shell portion relative to cooling filler, the breaking force of inner shell thin portion is less than the opening force of explosion -proof valve, when the battery roll core inside setting in the inboard of inner shell portion starts to fail and forms certain gas pressure, the stress groove on the stress groove on the inboard of inner shell portion is acted by the gas pressure and will break first, so the sealed gap of shell portion and inner shell portion formed in the fire -retardant fire extinguishing agent will flow into the inboard of inner shell portion through the stress groove of break, that is, battery roll core place, absorbs heat and prevents battery roll core from further producing combustion momentarily, and the safety performance of battery roll core has been improved greatly.

Description

Technical Field

[0001] This utility model relates to the field of battery structure technology, specifically to a novel double-layer battery casing. Background Technology

[0002] In recent years, with the increasing demand for clean energy, the application fields of rechargeable batteries have been greatly expanded. However, rechargeable batteries still have many problems, especially safety issues. Among these safety issues, the flame retardancy of batteries remains a concern. Traditional battery casings are mostly made of aluminum alloy or stainless steel, which is not effective in delaying the spread of flames and the conduction of heat at high temperatures, making them prone to chain fire accidents.

[0003] The existing Chinese utility model patent with authorization announcement number CN220021491U discloses a safe flame-retardant battery. Although the casing used in this battery can provide flame-retardant function for the battery core, thus proposing the concept of a safe flame-retardant battery, the casing used in the battery still cannot solve the problem of cooling the heat-generating and gas-generating battery core when the battery is short-circuited or subjected to external impact. Therefore, this problem urgently needs to be solved. Utility Model Content

[0004] In order to overcome the above-mentioned technical problems, the purpose of this utility model is to provide a novel double-layer battery casing that enables rapid cooling of the battery core and effectively ensures safety performance.

[0005] The objective of this utility model can be achieved through the following technical solutions:

[0006] Specifically, a novel double-layer battery casing is provided, including an outer shell portion and an inner shell portion inside the outer shell portion. The sealed gap formed by the outer shell portion and the inner shell portion is filled with a cooling filler. A thin inner shell portion is provided in the inner shell portion relative to the cooling filler. The breaking force of the thin inner shell portion is less than the opening force of the explosion-proof valve. When the battery core located inside the inner shell portion begins to fail, generating heat and gas and forming a certain gas pressure, the thin inner shell portion will break first under the action of gas pressure, before the explosion-proof valve. In this way, the cooling filler in the sealed gap will flow into the battery core through the broken thin inner shell portion, absorbing the heat on the battery core and preventing the battery core from further burning. At the same time, it can ensure that the explosion-proof valve will not open and fail.

[0007] As a further aspect of this utility model: the thin inner shell portion is a strip-shaped stress groove formed on the surface of the inner shell portion. When the strip-shaped stress groove begins to fail and generate heat and gas inside the battery core and forms a certain gas pressure, it is easy to form a stress groove, which is conducive to the flow of cooling filler in the sealing gap into the battery core.

[0008] As a further aspect of this utility model: the number of strip stress grooves is several, and the several strip stress grooves are distributed on the surface of the inner shell in one or more ways, such as horizontal, vertical or inclined. When the strip stress grooves are evenly distributed on the surface of the inner shell, the strip stress grooves can achieve the effect of preferential fracture no matter where the battery core fails.

[0009] As a further embodiment of this utility model: the thin inner shell portion is formed by point-shaped stress grooves on the surface of the inner shell portion. The point-shaped stress grooves ensure that the cooling filler in the sealing gap flows into the battery core while also ensuring the overall strength of the thin inner shell portion.

[0010] As a further aspect of this utility model: the number of point-like stress grooves is several, and they are distributed in an array on the surface of the inner shell, so that the point-like stress grooves are maximized between the sealing gap and the battery core, which helps the cooling filler in the sealing gap to flow into the battery core.

[0011] As a further embodiment of this utility model: the inner shell includes an inner shell side plate and an inner shell bottom plate, and the thin inner shell portion is formed on the inner shell side plate. The thickness of the inner shell side plate and the inner shell bottom plate is 0.3mm to 0.4mm. When the thickness of the inner shell side plate and the inner shell bottom plate is preferably 0.3mm, the thickness of the thin inner shell portion is preferably 0.1mm, so that the pressure threshold of the thin inner shell portion is 0.6KPa, and the opening threshold of the explosion-proof valve is 1.0KPa, ensuring that the thin inner shell portion breaks before the explosion-proof valve.

[0012] As a further embodiment of this utility model: the top outer wall of the inner shell side plate is provided with a ring of inner shell outer wall protrusions. The bottom surface of the inner shell outer wall protrusions, the inner wall of the outer shell part and the outer wall of the inner shell part together form a sealing gap for accommodating the cooling filler. The sealing gap can be formed by the outer shell part, the inner shell part and the inner shell outer wall protrusions, reducing the assembly difficulty of the battery casing.

[0013] As a further aspect of this utility model: the sealing gap is shaped like an open box, so that the sealing gap covers the outside of the battery core well.

[0014] As a further aspect of this utility model: the cooling filler includes a flame retardant and an antifreeze agent, wherein the flame retardant and the antifreeze agent can achieve the cooling and flame retardant effect of the battery core, and the antifreeze agent, together with the sealing gap, will well cover the outside of the battery core, so that the battery core has an antifreeze effect.

[0015] As a further aspect of this invention: the flame-retardant extinguishing agent is a water-based extinguishing agent, which does not react adversely with lithium batteries.

[0016] As a further embodiment of this utility model: both the outer shell and the inner shell are integrally formed metal open box-shaped mechanisms, preferably made of aluminum alloy, as aluminum alloy outer shell and inner shell have high strength and light weight.

[0017] The beneficial effects of this utility model are:

[0018] 1. In this utility model, a flame-retardant extinguishing agent is filled in the sealed gap formed between the outer shell and the inner shell. At the same time, a thin inner shell section is provided on the inner shell. When the battery core inside the inner shell begins to fail, generate heat and gas and form a certain gas pressure, the thin inner shell section will break first under the action of gas pressure, which is faster than the explosion-proof valve. In this way, the flame-retardant extinguishing agent in the sealed gap will flow into the inner side of the inner shell through the broken thin inner shell section, that is, the battery core, to absorb heat and prevent the battery core from further burning, which greatly improves the safety performance of the battery core.

[0019] 2. In this utility model, by filling the sealing gap formed between the outer shell and the inner shell with antifreeze, when the external ambient temperature of the outer shell is too low, the shape of the sealing gap formed by the bottom surface of the inner shell outer wall protrusion, the inner wall of the outer shell and the outer wall of the inner shell together to accommodate the cooling filler is an open box shape. Therefore, the sealing gap will well cover the outside of the battery core. The antifreeze in the sealing gap, together with the sealing gap, makes the battery core have an antifreeze effect. Attached Figure Description

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 This is an exploded view of a novel double-layer battery casing according to this utility model;

[0022] Figure 2 This is a schematic diagram of the outer shell portion of this utility model;

[0023] Figure 3 This is a schematic diagram of the inner shell portion of this utility model;

[0024] Figure 4 This is a cross-sectional view of a novel double-layer battery casing according to this utility model;

[0025] Figure 5 This is a partial view of the upper left of the cross-sectional view in this utility model;

[0026] Figure 6 This is a partial left-middle view of the cross-sectional view in this utility model;

[0027] Figure 7 This is a partial view of the lower left of the cross-sectional view in this utility model;

[0028] Figure 8This is a schematic diagram of the structure of the thin inner shell of this utility model, which is a point-like stress groove.

[0029] Explanation of reference numerals in the attached drawings: 1. Outer shell; 11. Side plate of outer shell; 12. Bottom plate of outer shell; 2. Inner shell; 21. Side plate of inner shell; 22. Bottom plate of inner shell; 23. Boss on outer wall of inner shell; 3. Cooling filler; 4. Thin part of inner shell; 41. Strip stress groove; 42. Point stress groove. Detailed Implementation

[0030] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0031] Please see Figures 1-7 This utility model discloses a novel double-layer battery casing, including an outer shell portion 1 and an inner shell portion 2 disposed inside the outer shell portion 1. A cooling filler 3 is filled in the sealing gap formed between the outer shell portion 1 and the inner shell portion 2. An inner shell thin portion 4 is disposed on the inner shell portion 2. Since the thickness of the inner shell thin portion 4 is less than the thickness of other parts of the inner shell portion 2, the positional strength of the inner shell thin portion 4 is necessarily less than that of other parts of the inner shell portion 2. In one embodiment of this utility model, the thickness of the inner shell thin portion 4 does not exceed 0.1 mm. When the inner shell portion 2 is made of aluminum, the compressive force at which the inner shell thin portion 4 breaks is approximately 0.6 kPa, and the pressure threshold for opening the explosion-proof valve in the battery core is 1.0 kPa. When the pressure reaches 3.0 kPa, meaning the breaking force of the inner shell thin part 4 is less than the opening force of the explosion-proof valve, the inner shell thin part 4 will break first when the gas pressure inside the inner shell 2 reaches 0.6 kPa. The condition for the inner shell thin part 4 to break is determined by the thickness of the inner shell thin part 4 and the material of the inner shell 2. When the battery core inside the inner shell 2 starts to fail and generate heat and gas and forms a certain gas pressure, the inner shell thin part 4 will break first under the action of gas pressure, which is faster than the explosion-proof valve. In this way, the cooling filler 3 in the sealing gap will flow into the inner side of the inner shell 2, that is, the battery core, through the broken inner shell thin part 4, to absorb the heat on the battery core and prevent the battery core from burning further. At the same time, it can ensure that the explosion-proof valve will not open and fail.

[0032] When a sharp object, such as a steel nail, pierces the outside of the battery casing, or when the battery casing is subjected to mechanical impact, the inner shell thin part 4 on the inner wall of the inner shell part 2 will break first because the inner shell thin part 4 is thinner. This allows the cooling filler 3 to flow into the inner side of the inner shell part 2, preventing further safety problems from the battery core and greatly improving the safety performance of the battery core.

[0033] Please see Figure 2 The outer shell 1 includes an outer shell side plate 11 and an outer shell bottom plate 12. The outer shell side plate 11 and the outer shell bottom plate 12 form an open box-shaped mechanism, which allows the cooling filler 3 to be directly filled into it. At the same time, the inner shell 2 can also cooperate with the outer shell 1 of the open box-shaped mechanism.

[0034] The thickness of the outer shell side plate 11 is 0.6 mm to 0.8 mm, and the thickness of the outer shell bottom plate 12 is 1.0 mm to 1.4 mm. The thickness of the outer shell side plate 11 and the outer shell bottom plate 12 can be adaptively adjusted by those skilled in the art according to the thickness of the inner shell thin part 4, so as to ensure that the thickness of the outer shell side plate 11 and the outer shell bottom plate 12 is greater than the thickness of the inner shell thin part 4, so that the inner shell thin part 4 will break first.

[0035] Please see Figure 3 The inner shell 2 includes an inner shell side plate 21 and an inner shell bottom plate 22. The inner shell side plate 21 and the inner shell bottom plate 22 form an open box-shaped mechanism. The length and width of the horizontal cross section of the inner shell 2 are smaller than the length and width of the horizontal cross section of the outer shell 1, and the difference in length and the difference in width are equal. The depth of the outer shell side plate is greater than the height of the inner shell side plate 21, and the difference in height is equal to the difference in length. Therefore, when the outer shell 1 and the inner shell 2 are nested together, a uniform gap will be formed between the outer shell 1 and the inner shell 2, and the shape of the gap is an open box shape, in which the cooling filler 3 can be filled.

[0036] The thickness of both the inner shell side plate 21 and the inner shell bottom plate 22 is 0.3 mm to 0.4 mm, and the depth of the thin section 4 of the inner shell is 0.1 mm to 0.2 mm. Figure 3 Taking the inner shell 2 as an example, the thickness of the inner shell side plate 21 and the inner shell bottom plate 22 is 0.3mm, and the depth of the inner shell thin part 4 is 0.2mm. Thus, the thickness of the inner wall of the inner shell 2 corresponding to the position of the inner shell thin part 4 is 0.1mm, which is less than the thickness of other positions of the inner shell 2. Therefore, when the battery core inside the inner shell 2 starts to fail, generate heat and gas and form a certain gas pressure, the inner shell thin part 4 on the inner wall of the inner shell 2 will break first under the action of gas pressure. In this way, the cooling filler 3 will flow into the inner side of the inner shell 2, absorb heat and prevent the battery core from further burning.

[0037] Please see Figure 5, A circle of outer boss (23) of the inner casing is arranged on the top outer wall of the inner casing side plate (21), the height of the outer boss (23) of the inner casing is 0.5 mm to 1.0 mm, the outer boss (23) of the inner casing matches the inner cavity of the outer casing part (1), the thickness of the outer boss (23) of the inner casing is determined by the specifications of the outer casing part (1) and the inner casing part (2), so as to ensure that after the inner casing part (2) is embedded inside the outer casing part (1), the outer side surface of the outer boss (23) of the inner casing fits with the inner wall of the outer casing part (1), that is, the thickness of the outer boss (23) of the inner casing is equal to the difference between the inner side surface of the outer casing part (1) and the outer wall of the inner casing part (2), the connection between the outer boss (23) of the inner casing and the outer casing part (1) adopts welding, for example laser welding, so that the outer casing part (1) and the inner casing part (2) can achieve fixed connection, and the outer boss (23) of the inner casing can also seal the gap formed by the outer casing part (1) and the inner casing part (2) to form a sealing gap, so as to prevent the cooling filler (3) from leaking therein;

[0038] Specifically during assembly, according to the volume a of the gap, the cooling filler (3) with volume b (b < a) is injected into the inner cavity of the outer casing part (1) in advance, then the inner casing part (2) is pressed in, so that the top of the outer casing part (1) is flush with the top of the inner casing part (2), at this time the cooling filler (3) will automatically fill the gap due to the extrusion of the inner casing part (2), and finally the top of the outer casing part (1) and the inner casing part (2) are welded by laser.

[0039] The cooling filler (3) comprises a flame retardant extinguishing agent and an antifreeze, the flame retardant extinguishing agent and the antifreeze are mixed in any volume ratio. As an embodiment of the utility model, the volume ratio of the mixture of the flame retardant extinguishing agent and the antifreeze is 1:1, wherein the flame retardant extinguishing agent is a water-based extinguishing agent. On the one hand, the water-based extinguishing agent does not cause adverse reactions with the lithium battery; on the other hand, when the thin inner casing part (4) breaks preferentially, the liquid water-based extinguishing agent will flow into the inner side of the inner casing part (2) through the broken thin inner casing part (4), absorb the heat on the battery core, and prevent the battery core from further combustion.

[0040] In addition, it should be noted that since the shape of the sealing gap formed by the bottom surface of the outer boss (23) of the inner casing, the inner wall of the outer casing part (1) and the outer wall of the inner casing part (2) for accommodating the cooling filler (3) is an open box shape, the sealing gap can well cover the outer side of the battery core, and the antifreeze in the sealing gap cooperates with the sealing gap to also well cover the outer side of the battery core, so that the battery core has an anti-freezing effect.

[0041] See Figure 3 and Figure 4 , the number of the thin inner casing parts (4) on the inner wall of the inner casing part (2) is adaptively selected by those skilled in the art according to the height of the inner casing part (2), as long as it does not affect the overall strength of the inner casing part (2), Figure 3 and Figure 4 taking two thin inner casing parts (4) arranged on the inner wall of the inner casing part (2) as an example, but the number of the thin inner casing parts (4) is not limited to two;

[0042] In one specific embodiment, please refer to Figure 6 When the thin inner shell 4 consists of several strip stress grooves 41, the several strip stress grooves 41 can also be distributed on the inner / outer / inner and outer sides of the inner shell 2 in one or any combination of horizontal, vertical or inclined manner. The strip stress grooves 41 can be laser etched.

[0043] In another specific embodiment, please refer to Figure 8 When the thin inner shell 4 is a number of point stress grooves 42 (the point stress grooves 42 include but are not limited to circular, polygonal, and irregular polygonal shapes), the number of point stress grooves 42 are distributed in an array on the inner / outer / inner / outer sides of the inner shell 2. The point stress grooves 42 can be laser etched.

[0044] The above description provides a detailed account of one embodiment of the present invention. However, this description is merely a preferred embodiment and should not be construed as limiting the scope of the present invention. All equivalent variations and improvements made within the scope of the claims of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A novel double-layer battery casing, characterized in that, include: Outer shell (1); The inner shell (2) is disposed inside the outer shell (1); Cooling filler (3) is filled in the sealing gap formed between the outer shell (1) and the inner shell (2); The inner shell thin part (4) is disposed on the inner shell part (2), and the breaking force of the inner shell thin part (4) is less than the opening force of the explosion-proof valve.

2. The novel double-layer battery casing according to claim 1, characterized in that, The inner shell thin section (4) is a strip stress groove (41) formed on the surface of the inner shell section (2).

3. The novel double-layer battery casing according to claim 2, characterized in that, The number of the strip stress grooves (41) is several, and the several strip stress grooves (41) are distributed on the surface of the inner shell (2) in one or more ways, such as horizontal, vertical or inclined.

4. The novel double-layer battery casing according to claim 1, characterized in that, The inner shell thin section (4) is a point stress groove (42) formed on the surface of the inner shell section (2).

5. A novel double-layer battery casing according to claim 4, characterized in that, The number of point stress grooves (42) is several, and they are distributed in an array on the surface of the inner shell (2).

6. A novel double-layer battery casing according to any one of claims 1-5, characterized in that, The inner shell portion (2) includes an inner shell side plate (21) and an inner shell bottom plate (22), and the inner shell thin portion (4) is formed on the inner shell side plate (21).

7. A novel double-layer battery casing according to claim 6, characterized in that, The top outer wall of the inner shell side plate (21) is provided with a ring of inner shell outer wall protrusions (23). The bottom surface of the inner shell outer wall protrusions (23), the inner wall of the outer shell part (1) and the outer wall of the inner shell part (2) together form a sealing gap for accommodating the cooling filler (3).

8. A novel double-layer battery casing according to any one of claims 1-5, characterized in that, The sealing gap is shaped like an open box.

9. A novel double-layer battery casing according to any one of claims 1-5, characterized in that, The cooling filler (3) includes flame retardant fire extinguishing agent and antifreeze agent.

10. A novel double-layer battery casing according to claim 9, characterized in that, The flame-retardant extinguishing agent is a water-based extinguishing agent.

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