Cover plate, battery and battery pack

Abstract

The invention discloses a cover plate, a battery and a battery pack, the cover plate comprises a body and an explosion-proof structure, the explosion-proof structure comprises a first sub-part and a second sub-part, the first sub-part is adjacent to the second sub-part, the first sub-part is close to the edge of the body along the radial direction of the body, the second sub-part comprises a sinking table and a boss which are connected, and the sinking table and the boss are located on the same circumference; the second sub-part is provided with a first side face and a second side face which are oppositely arranged, and the boss is higher than the sinking table and the first sub-part in the direction from the second side face to the first side face; the anti-explosion groove is formed in the first side face and comprises a first sub-groove and a second sub-groove, at least part of the first sub-groove is located on the sinking table, and the second sub-groove is located on the boss. The directional opening of the explosion-proof structure can be realized.

Description

[0001] This application claims the priority of the international application with the application number PCT / CN2023 / 143532 filed with the China National Patent Office on December 29, 2023. The entire content of the above application is incorporated herein by reference. Technical Field

[0002] This application belongs to the technical field of batteries, and particularly relates to a cover plate, a battery, and a battery pack. Background Art

[0003] During the use of power batteries, due to short circuits or other reasons, the internal air pressure of the battery may increase and exceed the safety value, resulting in potential hazards such as explosions. To minimize such hazards, an explosion-proof structure is generally provided on the battery cover plate. The explosion-proof structure gradually deforms until it explodes and opens as the internal pressure increases. As the explosion-proof structure opens, the substances inside the battery will be ejected. Since the opening direction of the explosion-proof structure is uncertain, the flow direction of the ejected substances is also uncertain, and the ejected substances randomly flow onto the surrounding batteries, affecting the surrounding batteries and expanding the scope of thermal runaway. Summary of the Invention

[0004] Embodiments of this application provide a cover plate, a battery, and a battery pack to solve the problem that the opening direction of the explosion-proof structure in the related art is uncertain.

[0005] In a first aspect, an embodiment of this application provides a cover plate applied to a battery, including: a body including a first sub-part and a second sub-part, the first sub-part and the second sub-part being adjacent to each other. Along the radial direction of the body, the first sub-part is close to the edge of the body. Among them, the second sub-part includes a connected sunken platform and a convex platform, the sunken platform and the convex platform are located on the same circumference, and the second sub-part has a first side surface and a second side surface arranged opposite to each other. In the direction from the second side surface to the first side surface, the height of the convex platform is higher than that of the sunken platform and the first sub-part;

[0006] An explosion-proof groove including a first sub-groove and a second sub-groove, the first sub-groove is at least partially located on the sunken platform, and the second sub-groove is located on the convex platform.

[0007] In a second aspect, a battery includes the cover plate according to any one of the above.

[0008] A winding core including a positive extreme and a negative extreme;

[0009] A housing, the winding core is installed in the housing, one end of the housing is provided with an opening, and the body is hermetically connected to the housing to block the opening.

[0010] In a third aspect, a battery pack includes a plurality of the above-mentioned batteries.

[0011] The cover plate, battery, and battery pack provided by the embodiments of the present application. The cover plate includes a body and an explosion-proof groove. The body includes an adjacent first sub-part and a second sub-part. The explosion-proof groove is provided on the second sub-part. The second sub-part has a boss and a sunk platform. The boss is higher than the sunk platform and the first sub-part. The first groove is located on the sunk platform, and the second groove is located on the boss. When the cover plate relieves pressure, the force received at the position of the sunk platform is relatively large, and the explosion-proof groove is first opened from the sunk platform, thereby overcoming the problem of the uncertain opening direction of the existing explosion-proof structure and realizing the directional opening when the cover plate relieves pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0013] In order to more completely understand the present application and its beneficial effects, the following will be described in conjunction with the drawings. Among them, the same reference numerals represent the same parts in the following description.

[0014] Figure 1 It is a top view of the first form of the cover plate provided by the embodiment of the present application.

[0015] Figure 2 It is Figure 1 the A-A cross-sectional view in

[0016] Figure 3 It is Figure 1 the partial enlarged view at B in

[0017] Figure 4 It is Figure 3 the C-C cross-sectional view in

[0018] Figure 5 It is Figure 4 the partial enlarged view at D in

[0019] Figure 6 It is Figure 3 the E-E cross-sectional view in

[0020] Figure 7 It is the marked drawing of the cover plate provided by the embodiment of the present application.

[0021] Figure 8 It is the three-dimensional view of the cover plate provided by the embodiment of the present application.

[0022] Figure 9 It is the three-dimensional view of the battery provided by the embodiment of the present application.

[0023] Figure 10It is a top view of the battery provided by the embodiment of the present application.

[0024] Figure 11 It is Figure 10 the G-G cross-sectional view in

[0025] Figure 12 It is Figure 11 the partial enlarged view at H in

[0026] Figure 13 It is Figure 11 the partial enlarged view at M in

[0027] Figure 14 It is a three-dimensional schematic diagram of the battery pack provided by the embodiment of the present application.

[0028] Figure 15 It is Figure 14 the side view of

[0029] Figure 16 It is Figure 15 the H-H cross-sectional view in

[0030] Explanation of reference numerals:

[0031] 100, battery; 110, cover plate; 111, body;; 113, first sub-part; 114, second sub-part; 1141, sunk platform; 1142, boss; 1143, first side; 1144, second side; 115, third sub-part; 116, fourth sub-part; 120, explosion-proof groove; 121, first sub-groove; 1211, first groove wall; 1212, second groove wall; 122, second sub-groove; 130, mounting seat; 131, mounting groove; 132, baffle; 133, first sub-plate; 134, second sub-plate; 140, wound core; 150, housing; 151, opening; 152, positive terminal; 153, flange; 154, pressing plate; 155, seal; 160, first current collector plate; 170, second current collector plate; 180, insulating part. Detailed implementation manners

[0032] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present application.

[0033] The embodiments of the present application provide a cover plate, a battery and a battery pack to solve the problem that the opening direction of the explosion-proof structure in the related art is uncertain. The following will be described in conjunction with the accompanying drawings.

[0034] See Figure 1 ,Figure 2 and Figure 8 As shown, an embodiment of the present application provides a cover plate 110 , including a body 111 and an explosion-proof groove 120 .

[0035] In this embodiment, the main body 111 includes a first sub-section 113 and a second sub-section 114, the first sub-section 113 is adjacent to the second sub-section 114, and along the radial direction of the main body 111, the first sub-section 113 is close to the edge of the main body 111, wherein the second sub-section 114 includes a connected countersunk platform 1141 and a boss 1142, the countersunk platform 1141 and the boss 1142 are located on the same circumference, the second sub-section 114 has a first side surface 1143 and a second side surface 1144 arranged opposite to each other, the first side surface 1143 is the surface of the second sub-section 114 facing away from the winding core 140, the second side surface 1144 is the surface of the second sub-section 114 facing the winding core 140, and the direction from the second side surface 1144 to the first side surface 1143, the height of the boss 1142 is higher than the countersunk platform 1141 and the first sub-section 113. The explosion-proof groove 120 is opened on the first side surface 1143 or the second side surface 1144 , and includes a first sub-groove 121 and a second sub-groove 122 that are connected. The first sub-groove 121 is at least partially located on the sink 1141 , and the second sub-groove 122 is located on the boss 1142 .

[0036] In this embodiment, by setting the second sub-section 114 on the body 111, the second sub-section 114 has a boss 1142 and a sink 1141, the boss 1142 is higher than the sink 1141 and the first sub-section 113, the first side 1143 of the boss 1142 is higher than the first side 1143 of the sink 1141, and the second side 1144 of the boss 1142 is higher than the second side 1144 of the sink 1141. When the cover plate 110 is depressurized, the force acting on the position of the sink 1141 is relatively large, and the explosion-proof groove 120 is first opened from the sink 1141, thereby overcoming the problem of the uncertainty of the opening direction of the explosion-proof structure in the related art, and realizing the directional opening when the cover plate 110 is depressurized. Among them, the explosion-proof groove 120 is first opened from the sink 1141, and there are multiple opening methods, such as the first sub-groove 121 on the sink 1141 is instantly fully opened, or the first sub-groove 121 has an opening point, and starts to open from the opening point until the first sub-groove 121 is fully opened. The opening point may be the intersection of the protrusion 1142 and the depression 1141 on the first sub-groove 121 , or may be any position on the first sub-groove 121 within the depression 1141 area.

[0037] In some embodiments, see Figure 2 and Figure 4As shown, the surface of the first sub - part 113 facing the core 140 and the surface of the sunk - table 1141 facing the core 140 are at the same height, and the surface of the first sub - part 113 away from the core 140 and the surface of the sunk - table 1141 away from the core 140 are at the same height. When the cover plate 110 relieves pressure, the force received at the position of the sunk - table 1141 is relatively large, and the explosion - proof groove 120 starts to open first from the sunk - table 1141, which is beneficial to the directional opening of the explosion - proof groove 120.

[0038] In some embodiments, referring to Figure 1 As shown, the body 111 further includes a third sub - part 115. The first sub - part 113 and the second sub - part 114 are annular, and the third sub - part 115 is circular. Along the radial direction of the body 111, the first sub - part 113, the second sub - part 114, and the third sub - part 115 are concentrically arranged in sequence, and the sunk - table 1141 and the boss 1142 enclose a closed ring.

[0039] It can be understood that in this embodiment, the second sub - part 114 is circular - annular, and the second sub - part 114 is composed of two parts, namely the sunk - table 1141 and the boss 1142. Both the sunk - table 1141 and the boss 1142 are arc - shaped rings, and the inner and outer diameters of the sunk - table 1141 and the boss 1142 are the same. When the cover plate 110 is in use, the first sub - part 113 of the cover plate 110 is pressed and fixed by other components of the battery. When the air pressure inside the battery increases, the cover plate 110 deforms, the third sub - part 115 bulges outwards and deforms, and the first sub - part 113 and the third sub - part 115 apply forces in different directions to both sides of the second sub - part 114, so that it cracks at the explosion - proof groove 120, which is beneficial to the opening of the explosion - proof groove 120.

[0040] In some embodiments, referring to Figure 1 As shown, the body 111 further includes a fourth sub - part 116. The fourth sub - part 116 is annular, the fourth sub - part 116 is located between the second sub - part 114 and the third sub - part 115, and the fourth sub - part 116 connects the second sub - part 114 and the third sub - part 115.

[0041] When the cover plate 110 is deformed under pressure, the cover plate 110 bulges upwards to form a hemispherical or hat - shaped structure, increasing the space between the cover plate 110 and the end of the battery core, preventing the air pressure inside the battery from increasing sharply and causing the battery to explode. In addition, the explosion - proof groove 120 is also arranged on the second sub - part 114. During the deformation process of the cover plate 110, the deformation forces of the first sub - part 113 and the fourth sub - part 116 act on the explosion - proof groove 120, which is beneficial to the smooth opening of the explosion - proof groove 120 and the reliability of the explosion - proof structure.

[0042] In some embodiments, the surface of the first sub - part 113 facing the core 140, the surface of the counterbore 1141 facing the core 140, and the surface of the fourth sub - part 116 facing the core 140 are at the same height. Additionally, the surface of the first sub - part 113 away from the core 140, the surface of the counterbore 1141 away from the core 140, and the surface of the fourth sub - part 116 away from the core 140 are at the same height.

[0043] It can be understood that when the boss 1142 deforms, a force is generated between the first sub - part 113 and the boss 1142 and acts on the body 111 at the position of the second sub - groove 122, which is beneficial to the opening of the second sub - groove 122 and ensures the explosion - proof effect.

[0044] In some embodiments, the surface of the first sub - part 113 facing the core 140 and the surface of the counterbore 1141 facing the core 140 are both higher than the surface of the fourth sub - part 116 facing the core 140, and the fourth sub - part 116 is used to contact the electrode of the battery. Additionally, the surface of the first sub - part 113 facing away from the core 140 and the surface of the counterbore 1141 facing away from the core 140 are both higher than the surface of the fourth sub - part 116 facing the core 140.

[0045] It can be understood that the fourth sub - part 116 is the part of the cover plate 110 closest to the battery cell core. The fourth sub - part 116 is in fit connection with the electrode, and the fourth sub - part 116 has the same electric potential as the electrode. When the cover plate 110 contacts the housing 150, there is no potential difference between the battery cover plate 110 and the housing 150, reducing the risk of corrosion of the cover plate 110 and improving the reliability of the battery.

[0046] In some embodiments, the surface of the third sub - part 115 facing the core 140 is not lower than the surface of the boss 1142 facing the core 140, and the surface of the third sub - part 115 facing away from the core 140 is not lower than the surface of the boss 1142 facing away from the core 140.

[0047] It can be understood that the cover plate 110 has an uneven structure. The third sub - part 115 is set to be the highest. As the air pressure inside the battery increases, the cover plate 110 deforms, and the third sub - part 115 bulges outwards, maximizing the space after the deformation of the cover plate 110, which is beneficial to the opening of the explosion - proof groove 120 and prevents the cover plate 110 from exploding.

[0048] In some embodiments, along the thickness direction of the cover plate 110, the cross - sectional shape of the explosion - proof groove 120 is V - shaped, trapezoidal, "U" - shaped, or parabolic. The cross - sectional shape of the explosion - proof groove 120 can be set as needed.

[0049] In some embodiments, the material of the cover plate 110 can be steel, such as SPCC material, stainless steel materials SUS410, SUS306, SUS316, SUS430, SUS444, etc. When using SPCC material, nickel can be plated on both surfaces of the cover plate 110, and the thickness of the plating layer is 0.3μm to 8μm, and the plating layer thicknesses on both sides can be the same or different.

[0050] In some embodiments, referring to Figure 1 As shown, along the top view direction of the cover plate 110, the shape of the explosion-proof groove 120 is a closed circular ring.

[0051] It can be understood that the explosion-proof groove 120 is set as a circular ring. When the cover plate 110 relieves pressure, a part of the cover plate 110 inside the explosion-proof groove 120 is completely separated from a part of the cover plate 110 outside the explosion-proof groove 120, realizing the complete opening of the explosion-proof structure, smooth pressure relief, and ensuring the explosion-proof effect.

[0052] In some embodiments, referring to Figure 1 and Figure 2 As shown, the depth of the counterbore 1141 is A, and 0.8C ≤ A ≤ 1.5C, where C is the thickness of the area outside the explosion-proof groove 120 on the body 111. For example, 1C ≤ A ≤ 1.3C, where A can be 0.8C, 0.9C, 1.0C, 1.1C, 1.2C, 1.3C, 1.4C, 1.5C or other unlisted values.

[0053] It can be understood that the body 111 is integrally formed, and the value of the depth A of the counterbore 1141 is associated with the thickness of the body 111, avoiding the situation that the depth of the counterbore 1141 is too different from the thickness of the body 111, which is not conducive to processing, ensuring the formation of the counterbore 1141, and the processing technology is simple.

[0054] In some embodiments, the thickness of the area outside the explosion-proof groove 120 on the body 111 is C, and 0.4mm ≤ C ≤ 1.0mm. Among them, the value of C can be 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm or other unlisted values.

[0055] It can be understood that the thicker the thickness of the body 111, the better the structural strength of the cover plate 110, but the greater the pressure required for the explosion-proof groove 120 to open. In the embodiments of the present application, the thickness of the body 111 is designed within a reasonable range, taking into account the structural strength of the cover plate 110 and the opening pressure of the explosion-proof groove 120, and improving the comprehensive performance of the cover plate 110.

[0056] In some embodiments, referring to Figure 1 and Figure 7As shown, the width of the top of the sunk platform 1141 is D1, and the width of the bottom of the sunk platform 1141 is D2, where

[0057] 4mm ≤ D1 ≤ 12mm;

[0058] D2 = D1 - 2C * tan(α - 90°), and D2 > 2mm;

[0059] α is the angle formed between the bottom and the side of the sunk platform 1141, 100° ≤ α ≤ 170°;

[0060] C is the thickness of the area outside the explosion-proof groove 120 on the body 111.

[0061] For example, D1 takes values of 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm or other unlisted values, and α takes values of 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170° or other unlisted values. The width D2 of the bottom can be calculated based on D1 and α.

[0062] It can be understood that the larger D1 and D2 of the sunk platform 1141 are, the larger the directionally opened area is, which can achieve rapid pressure relief and prevent the occurrence of battery explosion. However, if D1 and D2 of the sunk platform 1141 are too large, the splashing area of the battery liquid is also larger, affecting the surrounding batteries. In the embodiments of the present application, the size of the sunk platform 1141 is reasonably set to ensure the effect of directional opening and pressure relief of the explosion-proof structure.

[0063] In some embodiments, as shown in Figure 7 As shown, along the top view direction of the body 111, the outer diameter of the ring where the explosion-proof groove 120 is located is E1, the inner diameter of the second sub-part 114 is E2, the outer diameter of the second sub-part 114 is E3, and the diameter of the body 111 is E4, where 42mm ≤ E4 ≤ 46mm. For example, E4 takes values of 42mm, 43mm, 44mm, 45mm, 46mm, or other unlisted values;

[0064] 0.75E4 ≤ E3 ≤ 0.96E4, 0.4E4 ≤ E2 ≤ 0.72E4 and 3C ≤ E3 - E2 ≤ 22.8C;

[0065] E2 + C ≤ E1 ≤ E3 - C, where C is the thickness of the area outside the explosion-proof groove 120 on the body 111.

[0066] It can be understood that in the embodiments of the present application, the size of the diameter E4 of the body 111 is associated with the corresponding battery product specifications, the sizes of E2 and E3 are associated with E4, the size of E1 is associated with E2 and E3, and the structural size of the cover plate 110 is reasonably designed. By reasonably setting the area of the second sub - part 114, it is convenient to process the explosion - proof groove 120. The larger E1 is, the larger the opening area of the explosion - proof groove 120 is, and the better the pressure relief effect is.

[0067] On the basis of the above - mentioned implementation manner, the thickness of the body 111 at the position where the explosion - proof groove 120 is located is H, and 50μm ≤ H ≤ 120μm.

[0068] It can be understood that the thicker the thickness of the body 111 at the position where the explosion - proof groove 120 is located, the greater the pressure required for the explosion - proof groove 120 to open. The thickness of the body 111 at the position where the explosion - proof groove 120 is located is positively correlated with the pressure required for the explosion - proof groove 120 to open. If the thickness of the body 111 at the position where the explosion - proof groove 120 is located is relatively thin, the explosion - proof groove 120 may open within the normal working range of the battery, affecting the performance of the battery. If the thickness of the body 111 at the position where the explosion - proof groove 120 is located is relatively thick, the pressure required for the explosion - proof groove 120 to open is large, and the battery is prone to explosion. In the embodiments of the present application, the thicknesses of the first sub - groove 121 and the second sub - groove 122 are the same. The thickness of the body 111 at the position where the explosion - proof groove 120 is located can be 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 120μm or other unlisted values. The thickness range of the body 111 where the explosion - proof groove 120 is located is reasonably designed, which can prevent the battery from exploding while meeting the normal operation of the battery.

[0069] In some implementation manners, as shown in Figure 6 the width of the notch of the explosion - proof groove 120 is a, and 0.6mm ≤ a ≤ 1.5mm. Among them, the value of a can be 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm or other unlisted values.

[0070] It can be understood that the width of the notch of the explosion - proof groove 120 is reasonably designed, which is beneficial to the processing and forming of the explosion - proof groove 120 on the second sub - part 114.

[0071] In some implementation manners, the ratio of the arc length of the first sub - groove 121 to the arc length of the second sub - groove 122 is G, wherein, the value of G can be or other unlisted values.

[0072] Reasonably arrange the arc lengths of the first sub-groove 121 and the second sub-groove 122, and reasonably arrange the opening sizes of the primary pressure relief and the secondary pressure relief to ensure the explosion-proof effect.

[0073] In some embodiments, the thickness of the body 111 at the location of the explosion-proof groove 120 is H.

[0074]

[0075] Wherein, E1 is the outer diameter of the ring where the explosion-proof groove 120 is located.

[0076] P is the pressure at which the cover plate 110 at the explosion-proof groove 120 opens.

[0077] Q is the tensile strength of the material used to prepare the cover plate 110.

[0078] According to the required pressure, combined with the material of the cover plate 110 and the perimeter of the explosion-proof groove 120, the thickness H of the body 111 at the location of the explosion-proof groove 120 can be designed. The design is simple and the performance of the cover plate 110 is ensured.

[0079] In some embodiments, the thickness of the body 111 at the location of the explosion-proof groove 120 is H, 50 μm ≤ H ≤ 120 μm. The depths of the first sub-groove 121 and the second sub-groove 122 are the same. Among them, the value of H can be 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm, 120 μm or other unlisted values.

[0080] In some embodiments, refer to Figure 5 and Figure 6 As shown, the thickness of the body 111 at the location of the first sub-groove 121 is H1, and the thickness of the body 111 at the location of the second sub-groove 122 is H2, where H1 < H2.

[0081] It can be understood that the first sub-groove 121 and the second sub-groove 122 are arranged on the first side surface 1143. By arranging the first sub-groove 121 and the second sub-groove 122 on the body 111, the thickness of the body 111 at the position where the first sub-groove 121 is located is less than the thickness of the body 111 at the position where the second sub-groove 122 is located. When the internal pressure of the battery increases, the position of the first sub-groove 121 on the body 111 is opened first, and then the position of the second sub-groove 122 on the body 111 is opened, forming secondary pressure relief of the battery. The first opening can discharge combustible gas, and the second opening can discharge combustion-supporting gas, so as to achieve the purpose of discharging combustible gas and combustion-supporting gas at different times, overcoming the problem that when the existing explosion-proof structure explodes, due to the interaction of combustible gas, combustion-supporting gas and the substances in the battery, the degree of thermal runaway is aggravated, causing the battery to explode. After the body 111 at the position of the first sub-groove 121 is opened, the body 111 at the position of the second sub-groove 122 is broken through from the connection between the first sub-groove 121 and the second sub-groove 122, which is beneficial to the opening of the body 111 at the position of the second sub-groove 122, improving the reliability of the cover plate and ensuring the explosion-proof effect.

[0082] In some embodiments, referring to Figure 5 and Figure 6 As shown, the thickness of the body 111 at the position where the first sub-groove 121 is located is H1, and the thickness of the body 111 at the position where the second sub-groove 122 is located is H2. 20μm ≤ H1 ≤ 115μm, 25μm ≤ H2 ≤ 135μm, and 5μm ≤ H2 - H1 ≤ 20μm. For example, 45μm ≤ H1 ≤ 55μm, 80μm ≤ H2 ≤ 100μm. Among them, the value of H1 can be 20μm, 30μm, 40μm, 50μm, 60μm, 70μm, 80μm, 90μm, 100μm, 110μm, 115μm or other unlisted values. The value of H2 can be 25μm, 35μm, 45μm, 55μm, 65μm, 75μm, 85μm, 95μm, 105μm, 115μm, 125μm, 135μm or other unlisted values, and the value of H2 - H1 can be 5μm, 10μm, 15μm, 20μm or other unlisted values.

[0083] It can be understood that the thickness of the body 111 at the position where the first sub-groove 121 is located and the thickness of the body 111 at the position where the second sub-groove 122 is located are positively correlated with the pressure required for the explosion-proof groove 120 to open. The thickness ranges of the body 111 at the position where the first sub-groove 121 is located and the body 111 at the position where the second sub-groove 122 is located are reasonably designed to ensure the normal operation of the battery, achieve secondary pressure relief, and prevent the battery from exploding.

[0084] Referring to Figure 9 、 Figure 10 、 Figure 11 and Figure 12As shown in the figure, an embodiment of the present application further provides a battery, which is a cylindrical battery and includes the cover plate 110 of any one of the embodiments. It can be applied to the positive side or the negative side of the battery. Taking the cover plate 110 applied to the negative side of the cylindrical battery as an example for illustration. The battery includes the above-mentioned cover plate 110, winding core 140 and housing 150. The winding core 140 is installed in the housing 150. One end of the housing 150 is provided with an opening 151, and the cover plate 110 is hermetically connected to the housing 150 to block the opening 151. The battery has the same technical effect as the battery explosion-proof structure, which will not be elaborated here.

[0085] Based on the above embodiments, referring to Figure 11 and Figure 12 As shown in the figure, the battery further includes a first current collector plate 160, a second current collector plate 170 and an insulating member 180. The other end of the housing 150 is provided with a positive terminal 152. The winding core 140, the first current collector plate 160 and the second current collector plate 170 are all arranged in the housing 150. The cover plate 110 is hermetically connected to the housing 150 and blocks the opening 151. The second side surface 1144 of the cover plate 110 abuts against one side surface of the first current collector plate 160. The other side surface of the first current collector plate 160 is welded to the negative terminal of the winding core 140. The peripheral side of the first current collector plate 160 is connected to the inner surface of the housing 150 to make the housing 150 charged. There is no potential difference between the cover plate 110 and the housing 150, reducing the risk of corrosion of the cover plate 110 and improving the reliability of the battery. The positive terminal 152 is arranged at one end of the housing 150 away from the cover plate 110 and is hermetically connected to the housing 150 through a sealing ring. The second current collector plate 170 is welded to the winding core 140 and the positive terminal 152. The second current collector plate 170 is arranged between the positive terminal of the winding core 140 and the positive terminal 152. In addition, an insulating member 180 is provided between the second current collector plate 170 and the end of the housing 150 to insulate the second current collector plate 170 and the housing 150.

[0086] In some embodiments, a part of the side wall of the housing 150 near the opening 151 is inwardly contracted to form a flange 153. A pressing plate 154 is provided on the opening 151 of the housing 150. The pressing plate 154 is arranged at a relative interval with the flange 153. The cover plate 110 is installed between the flange 153 and the pressing plate 154. A sealing member 155 is provided between the cover plate 110 and the flange 153 and the pressing plate 154 to ensure the sealing performance of the cover plate 110. The sealing member 155 is a sealing ring, and the compression rate of the sealing ring is between 30% and 70%, improving the pressure relief effect of the explosion-proof structure.

[0087] In other embodiments, the cover plate 110 is connected to the housing 150 by laser welding. The laser welding process is simple and has good sealing performance. At this time, the first current collector plate 160 is in direct contact with the housing 150 and can also be in direct contact with the cover plate 110 to make the housing 150 negatively charged.

[0088] See also Figure 14 As shown, a battery pack according to an embodiment of the present application includes the above-mentioned battery.

[0089] In some embodiments, see Figure 14 , Figure 15 and Figure 16 As shown, the battery pack further includes a mounting seat 130, the mounting seat 130 is provided with a plurality of mounting grooves 131 and a plurality of baffles 132, the battery, the mounting grooves 131 and the baffles 132 correspond to each other, the end of the battery 100 close to the cover plate 110 is mounted in the mounting groove 131, the baffle 132 is located on the side of the mounting groove 131 away from the battery 100, the first sub-groove 121 has a first groove wall 1211 and a second groove wall 1212, the second groove wall 1212 is closer to the center of the cover plate 110 than the first groove wall 1211, the projection of the baffle 132 on one side of the cover plate 110 is located on the side of the first groove wall 1211 away from the second groove wall 1212, and the width of the baffle 132 is greater than or equal to the length of the first sub-groove 121. The baffle 132 may be a flat plate or an arc-shaped plate.

[0090] It can be understood that as the pressure inside the battery 100 increases, the first sub-groove 121 in the sink 1141 opens, and the gas and substances in the battery 100 are ejected from the side of the first sub-groove 121. By setting a baffle 132 on the mounting base 130, the baffle 132 is located below the sink 1141, and the projection of the baffle 132 on the plane where the cover plate 110 is located is aligned with the sink 1141. The baffle 132 blocks the substances ejected from the battery 100 to prevent the ejected substances from entering the adjacent battery 100 and contaminating the adjacent battery 100.

[0091] See also Figure 16 It can be seen that the baffle 132 is an arc-shaped plate, the arc length of the baffle 132 is L4, and the arc length in the area where the sink 1141 is located is L5, L4≥L5, so that the baffle 132 has a larger blocking area and a better blocking effect.

[0092] Based on the above implementation, see Figure 14 As shown, the mounting base 130 includes a first sub-plate 133 and a second sub-plate 134, the first sub-plate 133 and the second sub-plate 134 are arranged relatively spaced apart, the first sub-plate 133 is connected to the second sub-plate 134, the mounting groove 131 is opened on the first sub-plate 133, the baffle 132 is located between the first sub-plate 133 and the second sub-plate 134, and the baffle 132 is connected to the first sub-plate 133. The mounting base 130 is convenient for processing and molding, and the gap between the first sub-plate 133 and the second sub-plate 134 can accommodate the substances sprayed out by the battery to prevent the substances sprayed out from the battery from affecting other batteries.

[0093] The technical scheme and technical effects of the present application are described in detail below through specific embodiments and comparative examples. The following embodiments are only some embodiments of the present application and do not specifically limit the present application.

[0094] This example is intended to investigate the effect of the explosion-proof structure on battery performance.

[0095] The first test group

[0096] The structure of the cover plate 110 in this test group is as follows: the body 111 includes a first sub-section 113, a second sub-section 114, a third sub-section 115 and a fourth sub-section 116. The second sub-section 114 includes a connected sink 1141 and a boss 1142, the sink 1141 and the boss 1142 are located on the same circumference, the second sub-section 114 has a first side surface 1143 and a second side surface 1144 that are arranged opposite to each other, the first side surface 1143 is the surface of the second sub-section 114 away from the winding core 140, the second side surface 1144 is the surface of the second sub-section 114 facing the winding core 140, the direction from the second side surface 1144 to the first side surface 1143, and the height of the boss 1142 is higher than the sink 1141 and the first sub-section 113. The explosion-proof groove 120 is opened on the first side surface 1143 or the second side surface 1144 , and includes a first sub-groove 121 and a second sub-groove 122 that are connected. The first sub-groove 121 is at least partially located on the sink 1141 , and the second sub-groove 122 is located on the boss 1142 .

[0097] Test method: Adopt Article 6.2.4 of GB / T31485-2015 standard.

[0098] Evaluation criteria: the opening time of the first sub-slot 121 is T1, the opening time of the second sub-slot 122 is T2, and the opening time difference between the first sub-slot 121 and the second sub-slot 122 is ΔT, wherein T1 and T2 satisfy the following conditions: 50s≤T1≤100s, 60s≤T2≤150s, 5s≤ΔT≤50s.

[0099] It is understandable that when the T1 time is too short, within 50s, the battery may have a problem of valve leakage when opening. If it exceeds 100s, the temperature when opening is too high, and a large amount of combustible gas will explode when it comes into contact with the air after the valve opens instantly after reaching the flash point. In the embodiment of the present application, the T1 time is set reasonably, and a pressure relief is achieved within the T1 time period to release the combustible gas.

[0100] The parameters involved in the cover plate 110 include: H1, H2, H2-H1, a, C, G, A, E1, E2, E3, E4, E3-E2, D1 and D2. The parameters of the basic group 1 are shown in the following Table 1.1.

[0101] Set basic group 1. The parameters and verification results of basic group 1 are shown in Table 1.1 below.

[0102] Table 1.1: Parameters of Basic Group 1

[0103]

[0104] According to the verification results in Table 1.1, while the cover plate 110 realizes directional opening, the opening time of the first sub-slot 121 and the opening time of the second sub-slot 122 both meet the evaluation criteria. While meeting the performance of the explosion-proof structure, secondary pressure relief is realized.

[0105] Based on the parameters of Basic Group 1, by controlling the parameter changes of the cover plate 110 through the single-variable method, the comparative examples and examples are set. The changed parameters and verification results of the comparative examples and examples are shown in Table 1.2.

[0106] Table 1.2: Verification Results of Comparative Examples and Examples Set by Changing D1 and D2 with the Change of D1 Based on Basic Group 1

[0107] D1 / mm D2 / mm Verification result Example 1 4.00 3.20 T1 = 74 s, T2 = 122 s, ΔT = 48 s Example 2 12.00 11.20 T1 = 97 s, T2 = 126 s, ΔT = 29 s Comparative example 1 1.00 0.20 T1 = 60 s, T2 = 124 s, ΔT = 64 s Comparative example 2 18.00 17.20 T1 = 100 s, T2 = 104 s, ΔT = 4 s

[0108] According to Table 1.2: While the cover plate 110 realizes directional opening, when D1 is within the set range, while meeting the performance of the explosion-proof structure, secondary pressure relief is realized. When D1 is lower or higher than the set range, the time interval between the two pressure relieves is shorter or longer, and the secondary pressure relief effect of the explosion-proof structure is reduced.

[0109] In the above embodiments, the descriptions of each embodiment have their own emphases. For the parts not detailed in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0110] In the description of the present application, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features.

[0111] The above has introduced in detail the cover plate, battery and battery pack provided by the embodiments of the present application. Specific examples are used in this article to elaborate on the principle and implementation manner of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those skilled in the art, according to the idea of the present application, there will be changes in the specific implementation manner and application scope. In summary, the content of this specification should not be construed as a limitation to the present application.

Claims

1. A cover plate, applied to a battery, characterized in that: include: A body (111), comprising a first sub-section (113) and a second sub-section (114), wherein the first sub-section (113) is adjacent to the second sub-section (114), and along the radial direction of the body (111), the first sub-section (113) is close to the edge of the body (111), wherein the second sub-section (114) comprises a connected sink (1141) and a convex platform (1142), wherein the sink (1141) and the convex platform (1142) are located on the same circumference, and the second sub-section (114) has a first side surface (1143) and a second side surface (1144) arranged opposite to each other, and the direction from the second side surface (1144) to the first side surface (1143) is the same, and the height of the convex platform (1142) is higher than the sink (1141) and the first sub-section (113); The explosion-proof groove (120) comprises a first sub-groove (121) and a second sub-groove (122), wherein the first sub-groove (121) is at least partially located on the sink (1141), and the second sub-groove (122) is located on the boss (1142).

2. The cover plate according to claim 1, characterized in that: The body (111) further comprises a third sub-portion (115), the third sub-portion (115) is circular, the third sub-portion (115) is concentrically arranged with the second sub-portion (114), and the sink (1141) and the protrusion (1142) form a closed ring.

3. The cover plate according to claim 2, characterized in that: The body (111) further comprises a fourth sub-section (116), which is annular in shape and is located between the second sub-section (114) and the third sub-section (115), and the fourth sub-section (116) connects the second sub-section (114) and the third sub-section (115).

4. The cover plate according to claim 3, characterized in that: The surface of the first sub-portion (113) facing the winding core (140), the surface of the sink (1141) facing the winding core (140), and the surface of the fourth sub-portion (116) facing the winding core (140) are located at the same height; Alternatively, the surface of the first sub-portion (113) facing the winding core (140) and the surface of the sink (1141) facing the winding core (140) are both higher than the surface of the fourth sub-portion (116) facing the winding core (140), and the fourth sub-portion (116) is used to contact the electrode of the battery.

5. The cover plate according to claim 2, characterized in that: The surface of the third sub-portion (115) facing the winding core (140) is not lower than the surface of the boss (1142) facing the winding core (140), and the surface of the third sub-portion (115) away from the winding core (140) is not lower than the surface of the boss (1142) away from the winding core (140).

6. The cover plate according to claim 2, characterized in that: The explosion-proof groove (120) is in the shape of a ring, the outer diameter of the ring where the explosion-proof groove (120) is located is E1, the inner diameter of the second sub-section (114) is E2, the outer diameter of the second sub-section (114) is E3, the diameter of the body (111) is E4, and the thickness of the area outside the explosion-proof groove (120) on the body (111) is C, wherein: 42mm≤E4≤46mm; 0.75E4≤E3≤0.96E4, 0.4E4≤E2≤0.72E4 and 3C≤E3-E2≤27.8C; E2+C≤E1≤E3-C.

7. The cover plate according to claim 1, characterized in that: The surface of the first sub-portion (113) facing the winding core (140) and the surface of the sinking platform (1141) facing the winding core (140) are located at the same height, and the surface of the first sub-portion (113) away from the winding core (140) and the surface of the sinking platform (1141) away from the winding core (140) are located at the same height.

8. The cover plate according to claim 1, characterized in that: The depth of the sink (1141) is A, 0.8C≤A≤1.5C, wherein C is the thickness of the area outside the explosion-proof groove (120) on the body (111).

9. The cover plate according to claim 1, characterized in that: The thickness of the body (111) is C, 0.4 mm ≤ C ≤ 1.0 mm.

10. The cover plate according to claim 1, characterized in that: The width of the top of the sink (1141) is D1, and the width of the bottom of the sink (1141) is D2, wherein: 4mm≤D1≤12mm; D2=D1-2C*tan(α-90°), and D2>2mm; α is the angle formed between the bottom and the side of the sink (1141), 100°≤α≤170°; C is the thickness of the area outside the explosion-proof groove (120) on the body (111).

11. The cover plate according to any one of claims 1 to 10, characterized in that: The thickness of the body (111) at the location of the explosion-proof groove (120) is H, Wherein, E1 is the outer diameter of the circular ring where the explosion-proof groove (120) is located; P is the pressure at which the body (111) is opened at the position of the explosion-proof groove (120); Q is the tensile strength of the material used to make the cover plate (110).

12. The cover plate according to any one of claims 1 to 10, characterized in that: The thickness of the body (111) at the location of the explosion-proof groove (120) is H, 50 μm≤H≤120 μm.

13. The cover plate according to any one of claims 1 to 10, characterized in that: The thickness of the main body (111) at the location of the first sub-groove (121) is H1, and the thickness of the main body (111) at the location of the second sub-groove (122) is H2, and H1<H2.

14. The cover plate according to claim 13, characterized in that: 20μm≤H1≤115μm, 25μm≤H2≤135μm, and 5μm≤H2-H1≤20μm.

15. The cover plate according to claim 13, characterized in that: The explosion-proof groove (120) is in the shape of a circular ring, and the ratio of the arc length of the first sub-groove (121) to the arc length of the second sub-groove (122) is G.

16. A battery, characterized in that: include: The cover plate according to any one of claims 1 to 15; A winding core (140) including a positive terminal and a negative terminal; A shell (150), the winding core (140) is installed in the shell (150), one end of the shell (150) is provided with an opening (151), and the body (111) is sealedly connected to the shell (150) to block the opening (151).

17. The battery according to claim 16, characterized in that Also includes: A positive terminal (152), a first current collecting disc (160), a second current collecting disc (170) and an insulating member (180), wherein the positive terminal (152) is arranged at one end of the shell (150) away from the main body (111), the first current collecting disc (160) is welded to the winding core (140) and is arranged between the main body (111) and one end of the winding core (140), the second current collecting disc (170) is welded to the winding core (140) and the positive terminal (152) and is arranged between the winding core (140) and the positive terminal (152), and the insulating member (180) is arranged between the second current collecting disc (170) and the shell (150).

18. A battery pack, characterized in that: Comprising a plurality of batteries as claimed in claim 16 or 17.

19. The battery pack according to claim 18, characterized in that: Also includes: The mounting seat (130) is provided with a plurality of mounting grooves (131) and a plurality of baffles (132); one end of the battery close to the body (111) is mounted in the mounting groove (131); the baffle (132) is located on a side of the mounting groove (131) away from the battery; the first sub-groove (121) has a first groove wall (1211) and a second groove wall (1212); the second groove wall (1212) is closer to the center of the body (111) than the first groove wall (1211); and the projection of the baffle (132) on a side surface of the body (111) is located on a side of the first groove wall (1211) away from the second groove wall (1212).

20. The battery pack according to claim 19, characterized in that: The mounting seat (130) comprises a first sub-plate (133) and a second sub-plate (134), wherein the first sub-plate (133) and the second sub-plate (134) are arranged relatively spaced apart, the mounting groove (131) is provided on the first sub-plate (133), the baffle plate (132) is located between the first sub-plate (133) and the second sub-plate (134), and the baffle plate (132) is connected to the first sub-plate (133).

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