Battery monomer and electric equipment

Abstract

The utility model relates to a battery monomer and electric equipment, comprising: a housing which is provided with an accommodating cavity and an end cover, the end cover is provided with a first opening, the end cover is provided with at least one weak part, and the weak part is configured to be damaged when the pressure or temperature in the battery monomer reaches a threshold value; the battery cell is accommodated in the accommodating cavity, and the battery cell is provided with a first tab; the first cover plate assembly comprises a first cover plate and a first pole arranged on the first cover plate, the first cover plate seals the first opening, and the first pole is electrically connected with the first tab of the battery cell. According to the battery monomer disclosed by the utility model, the weak part and the first opening are arranged on the end cover, and the area outside the first opening on the end cover is larger, so that the area for arranging the weak part is increased compared with the area of an anti-explosion valve in the prior art, and the battery monomer is beneficial to preventing the battery cell from being damaged when the battery cell is in thermal runaway. And gas in the battery can rapidly gush out of the damaged weak part with a relatively large area, so that the aim of timely exhausting and pressure relief is fulfilled.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a battery cell and an electrical device. Background Art

[0002] The blade battery is a lithium-ion battery made of lithium iron phosphate material, which is named because its shape is similar to a blade. The uniqueness of the blade battery lies in its shape and size, as well as its production process. This design enables the battery to be directly embedded into the battery pack, thereby improving the energy density and the structural strength of the battery pack.

[0003] When the battery malfunctions, due to internal short circuit or overcharging, various reactions will occur inside the battery (such as evaporation reaction of the electrolyte, oxidative decomposition of the electrolyte, reaction between the negative electrode and the electrolyte, etc.), which will cause the battery to be damaged. During this process, the heat and gas generated by the battery will lead to an explosion. Therefore, a readily openable explosion-proof valve design is necessary to prevent the battery from exploding.

[0004] Currently, the explosion-proof valve of the blade battery is located on the first cover plate, but the area of the explosion-proof valve is small. When thermal runaway occurs, it still cannot exhaust gas and relieve pressure in time, which easily causes the blade battery to explode. Summary of the Utility Model

[0005] Embodiments of the present application provide a battery cell and an electrical device to solve the problem of battery explosion caused by the inability to exhaust gas and relieve pressure in time in the prior art.

[0006] To solve the above technical problems, an embodiment of the utility model provides a battery cell, including:

[0007] A housing having an accommodation cavity, the housing having an end cover disposed along a first direction, the end cover being provided with a first opening. Wherein, the end cover has at least one weak part, and the weak part is configured to be damaged when the pressure or temperature inside the battery cell reaches a threshold value;

[0008] An electric core accommodated in the accommodation cavity, the electric core having a first tab;

[0009] A first cover plate assembly including a first cover plate and a first pole column disposed on the first cover plate, the first cover plate sealing the first opening, and the first pole column being electrically connected to the first tab of the electric core.

[0010] In an embodiment of the utility model, the end cover further includes at least one connecting part, at least one of the weak parts and at least one of the connecting parts are connected to form the end cover having the first opening, and at least one of the weak parts and at least one of the connecting parts are both welded to the first cover plate.

[0011] In an embodiment of the present utility model, the penetration depth of the weld between the weak part and the first cover plate is H1, and the penetration depth of the weld between the connecting part and the first cover plate is H2, where H1 / H2 = 1 / 3 to 1 / 2.

[0012] In an embodiment of the present utility model, the thickness of the weak part is 0.3 mm to 1.5 mm; the thickness of the first cover plate is 2 mm to 5 mm.

[0013] In an embodiment of the present utility model, at least one of the weak parts is distributed on at least one side of the end cover in the second direction, and the second direction is perpendicular to the first direction.

[0014] In an embodiment of the present utility model, the total length of the weld between at least one of the weak parts and the first cover plate is L1, and the inner perimeter of the end cover is L2, where L1 / L2 = 1 / 4 to 1 / 2.

[0015] In an embodiment of the present utility model, the weak part is provided with a notch, and the depth of the notch is 0.03 mm to 0.1 mm.

[0016] In an embodiment of the present utility model, it further includes a second cover plate assembly. The outer shell further includes a second opening. The second opening and the end cover are arranged opposite to each other in the first direction, and the orthographic projection of the first opening on the projection plane is located within the orthographic projection of the second opening on the projection plane. The projection plane is perpendicular to the first direction; the battery cell further has a second tab, and the second tab and the first tab are arranged opposite to each other in the first direction; the second cover plate assembly includes a second cover plate and a second pole column arranged on the second cover plate, and the second cover plate seals the second opening.

[0017] In an embodiment of the present utility model, the length of the first cover plate in the second direction is L3, the length of the second cover plate in the second direction is L4, the width of the first cover plate in the third direction is D1, and the width of the second cover plate in the third direction is D2. 1 / 2L4 ≤ L3 ≤ 2 / 3L4, 2 / 3D2 ≤ D1 ≤ 3 / 4D2, where the first direction, the second direction, and the third direction are perpendicular to each other in pairs.

[0018] An embodiment of the present utility model further provides an electrical device, including the above-mentioned battery cell.

[0019] The above technical solution of the present utility model has at least the following advantages compared with the prior art:

[0020] The battery cell described in the present utility model is provided with a weak part for explosion prevention and a first opening for assembling the first cover plate on the end cover of the outer shell. On the one hand, it is convenient to minimize the size design of the first cover plate, that is, to minimize the weld circumference of the first cover plate and the end cover, reduce the metal filling amount, thereby reducing welding deformation and improving welding efficiency; on the other hand, setting the weak part on the end cover is convenient for designing the size of the weak part that meets the exhaust requirements when the battery core undergoes thermal runaway, and then achieving the purpose of timely exhausting and relieving pressure, greatly improving the safety performance of the battery during thermal runaway. Description of the Drawings

[0021] In order to make the content of the present utility model easier to be clearly understood, the following further details the present utility model according to specific embodiments of the present utility model and in conjunction with the drawings, where

[0022] Figure 1 is a schematic structural diagram of the battery housing in the embodiment of the present utility model;

[0023] Figure 2 is a schematic structural diagram of the battery core in the embodiment of the present utility model;

[0024] Figure 3 is a schematic structural diagram of the connection between the battery core and the first cover plate in the embodiment of the present utility model;

[0025] Figure 4 is a schematic structural diagram of the connection between the tab and the first cover plate and the second cover plate in the embodiment of the present utility model;

[0026] Figure 5 is a schematic structural diagram of the weak part in the embodiment of the present utility model Figure 1 ;

[0027] Figure 6 is a schematic structural diagram of the weak part in the embodiment of the present utility model Figure 2 ;

[0028] Figure 7 is a schematic structural diagram of the weak part in the embodiment of the present utility model Figure 3 。

[0029] Explanation of the reference numerals in the drawings: 10. Outer shell; 11. First opening; 12. Weak part; 13. Connection part; 20. Battery core; 21. Battery core body; 22. First tab; 23. Second tab; 30. First cover plate; 40. Second cover plate. Detailed Embodiments

[0030] The following further describes the present utility model in conjunction with the drawings and specific embodiments, so that those skilled in the art can better understand the present utility model and can implement it, but the embodiments cited do not limit the present utility model.

[0031] Referring to Figures 1 to 3 as shown, an embodiment of the present utility model provides a battery cell, comprising:

[0032] A housing 10 having a receiving cavity. The housing 10 has an end cap and a second opening. The end cap is provided with a first opening 11. The second opening and the end cap are oppositely arranged along a first direction, and the orthographic projection of the first opening 11 on a projection plane is located within the orthographic projection of the second opening on the projection plane. The projection plane and the first direction are perpendicular to each other. Wherein, the end cap has at least one weak part 12. The weak part 12 refers to a part that is thinner than other parts of the end cap and has been thinned relative to other parts of the end cap. The weak part 12 is configured to be damaged when the pressure or temperature inside the battery cell reaches a threshold value;

[0033] A battery core 20 received in the receiving cavity. The battery core 20 includes a battery core body 21, a first tab 22 and a second tab 23. The first tab 22 is led out from one end of the battery core body 21 along the first direction, and the second tab 23 is led out from the other end of the battery core body 21 along the first direction. The second tab 23 and the first tab 22 are oppositely arranged along the first direction;

[0034] A first cover plate assembly, including a first cover plate 30 and a first pole column arranged on the first cover plate 30. The first cover plate 30 seals the first opening 11, and the first pole column is electrically connected to the first tab 22 of the battery core 20;

[0035] A second cover plate assembly, including a second cover plate 40 and a second pole column arranged on the second cover plate 40. The second cover plate 40 seals the second opening, and the second pole column is electrically connected to the second tab 23 of the battery core 20.

[0036] Wherein, the first pole column is a positive pole column, and the first tab 22 is a positive tab. Correspondingly, the second pole column is a negative pole column, and the second tab 23 is a negative tab. Of course, the first pole column can also be a negative pole column, and the first tab 22 is a negative tab. Correspondingly, the second pole column is a positive pole column, and the second tab 23 is a positive tab. The shape of the first cover plate 30 can be square, circular, irregular, etc. Preferably, the weak part 12 and the entire housing 10 are integrally manufactured during mold opening.

[0037] For the battery cell provided by the embodiment of the present utility model, since the size of the first opening 11 is smaller than the size of the second opening, that is to say, the size of the first cover plate 30 is smaller than the size of the second opening. For the first cover plate 30, as long as the size of the first cover plate 30 is smaller than the size of the second opening, the first cover plate assembly and the battery core 20 can enter the housing 10 together from the second opening, and as long as the size of the first cover plate 30 is smaller than the size of the first pole column, the electrical connection between the first cover plate assembly and the battery core 20 can be achieved.

[0038] On the one hand, for the battery cell provided in the embodiment of the present utility model, since the weak part 12 for explosion prevention is directly provided on the end cover, the size of the first cover plate can be minimized in this way, that is, the weld circumference of the first cover plate and the end cover can be minimized, reducing the metal filling amount, thereby reducing welding deformation and also improving welding efficiency.

[0039] On the other hand, since the size of the first cover plate 30 is smaller than that of the second cover plate 40, that is to say, compared with the existing explosion-proof valve arranged on the pole cover plate with the same size as the second cover plate 40, the area provided by the first cover plate 30 for arranging the explosion-proof valve is smaller. Therefore, in order to adapt to the size of the first cover plate 30, the area of the explosion-proof valve is often reduced. In this case, it is not conducive to exhausting gas when the battery core undergoes thermal runaway. Therefore, in order to overcome the above problems, the weak part is arranged on the end cover, and at the same time, the size of the first cover plate 30 is minimized, so as to ensure that the size of the weak part that can meet the exhaust requirements when the battery core undergoes thermal runaway can be designed.

[0040] It should be noted that the outer shell 10 can be an integrally formed structure, that is, the end cover is a part of the outer shell 10; the outer shell 10 can also be a split structure, that is, the outer shell includes a shell body and an end cover. The shell body has a first opening 11 and an open end arranged opposite to each other in the first direction. The end cover covers the open end, and the end cover and the shell body are welded.

[0041] Specifically, the assembly process of the battery cell in this embodiment is as follows:

[0042] Step (1): Take a battery core 20. Among them, the battery core body 21 of the battery core 20 is wound or laminated according to the design requirements, and a first pole ear 22 and a second pole ear 23 are respectively led out from both ends of the battery core body 21 along the first direction;

[0043] Step (2): As Figure 3 shown, weld the first cover plate 30 provided with the first pole column to the first pole ear 22;

[0044] Step (3): As Figure 4 shown, then weld the second cover plate 40 provided with the second pole column to the second pole ear 23;

[0045] Step (4): Feed the first cover plate 30 into the outer shell 10 from the second opening of the outer shell 10, and then pass it out from the first opening 11;

[0046] Step (5): Weld the first cover plate 30 to the end cover, and weld the second cover plate 40 to the outer shell 10.

[0047] Of course, step (2) and step (3) can also be exchanged, that is, first weld the second cover plate 40 provided with the second pole column to the second pole ear 23, and then weld the first cover plate 30 provided with the first pole column to the first pole ear 22.

[0048] For the battery cell of the present utility model, in some embodiments, the end cover further includes at least one connecting portion 13. At least one weak portion 12 and at least one connecting portion 13 are connected to form an end cover having a first opening 11. At least one weak portion 12 and at least one connecting portion 13 are both welded to the first cover plate 30.

[0049] Specifically, the connecting portion 13 is thicker than the weak portion 12. The connecting portion 13 and the weak portion 12 are combined and connected arbitrarily to form an end cover having a first opening 11; the connecting portion 13 and the weak portion 12 can be integrally provided.

[0050] It should be noted that the weak portion 12 and the connecting portion 13 can be arranged around the first opening 11 together, that is, the edges of both the weak portion 12 and the connecting portion 13 form the edge of the first opening 11; or only the weak portion 12 is arranged around the first opening 11, and the weak portion 12 separates the connecting portion 13 from the first opening 11, that is, the edge of the weak portion 12 forms the edge of the first opening 11.

[0051] For the battery cell of the present utility model, in some embodiments, refer to 5- Figure 6 As shown, at least one weak portion 12 is distributed on at least one side of the end cover in the second direction, and the second direction is perpendicular to the first direction; wherein, the second direction is the length direction of the end cover, that is to say, at least one weak portion 12 is distributed on at least one side of the length direction of the end cover, and both sides in the width direction (the third direction) of the end cover are left empty. In this way, the welding perimeter of the weak portion 12 is shorter and the remaining space of the end cover is larger, thereby ensuring the welding strength between the first cover plate 30, the end cover and the weak portion 12.

[0052] Specifically, weak portions 12 are provided on both sides of the end cover in the second direction. The shape of the weak portion 12 can be square (as shown in Figure 5 ), or trapezoidal (as shown in Figure 6 ), or other irregular shapes; as shown in Figure 5 , when the weak portion 12 is square, one edge of the weak portion 12 is connected to one edge of the first cover plate 30. As shown in Figure 6 , when the weak portion 12 is trapezoidal, the shorter edge of the weak portion 12 is connected to one edge of the first cover plate 30.

[0053] Of course, the weak portion 12 does not necessarily have to be provided on at least one side of the end cover in the second direction. The weak portion 12 can also be distributed on at least one side of the end cover in the third direction, as long as the welding strength between the first cover plate 30, the end cover and the weak portion 12 can be ensured. Specifically, as shown in Figure 7 , weak portions 12 are provided on both sides of the end cover in the third direction; the shape of the weak portion 12 can be square or trapezoidal (as shown in Figure 7 ) or other shapes.

[0054] For the battery cell of the present utility model, in some embodiments, the penetration depth of the weld between the weak part 12 and the first cover plate 30 is H1, and the penetration depth of the weld between the connecting part 13 and the first cover plate 30 is H2, where H1 / H2 = 1 / 3 to 1 / 2.

[0055] Designing the penetration depth of the weld between the weak part 12 and the first cover plate 30 with reference to the penetration depth value of the weld between the connecting part 13 and the first cover plate 30 is more accurate and well-founded. It can not only ensure that the weld between the weak part 12 and the first cover plate 30 has sufficient penetration depth, so that the weak part 12 and the first cover plate 30 can be firmly welded, but also avoid the phenomenon that the penetration depth of the weld between the weak part 12 and the first cover plate 30 is too large, resulting in deformation and cracks in the weak part 12, thereby affecting the welding quality.

[0056] Specifically, the value of H1 / H2 can be 1 / 3 or 2 / 5 or 3 / 7 or 1 / 2, but is not limited thereto.

[0057] For the battery cell of the present utility model, in some embodiments, the thickness of the weak part 12 is 0.3 mm to 1.5 mm; the thickness of the first cover plate 30 is 2 mm to 5 mm.

[0058] The thickness of the weak part 12 is designed in contrast to the thickness of the first cover plate 30, that is, on the basis of the thickness of the first cover plate 30, the thickness of the weak part 12 is designed. This not only ensures that the weak part 12 has sufficient thickness to guarantee the strength of the weak part 12, but also avoids the thickness of the weak part 12 being too large to be damaged when the pressure or temperature inside the battery cell reaches the threshold value.

[0059] Specifically, the value of the thickness of the weak part 12 can be 0.3 mm or 0.5 mm or 0.7 mm or 0.9 mm or 1.2 mm or 1.5 mm, but is not limited thereto; the value of the thickness of the cover plate can be 2 mm or 2.5 mm or 3 mm or 3.5 mm or 4 mm or 5 mm, but is not limited thereto.

[0060] For the battery cell of the present utility model, in some embodiments, the total length of the weld between at least one weak part 12 and the first cover plate 30 is L1, and the perimeter of the first cover plate 30 is L2, where L1 / L2 = 1 / 4 to 1 / 2.

[0061] Designing the total length of the weld between the weak part 12 and the first cover plate 30 with reference to the perimeter value of the first cover plate 30 is more accurate and well-founded. It can not only ensure that there is a sufficient length of weld between the weak part 12 and the first cover plate 30 to guarantee sufficient connection between the weak part 12 and the first cover plate 30, but also avoid the weld between the weak part 12 and the first cover plate 30 being too long and affecting the welding strength.

[0062] Specifically, the value of L1 / L2 can be 1 / 4 or 1 / 3 or 2 / 5 or 3 / 7 or 1 / 2, but is not limited thereto.

[0063] In some embodiments of the battery cell of the present utility model, the weak part 12 is provided with a notch, and the depth of the notch is 0.03 mm to 0.1 mm. By providing the notch on the weak part 12, the strength of the weak part 12 is weakened, so that the weak part 12 is more easily opened under pressure, thereby further ensuring that the weak part 12 is damaged when the pressure or temperature inside the battery cell reaches the threshold value.

[0064] The depth of the notch is 0.03 mm to 0.1 mm. With an appropriate depth of the notch, it can not only ensure that the weak part 12 is damaged when the pressure or temperature inside the battery cell reaches the threshold value, but also avoid excessive reduction of the strength of the weak part 12 due to too large a depth of the notch, thereby affecting the welding strength between the weak part 12 and the first cover plate 30.

[0065] Specifically, the value of the depth of the notch can be 0.03 mm or 0.04 mm or 0.05 mm or 0.06 mm or 0.08 mm or 0.1 mm, but is not limited thereto.

[0066] In some embodiments of the battery cell of the present utility model, the length of the first cover plate 30 in the second direction is L3, the length of the second cover plate 40 in the second direction is L4, the width of the first cover plate 30 in the third direction is D1, and the width of the second cover plate 40 in the third direction is D2. 1 / 2L4 ≤ L3 ≤ 2 / 3L4, 2 / 3D2 ≤ D1 ≤ 3 / 4D2, wherein the first direction, the second direction, and the third direction are perpendicular to each other in pairs.

[0067] Designing the length and width of the first cover plate 30 with reference to the length and width values of the second cover plate 40 is more accurate and well-founded. It can not only ensure that the first cover plate 30 has sufficient length and width to install the second pole and ensure its own strength, but also ensure that the length and width of the first cover plate 30 are not too large, resulting in too small an area of the end cover outside the first opening 11, thereby limiting the area of the weak part 12.

[0068] Specifically, the value of L3 can be 1 / 2L4 or 5 / 9L4 or 4 / 7L4 or 5 / 8L4, but is not limited thereto.

[0069] An embodiment of the present utility model also discloses an electrical device, including the above-mentioned battery cell. It has the same technical effects as the above-mentioned battery, and will not be elaborated here.

[0070] Obviously, the above embodiments are merely examples for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of this utility model creation.

Claims

1. A battery cell, characterized in that, Comprising: A housing (10) having a receiving cavity, the housing (10) having an end cap disposed along a first direction, the end cap being provided with a first opening (11), wherein the end cap has at least one weak portion (12), and the weak portion (12) is configured to be broken when the pressure or temperature inside the battery cell reaches a threshold; A battery cell (20) received in the receiving cavity, the battery cell (20) having a first tab (22); A first cover assembly including a first cover (30) and a first terminal provided on the first cover (30), the first cover (30) sealing the first opening (11), and the first terminal being electrically connected to the first tab (22) of the battery cell (20).

2. The battery cell according to claim 1, characterized in that, The end cap further includes at least one connecting portion (13), at least one of the weak portions (12) and at least one of the connecting portions (13) are connected to form the end cap having the first opening (11), and at least one of the weak portions (12) and at least one of the connecting portions (13) are both welded to the first cover (30).

3. The battery cell according to claim 2, characterized in that, The penetration depth of the weld between the weak portion (12) and the first cover (30) is H1, and the penetration depth of the weld between the connecting portion (13) and the first cover (30) is H2, wherein, H1 / H2 = 1 / 3 to 1 / 2.

4. The battery cell according to claim 3, wherein The thickness of the weak portion (12) is 0.3 mm to 1.5 mm; the thickness of the first cover (30) is 2 mm to 5 mm.

5. The battery cell according to claim 2, characterized in that, At least one of the weak portions (12) is distributed on at least one side of the end cap in a second direction, and the second direction is perpendicular to the first direction.

6. The battery cell according to claim 2, characterized in that, The total length of the weld between at least one of the weak portions (12) and the first cover (30) is L1, and the perimeter of the first cover (30) is L2, wherein, L1 / L2 = 1 / 4 to 1 / 2.

7. The battery cell according to claim 2, characterized in that, The weak portion (12) is provided with a notch, and the depth of the notch is 0.03 mm to 0.1 mm.

8. The battery cell according to any one of claims 1 to 7, characterized in that, It further includes a second cover assembly, the housing (10) further includes a second opening, the second opening and the end cap are disposed opposite to each other along the first direction, and the orthographic projection of the first opening (11) on the projection plane is located within the orthographic projection of the second opening on the projection plane, and the projection plane is perpendicular to the first direction; the battery cell (20) further has a second tab (23), and the second tab (23) and the first tab (22) are disposed opposite to each other along the first direction; the second cover assembly includes a second cover (40) and a second terminal provided on the second cover (40), and the second cover (40) seals the second opening.

9. The battery cell according to claim 8, wherein, The length of the first cover (30) in the second direction is L3, the length of the second cover (40) in the second direction is L4, the width of the first cover (30) in the third direction is D1, the width of the second cover (40) in the third direction is D2, 1 / 2L4 ≤ L3 ≤ 2 / 3L4, 2 / 3D2 ≤ D1 ≤ 3 / 4D2, wherein the first direction, the second direction and the third direction are perpendicular to each other in pairs.

10. An electrical device, characterized in that, Comprising the battery cell according to any one of claims 1 to 9.

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