Battery and battery pack

Abstract

The present application provides a battery and a battery pack. The battery comprises: a case, wherein the case comprises a top wall and a bottom wall arranged opposite to each other, and a plurality of side walls arranged between the top wall and the bottom wall, and the top wall is provided with at least one pole; and at least one explosion-proof valve arranged on the side walls, wherein the distance between the center of the explosion-proof valve and the top wall is set to h, the height of the side walls is set to H, and h / H satisfies: 1 / 4<h / H<1 / 2.

Description

Battery and battery pack

[0001] The present application claims priority to the Chinese patent application No. 202410822827.4, filed on June 24, 2024, to the Chinese Patent Office, the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of battery, in particular to a battery and a battery pack. BACKGROUND

[0003] An explosion-proof valve is arranged in a single battery in a power battery pack or an energy storage battery pack, and the explosion-proof valve is crucial to the safety performance of the single battery. The top of the battery is usually provided with a positive pole and a negative pole, and the explosion-proof valve is usually arranged between the positive pole and the negative pole. SUMMARY

[0004] In the related art, when the battery pack is used in a new energy vehicle or an energy storage battery cabinet, the height space of the battery cavity available for the installation of the battery pack in the new energy vehicle or the energy storage battery cabinet is limited, and when the explosion-proof valve is arranged at the top of the single battery, the upper part of the explosion-proof valve needs to be provided with an exhaust passage, which further increases the height design size of the battery pack, thereby causing the design size of the battery pack to exceed the installation height size of the battery accommodating cavity of the new energy vehicle or the energy storage battery cabinet.

[0005] In a first aspect, embodiments of the present application provide a battery, comprising:

[0006] a shell, the shell comprising a top wall, a bottom wall arranged oppositely to the top wall, and a plurality of side walls arranged between the top wall and the bottom wall, at least one pole being arranged on the top wall;

[0007] at least one explosion-proof valve, the explosion-proof valve being arranged on the side wall;

[0008] wherein a distance between the center of the explosion-proof valve and the top wall is h, a height of the side wall is H, and h / H satisfies: 1 / 4≤h / H≤1 / 2.

[0009] In a second aspect, embodiments of the present application provide a battery pack, comprising a box body and at least two battery modules arranged in the box body, each battery module comprising a battery, and the battery module comprising an upper layer battery module and a lower layer battery module arranged along the height direction of the box body. ADVANTAGEOUS EFFECTS

[0010] The battery provided in the application can improve the design size of the battery pack caused by the explosion-proof valve designed on the top of the battery exceeding the installation height size of the battery accommodating cavity of the new energy vehicle or the energy storage battery cabinet by arranging the explosion-proof valve on at least one side wall of the shell. Moreover, by setting the ratio between the distance h between the center of the explosion-proof valve and the top wall and the height H of the first side wall, i.e., h / H, to 0.25≤h / H≤0.5, the opening pressure of the explosion-proof valve is stable, the corrosion of the electrolyte to the explosion-proof valve is reduced, and the safety performance of the battery is improved.

[0011] The battery pack provided in the application is designed based on the battery, and the beneficial effects thereof are described in the beneficial effects of the battery, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0012] FIG. 1 is a perspective structural schematic view of the battery pack provided in the embodiment of the application;

[0013] FIG. 2a is a front view of the battery provided in one embodiment of the application;

[0014] FIG. 2b is a perspective view of the battery provided in one embodiment of the application;

[0015] FIG. 2c is a side view of the battery provided in one embodiment of the application;

[0016] FIG. 2d is a schematic view of the surface area size of the side wall and the explosion-proof valve provided in one embodiment of the application;

[0017] FIG. 3a is a side view of the battery provided in another embodiment of the application;

[0018] FIG. 3b is a perspective view of the battery provided in another embodiment of the application;

[0019] FIG. 4 is a structural schematic view of the explosion-proof valve provided in one embodiment of the application;

[0020] FIG. 5 is a structural schematic view of the explosion-proof valve provided in another embodiment of the application;

[0021] FIG. 6 is a schematic view of the exhaust structure inside the box provided in one embodiment of the application;

[0022] FIG. 7 is a schematic view of the exhaust port structure of the box provided in one embodiment of the application;

[0023] LIST OF REFERENCE NUMBERS

[0024] 1. battery pack; 100, battery module; 10, box body; 11, side plate; 12, end plate; 13, exhaust passage; 14, through hole; 15, exhaust port; 110, battery cavity; 120, electrical cavity; 20, battery; 21, shell; 211, top wall; 212, bottom wall; 213, side wall; 2131, first side wall; 21311, first side edge; 21312, second side edge; 2132, second side wall; 2133, third side wall; 2134, fourth side wall; 30, connecting piece; 31, pole; 40, explosion-proof valve; 41, first main body part; 411, first score part; 4111, first section; 4112, second section; 4113, third section; 42, first reinforcing part; 421, first part; 422, second part; 423, third part; 43, second main body part; 431, second score part; 4311, fourth section; 4312, fifth section; 4313, sixth section; 44, second reinforcing part; 441, fourth part; 442, fifth part; 451, first interval; 452, second interval; Embodiments of the present application

[0025] In this application, the orientation words such as "up" and "down" generally refer to the up and down of the device in the actual use or working state, and specifically refer to the direction of the drawing surface in the drawing; and "inner" and "outer" refer to the outline of the device.

[0026] Embodiments of the present application provide a battery pack, which can be a power battery pack used for storing electrical energy as a power source for electric vehicles, hybrid vehicles. The battery pack can also be an energy storage battery pack, which includes an energy storage container for storing electrical energy to provide various functions for the power system, such as a smart mobile power grid. As shown in FIG. 1, the battery pack 1 includes a box body 10, a plurality of single batteries 20, and a BMS (battery management system).

[0027] The box body 10 is used to fix and protect a plurality of single batteries and other components, and the box body can be assembled by several sub-boxes. The material suitable for preparing the box body has good anti-vibration, waterproof and insulation properties, and suitable materials include metal or plastic materials. The box body 10 is provided with a hollow inner cavity, and the inner cavity of the box body 10 can be divided into a battery cavity 110 and an electrical cavity 120. The battery cavity 110 is used to place a plurality of batteries 20, and the electrical cavity 120 is used to place a BMS and other fixed components.

[0028] The plurality of single batteries 20 are arranged in a matrix form in the battery cavity 110, and the plurality of single batteries 20 can be connected in series, or the plurality of single batteries 20 can be connected in parallel, or the plurality of single batteries 20 can be connected in a mixed connection of series and parallel, so that the battery pack 1 has a capacity and power suitable for use by the electrical equipment. The single battery 20 includes a lithium ion battery, a nickel-hydrogen battery, a lead-acid battery, a lithium iron phosphate battery, or a multi-element composite material battery.

[0029] The battery pack 1 further includes a plurality of connecting pieces 30, each connecting piece 30 being used to connect the positive and negative electrodes of two adjacent batteries 20, so that the plurality of batteries 20 have a stable series-parallel connection structure between the positive and negative electrodes, and the material used to prepare the connecting piece 30 includes copper, aluminum, or a composite material of copper and aluminum.

[0030] As a power battery pack or an energy storage battery pack, the battery pack further includes a BMS (Battery Management System) for monitoring, protecting, and managing the working state of the battery pack. The BMS can monitor and balance the voltage and temperature of each single battery cell, and can also control the power and protection function during the charging and discharging process of the battery pack.

[0031] Embodiments of the present application provide a single battery 20, which includes a shell 21, an electrode assembly, and an electrolyte.

[0032] Taking a square single battery 20 as an example, the shell 21 is configured to be made of a metal material having certain mechanical strength and corrosion resistance, and suitable metal materials include nickel or steel. The shell 21 has a hollow inner cavity, and the electrode assembly is received in the inner cavity of the shell 21, and the shell 21 is used to fix and protect the electrode assembly.

[0033] The electrode assembly includes a positive electrode sheet, a separator, and a negative electrode sheet, the separator is arranged between the positive electrode sheet and the negative electrode sheet and is used to separate the positive electrode sheet and the negative electrode sheet. The electrode assembly can be formed by winding the positive electrode sheet, the separator, and the negative electrode sheet to form a winding core assembly, or the electrode assembly can be formed by stacking the positive electrode sheet, the separator, and the negative electrode sheet to form a laminated core assembly.

[0034] The electrolyte is filled in the inside of the battery 20, so that the positive electrode sheet, the negative electrode sheet, and other internal structures of the battery are fully soaked in the electrolyte. The electrolyte serves as an ion transmission carrier between the positive electrode sheet and the negative electrode sheet, maintains the continuity of the electron transmission inside the battery, and enables the battery to be normally charged and discharged.

[0035] The shell 21 further comprises a top cover assembly connected to the top open end of the shell and used to seal the open end of the shell, and the positive electrode pole and the negative electrode pole are usually arranged on the top cover assembly, and the positive electrode plate is electrically connected to the positive electrode pole through the positive electrode tab, and the negative electrode plate is electrically connected to the negative electrode pole through the negative electrode tab. Alternatively, at least one positive electrode pole is arranged on the top cover assembly, the positive electrode plate is electrically connected to the positive electrode pole through the positive electrode tab, and the negative electrode plate is electrically connected to the negative electrode pole on the bottom of the shell or the negative electrode pole on the bottom of the shell. Alternatively, at least one negative electrode pole is arranged on the top cover assembly, the negative electrode plate is electrically connected to the negative electrode pole through the negative electrode tab, and the positive electrode plate is electrically connected to the positive electrode pole on the bottom of the shell or the positive electrode pole on the bottom of the shell.

[0036] In the related art, the single battery in the power battery pack or the energy storage battery pack further comprises an explosion-proof valve, which is crucial to the safety performance of the single battery. The explosion-proof valve is usually arranged on the top cover assembly and located between the positive electrode pole and the negative electrode pole or between two positive electrode poles or two negative electrode poles. When the power battery pack is used in a new energy vehicle, the height space of the accommodating cavity available for the installation of the battery pack in the new energy vehicle is limited, and when the explosion-proof valve is arranged on the top of the single battery, the upper part of the explosion-proof valve needs to be provided with an exhaust passage, which will further increase the height design size of the battery pack, thereby causing the design size of the battery pack to exceed the installation height size of the battery accommodating cavity of the new energy vehicle.

[0037] When a plurality of poles are arranged on the top cover assembly, the plurality of poles can be one of the positive electrode pole and the negative electrode pole or both, and the size of the cover plate of the top cover assembly is limited, thereby limiting the size available for the installation of the explosion-proof valve on the top cover assembly, further limiting the design size of the explosion-proof valve and affecting the explosion-proof performance of the explosion-proof valve.

[0038] When the explosion-proof valve is installed at the bottom of the shell, the explosion-proof valve will be soaked in the electrolyte and corroded by the electrolyte, affecting its normal use.

[0039] In the embodiments of the present application, the structure of the explosion-proof valve is further optimized, thereby reducing the design size of the battery pack caused by the design of the explosion-proof valve on the single battery exceeding the installation height size of the battery accommodating cavity of the new energy vehicle.

[0040] Referring to FIGS. 2a, 2b and 2c, the shell 21 of the battery 20 includes oppositely arranged top wall 211 and bottom wall 212, and a plurality of side walls 213 connected between the top wall 211 and the bottom wall 212, the plurality of side walls 213 including oppositely arranged first side wall 2131 and second side wall 2132, and oppositely arranged third side wall 2133 and fourth side wall 2134. Taking a blade battery as an example, the surface area of the first side wall 2131 and the second side wall 2132 is smaller than the surface area of the third side wall 2133 and the fourth side wall 2134. In one example, the plurality of side walls 213 and the bottom wall 212 are integrally formed as a main shell with an open structure, and the top wall 211 is arranged as a top cover assembly and connected at the opening of the main shell. The top cover assembly generally includes a cover plate and a lower plastic structure, and the cover plate is welded to the main shell and the lower plastic structure is fixed to the cover plate.

[0041] The battery 20 further includes a plurality of pole posts 31 fixed to the lower plastic structure. At least two pole posts 31 are arranged on the top wall 211, and the two pole posts 31 can be one or both of positive pole posts or negative pole posts.

[0042] The battery 20 further includes at least one explosion-proof valve 40 arranged on at least one side wall 213. Specifically, the explosion-proof valve 40 is arranged as one, which can be arranged on the first side wall 2131 or the second side wall 2132, or the explosion-proof valve 40 is arranged as at least two, which are arranged on the first side wall 2131 and the second side wall 2132, respectively.

[0043] By arranging the explosion-proof valve 40 on at least one side wall 213 of the battery 20, the design size of the battery pack caused by arranging the explosion-proof valve on the top of the battery can be improved to be within the installation height of the battery accommodating cavity of the new energy vehicle or the energy storage battery cabinet.

[0044] Continuing to refer to FIG. 2c, taking the example of arranging the explosion-proof valve 40 on the first side wall 2131, the first side wall 2131 includes oppositely arranged first side edge 21311 and second side edge 21312, and the top wall 211 is connected to the top end of the first side edge 21311 and the top end of the second side edge 21312, and the bottom wall 212 is connected to the bottom end of the first side edge 21311 and the bottom end of the second side edge 21312.

[0045] The distance between the center of the explosion-proof valve 40 and the top wall 211 is h, and the height of the first side wall 2131 is H. In the square battery, the height H of the first side wall 2131 is the distance between the top wall 211 and the bottom wall 212. In the preferred embodiment, the ratio between the distance h between the center of the explosion-proof valve 40 and the top wall 211 and the height H of the first side wall 2131, i.e. h / H, satisfies: 0.25≤h / H≤0.5. In the specific embodiment, h / H can be 0.25, 0.30, 0.35, 0.40, 0.45, 0.5, and any value between any two values or a range between any two values.

[0046] The inventors found that when the ratio between the distance h between the center of the explosion-proof valve 40 and the top wall 211 and the height H of the first side wall 2131, i.e. h / H, is less than 0.25, the distance between the explosion-proof valve 40 and the top wall 211 is too close. The top wall 211 is usually provided as a top cover assembly structure, which usually includes a cover plate, a lower plastic, and a pole column structure. The pole column is fixed on the lower plastic part, and the cover plate is welded on the main shell. The explosion-proof valve 40 is usually provided with a notch structure. High-energy laser is used in the welding process of the cover plate and the main shell. The high heat of the laser will affect the stability of the notch of the explosion-proof valve 40, thereby causing the opening pressure of the explosion-proof valve 40 to be unstable, and further affecting the safety performance of the battery 20.

[0047] The inventors also found that when the ratio between the distance h between the center of the explosion-proof valve 40 and the top wall 211 and the height H of the first side wall 2131, i.e. h / H, is greater than 0.5, the distance between the explosion-proof valve 40 and the bottom wall 212 is too close. The free electrolyte is usually deposited at the bottom of the battery 20, so that the electrolyte will immerse or at least partially immerse the explosion-proof valve 40. On the one hand, it will corrode the explosion-proof valve 40, thereby affecting the normal opening of the explosion-proof valve 40. On the other hand, when the explosion-proof valve 40 is opened, the explosion-proof valve 40 forms a pressure relief hole, and the electrolyte will be sprayed out through the pressure relief hole of the explosion-proof valve 40, thereby causing the risk of combustion, which greatly affects the safety performance of the battery 20.

[0048] The inventors found through experimental tests on the setting position of the explosion-proof valve 40 and the opening valve pressure range of the explosion-proof valve 40 that when the ratio between the distance h between the center of the explosion-proof valve 40 and the top wall 211 and the height H of the side wall 213, i.e. h / H, satisfies 0.25≤h / H≤0.5, the opening valve pressure range of the explosion-proof valve 40 is 0.7MPa~0.9MPa. When h / H satisfies h / H<0.25 or when h / H satisfies h / H>0.5, the opening valve pressure range of the explosion-proof valve 40 is 0.6MPa~1.0MPa. It can be seen that when h / H satisfies 0.25≤h / H≤0.5, the stability of the opening valve pressure of the explosion-proof valve 40 is obviously greater than that when h / H<0.25 or h / H>0.5.

[0049] In a further preferred implementation, the inventors found through research that when the ratio between the distance h between the center of the explosion-proof valve 40 and the top wall 211 and the height H of the side wall 213, i.e. the ratio of h / H, is set to 1 / 3, the stability of the opening valve pressure of the explosion-proof valve 40, the influence of the high-energy laser used in the welding process on the explosion-proof valve 40, and the influence of the electrolyte on the corrosion of the explosion-proof valve are in an optimal state, which is conducive to improving the safety performance of the battery 20.

[0050] By setting the explosion-proof valve 40 on at least one side wall 213 of the shell 21, correspondingly, the exhaust channel of the explosion-proof valve 40 also does not need to be designed in the top space of the monomer battery, so as to effectively exceed the installation height size of the battery containing cavity of the new energy vehicle.

[0051] By setting the explosion-proof valve 40 on at least one side wall 213 of the shell 21, and setting the pole 31 on the top wall 211, on the one hand, the size limitation of the top wall 211 cannot simultaneously design multiple poles and explosion-proof valves 40, and on the other hand, the explosion-proof valve 40 and the pole 31 are designed separately, so that the gas and electricity structure of the battery 20 is separated, so that the explosion-proof valve 40 can timely release the high-pressure gas generated inside the battery, and the safety performance of the battery is improved.

[0052] The explosion-proof valve 40 is set on the side wall 213, which can effectively improve the corrosion of the explosion-proof valve 40 soaked by the electrolyte, compared with setting the explosion-proof valve 40 on the bottom wall 212.

[0053] Continuing to refer to FIG. 2c, the first side wall 2131 includes oppositely arranged first side edge 21311 and second side edge 21312, the interval between the first side edge 21311 and the second side edge 21312 is set as the width w of the first side wall 2131, the distance between the center of the explosion-proof valve 40 and the first side edge 21311 or the second side edge 21312 is d, and in a preferred implementation, d / w satisfies: 1 / 3 < d / w < 2 / 3. The inventors have found through research on the ratio between the distance d between the center of the explosion-proof valve 40 and the first side edge 21311 or the second side edge 21312 and the width w of the first side wall 2131 on which the explosion-proof valve 40 is located and the opening pressure range of the explosion-proof valve 40 that when d / w satisfies: d / w ≤ 1 / 3 or d / w ≥ 2 / 3, the opening pressure of the explosion-proof valve 40 is 0.6 MPa-1.0 MPa, and when d / w satisfies: 1 / 3 < d / w < 2 / 3, the opening pressure of the explosion-proof valve 40 is 0.7 MPa-0.9 MPa. It can be seen that when d / w satisfies: 1 / 3 < d / w < 2 / 3, the stability of the opening pressure of the explosion-proof valve 40 is obviously greater than that when d / w ≤ 1 / 3 or d / w ≥ 2 / 3.

[0054] In a further preferred implementation, the axis on which the center of the explosion-proof valve 40 is located coincides with the central axis of the first side wall 2131, that is, the distance between the center of the explosion-proof valve 40 and the first side edge 21311 and the distance between the center of the explosion-proof valve 40 and the second side edge 21312 are the same, that is, d / w = 1 / 2. When d / w = 1 / 2, since the explosion-proof valve 40 is located on the central axis of the first side wall 2131, the distance between the center of the explosion-proof valve 40 and the first side edge 21311 and the distance between the center of the explosion-proof valve 40 and the second side edge 21312 are the same, thus under the action of the internal pressure of the battery, the deformation amount of each part of the explosion-proof valve 40 is relatively balanced, thereby being conducive to maintaining the consistency and stability of the opening pressure of the explosion-proof valve 40.

[0055] Referring to FIG. 2d, the projection area of the explosion-proof valve 40 on the first side wall 2131 is m, and the surface area of the first side wall 2131 is M, and in a preferred implementation, the ratio between the projection area m of the explosion-proof valve 40 on the first side wall 2131 and the surface area M of the first side wall 2131 is m / M, and m / M is preferably set to: 0.025 ≤ m / M ≤ 0.2. The ratio between m / M can be 0.03, 0.05, 0.06, 0.08, 0.09, 0.10, 0.11, 0.13, 0.15, 0.16, 0.18, 0.2, or a value between any two values or a range between any two values.

[0056] The inventor found through research that when the ratio m / M between the projected area m of the explosion-proof valve 40 on the first side wall 2131 and the surface area M of the first side wall 2131 is set to be less than 0.025, the pressure relief area corresponding to the explosion-proof valve 40 is too small, the exhaust speed of the explosion-proof valve 40 after opening is slow, and the shell 21 may be at risk of explosion. When the ratio m / M between the projected area m of the explosion-proof valve 40 on the first side wall 2131 and the surface area M of the first side wall 2131 is set to be greater than 0.2, the first side wall 2131 needs to be provided with a larger opening area to facilitate the design of the explosion-proof valve, thereby resulting in insufficient strength of the first side wall 2131 itself. Especially in the blade battery, when the explosion-proof valve 40 is arranged on the first side wall 2131 with a small surface area, the balance between the structural strength of the first side wall 2131 itself and the exhaust speed of the explosion-proof valve 40 is crucial.

[0057] In a further preferred implementation, the ratio between the projected area m of the explosion-proof valve 40 on the first side wall 2131 and the surface area M of the first side wall 2131 is set to 0.08. When m / M is set to 0.08, the battery 20 has outstanding effects in balancing the opening speed of the explosion-proof valve 40 and maintaining the strength of the shell 21, thereby facilitating the improvement of the overall performance of the battery 20.

[0058] Continuing to refer to FIGS. 3a and 3b, when the top wall 211 is provided with a plurality of pole columns 31, if the explosion-proof valve 40 is further arranged on the top wall 211, and the top wall 211 cannot reserve enough space to design the explosion-proof valve 40, thereby causing the projected area of the explosion-proof valve 40 designed on the top wall 211 to be too small, which makes the explosion-proof valve 40 designed on the top wall 211 cause the exhaust speed after opening to be slow, further causing the shell 21 to be at risk of explosion. Therefore, when the battery top wall 211 is provided with a plurality of pole columns 31, the explosion-proof valve 40 is preferably arranged on the side wall 213.

[0059] Referring to FIGS. 2b and 4, in an embodiment provided in the present application, a mounting hole for mounting the explosion-proof valve 40 is arranged on the side wall 213, the explosion-proof valve 40 is arranged separately from the side wall 213, the explosion-proof valve 40 is separately formed, and then the explosion-proof valve 40 is connected to the side wall 213, and the explosion-proof valve 40 is preferably welded to the side wall 213. The explosion-proof valve 40 comprises a first main body part 41 and a first reinforcing part 42, and the first reinforcing part 42 is located inside the first main body part 41. The first main body part 41 is provided with a first notch part 411, the first notch part 411 is configured as a non-closed circular arc, and the first reinforcing part 42 is configured to extend inside the first notch part 411.

[0060] When the high pressure gas flow is generated inside the battery 20, the explosion-proof valve 40 is deformed by the high pressure force. When the pressure value of the first score part 411 exceeds the rated pressure value, the first score part 411 is broken to form a pressure relief port, and the high pressure gas flow inside the battery 20 is discharged through the pressure relief port. By configuring the first score part 411 as a non-closed circular arc, and by configuring the first reinforcing part 42 inside the first score part 411, the first reinforcing part 42 is used to improve the structural strength of the explosion-proof valve 40 as a whole, to prevent the explosion-proof valve 40 from being severely deformed when being extruded from outside. The first reinforcing part 42 can also prevent the explosion-proof valve 40 as a whole from being separated from the side wall 213 after the first score part 411 is broken, and thus prevent the electrolyte from being seriously spilled.

[0061] With reference to FIGS. 2b and 4, the first score part 411 includes a first segment 4111, a second segment 4112, and a third segment 4113. The first segment 4111 is connected between one end of the second segment 4112 and one end of the third segment 4113. The other end of the second segment 4112 is oppositely arranged from the other end of the third segment 4113, and the other end of the second segment 4112 is arranged in a spaced-apart manner from the other end of the third segment 4113.

[0062] The first reinforcing part 42 includes a first portion 421, a second portion 422, and a third portion 423. One end of the first portion 421, one end of the second portion 422, and one end of the third portion 423 are connected to each other. The other end of the first portion 421 is close to the midpoint of the virtual connection line of the other end of the second segment 4112 and the other end of the third segment 4113 of the first score part 411. The other end of the second portion 422 of the first reinforcing part 42 is close to the second segment 4112 of the first score part 411, and the other end of the third portion 423 of the first reinforcing part 42 is close to the third segment 4113 of the first score part 411.

[0063] By configuring the first score part 411 as three segments, configuring the first reinforcing part 42 as three portions, and configuring each segment of the first score part 411 to correspond to a portion of the first reinforcing part 42, the strength of the explosion-proof valve 40 as a whole is kept balanced, and the corresponding opening valve threshold values at different positions of the first score part 411 are basically kept the same, which is conducive to maintaining the stability of the opening valve pressure of the explosion-proof valve 40 as a whole.

[0064] In a specific implementation, the explosion-proof valve 40 as a whole is configured as an oval shape. The first segment 4111 of the first score part 411 is configured as a straight line. The second segment 4112 and the third segment 4113 of the first score part 411 are configured as circular arc segments arranged symmetrically about the first segment 4111. The first portion 421, the second portion 422, and the third portion 423 of the first reinforcing part 42 are all configured as straight lines. The intersection point of the first portion 421, the second portion 422, and the third portion 423 is substantially located at the center of the first score part 411.

[0065] The explosion-proof valve 40 is usually formed by stamping an aluminum shell, and the wall thickness of the explosion-proof valve 40 itself is thin. Therefore, when the battery is subjected to external extrusion, the explosion-proof valve 40 connected to the side wall 213 is prone to deformation. In order to improve the deformation of the explosion-proof valve 40, in another embodiment provided in the present application, the explosion-proof valve 40 is configured to be integrally formed with the side wall 213. Since there is no welding seam between the explosion-proof valve 40 and the side wall 213, the severe deformation of the explosion-proof valve 40 after being subjected to external force can be effectively improved.

[0066] Referring to FIGS. 2b and 5, the explosion-proof valve 40 includes a second main body part 43 and a second reinforcing part 44, the second reinforcing part 44 is located on the second main body part 43, the second main body part 43 includes a second score part 431, the second score part 431 defines at least part of the profile shape of the explosion-proof valve 40, and the second score part 431 is configured as a non-closed arc structure, and the second reinforcing part 44 is arranged close to the second score part 431.

[0067] By integrally forming the explosion-proof valve 40 with the side wall 213, the second score part 431 on the explosion-proof valve 40 is configured to be stamped on the side wall 213, which can effectively improve the severe deformation of the explosion-proof valve 40 after being subjected to external force.

[0068] When high-pressure gas flow is generated inside the battery 20, the explosion-proof valve 40 is deformed under the action of high pressure. Since the wall thickness of the second score part 431 is thin, when the pressure value acting on the second score part 431 exceeds the rated pressure value, the second score part 431 will be broken to form a pressure relief port, and the high-pressure gas flow inside the battery 20 will be discharged through the pressure relief port. By arranging the second reinforcing part 44 close to the second score part 431, the second reinforcing part 44 is used to improve the structural strength of the explosion-proof valve 40, so as to prevent the explosion-proof valve 40 from being severely deformed when subjected to external extrusion. The second reinforcing part 44 can also prevent the explosion-proof valve 40 from being separated from the side wall 213 after the second score part 431 is broken, thereby causing serious electrolyte overflow.

[0069] Continuing to refer to FIG. 5, the second score part 431 includes a fourth segment 4311, a fifth segment 4312, and a sixth segment 4313. One end of the fourth segment 4311 is connected to the fifth segment 4312, and the other end of the fourth segment 4311 is connected to the sixth segment 4313. One end of the fifth segment 4312 is arranged opposite to one end of the sixth segment 4313 and forms a first gap 451, and the other end of the fifth segment 4312 is arranged opposite to the other end of the sixth segment 4313 and forms a second gap 452.

[0070] The second reinforcing portion 44 includes a fourth portion 441 and a fifth portion 442 arranged at intervals, wherein the fourth portion 441 is arranged in the first interval 451, and the fifth portion 442 is arranged in the second interval 452.

[0071] By configuring the second score portion 431 into three segments, and connecting the fourth segment 4311 of the second score portion 431 to the fifth segment 4312 and the sixth segment 4313 respectively, when the fourth segment 4311 is deformed under high pressure, the fifth segment 4312 and the sixth segment 4313 will be further deformed and broken, so that the overall structure of the second score portion 431 is beneficial to pressure relief. By arranging two reinforcing portions 44 in the first interval 451 and the second interval 452 formed at both ends of the fifth segment 4312 and both ends of the sixth segment 4313, the explosion-proof valve 40 maintains a suitable strength, and when the explosion-proof valve 40 is extruded by external force, the explosion-proof valve 40 will not be severely deformed, and when the explosion-proof valve 40 is subjected to internal high pressure and reaches the rated high pressure, the second score portion 431 of the explosion-proof valve 40 will be broken to form a pressure relief port, but the explosion-proof valve 40 as a whole will not be separated from the side wall 213, avoiding serious electrolyte overflow.

[0072] In a specific implementation, the fifth segment 4312 and the sixth segment 4313 of the second score portion 431 are configured as non-closed circular arcs, and the two ends of the fifth segment 4312 and the sixth segment 4313 are oppositely arranged, the fourth segment 4311 can be a straight segment, the fourth segment 4311 is located on the central axis of the explosion-proof valve 40, one end of the fourth segment 4311 is connected to the midpoint of the fifth segment 4312, and the other end of the fourth segment 4311 is connected to the midpoint of the sixth segment 4313. In other alternative examples, the fourth segment 4311 can also be two connected circular arcs, the connecting point of the two connected circular arcs is located at the center of the explosion-proof valve 40, the two connected circular arcs are oppositely arranged, and the two ends of each circular arc are connected to the fifth segment 4312 and the sixth segment 4313 respectively, so that the overall structure of the explosion-proof valve 40 is a central symmetric structure.

[0073] The fourth portion 441 and the fifth portion 442 of the second reinforcing portion 44 can be straight lines or circular arcs.

[0074] The embodiments of the present application also provide a battery pack 1, which includes a box body 10 and at least two battery modules 100 arranged inside the box body 10, the at least two battery modules 100 including an upper layer battery module and a lower layer battery module arranged along the height direction of the box body 10, thereby facilitating the improvement of the energy density of the battery pack. Each battery module 100 includes a plurality of batteries, at least one side wall of each battery is provided with an explosion-proof valve, and a pole is arranged on the top wall of each battery.

[0075] For the battery pack arranged with the upper layer battery module and the lower layer battery module, the plurality of batteries in the two layer battery modules are arranged more densely, if the explosion-proof valve is arranged on the top wall of each battery in each battery module, when the lower layer battery module occurs thermal runaway, the explosion-proof valve of the lower layer battery module opens to discharge high pressure gas flow, the high pressure gas flow further impacts the upper layer battery module, and further causes the upper layer battery module to occur thermal runaway, and further extremely likely causes the whole battery pack to occur thermal runaway or even thermal explosion, thereby greatly reducing the safety performance of the whole battery pack.

[0076] In the embodiment of the present application, the explosion-proof valve of each battery in the battery pack arranged with the upper layer battery module and the lower layer battery module is arranged on the side wall of the battery, when the lower layer battery module occurs thermal runaway, the high pressure gas flow discharged by the explosion-proof valve flows into both sides of the box, thereby effectively reducing the influence on the upper layer battery module.

[0077] Referring to FIG. 6, the box 10 of the battery pack 1 includes a plurality of side plates 11 enclosing a battery cavity 110, the side plates 11 include inner and outer layers, a hollow cavity is arranged between the inner and outer layers, the spacing between the inner and outer layers is arranged as an exhaust channel 13, a plurality of through holes 14 are further arranged on the inner layer, the plurality of through holes 14 are one-to-one corresponding to the plurality of explosion-proof valves 40 arranged on the plurality of batteries 20, the through holes 14 are used to communicate the explosion-proof valves 40 and the exhaust channel 13.

[0078] When a part of the batteries 20 in the battery pack 1 occurs thermal runaway, the explosion-proof valves 40 of the part of the batteries 20 are arranged on the side wall 213, by corresponding arranging the through holes 14 and the exhaust channel 13 on the side plates 11 of the box 10, thereby making the high pressure gas flow discharged by the explosion-proof valves 40 of the part of the batteries 20 enter the exhaust channel 13 through the through holes 14 after the explosion-proof valves 40 open, reducing the influence of the thermal runaway of the part of the batteries 20 on other batteries 20 inside the battery pack 1.

[0079] Referring to FIG. 7, the box 10 further includes an end plate 12 connected to one end of the side plate 11, the end plate 12 is provided with a hollow inner cavity, the inner cavity of the end plate 12 is communicated with the inner cavity of the side plate 11, and at least one exhaust port 15 is further arranged on the end plate 12, the exhaust port 15 is used for discharging the gas inside the exhaust channel 13. Alternatively, the exhaust port 15 can also be arranged on the side plate 11. Alternatively, when the exhaust port 15 is arranged with a plurality of exhaust ports, a part of the exhaust ports 15 are arranged on the side plate 11, and a part of the exhaust ports 15 are arranged on the end plate 12, the position of the exhaust port 15 is designed and adjusted according to the equipment installation condition inside the battery containing cavity of the new energy vehicle or the energy storage battery cabinet to which the battery pack 1 is applied.

[0080] The high pressure gas flow discharged through the explosion-proof valve 40 escapes to the outside of the box 10 through the through hole 14, the exhaust channel 13 and the exhaust port 15, thereby preventing the thermal runaway inside the box 10.

[0081] Continuing to refer to FIGS. 6 and 7, the battery cavity 110 inside the box 10 is arranged separately from the electrical cavity 120, the battery cavity 110 is used to accommodate the battery module, and the electrical cavity 120 is used to accommodate the BMS. The exhaust passage 13 is arranged at one side of the battery cavity 110 and does not extend to the side where the electrical cavity 120 is located.

[0082] By configuring the exhaust passage 13 to extend only at one side of the battery cavity 110, it is beneficial to reduce the influence of high-pressure airflow on the stable operation of the BMS or other components arranged inside the electrical cavity 120, such as the high-pressure tank.

[0083] Experimental verification

[0084] The present application further sets embodiments and comparative examples to test the opening valve pressure of the battery, wherein the setting parameters of the explosion-proof valve of the battery provided by the embodiments and comparative examples are as shown in Table 1 and Table 2.

[0085] The test method of the opening valve pressure is as follows: the two sides of the battery with larger surface area are clamped with a steel plate to simulate the state of the battery in the battery pack, a hole is drilled on the top wall of the battery, and the battery is inflated through the hole at a pressure increasing speed of 0.03 MPa / s until the valve opens, and the air pressure value is recorded.

[0086] Table 1: Test record table of opening valve pressure of explosion-proof valve of battery

[0087] Serial number h (mm) H (mm) h / H Opening valve pressure (MPa) Experimental example 1 1200 0.37 0.76 Experimental example 2 1200 0.40 0.84 Experimental example 3 1002 0.50 0.9 Experimental example 4 502 0.25 0.7 Experimental example 5 902 0.45 0.85 Comparative example 1 422 0.21 0.7 Comparative example 2 202 0.10 0.61 Comparative example 3 1202 0.60 0.94 Comparative example 4 1022 0.51 0.92 Comparative example 5 1722 0.86 1.0

[0088] In Table 1, h is set as the height between the center of the explosion-proof valve and the top wall of the battery, and H is the height of the battery. According to the test data of the opening valve pressure in Table 1, when h / H satisfies: 1 / 4≤h / H≤1 / 2, the opening valve pressure of the explosion-proof valve is 0.7 MPa~0.9 MPa. When h / H is set as: h / H<1 / 4 or h / H>1 / 2, the opening valve pressure of the explosion-proof valve is 0.6 MPa~1.0 MPa. Therefore, when the position of the explosion-proof valve satisfies: 1 / 4≤h / H≤1 / 2, the opening valve pressure of the explosion-proof valve is relatively stable.

[0089] Table 2: Test record table of opening valve pressure of explosion-proof valve of battery

[0090] No. d (mm) W (mm) d / W Opening pressure (MPa) Experimental example 1 47 10.3 40.7 Experimental example 2 47 10.6 0.9 Experimental example 3 37 10.5 0.85 Experimental example 4 27 10.3 70.7 Experimental example 5 34 10.4 80.8 Comparative example 1 57 10.2 10.7 Comparative example 2 71 10.1 0.62 Comparative example 3 57 10.7 0.94 Comparative example 4 57 10.8 1.0 Comparative example 5 22 10.3 10.6

[0091] The d in Table 2 is set as the distance between the center of the explosion-proof valve and the side of the battery, and W is the width of the side wall of the battery. According to the test data of the opening pressure in Table 2, when d / W satisfies: 1 / 3 < d / w < 2 / 3, the opening pressure of the explosion-proof valve is 0.7 MPa~0.9 MPa. When d / W is set as d / w greater than or equal to 1 / 3, or d / w greater than or equal to 2 / 3, the opening pressure of the explosion-proof valve is 0.6 MPa~1.0 MPa. Thus, when the position of the explosion-proof valve satisfies 1 / 3 < d / w < 2 / 3, the opening pressure of the explosion-proof valve is relatively stable.

Claims

1. A battery (20), comprising: The housing (21) includes a top wall (211) and a bottom wall (212) disposed opposite to each other, and a plurality of side walls (213) disposed between the top wall (211) and the bottom wall (212). At least one pole post (31) is disposed on the top wall (211). At least one explosion-proof valve (40) is disposed on the side wall (213); The distance between the center of the explosion-proof valve (40) and the top wall (211) is set as h, and the height of the side wall (213) is set as H. The ratio of h / H satisfies: 1 / 4≤h / H≤1 / 2.

2. The battery (20) according to claim 1, wherein, The sidewall (213) includes a first side (21311) and a second side (21312) arranged opposite to each other. The interval between the first side (21311) and the second side (21312) is set as the width w of the sidewall (213). The distance from the center of the explosion-proof valve (40) to the first side (21311) or the second side (21312) is d, and d / w satisfies: 1 / 3 < d / w < 2 / 3.

3. The battery (20) according to claim 2, wherein, The projected area of ​​the explosion-proof valve (40) on the side wall (213) is m, and the surface area of ​​the side wall (213) is M. m / M satisfies: 0.025≤m / M≤0.

2.

4. The battery (20) according to claim 3, wherein, h / H = 1 / 3, and / or d / w = 1 / 2, and / or m / M = 0.

08.

5. The battery (20) according to any one of claims 1-4, wherein, The explosion-proof valve (40) is separately disposed from the side wall (213) and connected to the side wall (213). The explosion-proof valve (40) includes a first main body (41) and a first reinforcing part (42) located on the first main body (41). The first main body (41) is provided with a first groove (411). The first groove (411) is constructed as a non-closed arc shape. The first reinforcing part (42) is configured to extend inside the first groove (411).

6. The battery (20) according to claim 5, wherein, The first etched portion (411) includes a first segment (4111), a second segment (4112), and a third segment (4113). The first segment (4111) is connected between one end of the second segment (4112) and one end of the third segment (4113). The other end of the second segment (4112) and the other end of the third segment (4113) are disposed opposite to each other. The first reinforcing portion (42) includes a first part (421), a second part (422), and a third part (423). One end of the first part (421), one end of the second part (422), and one end of the third part (423) are connected to each other. The other end of the first part (421) is close to the midpoint of the virtual connecting line between the other end of the second segment (4112) and the other end of the third segment (4113). The other end of the second part (422) is close to the second segment (4112), and the other end of the third part (423) is close to the third segment (4113).

7. The battery (20) according to any one of claims 1-4, wherein, The explosion-proof valve (40) is configured to be integrally formed with the side wall (213). The explosion-proof valve (40) includes a second main body (43) and a second reinforcing part (44) located on the second main body (43). The second main body (43) is provided with a second groove (431), and the second reinforcing part (44) is disposed close to the second groove (431).

8. The battery (20) according to claim 7, wherein, The second etched portion (431) includes a fourth segment (4311), a fifth segment (4312), and a sixth segment (4313). One end of the fourth segment (4311) is connected to the fifth segment (4312), and the other end of the fourth segment (4311) is connected to the sixth segment (4313). The two ends of the fifth segment (4312) and the two ends of the sixth segment (4313) are arranged opposite to each other to form a first interval (451) and a second interval (452). The second reinforcing portion (44) includes a fourth part (441) and a fifth part (442) spaced apart. The fourth part (441) is disposed within the first interval (451), and the fifth part (442) is disposed within the second interval (452).

9. The battery (20) according to claim 1, wherein, The plurality of sidewalls (213) include a first sidewall (2131) and a second sidewall (2132) disposed opposite to each other, and a third sidewall (2133) and a fourth sidewall (2134) disposed opposite to each other. The surface area of ​​the first sidewall (2131) or the second sidewall (2132) is smaller than the surface area of ​​the third sidewall (2133) or the fourth sidewall (2134). The explosion-proof valve (40) is disposed on the first sidewall (2131) or the second sidewall (2132).

10. The battery (20) according to claim 9, wherein, The explosion-proof valve (40) is configured to be at least two, and the at least two explosion-proof valves (40) are respectively disposed on the first side wall (2131) and the second side wall (2132).

11. A battery pack, the battery pack comprising a housing (10) and at least two battery modules (100) disposed within the housing (10), each of the battery modules (100) comprising a plurality of batteries (20) as described in any one of claims 1-10.

12. The battery pack according to claim 11, wherein, The battery module (100) includes an upper battery module and a lower battery module arranged along the height direction of the housing (10).

13. The battery pack according to claim 11, wherein, The enclosure (10) includes a side plate (11), the side plate (11) is provided with an exhaust channel (13) and a plurality of through holes (14), the plurality of through holes (14) are provided in a one-to-one correspondence with a plurality of explosion-proof valves (40), and the through holes (14) are configured to connect the explosion-proof valves (40) and the exhaust channel (13).

14. The battery pack according to claim 13, wherein, The housing (10) further includes an end plate (12) connected to one end of the side plate (11), the end plate (12) is provided with at least one exhaust port (15), the exhaust port (15) is configured to allow gas inside the exhaust channel (13) to be discharged; and / or, the exhaust port (15) is provided on the side plate (11).

15. The battery pack according to claim 13, wherein, The housing (10) includes a battery cavity (110) and an electrical cavity (120) spaced apart. The battery cavity (110) is configured to accommodate the battery module, and the electrical cavity (120) is configured to accommodate the battery management system. The exhaust channel (13) is located inside the cavity wall of the battery cavity (110).

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