Battery cell, battery, electric device and energy storage device

Abstract

A battery cell (400), a battery (100), an electric device (1000) and an energy storage device (2000). The battery cell (400) comprises a casing (401), wherein the casing (401) has an accommodating space (S), the accommodating space (S) accommodates an electrode assembly (402), and the electrode assembly (402) comprises a positive electrode sheet, a negative electrode sheet and a separator, which are stacked in a first direction; and at least one pressure relief component (2) is provided on a casing wall of the casing (401), the pressure relief component (2) is configured to rupture under the action of the internal pressure of the casing (401) so as to release pressure, the pressure relief component (2) comprises a first groove part (5) and a second groove part (6) intersecting each other, the included angle formed by the first groove part (5) relative to the first direction is α, and the included angle formed by the second groove part (6) relative to the first direction is β, the included angle α and the included angle β satisfying: 0°≤α≤75°, and 0°≤β≤75°.

Description

Battery cell, battery, electric device and energy storage device

[0001] Cross-reference to related applications

[0002] The present disclosure is based on and claims priority to Chinese Patent Application No. 202410840413.4, filed on June 26, 2024, entitled “Battery cell, battery, electric device and energy storage device”, the entire contents of which are incorporated herein by reference. TECHNICAL FIELD

[0003] The present disclosure relates to the technical field of batteries, and in particular to a battery cell, a battery, an electric device and an energy storage device. BACKGROUND

[0004] New energy batteries are increasingly widely used in life and industry. For example, new energy vehicles equipped with batteries have been widely used, and batteries are also increasingly used in the energy storage field and the like.

[0005] In new energy vehicles equipped with batteries, the batteries can be used to provide power in whole or in part. In the energy storage field, the batteries can be installed in an energy storage box or directly installed at a user side. In these application scenarios, there are cases where the battery cracks in the shell during the charging and discharging cycle.

[0006] SUMMARY

[0007] To solve the above technical problems, the present disclosure provides a battery cell, a battery, an electric device and an energy storage device that can balance pressure relief performance and use reliability.

[0008] The present disclosure is implemented by the following technical solutions.

[0009] A first aspect of an embodiment of the present disclosure provides a battery cell, comprising a shell, the shell having a containing space, the containing space containing an electrode assembly, the electrode assembly comprising a positive electrode sheet, a negative electrode sheet and a separator stacked along a first direction;

[0010] At least one pressure relief component is provided on a first shell wall of the shell, the pressure relief component being configured to crack and relieve pressure under the action of internal pressure of the shell, the pressure relief component comprising a first slot portion and a second slot portion intersecting each other, an included angle of the first slot portion with respect to the first direction being α, an included angle of the second slot portion with respect to the first direction being β, the included angle α and the included angle β satisfying the following relationship: 0°≤α≤75°; 0°≤β≤75°.

[0011] Therefore, the intersection region is prone to become a cracking starting point of the pressure relief component, so that the pressure relief component timely cracks when the battery cell internally thermal runaway, thereby enabling the pressure relief component to release pressure or gas; in addition, since the pressure relief component is provided with the first groove portion and the second groove portion, the stress bearing capacity is stronger than that of the notch, and the cracking of the pressure relief component due to expansion in the charge and discharge cycle can be reduced. At the same time, since the groove portions are formed at a suitable angle with respect to the first direction, the pressure relief component can timely release pressure when the battery cell thermal runaway, and the accidental cracking of the pressure relief component during the normal cycle of the battery cell can be effectively reduced. Therefore, the pressure relief performance and use reliability of the battery cell are considered.

[0012] In some embodiments, the included angle α and the included angle β satisfy the following relationship: 15°≤α≤75°; 15°≤β≤75°.

[0013] Therefore, the pressure relief component can timely release pressure while further reducing the accidental cracking of the pressure relief component during the normal cycle of the battery cell.

[0014] In some embodiments, the included angle α and the included angle β satisfy the following relationship: 45°≤α≤60°; 45°≤β≤60°.

[0015] Since the included angle α and the included angle β are set to be in the range of 45° to 60°, the pressure relief component can timely release pressure as needed while further effectively reducing the accidental cracking of the pressure relief component during the normal cycle of the battery cell.

[0016] In some embodiments, the first groove portion and the second groove portion have the same groove shape and intersect to form an axisymmetric shape, and the difference between the included angle α and the included angle β is in the range of 0-10 degrees.

[0017] Therefore, the stress can be decomposed for the part with greater fatigue stress, and the stress received by the first groove portion and the second groove portion is basically the same, so that the first groove portion and the second groove portion can synchronously break when releasing pressure; and the expansion stress received in the battery cycle is also basically the same, so that the influence of the expansion stress is reduced through stress decomposition.

[0018] In some embodiments, the first groove portion and the second groove portion are formed by locally thinning the first housing wall along the thickness direction of the first housing wall; in the groove width direction perpendicular to the extension direction of the first groove portion, the width of the groove bottom wall of the first groove portion is in the range of 1mm to 5mm.

[0019] In the groove width direction perpendicular to the extension direction of the second groove portion, the width of the groove bottom wall of the second groove portion is in the range of 1mm to 5mm.

[0020] Since the first groove portion and the second groove portion have groove bottom walls with a certain width, the pressure relief performance of the pressure relief component and the performance of reducing accidental cracking can be considered.

[0021] In some embodiments, the difference between the width of the groove bottom wall of the first groove portion and the width of the groove bottom wall of the second groove portion is in the range of 0 to 0.5 mm.

[0022] Since the width of the groove bottom wall of the first groove portion and the width of the groove bottom wall of the second groove portion are close, when pressure relief occurs, the two groove portions can bear pressure evenly, crack synchronously, increase the pressure relief area, and further improve the pressure relief performance.

[0023] In some embodiments, the groove depth of the first groove portion and the second groove portion along the wall thickness direction of the shell wall is in the range of 30% to 70% of the wall thickness of the shell wall.

[0024] Since the first groove portion and the second groove portion have a suitable groove depth, the shell strength and the pressure relief performance can be considered.

[0025] In some embodiments, the area of the pressure relief area formed by the pressure relief component is S, and the capacity of the battery monomer is C, and S and C satisfy the following relationship: 1≤S / C≤20.

[0026] Since the area S of the pressure relief area formed by the pressure relief component and the capacity C satisfy the following relationship: 1≤S / C≤20, the area of the pressure relief component can be in a suitable range according to the battery capacity, and the pressure relief performance and the structural strength of the shell can be considered.

[0027] In some embodiments, the minimum distance between the pressure relief component and the outer periphery of the first shell wall is greater than 5 mm.

[0028] Since the minimum distance between the pressure relief component and the edge is greater than 5 mm, the groove portion can be in a suitable position on the surface of the shell, and the explosion-proof performance and the cycle stability of the pressure relief component can be considered.

[0029] A second aspect of the embodiments of the present disclosure discloses a battery, which comprises a box body and at least one battery monomer disclosed in the first aspect of the embodiments of the present disclosure contained in the box body.

[0030] Since the battery comprises the battery monomer disclosed in the first aspect of the embodiments of the present disclosure, when the internal pressure of the battery monomer exceeds the threshold value, the pressure can be released, and the risk of accidental cracking of the pressure relief component during cyclic use is reduced, which helps to improve the cycle life of the battery and helps to inhibit the negative effects caused by thermal runaway of the battery monomer.

[0031] A third aspect of the embodiments of the present disclosure discloses a power consuming device, which comprises the battery cell of the first aspect of the embodiments of the present disclosure or the battery of the second aspect of the embodiments of the present disclosure, and the battery cell is used to provide electric energy to the power consuming device.

[0032] Since the power consuming device comprises the battery cell of the first aspect or the battery of the second aspect, the battery cell can release pressure when the internal pressure exceeds the threshold value, while reducing the risk of accidental cracking of the pressure relief component during cyclic use. Thus, it helps to improve the service life of the battery and reduce the maintenance cost of the power consuming device.

[0033] A fourth aspect of the embodiments of the present disclosure discloses an energy storage device, which comprises the battery of the second aspect of the embodiments of the present disclosure, and the battery can store and provide electric energy.

[0034] Since the energy storage device comprises the battery of the second aspect, the battery can release pressure when the internal pressure exceeds the threshold value, while reducing the risk of accidental cracking of the pressure relief component during cyclic use of the battery. Thus, it helps to improve the service life of the battery and reduce the maintenance cost of the energy storage device.

[0035] Inventive effects

[0036] Through the present disclosure, the pressure relief component can timely release pressure when thermal runaway occurs in the battery cell; and the phenomenon of accidental cracking of the pressure relief component due to stress concentration during cyclic use can be reduced. Thus, the pressure relief performance and use reliability of the battery cell are taken into account. BRIEF DESCRIPTION OF DRAWINGS

[0037] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are intended to depict only preferred embodiments of the disclosure and therefore should not be considered to limit the scope of the disclosure. Wherever possible, like reference numbers have been used throughout the drawings to depict the same or similar elements. In the drawings:

[0038] FIG. 1 is a structural schematic diagram of a vehicle according to some embodiments of the present disclosure;

[0039] FIG. 2 is a perspective exploded schematic diagram of a battery according to some embodiments of the present disclosure;

[0040] FIG. 3 is a perspective exploded schematic diagram of a battery cell according to some embodiments of the present disclosure;

[0041] FIG. 4 is a top view of the battery cell according to some embodiments of the present disclosure;

[0042] FIG. 5 is a top view of the battery cell according to some other embodiments of the present disclosure;

[0043] FIG. 6 is a partial enlarged view of A in FIG. 5.

[0044] Fig. 7 is a schematic diagram of the first groove and the second groove according to some embodiments of the present disclosure, showing the shape (a), the shape (b) and the shape (c);

[0045] Fig. 8 is a schematic diagram of a partial cross-section according to some embodiments of the present disclosure;

[0046] Fig. 9 is a schematic diagram of a structure of an energy storage device according to some embodiments of the present disclosure.

[0047] Explanation of Reference Signs

[0048] 1 - first housing wall, 2 - pressure relief component, 2A - intersection site, 2B - intersection edge, 3 - first edge, 4 - second edge, 5 - first groove, 6 - second groove, 5A - first end, 5B - groove bottom wall, 5C - groove side wall, 6A - second end, 7 - first projected edge, 8 - second projected edge, 9 - third projected edge, 10 - fourth projected edge, 11 - opening portion, 100 - battery, 101 - case, 101A - upper case, 101B - lower case, 400 - battery cell, 401 - housing, 401A - end cover, 401B - opening, 402 - electrode assembly, 403 - electrode terminal, 404 - tab, 1000 - electrical device, 2000 - energy storage device, S - accommodation space. DETAILED DESCRIPTION

[0049] The embodiments of the technical solutions of the present disclosure will be described in detail below with reference to the drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present disclosure, and therefore only serve as examples, and cannot limit the protection scope of the present disclosure.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs; the terminology used herein is only for the purpose of describing specific embodiments and is not intended to limit the disclosure; the terms "include" and "have" and any variations thereof in the specification and claims of the present disclosure and the above description of drawings are intended to cover non-exclusive inclusion.

[0051] In the description of the embodiments of the present disclosure, the technical terms "first", "second", "third", "fourth" and the like are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the technical features indicated. In the description of the embodiments of the present disclosure, the meaning of "a plurality of" is two or more, unless otherwise explicitly and specifically limited.

[0052] Reference to“an embodiment” herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the disclosure. The appearances of the phrase“in an embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily mutually exclusive of one another. It is expressly understood that any of the embodiments described herein can be incorporated into any other embodiment.

[0053] In the description of the embodiments of the disclosure, the term“and / or” is merely an association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A existing alone, A and B existing together, and B existing alone. In addition, the character“ / ” herein generally represents that the front and rear associated objects are in an“or” relationship.

[0054] In the description of the embodiments of the disclosure, the technical terms“length”,“width”,“thickness”,“upper”,“lower”,“front”,“rear”,“left”,“right”,“vertical”,“horizontal”,“top”,“bottom”,“inner”,“outer”,“circumferential” and the like indicate the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the embodiments of the disclosure and simplifying the description, and does not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, operate or be used in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the disclosure.

[0055] In the description of the embodiments of the disclosure, unless otherwise explicitly specified and limited, the technical terms“mounting”,“connection”,“connection”,“fixing” and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be mechanically connected, or can be electrically connected; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above terms in the embodiments of the disclosure can be understood according to the specific circumstances.

[0056] In the description of the embodiments of the disclosure, unless otherwise explicitly specified and limited, the technical term“contact” should be understood in a broad sense, which can be direct contact or contact through an intermediate medium layer, and can be contact between two objects in contact without interaction force, or contact between two objects in contact with interaction force.

[0057] In the description of the embodiments of the disclosure, unless otherwise explicitly specified and limited, the technical terms“parallel” and“perpendicular” both allow a certain degree of tolerance and / or error, including approximately parallel and approximately perpendicular.

[0058] The disclosure will be described in detail below.

[0059] At present, new energy batteries are more and more widely used in life and industry. New energy batteries are not only used in energy storage power supply systems such as hydroelectric, thermal, wind and solar power stations, but also widely used in electric bicycles, electric motorcycles, electric vehicles and other electric vehicles, and aerospace and other fields. With the continuous expansion of the application field of power batteries, the market demand is also increasing.

[0060] In the use process of the battery, there is a situation that the battery monomer internally increases the internal pressure, temperature and other obvious increases, and even the content is ejected outside the battery monomer. Since the ejection of the battery monomer is easy to cause the surrounding battery monomer to catch fire, malfunction, etc., it is hoped that the ejection direction of the battery monomer can be controlled to be directional ejection. Therefore, the shell of the battery monomer is usually provided with a pressure relief component such as a pressure relief valve.

[0061] The inventors of the present disclosure noticed that the pressure relief component provided in the shell of the battery monomer has a situation that it may crack due to expansion and other reasons even when the battery monomer is normally cycled. Once such a situation occurs, the pressure relief component fails to function, and also causes the leakage of the content such as electrolyte inside the battery monomer.

[0062] Specifically, in the related art, a pressure relief valve notch area is formed on the end cover of the battery monomer. It is found through research that, in the cycling process of the battery monomer, due to the expansion of the battery monomer, breathing fatigue and other reasons, the closer to the edge of the shell of the battery monomer, the more concentrated the stress it bears. The pressure relief valve notch is a weak area in terms of structural strength, and if it is located near the edge of the shell, it is easy to break accidentally due to stress concentration, causing the shell of the battery monomer to crack during the cycling process.

[0063] Therefore, it is hoped to provide a battery monomer whose pressure relief component can timely relieve pressure when the battery monomer is in thermal runaway, and will not accidentally break when the battery monomer is normally cycled. That is, how to balance the pressure relief performance and use reliability of the pressure relief component becomes a problem.

[0064] The inventors of the present disclosure found through research that, as a pressure relief component, using intersecting pressure relief grooves instead of traditional ring notches can slow down the cracking of the pressure relief component caused by expansion and breathing fatigue during normal cycling. Since the pressure relief grooves have intersection points, the intersection points are easy to become the starting position of the cracking of the pressure relief component, so the pressure relief component can crack under the action of the internal pressure of the battery monomer when the battery monomer is in thermal runaway.

[0065] Based on such design concept, the inventors of the present disclosure designed a battery monomer, which comprises a shell, the shell has a containing space, the containing space contains an electrode assembly, the electrode assembly comprises a positive electrode sheet, a negative electrode sheet and a separator which are stacked along a first direction; at least one pressure relief component is arranged on the first shell wall of the shell, the pressure relief component is configured to be able to crack under the action of the internal pressure of the shell to relieve pressure, the pressure relief component comprises a first slot part and a second slot part which intersect with each other, the included angle of the first slot part with respect to the first direction is α, the included angle of the second slot part with respect to the first direction is β, the included angle α and the included angle β satisfy the following relationship: 0°≤α≤75°; 0°≤β≤75°.

[0066] Therefore, the intersection area is easy to become the cracking starting position of the pressure relief component, so that the pressure relief component cracks in time when the battery monomer is in thermal runaway, thereby being able to release pressure or gas through the pressure relief component; in addition, since the pressure relief component is arranged to comprise the first slot part and the second slot part, the stress bearing capacity is stronger than that of the pressure relief component such as annular notch, and the cracking of the pressure relief component due to expansion in the charge and discharge cycle can be reduced. At the same time, since the slot parts form appropriate angles with respect to the first direction, the pressure relief component can not only relieve pressure in time when the battery monomer is in thermal runaway, but also can effectively reduce the accidental cracking of the pressure relief component during the normal cycle of the battery monomer. Therefore, the pressure relief performance and use reliability of the battery monomer are taken into account.

[0067] The battery monomer provided by the embodiments of the present disclosure can be used in, but is not limited to, an electric device such as an energy storage device, a vehicle, a ship or an aircraft.

[0068] The battery monomer provided by the embodiments of the present disclosure can also be used as a battery (also known as a battery pack) in groups. The battery can also be used in, but is not limited to, an electric device such as an energy storage device, a vehicle, a ship or an aircraft.

[0069] The embodiments of the present disclosure also provide an electric device comprising the above-mentioned battery monomer or battery. The electric device can be, but is not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, an electric vehicle, an electric car, a ship, a spacecraft and the like. The electric toy can include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric plane toys, etc. The spacecraft can include an airplane, a rocket, a space shuttle and a spacecraft, etc.

[0070] The energy storage device can be used in a power storage plant, a wind power generation system, a solar power generation system, a mobile power system, or a temporary power supply system, etc. The energy storage device can store electric energy as needed and output electric energy at an appropriate time. For example, the energy storage device can store electric energy during a low electricity consumption period, and provide electric energy for related users or electric equipment during a high electricity consumption period. The energy storage system provided by the embodiments of the present application can be any power system that needs to use an energy storage device.

[0071] The energy storage device can be used in a power storage plant, a wind power generation system, a solar power generation system, a mobile power system, or a temporary power supply system, etc. The energy storage device can store electric energy as needed and output electric energy at an appropriate time. For example, the energy storage device can store electric energy during a low electricity consumption period, and provide electric energy for related users or electric equipment during a high electricity consumption period. The energy storage system provided by the embodiments of the present application can be any power system that needs to use an energy storage device.

[0072] In some embodiments, the energy storage device includes an energy storage container, an energy storage cabinet, etc.

[0073] In some embodiments, the energy storage device can include a cabinet body and one or more battery clusters, and the battery clusters are accommodated in the cabinet body.

[0074] For the convenience of description, the power consumption device of an embodiment of the present application is taken as a vehicle 1000 for example. The following is described in conjunction with the drawings.

[0075] FIG. 1 is a structural schematic diagram of a vehicle provided by some embodiments of the present application. The vehicle 1000 can be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile, etc. As shown in FIG. 1, the vehicle 1000 is internally provided with a battery 100, and the battery 100 can be arranged at the bottom, the head, or the tail of the vehicle 1000. The battery 100 can be used for power supply of the vehicle 1000, for example, the battery 100 can be used as an operating power supply of the vehicle 1000. The vehicle 1000 can further include a controller 200 and a motor 300, and the controller 200 is used to control the battery 100 to supply power to the motor 300, for example, to meet the working power demand of the vehicle 1000 during starting, navigation, and driving.

[0076] In some embodiments of the present application, the battery 100 can not only be used as an operating power supply of the vehicle 1000, but also be used as a driving power supply of the vehicle 1000, to replace or partially replace fuel or natural gas to provide driving power for the vehicle 1000.

[0077] FIG. 2 is a perspective exploded view of a battery according to some embodiments of the present disclosure. As shown in FIG. 2, the battery 100 includes an upper case 101A and a lower case 101B, which are opposite to each other to form a space for arranging the battery cells 400 therebetween.

[0078] In the battery 100, the battery cells 400 can be multiple, which can be connected in series, in parallel, or in a mixed manner. The mixed manner means that the multiple battery cells 400 are connected in series and in parallel. The multiple battery cells 400 can be directly connected in series, in parallel, or in a mixed manner, and the whole of the multiple battery cells 400 is placed in the space defined by the upper case 101A and the lower case 101B. Of course, the battery 100 can also be in the form of multiple battery modules, which are connected in series, in parallel, or in a mixed manner, and the multiple battery modules are connected in series, in parallel, or in a mixed manner to form a whole, which is accommodated in the space defined by the upper case 101A and the lower case 101B. The battery 100 can also include other structures, for example, the battery 100 can also include a busbar component (not shown in the figure) for realizing the electrical connection between the multiple battery cells 400.

[0079] In the embodiments of the present disclosure, the battery cell can be a secondary battery, which means that the battery cell can be activated by charging after discharging to continue to be used.

[0080] The battery cell can be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel hydrogen battery, a nickel cadmium battery, a lead-acid battery, etc., and the embodiments of the present disclosure are not limited thereto.

[0081] As shown in FIG. 3, the battery cell 400 generally includes an electrode assembly 402. The electrode assembly 402 includes a positive electrode, a negative electrode, and a separator. During the charging and discharging of the battery cell, active ions (such as lithium ions) are inserted and extracted between the positive electrode and the negative electrode. The separator is arranged between the positive electrode and the negative electrode, which can prevent the positive electrode and the negative electrode from short-circuiting, and at the same time, the active ions can pass through. In the embodiment shown in FIG. 3, as the electrode assembly 402, two laminated jelly rolls formed by laminating and winding the positive electrode, the negative electrode, and the separator are shown, but the electrode assembly 402 is not limited to the winding type shown in FIG. 3, for example, it can also be a laminated type or other structural form.

[0082] In some embodiments, the electrode assembly 402 is provided with a tab 404, which can guide the current out of the electrode assembly 402. The tab includes a positive tab and a negative tab.

[0083] In some embodiments, the battery cell 400 can include a shell 401. The shell 401 is used to encapsulate the electrode assembly 402 and electrolyte and the like. The shell 401 can be a steel shell, an aluminum shell, a plastic shell (such as polypropylene), a composite metal shell (such as a copper-aluminum composite shell), or an aluminum-plastic film, and the like.

[0084] As an example, the battery cell can be a cylindrical battery cell, a prismatic battery cell, a soft-pack battery cell, or a battery cell of other shapes, the prismatic battery cell including a square battery cell, a blade battery cell, a multi-prismatic battery cell (such as a hexagonal battery cell), and the like, without particular limitation in the present disclosure.

[0085] In some embodiments, as shown in FIG. 3, the shell 401 includes a plurality of shell walls, in which a portion of the shell walls enclose a space with an opening 401B, and the opening 401B can be closed by another shell wall to form a containing space S for containing the electrode assembly 402 and electrolyte and the like. The shell 401 can be provided with one or more openings. The shell wall closing the opening 4001B can also be configured as an end cover 401A.

[0086] In some embodiments, as shown in FIG. 3, the shell 401 is provided with at least one electrode terminal 403, which is electrically connected with the tab 404. The electrode terminal 403 can be directly connected with the tab 404, or indirectly connected with the tab 404 through an adapter component. The electrode terminal 403 can be provided on the end cover 401A, or on the shell wall of the shell 401.

[0087] In the following, some embodiments of the present disclosure will be described in detail with reference to FIGS. 3 to 8.

[0088] FIG. 3 is a perspective exploded schematic view of a battery cell according to some embodiments of the present disclosure; FIG. 4 is a top view of a battery cell according to some embodiments of the present disclosure; FIG. 5 is a top view of a battery cell according to some other embodiments of the present disclosure; FIG. 6 is a partial enlarged view of A in FIG. 5; FIG. 7 is a schematic view of the shape of a first groove and a second groove according to some embodiments of the present disclosure, showing shape (a), shape (b), and shape (c); and FIG. 8 is a partial cross-sectional schematic view according to some embodiments of the present disclosure.

[0089] In some embodiments of the present disclosure, a first direction and a second direction are set for the purpose of illustration, and the directions in which the first direction and the second direction are located are intersecting directions, which here include perpendicular intersecting directions. For the purpose of understanding the embodiments of the present disclosure, the embodiments shown in FIGS. 3-8 are illustrated by way of example in which the first direction and the second direction are perpendicular intersecting directions, but those skilled in the art should understand that the embodiments of the present disclosure are not limited to the case in which the two directions are perpendicular to each other. In addition, a third direction is also set, and the first direction, the second direction, and the third direction are directions that intersect with each other, which here also include perpendicular intersecting directions. In the embodiment shown in FIG. 3, the first direction, the second direction, and the third direction are perpendicular intersecting directions. For the purpose of illustration, as shown by the arrows in FIGS. 2-8, the direction in which the arrow X is located is the second direction, the direction in which the arrow Y is located is the first direction, and the direction in which the arrow Z is located is the third direction.

[0090] A first aspect of the embodiments of the present disclosure provides a battery monomer 400, as shown in FIGS. 3-8, which includes a housing 401 having an accommodation space S that accommodates an electrode assembly 402 including a positive electrode sheet, a negative electrode sheet, and a separator that are stacked along a first direction (Y direction); at least one pressure relief component 2 is provided on a first housing wall 1 of the housing 401, and the pressure relief component 2 is configured to be able to be ruptured under the action of the internal pressure of the housing 401 to relieve pressure, and the pressure relief component 2 includes a first slot portion 5 and a second slot portion 6 that intersect with each other, the acute angle in the included angle between the extension direction of the first slot portion 5 and the first direction Y is denoted by an included angle a, and the acute angle in the included angle between the extension direction of the second slot portion 6 and the first direction is denoted by an included angle β, and the included angle a and the included angle β satisfy the following relationship: 0°≤a≤75°; 0°≤β≤75°.

[0091] The pressure relief component 2 is provided on the housing wall of the housing 401, and the pressure relief component 2 is configured to be able to be ruptured under the action of the internal pressure of the housing 401 to relieve pressure. Illustratively, when thermal runaway occurs inside the battery monomer 400, gas generation, gas expansion, and the like may occur in the accommodation space S, and thus the gas pressure in the accommodation space S increases significantly. The pressure relief component 2 provided on the housing wall is a relatively weak part relative to other parts of the housing wall in which it is located, and thus it will be ruptured under the action of the pressure in the accommodation space S. Once the pressure relief component 2 is ruptured, the accommodation space S is in communication with the external environment, and pressure relief is rapid.

[0092] As shown in FIGS. 4 and 5, the pressure relief component 2 includes a first groove portion 5 and a second groove portion 6 intersecting each other. Here, the so-called intersection means that the first groove portion 5 and the second groove portion 6 have a meeting point or a crossing point, and can be a form of crossing each other as shown in form (c) of FIGS. 4 and 7, or a form of having a meeting point but not necessarily passing through as shown in forms (a) and (b) of FIG. 7.

[0093] In addition, the battery cell 400 can include one pressure relief component 2, or two or more pressure relief components 2, which can be provided on the same housing wall or different housing walls. In some embodiments, as shown in FIGS. 3 to 5, the housing has a plurality of housing walls, one of which is a first housing wall 1, and the pressure relief component 2 is provided on the first housing wall 1. In FIG. 4, an example of providing one pressure relief component 2 on the housing wall is shown; in FIG. 5, an example of providing two pressure relief components 2 on the housing wall is shown.

[0094] In the embodiment shown in FIG. 3, the first housing wall 1 is configured as an end cover 401A. Alternatively, although not shown, the pressure relief component 2 can also be provided on other housing walls of the battery cell 400, i.e., the first housing wall 1 can also be a large face or other side wall of the battery cell.

[0095] In some embodiments of the present disclosure, as shown in FIG. 5, the housing 401 has a first housing wall 1, and the pressure relief component 2 is provided on the first housing wall 1, and the edge enclosing the first housing wall 1 includes a first edge 3, and the extension direction of the first edge 3 is consistent with the second direction X.

[0096] Exemplarily, for a square cell, the first edge 3 can be an edge of the large face of the battery or an edge of the side wall.

[0097] Alternatively, as shown in FIGS. 4 to 6, the first edge 3 can be a long edge (e.g., the edge between the first housing wall 1 and the large face of the battery) of the plurality of edges enclosing the first housing wall 1. In other embodiments, the first edge 3 can also be a short edge (e.g., the edge between the first housing wall 1 and the side wall) of the plurality of edges enclosing the first housing wall 1.

[0098] Exemplarily, the battery cell 400 will swell during the charge-discharge cycle, and the positive plate, the negative plate and the separator are usually stacked along the first direction (Y direction in the figure), so the swelling force is relatively large in the stacking direction (i.e. the first direction), and the shell 401 mainly swells and deforms in the first direction. In the case where the pressure relief component 2 is arranged on the end cover 401A, the groove part of the pressure relief component 2 is pulled by the swelling force, and if the swelling force is large, a certain degree of deformation or even cracking may occur even during normal cycle use, resulting in damage to the shell 401 and affecting the normal operation of the battery cell 400. The above-mentioned stacking can be winding of the positive plate, the negative plate and the separator, or can be stacking of the positive plate, the negative plate and the separator alternately.

[0099] As shown in FIGS. 4-8, the so-called groove part refers to a sunken space with a certain depth relative to the outer surface of the shell wall, and the periphery of the sunken space has a groove side wall extending along the groove depth direction (the wall thickness direction of the shell wall) and a groove bottom wall located at the groove bottom and connected with each groove side wall. That is, the first groove part 5 and the second groove part 6 have a certain depth in the wall thickness direction of the shell wall. The first groove part 5 and the second groove part 6 intersecting with each other have a shared sunken space at the intersection site or the cross site. The groove side wall 5C of the first groove part 5 and the groove side wall of the second groove part 6 form an intersection edge 2B at the intersection site. In the embodiment shown in FIG. 4, although only one intersection edge 2B is shown, four intersection edges 2B are formed. As shown in FIG. 6, each intersection edge 2B and the groove side wall connected therewith define an opening part 11 which is approximately triangular in plan view, and in the embodiment shown in FIG. 6, there are four opening parts 11. When thermal runaway occurs inside the battery cell 400, the site where these intersection edges 2B are located is prone to become a stress concentration site, and thus is prone to become the first position to crack in the first groove part 5 and the second groove part 6. Then, the cracking continues along the groove side wall of the first groove part 5 and the second groove part 6 respectively, and the four opening parts 11 are turned outward under the action of the internal pressure of the battery cell 400, and the pressure relief area is further increased; in addition, part or all of the groove bottom wall 5B of the first groove part 5 and the groove bottom wall of the second groove part 6 can also be turned outward or fall off from the shell wall under the action of the internal pressure of the battery cell 400.

[0100] Optionally, the first groove part 5 intersects with the second groove part 6, and at least one opening part 11 is formed as shown in FIG. 7. Optionally, as shown in FIGS. 4-7, the pressure relief component 2 can be an axisymmetric shape; or can be a non-axisymmetric shape.

[0101] In addition, in the embodiments shown in FIGS. 4-8, the first groove part 5 and the second groove part 6 are configured as rectangular grooves, i.e. the projection along the wall thickness direction of the shell wall is rectangular. However, the first groove part 5 and the second groove part 6 are not limited to the above-mentioned shape, and can also be other shapes, for example, the projection along the wall thickness direction of the shell wall can be an oblong circle.

[0102] In specific embodiments of the present disclosure, the positive electrode sheet, the negative electrode sheet, and the separator in the electrode assembly 402 can be stacked along the first direction. As shown in FIG. 5, the battery cell 400 is a prismatic battery, and the Y direction is perpendicular to the large face of the battery cell 400; of course, in other embodiments not shown, the positive electrode sheet, the negative electrode sheet, and the separator in the electrode assembly 402 can also be stacked along the X direction or any other direction.

[0103] For example, as shown in FIG. 5, the included angle a can be 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, or 75°.

[0104] Similarly, the included angle β can be 0°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, or 75°. The included angle a and the included angle β can be the same or different. When the included angle a and the included angle β are different, the included angle a can be larger, or the included angle β can be larger. The present disclosure does not limit this.

[0105] Since the pressure relief component 2 is arranged on the housing wall of the housing, and the first groove portion 5 intersects with the second groove portion 5, the intersection region is prone to become the cracking starting position of the pressure relief component 2, so that the pressure relief component 2 cracks in time when the battery cell 400 is internally thermal runaway, thereby enabling the pressure or gas to be released through the pressure relief component 2; in addition, since the pressure relief component 2 is arranged to include the first groove portion 5 and the second groove portion 6, the stress bearing capacity is stronger than that of a notch, and the cracking of the pressure relief component 2 due to expansion during the charging and discharging cycle can be reduced. At the same time, since the groove portion is formed at a suitable angle with respect to the first direction, the pressure relief component 2 can timely release pressure when the battery cell 400 is thermal runaway, and the accidental cracking of the pressure relief component 2 during the normal cycle of the battery cell 400 can be effectively reduced. Thus, the pressure relief performance and use reliability of the battery cell 400 are taken into account.

[0106] In embodiments of the present disclosure, the included angle a and the included angle β satisfy the following relationship: 15°≤a≤75°; 15°≤β≤75°.

[0107] For example, the included angle a can be 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, or 75°.

[0108] Similarly, the included angle β can be 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, or 75°.

[0109] Thus, the included angle a and the included angle b are in a suitable range, which can further reduce the risk of accidental cracking of the pressure relief component 2 during the normal cycle of the battery monomer 400 while timely relieving the pressure of the pressure relief component 2.

[0110] In the embodiments of the present disclosure, the included angle a and the included angle b satisfy the following relationship: 45°≤a≤60°; 45°≤b≤60°.

[0111] In specific embodiments, the included angle a can be 45°, 50°, 55°, 60°; and the included angle b can be 45°, 50°, 55°, 60°.

[0112] Since the included angle a and the included angle b are set to be in the range of 45° to 60°, the risk of accidental cracking of the pressure relief component 2 during the normal cycle of the battery monomer 400 can be further reduced while the pressure relief component 2 is timely relieved according to the needs.

[0113] In the embodiments of the present disclosure, the first groove portion and the second groove portion have the same groove shape and intersect to form an axisymmetric shape, and the difference between the included angle a and the included angle b is in the range of 0 to 10 degrees.

[0114] For example, the difference between the included angle a and the included angle b can be 0°, 2°, 4°, 6°, 8° or 10°.

[0115] In specific embodiments, the first shell wall 1 further has a second edge 4, the extension direction of the second edge 4 is consistent with the first direction Y, the first direction Y and the second direction X are perpendicular to each other, the first edge 3 is longer than the second edge 4, the first groove portion 5 and the second groove portion 6 have the same groove shape and intersect to form an axisymmetric shape, the included angle a and the included angle b are equal, and the symmetry axis of the first groove portion 5 and the second groove portion 6 is parallel to the first direction Y.

[0116] In specific embodiments, as shown in FIG. 3, the battery monomer 400 can be a square shell battery, and the first shell wall 1 of the shell 401 where the pressure relief component 2 is arranged can have edges perpendicular to each other.

[0117] The first edge 3 is longer than the second edge 4, and thus the first edge 3 can be the edge between the end cover 401A and the large face of the shell 401 of the battery monomer 400. The large face usually expands to a large extent, breathes and fatigues during the cycle of the battery monomer, and accordingly the stress generated is also greater. The first groove portion 5 and the second groove portion 6 form the included angle a and the included angle b with respect to the first edge 3, which can effectively decompose the stress generated by the expansion of the large face.

[0118] In addition, the first groove portion 5 and the second groove portion 6 can have the same groove shape and intersect to form an axial symmetric shape as shown in the mode (b) of FIG. 4, FIG. 5, FIG. 6 and FIG. 7, and the included angle a and the included angle β are equal. That is, the first groove portion 5 and the second groove portion 6 are the same groove shape and can be symmetrical about the symmetry axis extending in the first direction Y. Of course, it can also be symmetrical about the symmetry axis extending in the second direction X.

[0119] Therefore, stress decomposition can be performed on the part with greater fatigue stress, the stress received by the first groove portion and the second groove portion is basically the same, and the first groove portion and the second groove portion can break synchronously when pressure relief; and the expansion stress received in the battery cycle is also basically the same, and the influence of the expansion stress is reduced through stress decomposition.

[0120] In some embodiments of the present disclosure, as shown in FIG. 5, FIG. 6 and FIG. 8, the first groove portion 5 and the second groove portion 6 are formed by locally thinning the shell wall along the wall thickness direction of the shell wall (which can be consistent with the third direction Z); in the groove width direction perpendicular to the extension direction of the first groove portion 5, the width D1 of the groove bottom wall 5B of the first groove portion 5 is in the range of 1mm to 5mm; in the groove width direction perpendicular to the extension direction of the second groove portion 6, the width D2 of the groove bottom wall of the second groove portion 6 is in the range of 1mm to 5mm.

[0121] For example, as shown in FIG. 5, the width D1 of the first groove portion 5 can be 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm, 5.0mm. For example, as shown in FIG. 5, the width D2 of the second groove portion 6 can be 1.0mm, 1.5mm, 2.0mm, 2.5mm, 3.0mm, 3.5mm, 4.0mm, 4.5mm, 5.0mm. If the width D1, D2 is too small, the opening portion 11 is not easy to flip; if it is too large, the opening portion 11 is easy to crack accidentally. Therefore, since the width D1 of the first groove portion 5 and the width D2 of the second groove portion 6 are in the range of 1mm to 5mm, the opening portion 11 can withstand a suitable range of stress, so that the opening portion 11 can not only open and flip when the battery monomer 400 occurs thermal runaway, but also can withstand the expansion breathing fatigue stress during normal cycle use to maintain the connection state, so as to balance the pressure relief performance of the pressure relief component 2 and the performance of reducing accidental cracking, that is, when the battery monomer 400 occurs thermal runaway, the pressure relief component 2 can normally crack to achieve pressure relief, on the other hand, it can also reduce the risk of cracking of the pressure relief component 2 during the cycle use.

[0122] Optionally, D1 and D2 can be equal or not equal.

[0123] In some specific embodiments, the difference between the groove bottom wall widths of the first groove portion 5 and the second groove portion 6 is in the range of 0 to 0.5mm.

[0124] Exemplarily, the difference between the groove bottom wall width of the first groove part 5 and the second groove part 6 can be 0, 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm or 0.5 mm.

[0125] Exemplarily, the groove bottom wall width of the first groove part 5 is equal to that of the second groove part 6, i.e. D1 is equal to D2. Since the groove bottom wall width of the first groove part 5 is equal to that of the second groove part 6, when pressure relief occurs, the two groove parts can bear pressure evenly, break synchronously, expand the pressure relief area and further improve the pressure relief performance.

[0126] In some embodiments of the present disclosure, the pressure relief part forms a pressure relief area with an area S, and the capacity of the battery cell is C, S / C satisfies the following relationship: 1≤S / C≤20.

[0127] In some specific embodiments, as shown in FIG. 6, if the length of the projection edge formed by the intersection of the first groove part 5 and the second groove part 6 along the second direction X is a, and the length of the projection edge formed along the first direction Y is b, then the area S of the pressure relief area formed by the pressure relief part is a*b. The second direction X and the first direction Y are perpendicular to each other and perpendicular to the wall thickness direction of the shell wall (which can be consistent with the third direction Z).

[0128] Exemplarily, as shown in FIG. 6, the pressure relief part 2 is arranged on the end cover 401A (which is also the first shell wall 1), the projection of the first groove part 5 and the second groove part 6 towards one side of the first direction Y is the first projection edge 7, the projection of the first groove part 5 and the second groove part 6 towards the other side of the first direction is the second projection edge 8, the projection of the first groove part 5 and the second groove part 6 towards one side of the second direction is the third projection edge 9, the projection of the first groove part 5 and the second groove part 6 towards the other side of the second direction is the fourth projection edge 10, and the first direction is perpendicular to the second direction, and both the first direction and the second direction are perpendicular to the wall thickness direction of the shell wall.

[0129] The area surrounded by the first projection edge 7, the second projection edge 8, the third projection edge 9 and the fourth projection edge 10 is represented by S, and the capacity of the battery cell 400 is represented by C (unit: Ah), and the area S / C satisfies the following relationship: 1≤S / C≤20. In the case where the first projection edge 7, the second projection edge 8, the third projection edge 9 and the fourth projection edge 10 form a rectangle (with side lengths a and b respectively), the area S can be calculated as follows: S=a×b (unit: mm 2 ). If the S / C area is too small, the area that the pressure relief part 2 can flip over when the battery cell 400 experiences thermal runaway is too small, which may cause the shell 401 of the battery cell 400 to burst when thermal runaway occurs; if S / C is too large, the pressure relief area of the pressure relief part 2 is too large, which may cause the contents inside the battery cell 400 to be ejected in large quantities when thermal runaway occurs, causing secondary disasters of the battery system.

[0130] Since the area S and the capacity C satisfy the following relationship: 1≤S / C≤20, the area of the pressure relief component 2 can be kept in an appropriate range according to the battery capacity, the pressure relief performance and the structural strength of the shell 401 are considered, and the area of the pressure relief component 2 is prevented from being too small to cause an undesirable pressure relief effect, and the active material of the electrode assembly 402 is prevented from being sprayed out in large quantities to affect the safety of the external structure.

[0131] In some embodiments of the present disclosure, the groove depth of the first groove portion 5 and the second groove portion 6 along the wall thickness direction of the first shell wall 1 is in the range of 30% to 70% of the wall thickness of the shell wall.

[0132] As shown in FIG. 8, the first groove portion 5 and the second groove portion 6 are formed by local thinning, and if H1 represents the groove depth of the first groove portion 5 and the second groove portion 6, and H2 represents the wall thickness of the first shell wall 1, then H1 is in the range of 30% to 70% of H2. Here, the first groove portion 5 and the second groove portion 6 have the same groove depth, but the groove depths of the two groove portions can also be designed to be different according to the situation.

[0133] Alternatively, the groove depth percentage of the first shell wall 1 can be 30%, 40%, 50%, 60%, 70%, and other values within the appropriate range are not listed.

[0134] The position of the first groove portion 5 and the second groove portion 6 is thinner than the surface of the first shell wall 1 without the pressure relief component 2, and the strength of the pressure relief component 2 is lower than the surface of the first shell wall 1 without the pressure relief component 2, so the battery monomer 400 can release pressure or gas through the pressure relief component 2.

[0135] Since the groove depth is in the range of 30% to 70% of the wall thickness of the first shell wall 1, the shell strength and the pressure relief performance can be considered. In addition, since changing the groove depth can change the ability of the first groove portion 5 and the second groove portion 6 to withstand fatigue stress, the groove depth can be determined according to the requirements of the pressure relief pressure to be withstood.

[0136] In some embodiments of the present disclosure, the minimum distance between the pressure relief component 2 and the outer periphery of the first shell wall 1 is greater than 5 mm.

[0137] Referring to FIG. 4, the outer periphery of the first shell wall 1 includes the first edge 3 and the second edge 4. Take the first edge 3 as an example for description. The distance between the end of the first groove portion 5 closest to the first edge 3 and the first edge 3 along the first direction Y is L1, and the distance between the end of the second groove portion 6 closest to the first edge 3 and the first edge 3 along the first direction Y is L2, both L1 and L2 are greater than 5 mm. If the distance is too small, when the battery monomer 400 experiences thermal runaway, the edge of the battery monomer may be torn, causing the large surface of the shell 401 to be damaged.

[0138] L1, L2 can be 5.01 mm, 5.02 mm, 5.03 mm, 5.04 mm, 5.05 mm, 5.1 mm, 5.2 mm, 5.3 mm, 5.4 mm, 5.5 mm, 5.6 mm, 5.7 mm, 5.8 mm, 5.9 mm, 6.0 mm, etc. The present disclosure does not list other suitable values within the range, which can be determined according to the profile size of the first shell wall 1, the size of the pressure relief component 2, etc.

[0139] As can be seen, the distance between the end of the first slot part 5 and the second slot part 6 closest to the first edge 3 and the first edge 3 in the first direction Y is greater than 5 mm. Similarly, although not shown, the distance between the end of the first slot part 5 and the second slot part 6 closest to the second edge 4 and the second edge 4 in the second direction X is also greater than 5 mm.

[0140] In addition, in the embodiment shown in FIG. 5, in which a plurality of pressure relief components 2 are arranged, a certain spacing distance is also left between adjacent pressure relief components 2, for example, greater than 5 mm. Here, in the embodiment shown in FIG. 5, the spacing distance refers to the distance between the closest parts of two pressure relief components 2 in the second direction X.

[0141] Since the shortest distance between the pressure relief component 2 and the edge is greater than 5 mm, the slot part can be in the appropriate position at the shell surface, taking into account the explosion-proof performance and cycle stability of the pressure relief component.

[0142] The embodiments of the present disclosure are further illustrated below through experimental examples.

[0143] Experimental Example 1

[0144] The pressure relief component 2 provided in the end cover 401A in this experimental example includes two first slot parts 5 and second slot parts 6, both of which are parallel to the second direction X (i.e., the included angle a is 90°, and the included angle β is 90°). The capacity of the battery monomer 400 to be tested is 150 Ah, the outer profile size of the shell 401 is 31 mm x 237 mm x 115 mm, the first edge 3 is parallel to the second direction X, and the second edge 4 is parallel to the first direction Y. In addition, the first slot part 5 and the second slot part 6 are equal in width, have the same slot shape, and form an axisymmetric shape intersecting each other. The battery monomer 400 to be tested is subjected to a charge-discharge cycle test at a test temperature of 35°C, and the following steps are performed in sequence:

[0145] a) 1 / 2C (0.5C) charging is performed on the battery monomer 400 to be tested;

[0146] b) the charging state is maintained for 30 minutes;

[0147] c) 1 / 2C (0.5C) discharging is performed on the battery monomer 400 to be tested;

[0148] d) maintain the discharging state for 30 minutes;

[0149] e) repeat steps a) to d) for 1500 cycles as one cycle.

[0150] wherein C is the unit of the charge-discharge rate, the charge-discharge rate (C) = the charge-discharge current (A) / the rated capacity (Ah). That is, in the present experiment, the charge-discharge current is 75 A.

[0151] Experimental Example 2

[0152] In comparison with Experimental Example 1, the included angle a and the included angle β are changed, and other experimental conditions remain unchanged. That is, in the present experimental example, the pressure relief component 2 provided on the end cover 401A includes two first groove portions 5 and two second groove portions 6, each of which is 80° to the first direction (i.e., the included angle a is 80°, and the included angle β is 80°), and the first groove portions 5 and the second groove portions 6 are crosswise arranged. The capacity of the battery cell 400 to be tested is 150 Ah, the outer contour size of the shell 401 is 31 mm x 237 mm x 115 mm, the first edge 3 is parallel to the second direction X, and the second edge 4 is parallel to the first direction Y. The battery cell 400 to be tested is subjected to a charge-discharge cycle test at a test temperature of 35°C, and the charge-discharge cycle test method of Experimental Example 2 is performed in the same manner as in Experimental Example 1.

[0153] Experimental Example 3

[0154] In comparison with Experimental Example 1, the included angle a and the included angle β are changed, and other experimental conditions remain unchanged. That is, in the present experimental example, the pressure relief component 2 provided on the end cover 401A includes two first groove portions 5 and two second groove portions 6, each of which is 10° to the first direction (i.e., the included angle a is 10°, and the included angle β is 10°), and the charge-discharge cycle test method of Experimental Example 3 is performed in the same manner as in Experimental Example 1.

[0155] Experimental Example 4

[0156] In comparison with Experimental Example 1, the included angle a and the included angle β are changed, and other experimental conditions remain unchanged. That is, in the present experimental example, the pressure relief component 2 provided on the end cover 401A includes two first groove portions 5 and two second groove portions 6, each of which is 75° to the first direction (i.e., the included angle a is 75°, and the included angle β is 75°), and the charge-discharge cycle test method of Experimental Example 4 is performed in the same manner as in Experimental Example 1.

[0157] Experimental Example 5

[0158] With respect to Experimental Example 1, the included angle a and the included angle β were changed, and the other experimental conditions were kept unchanged. That is, the pressure relief member 2 provided in the end cap 401A in this experimental example included two first groove portions 5 and two second groove portions 6 each of which was 30° to the first direction (that is, the included angle a was 30°, and the included angle β was 30°). The charge-discharge cycle test method of Experimental Example 6 was performed in the same manner as in Experimental Example 1.

[0159] Experimental Example 6

[0160] With respect to Experimental Example 1, the included angle a and the included angle β were changed, and the other experimental conditions were kept unchanged. That is, the pressure relief member 2 provided in the end cap 401A in this experimental example included two first groove portions 5 and two second groove portions 6 each of which was 30° to the first direction (that is, the included angle a was 30°, and the included angle β was 30°). The charge-discharge cycle test method of Experimental Example 6 was performed in the same manner as in Experimental Example 1.

[0161] Experimental Example 7

[0162] With respect to Experimental Example 1, the included angle a and the included angle β were changed, and the other experimental conditions were kept unchanged. That is, the pressure relief member 2 provided in the end cap 401A in this experimental example included two first groove portions 5 and two second groove portions 6 each of which was 30° to the first direction (that is, the included angle a was 30°, and the included angle β was 30°). The charge-discharge cycle test method of Experimental Example 6 was performed in the same manner as in Experimental Example 1.

[0163] The experimental results of Experimental Examples 1 to 7 are shown in the following table.

[0164] Table 1

[0165] The above-mentioned leakage refers to leakage of a liquid (for example, an electrolyte) inside the battery cell 400 to the outside of the battery case 401.

[0166] Referring to Experimental Example 1, the pressure relief component 2 is two non-intersecting groove portions parallel to the first edge 3. It is observed that the pressure relief component 2 of Experimental Example 1 leaks at 600 cycles, indicating that the non-intersecting groove portions are less effective in slowing the cracking of the shell 401 groove portions due to cyclic expansion. Referring to Experimental Examples 2 and 3, the pressure relief component 2 leaks at 800 cycles. In Experimental Example 2, the two groove portions form an angle of 80° with the second edge 4, and in Experimental Example 3, the two groove portions form an angle of 10° with the second edge 4, indicating that the angle between the groove portions and the edge is too small to significantly slow the cracking of the groove portions due to cyclic expansion. In Experimental Examples 4 to 7, the angle between the groove portions and the second edge 4 is between 15° and 75°, and no pressure relief component 2 burst or leakage occurs in 1500 cycles. This indicates that an angle between the groove portions and the edge of 15° to 75° can reduce the decomposition stress on the groove portions during the cycle and reduce the risk of cracking of the groove portions due to cyclic expansion. In detail, the two groove portions form an angle α and an angle β with the second edge 4, which is the edge in the direction of the battery surface. During the cyclic expansion of the battery, the two groove portions are pulled in a direction perpendicular to the battery surface, performing a breathing fatigue movement. Due to the stress decomposition effect, the cracking of the two groove portions due to expansion and cycling can be slowed down.

[0167] Experimental Examples 8 to 14 refer to GB / T36276-2018 standard for thermal runaway test.

[0168] Experimental Example 8

[0169] In this experimental example, the battery monomer to be tested is the same as in Experimental Example 1, and other test conditions remain unchanged. The thermal runaway test is performed according to GB / T36276-2018 standard, and the method is as follows:

[0170] a) Use a planar heating device with an insulating layer on its surface to complete the assembly of the battery monomer of Experimental Example 8 and the heating device, install a temperature detector, and arrange a point temperature sensor on the side away from heat conduction;

[0171] b) After the battery monomer is initialized and charged, continue to charge at 1C constant current for 12 minutes;

[0172] c) Start the heating device to continuously heat the test object, and stop triggering when thermal runaway occurs or the monitoring point temperature reaches 300°C, and turn off the heating device;

[0173] d) Record the test results.

[0174] Experimental Example 9

[0175] In this experimental example, the battery monomer to be tested is the same as in Experimental Example 2, and other test conditions remain unchanged. The test method is the same as that of Experimental Example 8.

[0176] Experimental Example 10

[0177] In this experimental example, the battery monomer to be measured is the same as that in Experimental Example 3, and other test conditions remain unchanged. The test method is the same as that in Experimental Example 8.

[0178] Experimental Example 11

[0179] In this experimental example, the battery monomer to be measured is the same as that in Experimental Example 4, and other test conditions remain unchanged. The test method is the same as that in Experimental Example 8.

[0180] Experimental Example 12

[0181] In this experimental example, the battery monomer to be measured is the same as that in Experimental Example 5, and other test conditions remain unchanged. The test method is the same as that in Experimental Example 8.

[0182] Experimental Example 13

[0183] In this experimental example, the battery monomer to be measured is the same as that in Experimental Example 6, and other test conditions remain unchanged. The test method is the same as that in Experimental Example 8.

[0184] Experimental Example 14

[0185] In this experimental example, the battery monomer to be measured is the same as that in Experimental Example 7, and other test conditions remain unchanged. The test method is the same as that in Experimental Example 8.

[0186] The experimental results of Experimental Examples 8 to 14 are shown in the following table.

[0187] Table 2

[0188] Referring to Experimental Examples 8 to 14, it can be seen that in the thermal runaway test, Experimental Example 11, Experimental Example 12, Experimental Example 13 and Experimental Example 14 have appropriate angles of the included angle a and the included angle β in the pressure relief component 2, so that the pressure relief component 2 can be normally opened and the pressure can be released, avoiding the risk of damage to the shell 401 structure as in Experimental Example 8, Experimental Example 9 and Experimental Example 10. The angles of the included angle a and the included angle β in Experimental Example 8, Experimental Example 9 and Experimental Example 10 are not appropriate, so that the pressure relief component 2 cannot be normally opened and thermal runaway occurs, resulting in the end cover 401A being blown open and the battery structure being completely destroyed. It is shown that the included angle between the groove and the edge within the appropriate range of 15° to 75° can reduce the risk of failure of the pressure relief component 2.

[0189] A second aspect of the embodiments of the present disclosure provides a battery 100, as shown in FIG. 2, which includes a box body 101 and at least one battery monomer 400 provided by the first aspect of the embodiments of the present disclosure and contained in the box body 101.

[0190] As shown in FIG. 2, the box body 101 includes a lower box body 101B and an upper box body 101A, and at least one battery monomer 400 is arranged in the box body 101.

[0191] As the battery 100 comprises the battery cell 400 disclosed in the first aspect of the embodiments of the present disclosure, the pressure inside the battery cell 400 can be released when the pressure exceeds the threshold, while reducing the risk of accidental cracking of the pressure relief component 2 during cyclic use, helping to improve the cycle life of the battery, and helping to suppress the negative effects caused by thermal runaway of the battery cell.

[0192] The third aspect of the embodiments of the present disclosure provides a power consuming device, as shown in FIG. 1 and FIG. 2, the power consuming device comprises the battery cell 400 disclosed in the first aspect of the embodiments of the present disclosure or the battery 100 disclosed in the second aspect of the embodiments of the present disclosure, and the battery cell 400 is used to provide electrical energy.

[0193] As the power consuming device comprises the battery cell 400 disclosed in the first aspect of the present disclosure or the battery 100 disclosed in the second aspect of the present disclosure, the battery cell 400 can release pressure when the internal pressure exceeds the threshold, while reducing the risk of accidental cracking of the pressure relief component during cyclic use. Thus, it helps to improve the service life of the battery 100 and reduce the maintenance cost of the power consuming device 1000.

[0194] The fourth aspect of the embodiments of the present disclosure provides an energy storage device 2000, as shown in FIG. 9, the energy storage device 2000 comprises the battery 100 disclosed in the second aspect of the embodiments of the present disclosure, and the battery 100 can store and provide electrical energy.

[0195] As the energy storage device 2000 comprises the battery 100 disclosed in the second aspect of the embodiments of the present disclosure, the pressure inside the battery can be released when the pressure exceeds the threshold, while reducing the risk of accidental cracking of the pressure relief component during cyclic use of the battery. Thus, it helps to improve the service life of the battery and reduce the maintenance cost of the energy storage device.

[0196] The specific embodiments of the present disclosure will be described below in conjunction with the accompanying drawings.

[0197] In some specific embodiments, a pressure relief component 2 is arranged on the end cover 401A of the shell 401 of the battery cell 400, the pressure relief component 2 comprises a groove portion, and the pressure relief component 2 is configured to be able to crack along the groove portion to release the pressure inside the battery cell 400; wherein the groove portion comprises intersecting first and second groove portions 5 and 6, and the intersection portion 2A becomes the detonation point, facilitating normal pressure relief when the battery is in thermal runaway.

[0198] As shown in FIG. 3 to FIG. 5, for a square cell, the pressure relief component 2 is arranged on the end cover 401A. Wherein the first groove portion 5 forms an angle α with the first direction Y, and 15°≤α≤75°; the second groove portion 6 forms an angle β with the first direction Y, and 15°≤β≤75°.

[0199] The smaller the included angles a and b, the greater the decomposition stress that the first groove 5 and the second groove 6 bear during the cycle process.

[0200] Because the groove is not parallel to the edge, during the cycle expansion process of the battery monomer 400, the groove of the battery shell 401 is pulled in a direction perpendicular to the large surface of the battery, and the current setting of the groove of the shell 401 and the battery presents a certain included angle, which can slow down the cracking of the groove of the shell 401 due to expansion cycle under the stress decomposition effect.

[0201] In addition, as shown in FIG. 4, the distance between the edge of the groove and the edge of the battery monomer 400 (i.e., L1, L2) is greater than 5 mm, which avoids affecting the edge structure when pressure relief and causing large surface damage.

[0202] As shown in FIG. 5, the groove width D is in the range of 1 mm≤D≤5 mm. D in the appropriate range can take into account the pressure relief performance and cycle life, which facilitates the groove rupture pressure relief and also reduces the risk of groove cracking during the cycle.

[0203] As shown in FIG. 6, the area S (S=a×b mm 2 ) of the pressure relief component 2 and the battery capacity C (Ah) are in the following relationship: 1≤S / C≤20 (mm 2 / Ah).

[0204] S / C in the appropriate range, i.e., the area of the pressure relief component 2 is in the appropriate range, can take into account the pressure relief function and safety performance, and avoid the situation that the inappropriate area of the pressure relief component 2 leads to the explosion of the battery out of control or the large amount of internal material spewing out to cause secondary disasters.

[0205] The above embodiments are only used to illustrate the technical solutions of the present disclosure, but not to limit it; although the present disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present disclosure, and they should be covered in the scope of the claims and the specification of the present disclosure. Especially, as long as there is no structural conflict, each technical feature mentioned in each embodiment can be combined in any way. The present disclosure is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, comprising a housing having a receiving space, the receiving space accommodating an electrode assembly, the electrode assembly comprising a positive electrode sheet, a negative electrode sheet, and a separator stacked along a first direction; At least one pressure relief component is provided on the first housing wall of the housing, the pressure relief component being configured to burst open and release pressure under the action of internal pressure in the housing. The pressure relief component includes a first groove and a second groove that intersect each other. The angle between the first groove and the first direction is α, and the angle between the second groove and the first direction is β. The angles α and β satisfy the following relationship: 0°≤α≤75°；0°≤β≤75°。 2. The battery cell according to claim 1, wherein, The included angle α and the included angle β satisfy the following relationship: 15°≤α≤75°；15°≤β≤75°。 3. The battery cell according to claim 1, wherein, The included angle α and the included angle β satisfy the following relationship: 45°≤α≤60°；45°≤β≤60°。 4. The battery cell according to any one of claims 1 to 3, wherein, The first groove and the second groove have the same groove shape and intersect to form an axisymmetric shape. The difference between the included angle α and the included angle β is in the range of 0-10 degrees.

5. The battery cell according to any one of claims 1 to 4, wherein, The first groove and the second groove are formed by locally thinning the first housing wall along the wall thickness direction of the first housing wall; In the groove width direction perpendicular to the extension direction of the first groove, the width of the bottom wall of the first groove is in the range of 1 mm to 5 mm. In the groove width direction perpendicular to the extension direction of the second groove, the width of the bottom wall of the second groove is in the range of 1 mm to 5 mm.

6. The battery cell according to claim 5, wherein, The difference in width between the bottom wall of the first groove and the bottom wall of the second groove is in the range of 0 to 0.5 mm.

7. The battery cell according to claim 5 or 6, wherein, The groove depth of the first groove and the second groove along the wall thickness direction of the first housing wall is in the range of 30% to 70% of the wall thickness of the first housing wall.

8. The battery cell according to any one of claims 1 to 7, wherein, The area of ​​the pressure relief zone formed by the pressure relief component is S, and the capacity of the battery cell is C. S and C satisfy the following relationship: 1≤S / C≤20.

9. The battery cell according to any one of claims 1 to 8, wherein, The minimum distance between the pressure relief component and the outer periphery of the first housing wall is greater than 5 mm.

10. A battery comprising a housing and at least one battery cell according to any one of claims 1 to 9 housed within the housing.

11. An electrical device comprising a battery cell according to any one of claims 1 to 9 or a battery according to claim 10, wherein the battery cell is used to provide electrical energy to the electrical device.

12. An energy storage device comprising the battery of claim 10, the battery being capable of storing electrical energy and providing electrical energy.

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