Battery cells, battery devices and electrical equipment

Abstract

The present application provides a battery cell, a battery device and an electrical device to solve the problem of increasing the probability of explosion of the battery cell. The battery cell includes a housing, a heating element, a control circuit and a plurality of electrode assemblies; the plurality of electrode assemblies are installed in the housing; the heating element is located in the housing and is arranged on the electrode assembly; the heating element is electrically connected to the electrode assembly; the control circuit is electrically connected to the heating element and the electrode assembly; the control circuit is used to detect whether the electrode assembly is overcharged, and in response to the electrode assembly being overcharged, controls the heating element to heat the electrode assembly.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery cell, a battery device and an electrical equipment. Background Art

[0002] At present, from the perspective of market development, the application of battery devices is becoming more and more extensive. Battery devices can be power batteries or energy storage batteries. Battery devices can include multiple battery cells; when a battery cell is overcharged, the battery cell may experience thermal runaway, thereby increasing the probability of battery cell explosion. Summary of the invention

[0003] The main technical problem solved by the present application is to provide a battery cell, a battery device and an electrical device to solve the problem of increasing the probability of explosion of the battery cell.

[0004] In order to solve the above technical problems, the first technical solution adopted in this application is: to provide a battery cell, the battery cell includes a shell, a heating element, a control circuit and multiple electrode assemblies; the multiple electrode assemblies are installed in the shell; the heating element is located in the shell and is arranged on the electrode assembly; the heating element is electrically connected to the electrode assembly; the control circuit is electrically connected to both the heating element and the electrode assembly; the control circuit is used to detect whether the electrode assembly is overcharged, and in response to the electrode assembly being overcharged, controls the heating element to heat the electrode assembly.

[0005] In this embodiment, the control circuit detects that the electrode assembly is overcharged, and the control circuit controls the heating element to heat the electrode assembly, so that the thermal runaway start time of multiple electrode assemblies is inconsistent. Since the thermal runaway start time of multiple electrode assemblies is inconsistent, the safety valve can first discharge the thermal runaway products generated by the electrode assembly that first experiences thermal runaway, and then discharge the thermal runaway products generated by the electrode assembly that experiences thermal runaway later, thereby reducing the probability of battery monomer explosion, and further reducing the probability of battery device explosion.

[0006] In some embodiments, the heating element is disposed on only a portion of the surface of the electrode assembly.

[0007] In this embodiment, the heating element only contacts the surface of part of the electrode assembly, so that the heating element directly heats the part of the electrode assembly, so that the heated electrode assembly can quickly cause thermal runaway, and the electrode assembly without a heating element will not be directly heated, so that the start time of thermal runaway of the heated electrode assembly and the unheated electrode assembly is greatly different, further reducing the probability of explosion of the battery cell.

[0008] In some embodiments, a plurality of electrode assemblies are arranged along a first direction; and the number of the heating element is one and is located between the electrode assembly at the end and the shell.

[0009] In this embodiment, one heating element heats only the electrode assembly at the end, and the heat generated by one heating element is absorbed by the electrode assembly at the end as much as possible, so that the electrode assembly at the end can have thermal runaway faster, and the remaining electrode assemblies will have thermal runaway later, so that the thermal runaway start time of multiple electrode assemblies is different, thereby reducing the probability of battery cell explosion. One heating element can reduce costs and installation steps, etc.

[0010] In some embodiments, multiple electrode assemblies are arranged along a first direction, and the number is greater than two; the number of heating elements is multiple; wherein one heating element is located between the end electrode assembly and the shell; and each of the remaining heating elements is located between adjacent electrode assemblies.

[0011] In this embodiment, one heating element heats the electrode assembly at the end, and each of the remaining heating elements heats the corresponding adjacent electrode assembly, so that multiple heating elements can heat more electrode assemblies; thereby, the heat generated by one heating element is absorbed by the electrode assembly at the end as much as possible, so that the electrode assembly at the end thermally runs away first, the electrode assembly heated by the remaining heating elements thermally runs away later, and the electrode assembly that is not heated thermally runs away last, so that the start time of thermal runaway of multiple electrode assemblies is different, thereby reducing the probability of explosion of battery cells.

[0012] In some embodiments, at least two of the heating elements have different power ratings.

[0013] In this embodiment, the heating element with a higher rated power causes the electrode assembly to thermally run away first, and the heating element with a lower rated power causes the electrode assembly to thermally run away later, so that the thermal runaway start time of multiple electrode assemblies is different, thereby reducing the probability of battery cell explosion.

[0014] In some embodiments, the power ratings of the multiple heating elements are different.

[0015] In this embodiment, the rated powers of the multiple heating elements are all different, so that the heating temperatures of the multiple heating elements are all different, and thus the thermal runaway start times of the multiple electrode assemblies are all inconsistent, further reducing the probability of explosion of the battery cells.

[0016] In some embodiments, the control circuit is further configured to control the at least two heating elements to start heating at different times.

[0017] In this embodiment, a heating element that is turned on earlier can cause the corresponding electrode assembly to experience thermal runaway first, and a heating element that is turned on later can cause the corresponding electrode assembly to experience thermal runaway later, so that the thermal runaway start times of multiple electrode assemblies are different, reducing the probability of battery cell explosion.

[0018] In some embodiments, the control circuit is further used to control the heating time of the plurality of heating elements to be different.

[0019] In this embodiment, the control circuit is also used to control the start-up time of the heating of multiple heating elements to be different, so that the multiple heating elements can heat the multiple electrode assemblies in an orderly manner, so that the start time of thermal runaway of the multiple electrode assemblies is inconsistent, further reducing the probability of explosion of the battery cell.

[0020] In some embodiments, the control circuit includes a voltage comparator; the voltage comparator is located in the shell and is connected in series with the heating element; wherein the voltage comparator is used to detect the output voltage of the electrode assembly; the voltage comparator is turned on in response to the output voltage being greater than or equal to a threshold; the voltage comparator is turned off or not turned on in response to the output voltage being less than a threshold.

[0021] In this embodiment, the threshold detection feature of the voltage comparator can be used to automatically control the heating element to heat the electrode assembly according to the overcharge state. In addition, the voltage comparator has a simple structure and low cost. The heating element is electrically connected to the electrode assembly through the voltage comparator, making the circuit relatively simple.

[0022] In some embodiments, the rated power P of the heating element and the rated discharge energy Erd of the battery cell satisfy the following relationship:

[0023] Erd<50, 100≤P≤450; or, 50≤Erd<100, 250≤P≤650; or, 100≤Erd<400, 450≤P≤850; or, 400≤Erd<800, 600≤P≤1000; or, 800≤Erd<1000, 800≤P≤1200; or, Erd≥1000, 800≤P≤1500; wherein, the unit of the rated discharge energy Erd of the battery cell is W*h, and the unit of the rated power P of the heating element is W.

[0024] In this embodiment, the heating element is selected according to the rated discharge energy of the battery cell, so that the heating element can heat the electrode assembly to thermal runaway in a shorter time, making the difference in the start time of thermal runaway of multiple electrode assemblies larger, further reducing the probability of explosion of the battery cell.

[0025] In some embodiments, the heating element includes a conductive heating element and a corrosion-resistant thermally conductive film; the corrosion-resistant thermally conductive film wraps the conductive heating element; or, the heating element includes a corrosion-resistant conductive heating element.

[0026] In this embodiment, the heating element includes a corrosion-resistant heat-conductive film or the heating element includes a corrosion-resistant conductive heating element, which can extend the service life of the heating element.

[0027] In some embodiments, the battery cell also includes a pole and an adapter; the electrode assembly includes a tab; the tab adapters of multiple electrode assemblies are electrically connected to the pole; the tab, pole and adapter are all defined as live parts; the control circuit and the heating element are both electrically connected to the live parts.

[0028] In this embodiment, the control circuit and the heating element can be connected to at least one of the pole lug, the pole and the adapter, so that the heating element connection has more options and the connection is more convenient.

[0029] In order to solve the above technical problems, the second technical solution provided by the present application is to provide a battery device, the battery device includes a battery box and the above battery cells, and the battery cells are installed in the battery box. Since the battery device includes the above battery cells, the battery device at least has the technical effect of the above battery cells.

[0030] In order to solve the above technical problems, the third technical solution provided by the present application is: to provide an electric device, the electric device includes an electronic device and the above battery device, and the battery device is electrically connected to the electronic device. Since the electric device includes the above battery device, the electric device at least has the technical effect of the above battery device. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0032] Figure 1 It is a structural schematic diagram of the electrical equipment provided by this application;

[0033] Figure 2 is a schematic diagram of the structure of the battery device provided by the present application;

[0034] Figure 3 It is a schematic diagram of the structure of a battery cell provided in this application;

[0035] Figure 4 It is a structural schematic diagram of an electrode assembly and a heating element provided by the present application;

[0036] Figure 5 is a schematic diagram of the structure of another electrode assembly and heating element provided in the present application;

[0037] Figure 6 is a structural schematic diagram of another electrode assembly and heating element provided in the present application;

[0038] Figure 7 This is a schematic diagram of the structure of another electrode assembly and heating element provided in the present application.

[0039] In the figure: 1. battery device; 11. battery case; 111. upper case; 112. lower case; 12. battery cell; 121. pole; 122. safety valve; 123. cover plate; 124. adapter plate; 125. pole ear; 126. electrode assembly; 1261. main surface; 1262. side surface; 127. shell; 128. control circuit; 129. heating element; 2. electronic device. DETAILED DESCRIPTION

[0040] The scheme of the embodiment of the present application is described in detail below in conjunction with the drawings of the specification.

[0041] In the following description, for the purpose of explanation rather than limitation, specific details such as specific system structures, interfaces, and technologies are provided to facilitate a thorough understanding of the present application.

[0042] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by technicians in this field without making creative work are within the scope of protection of this application.

[0043] The terms "first", "second" and "third" in this application are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Thus, the features defined as "first", "second" and "third" can explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "multiple" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined. All directional indications (such as up, down, left, right, front, back...) in the embodiments of this application are only used to explain the relative position relationship, movement, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication also changes accordingly. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units inherent to these processes, methods, products or devices.

[0044] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0045] At present, from the perspective of market development, the application of battery devices is becoming more and more extensive. Battery devices can be power batteries, which are power sources for tools. Power batteries mostly refer to batteries that provide power for electric vehicles, electric trains, electric bicycles, golf carts and other transportation vehicles, as well as aerospace. Of course, battery devices can also be energy storage batteries, which refer to batteries used to store energy from renewable energy sources such as hydropower, thermal power, wind power and solar power stations. With the continuous expansion of the application fields of battery devices, the market demand is also constantly expanding.

[0046] When a battery cell is overcharged, it may experience thermal runaway. When a battery cell experiences thermal runaway, it will produce more thermal runaway products in a short period of time, and the safety valve cannot quickly discharge more thermal runaway products, causing the amount of thermal runaway products in the battery cell to increase rapidly, thereby increasing the probability of the battery cell exploding.

[0047] In order to solve the problem that the probability of battery cell explosion is increased, the embodiment of the present application also provides a battery cell. The battery cell includes a housing, a heating element, a control circuit and a plurality of electrode assemblies; the plurality of electrode assemblies are installed in the housing; the heating element is located in the housing and is arranged on the electrode assembly; the heating element is electrically connected to the electrode assembly; the control circuit is electrically connected to the heating element and the electrode assembly; the control circuit is used to detect whether the electrode assembly is overcharged, and in response to the electrode assembly being overcharged, the heating element is controlled to heat the electrode assembly. In this embodiment, the control circuit detects that the electrode assembly is overcharged, and the control circuit controls the heating element to heat the electrode assembly, so that the thermal runaway start time of the plurality of electrode assemblies is inconsistent. Since the thermal runaway start time of the plurality of electrode assemblies is inconsistent, the safety valve can first discharge the thermal runaway products generated by the electrode assembly that first experiences thermal runaway, and then discharge the thermal runaway products generated by the electrode assembly that later experiences thermal runaway, thereby reducing the probability of the battery cell explosion, and further reducing the probability of the battery device explosion.

[0048] The embodiment of the present application provides an electrical device. Figure 1 The electrical equipment includes an electronic device 2 and a battery device 1 , and the battery device 1 is electrically connected to the electronic device 2 .

[0049] Electrical equipment can be vehicles, mobile phones, portable devices, laptops, ships, spacecraft, electric toys and electric tools, etc. Vehicles can be fuel vehicles, gas vehicles or new energy vehicles, and new energy vehicles can be pure electric vehicles, hybrid vehicles or extended-range vehicles, etc. Spacecraft include airplanes, rockets, space shuttles and spacecrafts, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys and electric airplane toys, etc.; electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators and electric planers, etc. For the convenience of explanation, the following embodiments are described by taking the electric equipment as a vehicle as an example.

[0050] The electric device may be a vehicle, and the electronic device 2 may be a lamp (such as a headlight, a taillight, etc.), a display screen, a dashboard, a control system (such as a controller), etc. of the vehicle. The electric device may also include other parts, such as a vehicle frame, and the battery device 1 and the electronic device 2 are both mounted on the vehicle body.

[0051] The electronic device 2 may be a component or device that can use electricity. The electronic device 2 may be a controller and an electronic component, etc. The controller may be a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0052] The battery device 1 may be a device capable of providing electrical energy to the electronic device 2. Figure 2 The battery device 1 may include a battery case 11 and a battery cell 12 , and the battery cell 12 is installed in the battery case 11 .

[0053] The battery case 11 has a chamber, and one or more battery cells 12 are accommodated in the accommodating chamber. The battery case 11 plays a role in protecting the battery cells 12, and is also convenient for gathering multiple battery cells 12 together. The battery case 11 may include an upper case 111 and a lower case 112 that can be covered, and the upper case 111 and the lower case 112 may define an accommodating chamber.

[0054] The shape of the battery case 11 can be specifically set as needed; for example, the shape of the battery case 11 can be cylindrical, and the corresponding battery device 1 can be called a round battery; for another example, the shape of the battery case 11 can be rectangular, and the corresponding battery device 1 can be called a rectangular battery.

[0055] The battery cell 12 may be a secondary battery, which refers to a battery cell 12 that can be continuously used by activating active materials by charging after the battery cell 12 is discharged. The battery cell 12 may include, but is not limited to, 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 metal hydride battery, a nickel cadmium battery, a lead storage battery, and the like.

[0056] The embodiment of the present application also provides a battery cell 12. Figure 3 The battery cell 12 includes a shell 127, a heating element 129, a control circuit 128 and a plurality of electrode assemblies 126; the plurality of electrode assemblies 126 are installed in the shell 127; the heating element 129 is located in the shell 127 and is arranged on the electrode assembly 126; the heating element 129 is electrically connected to the electrode assembly 126; the control circuit 128 is electrically connected to both the heating element 129 and the electrode assembly 126; the control circuit 128 is used to detect whether the electrode assembly 126 is overcharged, and in response to the electrode assembly 126 being overcharged, controls the heating element 129 to heat the electrode assembly 126.

[0057] The shell 127 is filled with an electrolyte, such as an electrolyte. The electrode assembly 126 may include an anode electrode sheet, a first separator, a cathode electrode sheet, and a second separator, which are wound in sequence. The second separator can prevent the cathode electrode sheet from contacting a structure that is not the electrode assembly 126. During the charge and discharge process of the battery cell 12, active ions (such as lithium ions) are embedded and removed back and forth between the anode electrode sheet and the cathode electrode sheet. The first separator can prevent the anode electrode sheet from short-circuiting with the cathode electrode sheet to a certain extent, and at the same time allow active ions to pass through. In some examples, the electrode assembly 126 also includes a tab 125, which can be connected to the same electrical tabs of multiple electrode assemblies 126. For example, the tab 125 may include an anode electrode tab 125 and a cathode electrode tab 125, and the anode electrode sheets of multiple electrode assemblies 126 are connected to the anode electrode tab 125, and the cathode electrode sheets of multiple electrode assemblies 126 are connected to the cathode electrode tab 125.

[0058] Continue to see Figure 3 The shell 127 has a connected cavity and an installation opening. Multiple electrode assemblies 126 are installed in the cavity of the shell 127 through the installation opening. The battery cell 12 may also include a cover plate 123; the cover plate 123 is connected to the shell 127 and covers the installation opening. The shell 127 is a hollow structure, and the material of the shell 127 can be metal or plastic; for example, the material of the shell 127 can be copper, iron, aluminum, steel, aluminum alloy, etc.

[0059] The battery cell 12 may further include a safety valve 122 (also referred to as a pressure relief valve), a pole 121, and an adapter 124 (also referred to as a current collecting member). The safety valve 122 may be disposed on the cover plate 123, for example, the safety valve 122 is fixed on the cover plate 123, and the safety valve 122 is used to actuate when the internal pressure or temperature of the battery cell 12 reaches a threshold value to discharge the internal electrolyte to reduce the internal pressure or temperature of the battery cell 12. For example, the safety valve 122 may be a temperature-sensitive valve, a pressure-sensitive valve, etc.

[0060] The pole 121 can be arranged on the cover plate 123, and the adapter 124 is located between the cover plate 123 and the electrode assembly 126. In some examples, the pole tabs 125 of multiple electrode assemblies 126 are directly connected to the pole 121 through the adapter 124. In other examples, the pole tabs 125 of multiple electrode assemblies 126 can be connected to the main pole tab 125, and the main pole tab 125 is directly electrically connected to the pole 121 through the adapter 124. Among them, the number of poles 121 can be two, namely the positive pole 121 and the negative pole 121; accordingly, the number of adapters 124 is also two, namely the positive adapter 124 and the negative adapter 124; the number of pole tabs 125 of each electrode assembly 126 is also two, namely the positive pole tab 125 and the negative pole tab 125. For example, the positive electrode tabs 125 of the plurality of electrode assemblies 126 are connected to the positive electrode posts 121 via the positive electrode adapter sheets 124 , and the negative electrode posts 121 of the plurality of electrode assemblies 126 are connected to the negative electrode tabs 125 via the negative electrode adapter sheets 124 .

[0061] The heating element 129 is a type of device capable of heating; the shape of the heating element 129 is not limited, and can be a mesh, a film, a wire, etc. For example, the shape of the heating element 129 is a wire, in which case the heating element 129 can be called a heating wire, and the heating wire can be coiled into a required structure. For another example, the shape of the heating element 129 is a film (continuous layer), in which case the heating element 129 can be called a heating film. For another example, the shape of the heating element 129 is a mesh (porous non-continuous layer), in which case the heating element 129 can be called a heating mesh.

[0062] The heating element 129 is electrically connected to the electrode assembly 126, so that the electrode assembly 126 can provide electrical energy to the heating element 129. In some examples, the heating element 129 is directly connected to the electrode assembly 126, for example, the heating element 129 is directly connected to the electrode lug 125 of the electrode assembly 126. In other examples, the heating element 129 is indirectly connected to the electrode assembly 126, for example, the heating element 129 is directly connected to the electrode column 121 or the adapter 124.

[0063] The heating element 129 is disposed on the electrode assembly 126, and the heating element 129 heats the electrode assembly 126, so that the thermal runaway start time of the plurality of electrode assemblies 126 is inconsistent. The thermal runaway start time of the plurality of electrode assemblies 126 can be inconsistent by changing the number, installation position, rated power, heating start time, etc. of the heating element 129. The number of the heating element 129 can be one or more. For example, Figure 4 and Figure 5 As shown, a heating element 129 can be disposed between the end electrode assembly 126 and the housing 127. For another example, Figure 5 As shown, the number of electrode assemblies 126 is greater than or equal to three, and a heating element 129 can be arranged between two adjacent electrode assemblies 126. The heating element 129 can be in direct contact with the electrode assembly 126 to heat the electrode assembly 126 by heat conduction; the heating element 129 can also be spaced apart from the electrode assembly 126 to heat by heat radiation.

[0064] For example, see Figure 4~Figure 7 , the heating element 129 can be only set on part of the electrode assembly 126, so that the heating element 129 can heat part of the electrode assembly 126, and the other part of the electrode assembly 126 is not heated. The heated part of the electrode assembly 126 first undergoes thermal runaway, and the other part of the electrode assembly 126 that is not heated undergoes thermal runaway later; thus, the start time of thermal runaway of multiple electrode assemblies 126 is inconsistent. At this time, the rated power of multiple heating elements 129 can be the same or different. Of course, the part of the electrode assembly 126 that is not heated may not also experience thermal runaway. The rated power refers to the constant power at a certain constant voltage.

[0065] As another example, the number of heating elements 129 is multiple, and the multiple heating elements 129 can be set on all electrode assemblies 126, so that the multiple heating elements 129 can heat all electrode assemblies 126, but the heating temperatures of at least two heating elements 129 among the multiple heating elements 129 are different; so that the thermal runaway occurs first in some electrode assemblies 126 with higher heating temperatures, and thermal runaway occurs later in some electrode assemblies 126 with lower heating temperatures; thus, the thermal runaway start time of the multiple electrode assemblies 126 is inconsistent. At this time, the heating temperatures of at least two heating elements 129 can be different by changing the rated power of the heating element 129, etc. Among them, the rated power of the heating element 129 is adjusted by selecting the area, thickness or material of the heating element 129.

[0066] The control circuit 128 may be a type of electronic device with a control function; for example, the control circuit 128 may be a central processing unit (CPU), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The control circuit 128 may be located inside the housing 127 or outside the housing 127.

[0067] The control circuit 128 is electrically connected to the electrode assembly 126, so that the electrode assembly 126 provides power to the control circuit 128 and the control circuit 128 detects whether the electrode assembly 126 is overcharged. The control circuit 128 and the electrode assembly 126 may be directly connected or indirectly connected.

[0068] The control circuit 128 determines whether the electrode assembly 126 is overcharged by detecting the electrical parameters of the electrode assembly 126, which may be voltage values, current values, etc. For example, the control circuit 128 detects the voltage value of the electrode assembly 126; when the voltage value is greater than a threshold value, it indicates that the electrode assembly 126 is overcharged; when the voltage value is less than the threshold value, it indicates that the electrode assembly 126 is not overcharged.

[0069] The thermal runaway start time refers to the time when the electrode assembly 126 starts to experience thermal runaway.

[0070] In this embodiment, the control circuit 128 detects that the electrode assembly 126 is overcharged, and the control circuit 128 controls the heating element 129 to heat the electrode assembly 126, so that the thermal runaway start time of the multiple electrode assemblies 126 is inconsistent. Since the thermal runaway start time of the multiple electrode assemblies 126 is inconsistent, the safety valve 122 can first discharge the thermal runaway products generated by the electrode assembly 126 that first experiences thermal runaway, and then discharge the thermal runaway products generated by the electrode assembly 126 that later experiences thermal runaway, thereby reducing the probability of explosion of the battery cell 12, and further reducing the probability of explosion of the battery device 1.

[0071] Among them, the thermal runaway products can be electrolytes, products after battery reactions, etc.

[0072] In some embodiments, the heating element 129 is only disposed on a portion of the surface of the electrode assembly 126 .

[0073] The heating element 129 is only disposed on the surface of a portion of the electrode assembly 126 . It can be understood that the heating element 129 is disposed in contact with the surface of a portion of the electrode assembly 126 , and the heating element 129 is not disposed on the other portion of the electrode assembly 126 .

[0074] The surface of the electrode assembly 126 may be the main surface 1261 of the electrode assembly 126 or the side surface 1262 of the electrode assembly 126. The plurality of electrode assemblies 126 are arranged along the first direction X, the main surface 1261 of the electrode assembly 126 is perpendicular to the first direction X, and the side surface 1262 of the electrode assembly 126 intersects with the main surface 1261 of the electrode assembly 126. In some examples, the electrode assembly 126 may be flat, and the thickness direction of the flat electrode assembly 126 is parallel to the first direction X; the main surface 1261 of the electrode assembly 126 is a plane surrounded by a length and a height, and the side surface 1262 of the electrode assembly 126 is a surface surrounded by a height and a thickness. For example, the side surface 1262 may be a curved surface or a flat surface.

[0075] In this embodiment, the heating element 129 only contacts the surface of a portion of the electrode assembly 126, so that the heating element 129 directly heats the portion of the electrode assembly 126, so that the heated electrode assembly 126 can quickly undergo thermal runaway, and the electrode assembly 126 without the heating element 129 will not be directly heated, so that the start time of thermal runaway of the heated electrode assembly 126 and the unheated electrode assembly 126 is significantly different, further reducing the probability of explosion of the battery cell 12.

[0076] In some embodiments, a plurality of electrode assemblies 126 are arranged along the first direction X; the number of the heating element 129 is one and is located between the electrode assembly 126 at the end and the shell 127 .

[0077] A heating element 129 is located between the main surface 1261 of the end electrode assembly 126 and the inner surface of the shell 127, and contacts the main surface 1261 of the electrode assembly 126. The end electrode assembly 126 refers to the electrode assembly 126 at the edge of the plurality of electrode assemblies 126 along the first direction X.

[0078] In this embodiment, one heating element 129 heats only the electrode assembly 126 at the end, and the heat generated by one heating element 129 is absorbed by the electrode assembly 126 at the end as much as possible, so that the electrode assembly 126 at the end can have thermal runaway faster, and the remaining electrode assemblies 126 have thermal runaway later, so that the thermal runaway start time of multiple electrode assemblies 126 is different, thereby reducing the probability of explosion of the battery cell 12. One heating element 129 can reduce costs and installation steps, etc.

[0079] In some embodiments, multiple electrode assemblies 126 are arranged along the first direction X, and the number is greater than two; the number of heating elements 129 is multiple; one heating element 129 is located between the end electrode assembly 126 and the shell 127; and each of the remaining heating elements 129 is located between adjacent electrode assemblies 126.

[0080] The number of the plurality of electrode assemblies 126 is greater than two, for example, may be three, four, five, six, etc. The number of the plurality of heating elements 129 may be two, three, four, five, six, etc.

[0081] The plurality of heating elements 129 can heat the plurality of electrode assemblies 126 respectively. The plurality of heating elements 129 heat all the electrode assemblies 126. In some examples, the number of the plurality of electrode assemblies 126 can be the same as the number of the plurality of heating elements 129; for example, the plurality of electrode assemblies 126 and the plurality of heating elements 129 are stacked in sequence. In other examples, the number of the plurality of heating elements 129 is greater than the number of the plurality of electrode assemblies 126.

[0082] The plurality of heating elements 129 heats a portion of the electrode assemblies 126 of the plurality of electrode assemblies 126. In other examples, the number of the plurality of electrode assemblies 126 is greater than the number of the plurality of heating elements 129; for example, the difference between the number of the plurality of electrode assemblies 126 and the number of the plurality of heating elements 129 is greater than or equal to two. Wherein, the surface of a portion of the electrode assemblies 126 is not provided with heating elements 129, and the portion of the electrode assemblies 126 not provided with heating elements 129 eventually experiences thermal runaway.

[0083] In this embodiment, one heating element 129 heats the electrode assembly 126 at the end, and each of the remaining heating elements 129 heats the corresponding adjacent electrode assembly 126, so that multiple heating elements 129 can heat more electrode assemblies 126; thereby, the heat generated by one heating element 129 is absorbed by the electrode assembly 126 at the end as much as possible, so that the electrode assembly 126 at the end thermal runaways first, the electrode assembly 126 heated by the remaining heating elements 129 thermal runaways later, and the electrode assembly 126 that is not heated thermal runaways last, so that the thermal runaway start time of the multiple electrode assemblies 126 is different, thereby reducing the probability of explosion of the battery cell 12.

[0084] In some embodiments, the power ratings of at least two heating elements 129 are different.

[0085] In some examples, the number of heating elements 129 is two, and the rated powers of the two heating elements 129 are different. In other examples, the number of heating elements 129 is three or more, for example, only two heating elements 129 have different rated powers, or for example, all heating elements 129 have different rated powers.

[0086] In this embodiment, the heating element 129 with a higher rated power causes the electrode assembly 126 to thermally run away first, and the heating element 129 with a lower rated power causes the electrode assembly 126 to thermally run away later, so that the thermal runaway start times of the multiple electrode assemblies 126 are different, thereby reducing the probability of explosion of the battery cell 12.

[0087] In some embodiments, the power ratings of the plurality of heating elements 129 are different.

[0088] The rated powers of the plurality of heating elements 129 are all different, that is, the rated powers of the plurality of heating elements 129 increase or decrease sequentially. In some examples, the rated powers of the plurality of heating elements 129 increase or decrease sequentially, and the difference between the rated powers of any two adjacent heating elements 129 is equal; that is, the rated powers of the plurality of heating elements 129 can form an arithmetic progression.

[0089] In this embodiment, the rated powers of the multiple heating elements 129 are different, so that the heating temperatures of the multiple heating elements 129 are different, and thus the thermal runaway start times of the multiple electrode assemblies 126 are inconsistent, further reducing the probability of explosion of the battery cell 12.

[0090] In some embodiments, the control circuit 128 is further configured to control the at least two heating elements 129 to start heating at different times.

[0091] In some examples, the control circuit 128 includes a controller, which is electrically connected to the plurality of heating elements 129 ; by designing a control program of the controller, the controller can control at least two heating elements 129 to start heating at different times.

[0092] In other examples, the control circuit 128 includes multiple controllers (or voltage comparators) and multiple delay devices, and a heating element 129 is electrically connected to a controller (or voltage comparator) through a delay device; the delay times of at least two of the delay devices are different, so that the start-up time of the heating elements 129 corresponding to at least two delay devices is different.

[0093] In this embodiment, a heating element 129 that is turned on earlier can cause the corresponding electrode assembly 126 to experience thermal runaway first, and a heating element 129 that is turned on later can cause the corresponding electrode assembly 126 to experience thermal runaway later, so that the thermal runaway start times of multiple electrode assemblies 126 are different, reducing the probability of explosion of the battery cell 12.

[0094] In some embodiments, the control circuit 128 is further configured to control the heating elements 129 to start heating at different times.

[0095] The heating start times of the plurality of heating elements 129 are all different, that is, the heating start times of the plurality of heating elements 129 increase or decrease sequentially. In some examples, the heating start times of the plurality of heating elements 129 increase or decrease sequentially, and the difference between the heating start times of any two adjacent heating elements 129 is equal; that is, the heating start times of the plurality of heating elements 129 can form an arithmetic progression.

[0096] In this embodiment, the control circuit 128 is also used to control the start-up time of the heating elements 129 to be different, so that the multiple heating elements 129 can heat the multiple electrode assemblies 126 in an orderly manner, so that the start time of thermal runaway of the multiple electrode assemblies 126 is inconsistent, further reducing the probability of explosion of the battery cell 12.

[0097] In some embodiments, the control circuit 128 includes a voltage comparator; the voltage comparator is located in the shell 127 and is connected in series with the heating element 129; the voltage comparator is used to detect the output voltage of the electrode assembly 126; the voltage comparator is turned on in response to the output voltage being greater than or equal to a threshold; the voltage comparator is turned off or not turned on in response to the output voltage being less than a threshold.

[0098] The number of the heating elements 129 can be one or more, and the number of the voltage comparators can be one or more. For example, one voltage comparator is connected to one or more heating elements 129; for another example, multiple voltage comparators are arranged in one-to-one correspondence with multiple heating elements 129 and are respectively connected in series.

[0099] In response to the output voltage being greater than or equal to the threshold, the voltage comparator is turned on; at this time, the electrode assembly 126 is in overcharge. In response to the output voltage being less than the threshold, the voltage comparator is turned off, for example, charging is stopped; at this time, the electrode assembly 126 exits overcharge. In response to the output voltage being less than the threshold, the voltage comparator is not turned on; at this time, the electrode assembly 126 is not charged or the charging does not reach overcharge. Among them, the voltage comparator is a prior art, and the threshold of the voltage comparator is a property of the voltage comparator itself.

[0100] In this embodiment, by utilizing the threshold detection feature of the voltage comparator, the heating element 129 can be automatically controlled according to the overcharge state to heat the electrode assembly 126. In addition, the voltage comparator has a simple structure and low cost, and the heating element 129 is electrically connected to the electrode assembly 126 through the voltage comparator, making the circuit relatively simple.

[0101] In some embodiments, the rated power P of the heating element 129 and the rated discharge energy Erd of the battery cell 12 satisfy the following relationship:

[0102] Erd<50, 100≤P≤450; or, 50≤Erd<100, 250≤P≤650; or, 100≤Erd<400, 450≤P≤850; or, 400≤Erd<800, 600≤P≤1000; or, 800≤Erd<1000, 800≤P≤1200; or, Erd≥1000, 800≤P≤1500; wherein, the unit of the rated discharge energy Erd of the battery cell is W*h, and the unit of the rated power P of the heating element is W.

[0103] The rated power P of the heating element 129 and the rated discharge energy Erd of the battery cell 12 satisfy the following relationship, which can be understood as shown in Table 1 below.

[0104] Table 1 is a table showing the relationship between the rated power of the heating element and the rated discharge energy of the battery cell.

[0105]

[0106] In this embodiment, the heating element 129 is selected according to the rated discharge energy of the battery cell 12, so that the heating element 129 can heat the electrode assembly 126 to thermal runaway in a shorter time, so that the difference in the start time of thermal runaway of multiple electrode assemblies 126 is larger, further reducing the probability of explosion of the battery cell 12.

[0107] In some embodiments, the heating element 129 includes a conductive heating element and a corrosion-resistant thermally conductive film; the corrosion-resistant thermally conductive film wraps the conductive heating element; or, the heating element 129 includes a corrosion-resistant conductive heating element.

[0108] The corrosion-resistant heat-conductive film may be a corrosion-resistant conductive material, for example, polyethylene terephthalate (PET). The conductive heating element may be a metal sheet or a metal wire, etc., which has a high heating efficiency. The conductive heating element may be in the shape of a sheet, a plate, a wire, a film, etc. The corrosion-resistant heat-conductive film prevents the conductive heating element from being corroded by the electrolyte in the battery cell 12.

[0109] The corrosion-resistant conductive heating element can be a conductive PET film. For example, the conductive PET film covers the entire main surface 1261 of the end electrode assembly 126 close to the shell 127, which advances the start time of thermal runaway of the end electrode assembly 126.

[0110] In this embodiment, the heating element 129 includes a corrosion-resistant heat-conductive film or the heating element 129 includes a corrosion-resistant conductive heating element, which can extend the service life of the heating element 129.

[0111] In some embodiments, the battery cell 12 also includes a pole 121 and an adapter plate 124; the pole tabs 125 and adapter plate 124 of multiple electrode assemblies 126 are electrically connected to the pole 121; the pole tabs 125, the pole 121 and the adapter plate 124 are all defined as live parts; the control circuit 128 and the heating element 129 are both electrically connected to the live parts.

[0112] For example, the control circuit 128 and the heating element 129 can be directly connected to the pole ear 125 , or can be directly connected to the pole 121 , or can be directly connected to the adapter sheet 124 .

[0113] In this embodiment, the control circuit 128 and the heating element 129 can be connected to at least one of the pole ear 125, the pole 121 and the adapter 124, so that the heating element 129 has more connection options and is more convenient to connect.

[0114] The above description is only an implementation method of the present application, and does not limit the patent protection scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly used in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A battery cell, characterized in that: include: case; Safety valve; A plurality of electrode assemblies are installed in the housing; A heating element is located in the housing and is disposed on the electrode assembly; the heating element is electrically connected to the electrode assembly; A control circuit is electrically connected to the heating element and the electrode assembly; the control circuit is used to detect whether the electrode assembly is overcharged, and in response to the overcharge of the electrode assembly, control the heating element to heat one or more of the electrode assemblies in a manner such that the start time of thermal runaway of the multiple electrode assemblies is inconsistent.

2. The battery cell according to claim 1, characterized in that: The heating element is only disposed on a portion of the surface of the electrode assembly.

3. The battery cell according to claim 2, characterized in that: The plurality of electrode assemblies are arranged along a first direction; the number of the heating element is one and is located between the electrode assembly at the end and the shell.

4. The battery cell according to claim 1, characterized in that: A plurality of the electrode assemblies are arranged along a first direction, and the number of the electrode assemblies is greater than two; a plurality of the heating elements are present; Among them, one heating element is located between the electrode assembly at the end and the shell; and each of the remaining heating elements is located between adjacent electrode assemblies.

5. The battery cell according to claim 4, characterized in that: The rated powers of at least two of the heating elements are different.

6. The battery cell according to claim 5, characterized in that: The rated powers of the plurality of heating elements are different.

7. The battery cell according to any one of claims 4 to 6, characterized in that: The control circuit is also used to control at least two of the heating elements to start heating at different times.

8. The battery cell according to claim 7, characterized in that: The control circuit is also used to control the heating elements to start heating at different times.

9. The battery cell according to any one of claims 1 to 6, characterized in that: The control circuit includes a voltage comparator; the voltage comparator is located in the housing and is connected in series with the heating element; Among them, the voltage comparator is used to detect the output voltage of the electrode assembly; the voltage comparator is turned on in response to the output voltage being greater than or equal to a threshold; the voltage comparator is turned off or not turned on in response to the output voltage being less than a threshold.

10. The battery cell according to any one of claims 1 to 6, characterized in that: The rated power P of the heating element and the rated discharge energy Erd of the battery cell satisfy the following relationship: Erd<50,100≤P≤450; or, 50≤Erd<100,250≤P≤650; or, 100≤Erd<400,450≤P≤850; or, 400≤Erd<800,600≤P≤1000; or, 800≤Erd<1000,800≤P≤1200; or, Erd≥1000,800≤P≤1500; The unit of the rated discharge energy Erd of the battery cell is W*h, and the unit of the rated power P of the heating element is W.

11. The battery cell according to any one of claims 1 to 6, characterized in that: The heating element comprises a conductive heating element and a corrosion-resistant heat-conductive film, wherein the corrosion-resistant heat-conductive film wraps the conductive heating element; or, the heating element comprises a corrosion-resistant conductive heating element.

12. The battery cell according to any one of claims 1 to 6, characterized in that: The battery cell also includes a pole and an adapter; the electrode assembly includes a pole ear; the pole ears of the plurality of electrode assemblies and the adapter are electrically connected to the pole; the pole ears, the pole and the adapter are all defined as live parts; the control circuit and the heating element are both electrically connected to the live parts.

13. A battery device, characterized in that: The invention comprises a battery case and a battery cell according to any one of claims 1 to 12, wherein the battery cell is installed in the battery case.

14. An electrical device, characterized in that: The invention comprises an electronic device and the battery device as claimed in claim 13, wherein the battery device is electrically connected to the electronic device.

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