Battery

Abstract

The invention relates to a battery. The box body is provided with a containing cavity and a bottom plate serving as a side wall of the containing cavity, and the bottom plate is provided with a plurality of first weak areas; the plurality of single batteries are mounted in the accommodating cavity, each single battery comprises a shell and a battery cell assembly, the shell is provided with an inner cavity and an exhaust passage communicated with the inner cavity, and the battery cell assembly is accommodated in the inner cavity of the shell; the ends, provided with the exhaust channels, of the shells face the first weak areas on the bottom plate in a one-to-one correspondence mode. Wherein high-pressure gas generated when thermal runaway happens to the single batteries passes through the exhaust channel and breaks through the corresponding first weak areas, so that the single batteries subjected to thermal runaway are sprayed out of the box body from the corresponding first weak areas.

Description

Technical Field

[0001] The present application relates to the technical field of battery manufacturing, and specifically to a battery. Background Art

[0002] Lithium-ion batteries have high energy density, long cycle life, good rate performance and safety, are green and environmentally friendly, and are important energy products for modern electronic products and power vehicles. In order to increase the output voltage or current, the battery usually includes multiple battery cells connected in series, parallel or mixed, and each battery cell is integrated in the battery box. During use, if one of the battery cells has a thermal runaway due to an abnormality, a large amount of high-temperature smoke and other substances will be ejected. If there are no effective blocking measures, the thermal runaway of the battery cell will quickly spread to other battery cells, causing other battery cells to also have thermal runaway, and then causing the entire battery to have thermal runaway, seriously threatening personal safety and property safety. Summary of the invention

[0003] Based on this, it is necessary to provide a battery that can prevent thermal runaway from spreading to other battery cells and improve battery safety in response to the above problems.

[0004] In one aspect, the present application provides a battery, comprising: The box body has a receiving cavity and a bottom plate as a side wall of the receiving cavity, and the bottom plate has a plurality of first weak areas; A plurality of battery cells are installed in the receiving cavity, each of the battery cells comprises a shell and a battery cell assembly, the shell has an inner cavity and an exhaust passage connected to the inner cavity, and the battery cell assembly is received in the inner cavity; one end of each of the shells having the exhaust passage faces each of the first weak areas on the bottom plate in a one-to-one correspondence; The high-pressure gas generated when the battery cell experiences thermal runaway passes through the exhaust passage and breaks through the corresponding first weak area, so that the battery cell experiencing thermal runaway is ejected from the corresponding first weak area to the outside of the box.

[0005] In some embodiments, the housing includes a shell and a cover plate, the shell has an opening on a side facing the bottom plate, the cover plate covers the opening of the shell, and the shell and the cover plate together enclose the inner cavity; The cover plate is provided with the exhaust channel and a second weak area for closing the exhaust channel. The high-pressure gas generated when the battery cell has thermal runaway can break through the second weak area and the corresponding first weak area on the cover plate.

[0006] In some embodiments, the cover plate further has an annular area arranged around the first weak area; In the radial direction from the outer edge to the inner edge of the annular region, the distance between the side surface of the annular region facing the inner cavity and the side surface of the annular region facing the bottom plate decreases gradually or in a step-like manner.

[0007] In some embodiments, the cover plate includes a first annular plate, a second annular plate and an explosion-proof plate, the inner edge of the first annular plate is fixedly connected to the inner edge of the second annular plate, and encloses the exhaust channel; the outer edge of the first annular plate and the outer edge of the second annular plate are arranged at intervals from each other, and the second annular plate is located between the first annular plate and the bottom plate; The explosion-proof disk is fixedly connected to the first annular plate and / or the second annular plate to close the exhaust passage, and the second weak area is located on the explosion-proof disk.

[0008] In some embodiments, one end of the shell facing the bottom plate has an annular end surface arranged around the opening, and the annular end surface connects the inner wall and the outer wall of the shell; The outer edge of the second annular plate has an annular connecting portion, and the annular connecting portion is attached to and fixed to the annular end surface by welding.

[0009] In some embodiments, an annular convex strip is protruded from a side of the annular connecting portion facing away from the bottom plate, and the annular convex strip abuts against an inner wall of the shell.

[0010] In some embodiments, each of the battery cells further includes a bonding block, and the bonding block is bonded and fixed between the annular connecting portion and the bottom plate.

[0011] In some embodiments, each of the battery cells further includes a current collecting plate disposed between the first annular plate and the battery cell assembly, wherein the outer peripheral edge of the current collecting plate is folded toward the cover plate to form a flange, and the flange is fixedly connected between the outer edge of the first annular plate and the inner wall of the shell.

[0012] In some embodiments, the first annular plate is enclosed by a side facing the inner cavity to form a first sub-channel, the second annular plate is enclosed by a side facing the bottom plate to form a second sub-channel, and the exhaust channel includes the first sub-channel and the second sub-channel; The maximum flow area and the minimum flow area of ​​the first subchannel are S1 and S2 respectively, and 0.1≤S2 / S1≤0.7.

[0013] In some embodiments, the first annular plate is enclosed by a side facing the inner cavity to form a first sub-channel, the second annular plate is enclosed by a side facing the bottom plate to form a second sub-channel, and the exhaust channel includes the first sub-channel and the second sub-channel; The maximum flow area and the minimum flow area of ​​the second subchannel are S3 and S4 respectively, and 0.2≤S4 / S3≤0.8.

[0014] In some of the embodiments, the orthographic projection of the shell on the base plate does not exceed the range of the corresponding first weak area.

[0015] In some embodiments, the battery further comprises a bus bar disposed in the receiving cavity, the bus bar being arranged on a side of each battery cell away from the bottom plate, each battery cell further comprises a pole, the pole being arranged on an end of the housing away from the bottom plate; One of the pole and the busbar is provided with an inserting hole, and the other is provided with an inserting protrusion, and the inserting protrusion is inserted and matched with the inserting hole.

[0016] In some embodiments, elastic contact fingers are provided on the inner wall of the peripheral side of the plug hole, and when the plug protrusion is inserted into the plug hole, the elastic contact fingers elastically abut against the plug protrusion.

[0017] In some embodiments, a plurality of first annular notch grooves are formed on the bottom plate, and each of the first annular notch grooves encloses and forms the first weak area.

[0018] In some embodiments, the distance between two adjacent first annular notch grooves is 1 mm to 5 mm.

[0019] Compared with the prior art, this application has the following beneficial effects: In the actual use of the above-mentioned battery, if a battery cell experiences thermal runaway, a large amount of high-pressure gas is generated inside the battery cell, and the high-pressure gas flows to the corresponding first weak area on the bottom plate through the exhaust channel on the shell, and breaks through the first weak area. After the first weak area corresponding to the battery cell experiencing thermal runaway ruptures, the battery cell experiencing thermal runaway is ejected from the corresponding first weak area on the bottom plate as a whole under the drive of the high-pressure airflow (that is, the battery cell experiencing thermal runaway is discharged outside the box), thereby preventing the thermal runaway from spreading to other battery cells in the box, and further preventing the entire battery from experiencing thermal runaway, greatly reducing the threat to personal safety and property safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of a battery in an embodiment of the present application (the side panels and top panel of the box are omitted); Figure 2 for Figure 1 A schematic structural diagram of a bottom plate of a battery shown; Figure 3 for Figure 2 A schematic diagram of the structure of the bottom plate shown in another viewing angle; Figure 4 for Figure 1 A cross-sectional view of a battery cell of the battery shown; Figure 5 for Figure 4 The battery cell shown is a partial enlarged view at the cover plate (i.e., position E); Figure 6 for Figure 4 The partial enlarged view of the battery cell at the pole (i.e., position F) shown; Figure 7 for Figure 4 A schematic structural diagram of a cover plate of a battery cell shown; Figure 8 for Figure 7 a cross-sectional view of the cover plate shown; Fig. 9 This is a schematic diagram of the structure of a cover plate in another embodiment of the present application; Fig.10 for Fig. 9 A cross-sectional view of the cover is shown. DETAILED DESCRIPTION

[0021] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0022] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0023] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0024] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0025] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0026] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0027] See also Figures 1 to 4The present application provides a battery, including a box body and a plurality of battery cells 20. The box body has a receiving cavity and a bottom plate 11 as a side wall of the receiving cavity. The bottom plate 11 has a plurality of first weak areas A1, each of which can be broken under high pressure. Each battery cell 20 is installed in the receiving cavity of the box body. Each battery cell 20 includes a shell 21 and a battery cell assembly 22. The shell 21 has an inner cavity 2110 and an exhaust channel B connected to the inner cavity 2110, and the battery cell assembly 22 is accommodated in the inner cavity 2110 of the shell 21. One end of the exhaust channel B of the shell 21 of each battery cell 20 corresponds to each first weak area A1 on the bottom plate 11, and one end of the exhaust channel B of the shell 21 of each battery cell 20 faces the corresponding first weak area A1, so that the high-pressure gas discharged from the exhaust channel B on the shell 21 can flow to the corresponding first weak area A1, and then break through the first weak area A1. When the battery cell 20 experiences thermal runaway, a large amount of high-pressure gas will be generated. The generated high-pressure gas passes through the exhaust channel B and breaks through the corresponding first weak area A1, so that the battery cell 20 experiencing thermal runaway is ejected out of the box from the corresponding first weak area A1 as a whole.

[0028] In the actual use of the above-mentioned battery, if a battery cell 20 has thermal runaway, a large amount of high-pressure gas is generated inside the battery cell 20, and the high-pressure gas flows to the corresponding first weak area A1 on the bottom plate 11 through the exhaust channel B on the shell 21, and breaks through the first weak area A1. After the first weak area A1 corresponding to the battery cell 20 with thermal runaway is ruptured, the battery cell 20 with thermal runaway is ejected from the corresponding first weak area A1 on the bottom plate 11 as a whole under the drive of the high-pressure airflow (that is, the battery cell 20 with thermal runaway is discharged outside the box), thereby preventing the thermal runaway from spreading to other battery cells 20 in the box, and further preventing the entire battery from having thermal runaway, which greatly reduces the threat to personal safety and property safety. In addition, since the battery cell 20 with thermal runaway is directly ejected outside the box, the high-pressure airflow will not circulate in the box, so the exhaust path is very short and the exhaust pressure relief efficiency is high.

[0029] Specifically in the embodiment, a plurality of first annular notched grooves 111 are provided on the bottom plate 11, and each first annular notched groove 111 encloses a first weak area A1. In this way, when the battery cell 20 undergoes thermal runaway, a large amount of high-pressure gas will be generated, and the generated high-pressure gas will be discharged from the exhaust channel B. Under the impact of the high-pressure gas discharged from the exhaust channel B, the corresponding first weak area A1 on the bottom plate 11 will rupture along the first annular notched groove 111. At this time, the battery cell 20 that has undergone thermal runaway is driven by the high-pressure gas and ejected from the broken first weak area A1 to the outside of the box as a whole. Optionally, each first annular notched groove 111 on the bottom plate 11 is arranged on a side surface of the bottom plate 11 that is away from the battery cell 20 (i.e., the outer surface). Of course, in other embodiments, each first annular notched groove 111 on the bottom plate 11 can also be arranged on a side surface of the bottom plate 11 that faces the battery cell 20 (i.e., the inner surface).

[0030] Optionally, the spacing between two adjacent first annular notched grooves 111 on the bottom plate 11 is 1mm-5mm. It should be noted that the inventor creatively discovered based on a large number of experiments that if the spacing between two adjacent first annular notched grooves 111 on the bottom plate 11 is less than 1mm, on the one hand, the strength of the portion between the two adjacent first annular notched grooves 111 on the bottom plate 11 is weak, resulting in weak rigidity and strength of the entire bottom plate 11, and easy deformation; on the other hand, there is a risk of affecting the adjacent battery cells 20 when the battery cells 20 with thermal runaway are discharged. If the spacing between the two adjacent first annular notched grooves 111 on the bottom plate 11 is greater than 5mm, it will cause space waste and greatly reduce the volume energy density of the battery. In this embodiment, the spacing between the two adjacent first annular notched grooves 111 on the bottom plate 11 is designed to be 1mm-5mm, so as to minimize the adverse effects on the rigidity and strength of the bottom plate 11, reduce the adverse effects on the adjacent battery cells 20 when the battery cells 20 with thermal runaway are discharged from the box, and reduce the adverse effects on the volume energy density of the battery. Specifically, the spacing is 1mm, 1.4mm, 1.7mm, 2.0mm, 2.2mm, 2.4mm, 2.6mm, 2.8mm, 3.0mm, 3.3mm, 3.5mm, 3.7mm, 4.0mm, 4.4mm, 4.7mm or 5.0mm, including but not limited to the values ​​listed above, and other values ​​within the range are also applicable.

[0031] Specifically in the embodiment, a plurality of positioning blocks 112 are provided on one side (i.e., the inner surface) of the bottom plate 11 facing each battery cell 20. The plurality of positioning blocks 112 are arranged around each first weak area A1, and are used to position each battery cell 20 one by one at each first weak area A1 on the bottom plate 11, that is, to limit each battery cell 20 at the corresponding first weak area A1.

[0032] See also Figure 4 and Figure 5 In the embodiment of the present application, the housing 21 includes a shell 211 and a cover plate 213. The shell 211 has an opening on one side facing the bottom plate 11, and the cover plate 213 covers the opening of the shell 211 to close the opening of the shell 211. The shell 211 and the cover plate 213 together enclose the above-mentioned inner cavity 2110. The cover plate 213 has an exhaust channel B and a second weak area A2 for closing the exhaust channel B. The high-pressure gas generated when the battery cell 20 has thermal runaway can break through the second weak area A2 on the cover plate 213 and the corresponding first weak area A1 on the bottom plate 11. In this way, by setting the second weak area A2 on the cover plate 213, it is ensured that the second weak area A2 will not start to rupture until the air pressure in the inner cavity 2110 of the shell 211 reaches a preset value, and then the corresponding first weak area A1 on the bottom plate 11 will start to rupture, which greatly reduces the risk of mis-starting or delayed start of the first weak area A1 on the bottom plate 11.

[0033] See also Figure 5 , Figure 7 and Figure 8 Specifically, in the embodiment, the cover plate 213 further has an annular area A3 arranged around the first weak area A1, the side of the annular area A3 facing the inner cavity 2110 is the first side A31, and the side facing the bottom plate 11 is the second side A32. In the radial direction from the outer edge to the inner edge of the annular area A3, the distance between the first side A31 and the second side A32 of the annular area A3 gradually decreases, so that the first side A31 encloses a first sub-channel B1 for high-pressure gas to pass through, and the second side A32 encloses a second sub-channel B2 for high-pressure gas to pass through, and the first sub-channel B1 and the second sub-channel B2 constitute the exhaust channel B mentioned above. In this way, after the first weak area A1 on the cover plate 213 is ruptured under the action of the high-pressure gas, in the discharge direction of the high-pressure airflow discharged from the first weak area A1, the flow area of ​​the first sub-channel B1 gradually increases, and the flow area of ​​the second sub-channel B2 gradually decreases. The first sub-channel B1 and the second sub-channel B2 form a Laval structure, so that the flow rate of the high-pressure airflow flowing through the first sub-channel B1 and the second sub-channel B2 increases rapidly and reaches supersonic speed. The supersonic airflow generates a huge thrust, which breaks through the corresponding first weak area A1 on the bottom plate 11, and drives the battery cell 20 as a whole to be ejected from the ruptured first weak area A1 on the bottom plate 11 to the outside of the box, thereby preventing thermal runaway from spreading to other battery cells 20 in the box.

[0034] The following is an explanation of the process of airflow acceleration. When the battery cell 20 is abnormally thermally runaway, a large amount of high-pressure gas is generated. When the air pressure in the inner cavity 2110 of the shell 211 reaches a preset value, the second weak area A2 on the cover plate 213 ruptures, and the high-pressure airflow is discharged from the inner cavity 2110 through the exhaust channel B, and reaches the space between the cover plate 213 and the corresponding first weak area A1 on the bottom plate 11. In the process of high-pressure airflow being discharged from the exhaust channel B, it first passes through the first sub-channel B1. Since the flow area of ​​the first sub-channel B1 gradually decreases, the airflow follows the principle that the smaller the flow area, the greater the flow velocity, and the larger the flow area, the smaller the flow velocity. Therefore, when the airflow passes through the first sub-channel B1, the flow velocity continues to increase and reaches the speed of sound. Since the transonic airflow no longer follows the principle that the larger the flow area, the smaller the flow velocity, but follows the principle that the larger the flow area, the greater the flow velocity. As the flow area of ​​the second sub-channel B2 becomes larger and larger, the airflow entering the second sub-channel B2 after being accelerated by the first sub-channel B1 continues to accelerate and becomes a supersonic airflow, thereby generating a huge thrust, ensuring that the corresponding first weak area A1 on the bottom plate 11 can be broken through, and the battery cell 20 as a whole can be driven to be ejected from the broken first weak area A1 on the bottom plate 11 to the outside of the box.

[0035] It should be noted that, in the radial direction from the outer edge to the inner edge of the annular area A3, the spacing between the first side surface A31 and the second side surface A32 is not limited to a gradual decrease, but can also be a step-by-step decrease, as long as a Laval structure can be formed to accelerate the airflow passing therethrough, and no special limitation is made here.

[0036] Specifically in the embodiment, the cover plate 213 includes a first annular plate 2131, a second annular plate 2133 and an explosion-proof plate 2135. The second annular plate 2133 is located between the first annular plate 2131 and the bottom plate 11, that is, the first annular plate 2131, the second annular plate 2133 and the bottom plate 11 are stacked in sequence. The inner edge of the first annular plate 2131 is fixedly connected to the inner edge of the second annular plate 2133, and the outer edge of the first annular plate 2131 and the outer edge of the second annular plate 2133 are arranged at intervals from each other, so that the distance between the first annular plate 2131 and the second annular plate 2133 gradually decreases in the radial direction from the outer edge to the inner edge, so that the side surface of the first annular plate 2131 away from the second annular plate 2133 is used as the above-mentioned first side surface A31, and encloses the above-mentioned first sub-channel B1; the side surface of the second annular plate 2133 away from the first annular plate 2131 is used as the above-mentioned second side surface A32, and encloses the above-mentioned second sub-channel B2.

[0037] The explosion-proof plate 2135 is fixedly connected to the inner edge of the first annular plate 2131 and the second annular plate 2133 to close the exhaust channel B (i.e., to isolate the first sub-channel B1 from the second sub-channel B2). The second weak area A2 is located on the explosion-proof plate 2135. When the battery cell 20 undergoes thermal runaway and the air pressure in the shell 211 reaches a preset value, the second weak area A2 on the explosion-proof plate 2135 ruptures, so that the first sub-channel B1 is connected to the second sub-channel B2, so that the airflow in the shell 211 is accelerated to supersonic speed in the first sub-channel B1 and the second sub-channel B2, and the accelerated airflow generates a huge thrust to break through the corresponding first weak area A1 on the bottom plate 11, and drive the battery cell 20 that has undergone thermal runaway to be ejected from the ruptured first weak area A1 to the outside of the box.

[0038] It should be noted that the cover plate 213 uses a first annular plate 2131 and a second annular plate 2133 to form a Laval structure. The cover plate 213 has a simple structure, and a weight-reducing cavity is formed between the first annular plate 2131 and the second annular plate 2133, which reduces the weight of the cover plate 213, is beneficial to improving the energy density of the battery and reducing processing costs.

[0039] It should also be noted that the explosion-proof disc 2135 is not limited to being fixedly connected to the inner edge of the first annular plate 2131 and the second annular plate 2133. In other embodiments, the explosion-proof disc 2135 can also be fixedly connected to the first side surface A31 of the first annular plate 2131, or can also be fixedly connected to the second side surface A32 of the second annular plate 2133, as long as it can close the exhaust channel B, which is not limited here. The inner edge of the first annular plate 2131 and the inner edge of the second annular plate 2133 can be fixedly connected by welding, and the explosion-proof disc 2135 and the first annular plate 2131 and / or the second annular plate 2133 can also be fixedly connected by welding, which can achieve mechanical connection between the first annular plate 2131, the second annular plate 2133 and the explosion-proof disc 2135 on the one hand, and also achieve sealing between the three on the other hand.

[0040] Specifically in the embodiment, a second annular notch groove L2 is formed on the explosion-proof disc 2135, and the area surrounded by the second annular notch groove L2 is the second weak area A2. Of course, the second weak area A2 on the explosion-proof disc 2135 can also be formed by notch grooves of other shapes, as long as it can achieve rupture and pressure relief when the air pressure in the housing 211 reaches a preset value, which is not limited here.

[0041] In some embodiments, the peripheral edge of the explosion-proof disc 2135 is welded and fixed to the inner edge of the first annular plate 2131 and the second annular plate 2133, so that the explosion-proof disc 2135 seals the central hole formed by the inner edge of the first annular plate 2131 and the inner edge of the second annular plate 2133, thereby achieving the purpose of closing the exhaust channel B. In this way, compared with the explosion-proof disc 2135 being set at other positions, the explosion-proof disc 2135 is fixedly connected to the inner edge of the first annular plate 2131 and the second annular plate 2133, which can reduce the area of ​​the second weak area A2 as much as possible, thereby reducing the difficulty of rupture of the second weak area A2, which is conducive to improving the accuracy and sensitivity of explosion-proof pressure relief of the battery cell 20.

[0042] Specifically, the maximum flow area of ​​the first sub-channel B1 is S1, the minimum flow area is S2, and S1 and S2 satisfy: 0.1≤S2 / S1≤0.7. It should be noted that in the direction perpendicular to the bottom plate 11 (i.e., the axial direction of the first annular plate 2131 and the second annular plate 2133), the height dimension from the outer edge to the inner edge of the first annular plate 2131 is H1. If S2 / S1<0.1, S1 is much larger than S2. When the inclination angle of the first annular plate 2131 remains unchanged, the required height value H1 is large, which will greatly reduce the volume energy density of the battery cell 20. If S2 / S1>0.7, S1 and S2 are not much different, and it is difficult for the airflow to reach the speed of sound after accelerating through the first sub-channel B1. In this way, the first annular plate 2131 is designed so that S1 and S2 satisfy: 0.1≤S2 / S1≤0.7, which is conducive to improving the volume energy density of the battery cell 20 and ensuring that the airflow can reach the speed of sound after accelerating through the first sub-channel B1. In some embodiments, S1 and S2 satisfy: 0.2≤S2 / S1≤0.6.

[0043] Specifically, the maximum flow area of ​​the second sub-channel B2 is S3, the minimum flow area is S4, and S3 and S4 satisfy: 0.2≤S4 / S3≤0.8. It should be noted that in the direction perpendicular to the bottom plate 11 (i.e., the axial direction of the first annular plate 2131 and the second annular plate 2133), the height dimension from the outer edge to the inner edge of the second annular plate 2133 is H2. If S4 / S3<0.2, S3 is much larger than S4. When the inclination angle of the second annular plate 2133 remains unchanged, the larger the required height value H2, the greater the volume energy density of the battery cell 20 will be. When S4 / S3>0.8, S3 and S4 are not much different, and the acceleration effect on the airflow flowing through the second sub-channel B2 is not significant, resulting in the thrust generated by the airflow being insufficient to discharge the battery cell 20 out of the box. In some embodiments, S4 and S3 satisfy: 0.3≤S4 / S3≤0.7.

[0044] It should be noted that the explosion-proof disk 2135 is not necessary. In other embodiments, see Fig. 9 and Fig.10 As shown, the cover plate 213 may not include the explosion-proof plate 2135, so that the first sub-channel B1 and the second sub-channel B2 are always connected. The high-pressure airflow generated when the battery cell 20 has thermal runaway is directly discharged through the first sub-channel B1 and the second sub-channel B2. For ease of understanding, the following description takes the embodiment in which the cover plate 213 includes the explosion-proof plate 2135 as an example.

[0045] Please continue to see Figure 5 , Figure 7 and Figure 8 Specifically, in the embodiment, each battery cell 20 further includes a current collecting plate 23 disposed between the first annular plate 2131 and the battery cell assembly 22. The outer peripheral edge of the current collecting plate 23 is folded toward the cover plate 213 to form a flange 231, and the flange 231 of the current collecting plate 23 is fixedly connected between the outer edge of the first annular plate 2131 and the inner wall of the shell 211, thereby achieving a fixed connection between the first annular plate 2131 and the current collecting plate 23 and the shell 211, and preventing the high-pressure airflow in the shell 211 from entering the space between the first annular plate 2131 and the second annular plate 2133 from between the first annular plate 2131 and the inner wall of the shell 211. Furthermore, the shell 211, the flange 231 of the collecting plate 23 and the outer edge of the first annular plate 2131 can be fixedly connected by welding, which on the one hand realizes the mechanical connection among the shell 211, the collecting plate 23 and the first annular plate 2131; on the other hand, it realizes the sealing of the gap between the inner wall of the shell 211 and the flange 231 of the collecting plate 23 and the gap between the flange 231 of the collecting plate 23 and the first annular plate 2131.

[0046] Specifically in the embodiment, the end of the shell 211 facing the bottom plate 11 has an annular end face 2112 arranged around the opening. The annular end face 2112 connects the inner wall and the outer wall of the shell 211. The outer edge of the second annular plate 2133 has an annular connecting portion 2136, and the annular connecting portion 2136 is attached to the annular end face 2112 and fixed by welding. Further, the side of the annular connecting portion 2136 facing away from the bottom plate 11 has an annular welding surface that is roughly parallel to the annular end face 2112. The annular connecting portion 2136 is attached to the annular end face 2112 on the shell 211 through the annular welding surface, and the annular welding surface of the annular connecting portion 2136 is fixedly connected to the annular end face 2112 of the shell 211 by welding.

[0047] It should be noted that the outer edges of the first annular plate 2131 and the second annular plate 2133 are spaced apart from each other and are both fixedly connected to the housing 211, and the inner edges of the first annular plate 2131 and the second annular plate 2133 are fixedly connected to each other, so that the first annular plate 2131, the second annular plate 2133 and the housing 211 form a triangular structure, which greatly improves the stability of the three structures and avoids deformation of the first annular plate 2131 and the second annular plate 2133. Since the first annular plate 2131 is not easy to deform, it can better guide the airflow to pass through the first sub-channel B1 and the second sub-channel B2 in sequence, and will not flow in from the gap between the first annular plate 2131 and the inner wall of the housing 211, so that the air pressure in the housing 211 has little effect on the connection between the second annular plate 2133 and the inner wall of the housing 211, and avoids the connection between the second annular plate 2133 and the housing 211 from failing before the second weak area A2.

[0048] Furthermore, an annular convex strip 2137 is convexly provided on the side of the annular connecting portion 2136 facing away from the bottom plate 11, and the annular convex strip 2137 abuts against the inner wall of the housing 211. Thus, the annular convex strip 2137 is provided, on the one hand, before welding and fixing, the annular convex strip 2137 and the annular connecting portion 2136 are used to realize the positioning of the second annular plate 2133 and the housing 211, which facilitates the assembly of the housing 211 and the cover plate 213, and is conducive to improving the welding quality; on the other hand, the annular convex strip 2137 can play the effect of strengthening the second annular plate 2133, which is conducive to improving the structural strength and stability.

[0049] Furthermore, the battery further includes a bonding block 40, which is bonded and fixed between the annular connection portion 2136 and the bottom plate 11, that is, the second annular plate 2133 of the cover plate 213 is bonded and fixed to the bottom plate 11 through the bonding block 40, so as to achieve the fixation of the battery cell 20 and the bottom plate 11. Specifically, the side of the annular connection portion 2136 facing the bottom plate 11 has an annular bonding surface that is substantially parallel to the surface of the bottom plate 11, and the bonding block 40 is arranged between the annular bonding surface of the annular connection portion 2136 and the bottom plate 11, so as to bond and fix the second annular plate 2133 to the bottom plate 11. Optionally, the bonding block 40 can be made of structural adhesive.

[0050] It is understandable that the shape of the bonding block 40 can be an annular shape that matches the annular bonding surface of the annular connecting portion 2136. Of course, the bonding block 40 can also include multiple bonding blocks 40, which are arranged at intervals along the circumference of the annular bonding surface of the annular connecting portion 2136, as long as the second annular plate 2133 can be bonded and fixed to the bottom plate 11, and this is not limited here.

[0051] Specifically in the embodiment, the orthographic projection of the shell 211 on the bottom plate 11 does not exceed the range of the corresponding first weak area A1, so that the size of the first weak area A1 on the bottom plate 11 is larger than the outer dimensions of the shell 211 of the corresponding battery cell 20, ensuring that the battery cell 20 can be ejected from the corresponding first weak area A1 on the bottom plate 11, and preventing the shell 211 of the battery cell 20 from being stuck at the first weak area A1 on the bottom plate 11. Preferably, the orthographic projection of the shell 211 on the bottom plate 11 roughly coincides with the edge of the first weak area A1, and on the basis of ensuring the smooth discharge of the battery cell 20, the impact on the adjacent battery cell 20 is minimized as much as possible, and the waste of space is reduced.

[0052] See also Figure 4 and Figure 6 In the embodiment of the present application, each battery cell 20 further includes a pole 24, which is insulated and arranged on the end of the shell 211 away from the bottom plate 11. Specifically, the end of the battery cell assembly 22 facing the collector plate 23 has a first pole ear, which is electrically connected to the collector plate 23, and the first pole ear is electrically connected to the shell 211. The end of the battery cell assembly 22 facing the pole 24 has a second pole ear with a polarity opposite to the first pole ear, and the second pole ear is electrically connected to the pole 24. In this way, the pole 24 and the shell 211 serve as two electrode terminals of the battery cell 20 respectively, and jointly realize the input and output of electric energy of the battery cell 20. It should be noted that if the first pole ear is a positive pole ear and the second pole ear is a negative pole ear, the shell 211 is a positive terminal and the pole 24 is a negative terminal; if the first pole ear is a negative pole ear and the second pole ear is a positive pole ear, the shell 211 is a negative terminal and the pole 24 is a positive terminal. It should be noted that the pole 24 and the second pole tab may be directly connected, or indirectly connected via a current collecting component, as long as electrical conduction between the pole 24 and the second pole tab can be achieved, and no limitation is made here.

[0053] Furthermore, the battery also includes a busbar 30 disposed in the receiving cavity of the box body, and the busbar 30 is arranged on the side of each battery cell 20 away from the bottom plate 11, and is electrically connected to the pole 24 of each battery cell 20, so as to realize the series connection, parallel connection or mixed connection of each battery cell 20. In this way, when the battery cell 20 has thermal runaway, under the action of the high-pressure airflow, the second weak area A2 on the explosion-proof plate 2135 is broken, and the corresponding first weak area A1 on the bottom plate 11 is broken, and the pole 24 of the battery cell 20 having thermal runaway is separated from the busbar 30, and then the whole is ejected from the corresponding first weak area A1 on the bottom plate 11 to the outside of the box.

[0054] Specifically, in one embodiment, a plug hole 241 is provided on the pole 24, and a plug protrusion 31 is provided on the bus 30. The plug protrusion 31 is plugged into the plug hole 241, that is, the pole 24 and the bus 30 are electrically connected by plugging and matching the plug protrusion 31 and the plug hole 241. In this way, the pole 24 and the bus 30 are connected by plugging and matching, and while ensuring the electrical connection between the two, the connection strength between the pole 24 and the bus 30 is reduced as much as possible, ensuring that the pole 24 can be smoothly separated from the bus 30 under the action of high-pressure airflow when the battery cell 20 has thermal runaway, so that when the battery cell 20 that has thermal runaway is ejected from the corresponding first weak area A1 on the bottom plate 11, the pole 24 has less damage to the bus 30, and thus has less impact on other battery cells 20.

[0055] Furthermore, elastic contact fingers 2410 are provided on the inner wall of the peripheral side of the plug hole 241. When the plug protrusion 31 is inserted into the plug hole 241, the elastic contact fingers 2410 elastically abut against the plug protrusion 31, thereby ensuring that the elastic contact fingers 2410 and the plug protrusion 31 are in close contact and achieve electrical connection, thereby ensuring that the pole 24 of the battery cell 20 and the busbar 30 are electrically connected.

[0056] It is understandable that the elastic contact finger 2410 can maintain contact with the plug-in protrusion 31 entering the plug-in hole 241 under the action of the spring or the spring sheet, and the specific structure can adopt the more mature existing technology, which is not specifically limited here. The elastic contact finger 2410 on the inner wall of the peripheral side of the plug-in hole 241 can be one or more, which is not specifically limited here.

[0057] Specifically in the embodiment, the box body also includes a top plate and a plurality of side plates, and the top plate is located on the side of each battery cell 20 away from the bottom plate 11. Each side plate is arranged between the top plate and the bottom plate 11, and is sequentially connected end to end, so that the top plate, the bottom plate 11 and each side plate are enclosed together to form the above-mentioned receiving cavity. In some embodiments, the number of side plates is four, and the four side plates, the top plate and the bottom plate 11 together form a box body in the shape of a rectangular parallelepiped. Of course, the box body can also be other shapes, which are not limited here.

[0058] Based on the above-mentioned battery, the present application also provides an electric device, which uses the battery cell 20 described in any of the above-mentioned embodiments as its power source. Specifically, the electric device can be a vehicle, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The vehicle can be a fuel vehicle, a gas vehicle, or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle, or an extended-range vehicle, etc.; the spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, etc.; the electric toy includes a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, and an electric airplane toy, etc.; the electric tool includes a metal cutting electric tool, a grinding electric tool, an assembly electric tool, and an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact drill, a concrete vibrator, and an electric planer, etc. The embodiments of the present application do not impose any special restrictions on the above-mentioned electric devices.

[0059] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A battery, characterized in that: include: A box body, comprising a receiving cavity and a bottom plate (11) serving as a side wall of the receiving cavity, wherein the bottom plate (11) has a plurality of first weak areas (A1); A plurality of battery cells (20) are installed in the receiving cavity, each of the battery cells (20) comprising a shell (21) and a battery cell assembly (22), the shell (21) having an inner cavity (2110) and an exhaust passage (B) communicating with the inner cavity (2110), the battery cell assembly (22) being accommodated in the inner cavity (2110); one end of each of the shells (21) having the exhaust passage (B) faces each of the first weak areas (A1) on the bottom plate (11) in a one-to-one correspondence; Wherein, the high-pressure gas generated when the battery cell (20) undergoes thermal runaway passes through the exhaust passage (B) and breaks through the corresponding first weak area (A1), so that the battery cell (20) undergoing thermal runaway is ejected from the corresponding first weak area (A1) to the outside of the box.

2. The battery according to claim 1, characterized in that The housing (21) comprises a shell (211) and a cover plate (213); the shell (211) has an opening on a side facing the bottom plate (11); the cover plate (213) covers the opening of the shell (211); the shell (211) and the cover plate (213) together enclose the inner cavity (2110); The cover plate (213) is provided with the exhaust channel (B) and a second weak area (A2) for closing the exhaust channel (B); the high-pressure gas generated when the battery cell (20) undergoes thermal runaway can break through the second weak area (A2) and the corresponding first weak area (A1) on the cover plate (213).

3. The battery according to claim 2, characterized in that The cover plate (213) further comprises an annular area (A3) arranged around the first weak area (A1); In the radial direction from the outer edge to the inner edge of the annular area (A3), the distance between the side of the annular area (A3) facing the inner cavity (2110) and the side facing the bottom plate (11) gradually decreases or decreases in a step-like manner.

4. The battery according to claim 3, characterized in that The cover plate (213) comprises a first annular plate (2131), a second annular plate (2133) and an explosion-proof plate (2135); the inner edge of the first annular plate (2131) is fixedly connected to the inner edge of the second annular plate (2133), and encloses the exhaust channel (B); the outer edge of the first annular plate (2131) and the outer edge of the second annular plate (2133) are arranged at intervals from each other, and the second annular plate (2133) is located between the first annular plate (2131) and the bottom plate (11); The explosion-proof plate (2135) is fixedly connected to the first annular plate (2131) and / or the second annular plate (2133) to close the exhaust channel (B), and the second weak area (A2) is located on the explosion-proof plate (2135).

5. The battery according to claim 4, characterized in that One end of the shell (211) facing the bottom plate (11) has an annular end surface (2112) arranged around the opening, and the annular end surface (2112) connects the inner wall and the outer wall of the shell (211); The outer edge of the second annular plate (2133) has an annular connecting portion (2136), and the annular connecting portion (2136) is attached to and fixed to the annular end surface (2112) by welding.

6. The battery according to claim 5, characterized in that An annular convex strip (2137) is provided on the side of the annular connecting portion (2136) facing away from the bottom plate (11), and the annular convex strip (2137) abuts against the inner wall of the shell (211).

7. The battery according to claim 5, characterized in that Each of the battery cells (20) further comprises a bonding block (40), wherein the bonding block (40) is bonded and fixed between the annular connecting portion (2136) and the bottom plate (11).

8. The battery according to claim 4, characterized in that Each of the battery cells (20) further comprises a current collecting plate (23) arranged between the first annular plate (2131) and the battery cell assembly (22); the outer peripheral edge of the current collecting plate (23) is folded toward the cover plate (213) to form a flange (231); the flange (231) is fixedly connected between the outer edge of the first annular plate (2131) and the inner wall of the shell (211).

9. The battery according to claim 4, characterized in that The first annular plate (2131) encloses a first sub-channel (B1) on the side facing the inner cavity (2110), and the second annular plate (2133) encloses a second sub-channel (B2) on the side facing the bottom plate (11), and the exhaust channel (B) includes the first sub-channel (B1) and the second sub-channel (B2); The maximum flow area and the minimum flow area of ​​the first sub-channel (B1) are S1 and S2 respectively, and the maximum flow area and the minimum flow area of ​​the second sub-channel (B2) are S3 and S4 respectively; Among them, 0.1≤S2 / S1≤0.7, and / or, 0.2≤S4 / S3≤0.

8.

10. The battery according to claim 1, characterized in that The bottom plate (11) is provided with a plurality of first annular notched grooves (111), each of the first annular notched grooves (111) encloses the first weak area (A1), and the distance between two adjacent first annular notched grooves (111) is 1 mm to 5 mm.

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