A battery and a battery operating method

Abstract

The application provides a battery and a battery operation method. The battery comprises a laminated core formed by alternately stacking first pole pieces and second pole pieces, and a diaphragm is arranged between adjacent first pole pieces and second pole pieces. The first pole piece comprises a first current collector and a first active material layer located on at least one side of the first current collector, and the second pole piece comprises a second current collector and a second active material layer located on at least one side of the second current collector. The first pole piece comprises a first soft tab connected with the first current collector, and the second pole piece comprises a second soft tab connected with the second current collector. The laminated core further comprises a third pole piece, and the third pole piece comprises a third current collector and at least two third soft tabs connected with the third current collector. In this way, when the battery is charged at low temperature, lithium precipitation of the battery can be slowed down, so that the internal resistance of the battery is prevented from increasing, the cycle life of the battery is improved, and the fast charging capacity is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to a battery and a battery operation method. Background Technology

[0002] In the battery field, especially lithium-ion batteries, due to their high energy density and good charge-discharge cycle capability, they have been widely used in mobile phones, laptops, electric vehicles, and other fields. However, charging lithium-ion batteries at low temperatures can lead to lithium plating at the negative electrode. Lithium plating increases the battery's internal resistance, shortens its cycle life, and limits its fast-charging capacity.

[0003] Furthermore, safety issues caused by battery thermal runaway primarily arise because when batteries are used under high loads such as high power and high current, or in harsh environments such as high temperatures, a large amount of heat is often generated inside the battery. As the battery temperature rises further, if this temperature increase cannot be suppressed or eliminated, the internal chemical system deteriorates further, internal materials are damaged, leading to thermal runaway and potentially causing accidents such as fires or explosions. A higher pass rate in thermal chamber testing indicates better battery safety performance. Summary of the Invention

[0004] In view of this, this application provides a battery that solves the problems of increased internal resistance, shortened cycle life, and limited fast-charging capacity caused by charging the battery at low temperatures. This application also provides a battery operation method applicable to the above-mentioned battery.

[0005] To achieve the above objectives, this application provides the following technical solution:

[0006] A battery includes a stacked cell formed by alternating stacking of a first electrode and a second electrode, wherein a separator is disposed between adjacent first and second electrodes;

[0007] The first electrode includes a first current collector and a first active material layer located on at least one side of the first current collector; the second electrode includes a second current collector and a second active material layer located on at least one side of the second current collector.

[0008] The first electrode includes a first flexible tab connected to the first current collector, and the second electrode includes a second flexible tab connected to the second current collector;

[0009] The laminated cell also includes a third electrode, which includes a third current collector and at least two third soft tabs connected to the third current collector.

[0010] Optionally, the third electrode has the same polarity as the first electrode, or the third electrode has the same polarity as the second electrode.

[0011] Optionally, the third electrode has the same polarity as the first electrode, all the first soft electrodes and one of the third soft electrodes of each third electrode are welded to form a first hard electrode, all the second soft electrodes are welded to form a second hard electrode, and the other third soft electrode of each third electrode is welded to form a third hard electrode. The third hard electrode and the second hard electrode are connected by a connecting branch, and a switching element for controlling the opening and closing of the connecting branch is provided on the connecting branch.

[0012] Optionally, the first hard electrode tab and the third hard electrode tab are positive electrode tabs, and the second hard electrode tab is a negative electrode tab.

[0013] Optionally, the resistivity of the third current collector is 8*10⁻⁶. -7 ~1*10 -5 Ω·m.

[0014] Optionally, the third current collector is a metal current collector, an alloy current collector, or a composite current collector.

[0015] Optional,

[0016] The third current collector is made of stainless steel, nickel-chromium alloy foil, iron-nickel alloy foil, iron-chromium-aluminum alloy, aluminum-nickel-iron alloy, or carbon paper; or...

[0017] The third current collector is a polymer surface coated with a metal foil; or...

[0018] The composite current collector includes an aluminum foil and an oxide layer disposed on both sides of the aluminum foil. The oxide layer is one or more of the following: aluminum oxide, zirconium oxide, boron oxide, titanium oxide, nickel oxide, zinc oxide, gallium oxide, cerium oxide, tin oxide, antimony oxide, boron nitride, magnesium nitride, gallium nitride, and potassium nitride.

[0019] Optionally, the switching element includes a normally open temperature switch and a normally closed temperature switch connected in series, wherein:

[0020] The normally open temperature switch closes when the temperature is at the first temperature T1, the normally closed temperature switch opens when the temperature is at the second temperature T2, and the normally closed temperature switch closes when the temperature is at the third temperature T3, wherein T1, T2 and T3 satisfy: T2 > T3 > T1.

[0021] Optional,

[0022] T1 satisfies: 70℃≤T1≤90℃; and / or,

[0023] T2 satisfies: 130℃≤T2≤180℃; and / or,

[0024] T3 satisfies: 100℃≤T3<130℃.

[0025] Optionally, the normally open temperature switch is disconnected when the temperature is at a fourth temperature T4, wherein T4 satisfies: T4≤50℃.

[0026] Optionally, in the stacking direction of the laminated cell, the third electrode is located at the end of the laminated cell.

[0027] Optionally, a third active material layer is provided on the side of the third current collector closer to the middle of the stacked cell, and the third active material layer is not provided on the side of the third current collector away from the middle of the stacked cell.

[0028] Optionally, the first hard tab, the second hard tab, and the third hard tab are disposed on the same side of the stacked cell, and in the width direction of the battery, the second hard tab is disposed between the first hard tab and the third hard tab.

[0029] Optionally, the first hard tab and the second hard tab are disposed on the same side of the laminated cell, and the first hard tab and the third hard tab are disposed on different sides of the laminated cell.

[0030] Optional,

[0031] A first insulating layer is provided in the end region of the first soft electrode near the first current collector, and the size of the first insulating layer is D in the length direction of the first electrode, wherein D satisfies: 0.5mm≤D≤2mm;

[0032] A second insulating layer is provided in the end region of the second soft electrode near the second current collector, and the dimension of the second insulating layer is E in the length direction of the second electrode, wherein E satisfies: 0.5mm≤E≤2mm;

[0033] A third insulating layer is provided in the end region of the third soft electrode near the third current collector, and the dimension of the third insulating layer is F in the length direction of the third electrode, wherein F satisfies: 0.5mm≤E≤2mm.

[0034] Optionally, a temperature sensor for detecting the battery temperature is disposed on the surface of the battery.

[0035] A battery operation method, applicable to any of the batteries described above, the battery operation method comprising a battery charging step and a battery discharging step, the battery charging step comprising at least the following steps:

[0036] S101: Before charging the battery, detect the temperature of the battery;

[0037] S102: If the battery reaches the target temperature, then charge the battery;

[0038] S103: If the battery does not reach the target temperature, connect the positive and negative terminals of the external power supply to the two identical tabs of the battery to heat the battery to the target temperature, and then connect the positive and negative terminals of the external power supply to the two different tabs of the battery to charge the battery.

[0039] Optionally, the battery discharge step includes at least the following steps:

[0040] S201: During the battery discharge process, the switching element controls the switching on and off of the connecting branch according to the temperature at which the switching element is located;

[0041] S202: When the temperature of the switching element is at the first temperature, the switching element controls the connection of the connecting branch;

[0042] S203: When the temperature of the switching element rises from the first temperature to the second temperature, the switching element controls the connection branch to disconnect;

[0043] S204: When the temperature of the switching element drops from the second temperature to the third temperature, the switching element controls the connection of the connecting branch;

[0044] S205: Repeat S203 and S204 according to the temperature of the battery.

[0045] The battery provided in this application, in addition to having a first and a second soft electrode tab, also has at least two third soft electrode tabs, with the third soft electrode tab having the same polarity as one of the first and second soft electrode tabs. This forms at least three hard electrode tabs: two hard electrode tabs with the same polarity and one hard electrode tab with a different polarity. Thus, during the initial charging phase, when the battery temperature is low, the positive and negative terminals of the external power supply are connected to the two identical electrode tabs of the battery. At this time, the identical electrode tabs act as resistors, and under the influence of the external power supply, the resistors heat up, causing the battery temperature to rise. Once a suitable temperature is reached, the positive and negative terminals of the external power supply are then connected to the two different electrode tabs of the battery to complete the charging process. This configuration can slow down lithium plating in the battery during low-temperature charging, thereby preventing an increase in internal resistance, improving battery cycle life, and increasing fast-charging capacity.

[0046] The battery provided in this application achieves self-discharge at high temperatures by setting a connecting branch between the second hard electrode and the third hard electrode, and setting a switching element on the connecting branch to control the on / off state of the connecting branch. This reduces the battery energy, thereby reducing the risk of the battery catching fire at high temperatures, and thus improving the safety performance of the battery during use and increasing the pass rate of the battery in the hot box test. Attached Figure Description

[0047] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0048] Figure 1 This is a schematic diagram of a battery structure under one embodiment provided in this example;

[0049] Figure 2 This is a schematic diagram of the structure of the first electrode in one embodiment;

[0050] Figure 3 This is a schematic diagram of the battery structure under another implementation method;

[0051] Figure 4 This is a schematic diagram of the structure of the first electrode in another implementation method;

[0052] Figure 5 This is a schematic diagram of the battery structure under another implementation method;

[0053] Figure 6 This is a schematic diagram of the structure of the first electrode in another implementation method;

[0054] Figure 7 This is a schematic diagram of the cell structure under the first embodiment;

[0055] Figure 8 This is a schematic diagram of the cell structure under the second embodiment;

[0056] Figure 9 This is a schematic diagram of the battery cell structure under the third embodiment.

[0057] exist Figures 1-9 middle:

[0058] 1-Battery cell, 2-First hard electrode tab, 3-Second hard electrode tab, 4-Connecting branch, 5-Connector, 6-Third hard electrode tab;

[0059] 11-First electrode, 12-Second electrode, 13-Diaphragm, 14-Third electrode, 51-Normally open temperature switch, 52-Normally closed temperature switch;

[0060] 111-First current collector, 112-First active material layer, 113-First soft electrode tab, 121-Second current collector, 122-Second active material layer, 123-Second soft electrode tab, 141-Third current collector, 142-Third active material layer, 143-Third soft electrode tab. Detailed Implementation

[0061] This application provides a battery. This application also provides a battery operation method applicable to the above-described battery.

[0062] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0063] like Figures 1 to 9 As shown, this application embodiment provides a battery, which can be a lithium-ion battery, a nickel-metal hydride battery, a lead-acid battery, etc. The battery includes a stacked cell 1 formed by alternating stacking of first electrode 11 and second electrode 12, and a separator 13 is disposed between adjacent first electrode 11 and second electrode 12; the first electrode 11 includes a first current collector 111 and a first active material layer 112 located on at least one side of the first current collector 111, the second electrode 12 includes a second current collector 121 and a second active material layer 122 located on at least one side of the second current collector 121; the first electrode 11 includes a first flexible tab 113 connected to the first current collector 111, and the second electrode 12 includes a second flexible tab 123 connected to the second current collector 121; the stacked cell 1 also includes a third electrode 14, the third electrode 14 including a third current collector 141 and at least two third flexible tabs 143 connected to the third current collector 141.

[0064] In this embodiment, an optional implementation is provided, in which the first soft tabs 113 of all the first electrode plates 11 and one third soft tab 143 of each third electrode plate 14 are welded together to form a first hard tab 2; the second soft tabs 123 of all the second electrode plates 12 are welded together to form a second hard tab 3; and the other third soft tab 143 of each third electrode plate 14 is welded together to form a third hard tab 6. It should be noted that in this embodiment, the first electrode plates 11 and the third electrode plates 14 have the same polarity.

[0065] In this embodiment, another optional implementation is provided: the second soft tabs 123 of all the second electrode plates 12 and one third soft tab 143 of each third electrode plate 14 are welded together to form a second hard tab 3; the first soft tabs 113 of all the first electrode plates 11 are welded together to form a first hard tab 2; and the other third soft tab 143 of each third electrode plate 14 is welded together to form a third hard tab 6. It should be noted that in this embodiment, the second electrode plates 12 and the third electrode plates 14 have the same polarity.

[0066] In this embodiment, another optional implementation is provided, which further includes a fourth electrode (not shown in the figure) based on the above embodiment. The fourth electrode includes a fourth current collector and at least two fourth soft electrodes connected to the fourth current collector. Further, the first soft electrodes 113 of all the first electrodes 11 and one third soft electrode 143 of each third electrode 14 are welded together to form a first hard electrode 2; the second soft electrodes 123 of all the second electrodes 12 and one fourth soft electrode 14 of each fourth electrode are welded together to form a second hard electrode 3; the other third soft electrode 143 of each third electrode 14 is welded together to form a third hard electrode 6; and the other fourth soft electrode 14 of each fourth electrode is welded together to form a fourth hard electrode 14. It should be noted that in this embodiment, the first electrodes 11 and the third electrodes 14 have the same polarity, and the second electrodes 12 and the fourth electrodes have the same polarity.

[0067] Here, the above configuration includes at least three rigid tabs, with two of these tabs having the same polarity and the third tab having a different polarity. With this configuration, during the initial charging phase when the battery temperature is low, the positive and negative terminals of the external power supply are connected to the two identical rigid tabs. The third current collector connected between these two identical tabs acts as a resistor, generating heat under the influence of the external power supply, thus raising the battery temperature. Once a suitable temperature is reached, the positive and negative terminals of the external power supply are then connected to the two non-identical rigid tabs to complete the charging process. This configuration slows down lithium plating during low-temperature charging, preventing increased internal resistance, improving battery cycle life, and enhancing fast-charging capacity.

[0068] It should be noted that the third electrode 14 has the same polarity as the first electrode 11 or the second electrode 12. Specifically, when the third electrode 14 and the first electrode 11 have the same polarity, the third electrode 14 is disposed between adjacent second electrodes 12, or the third electrode 14 is disposed adjacent to the second electrode 12. When the third electrode 14 and the second electrode 12 have the same polarity, the third electrode 14 is disposed between adjacent first electrodes 11, or the third electrode 14 is disposed adjacent to the first electrode 11. The first electrode 11, the second electrode 12, and the third electrode 14 are stacked to form the laminated battery cell 1.

[0069] It should also be noted that the number of third soft tabs 143 in the third electrode 14 is not limited here; two or more third soft tabs 143 can be provided. Similarly, the number of fourth soft tabs in the fourth electrode is not limited here; two or more fourth soft tabs can also be provided. Furthermore, the number of third electrode 14 is not limited here; one or more third electrode 14 can be provided.

[0070] It should also be noted that there are no restrictions on the first electrode 11 and the second electrode 12. The first electrode can be a positive electrode, in which case the second electrode 12 is a negative electrode; of course, the first electrode 11 can also be a negative electrode, in which case the second electrode 12 is a positive electrode.

[0071] The battery with the above structure, in addition to the first soft tab 113 and the second soft tab 123, also has at least two third soft tabs 143, and the third soft tabs 143 have the same polarity as one of the first soft tabs 113 and the second soft tab 123. This forms at least three hard tabs, namely two hard tabs of the same polarity and one hard tab of a different polarity. Thus, during the initial charging stage, when the battery temperature is low, the positive and negative terminals of the external power supply are connected to the two identical tabs of the battery. At this time, the identical tabs act as resistors, and under the influence of the external power supply, the resistors heat up, causing the battery temperature to rise. When the temperature reaches a suitable level, the positive and negative terminals of the external power supply are then connected to the two tabs of a different polarity to complete the charging process. This configuration can slow down lithium plating in the battery during low-temperature charging, thereby avoiding increased internal resistance, improving battery cycle life, and increasing fast-charging capacity.

[0072] In some embodiments, the third electrode 14 has the same polarity as the first electrode 11, or the third electrode 14 has the same polarity as the second electrode 12. That is, when the first electrode 11 is a positive electrode, the third electrode 14 is a positive electrode and the second electrode 12 is a negative electrode; when the first electrode 11 is a negative electrode, the third electrode 14 is a negative electrode and the second electrode 12 is a positive electrode.

[0073] In some embodiments, the third electrode 14 has the same polarity as the first electrode 11. All the first soft electrodes 113 and one third soft electrode 143 of each third electrode 14 are welded to form a first hard electrode 2. All the second soft electrodes 123 are welded to form a second hard electrode 3. The other third soft electrode 143 of each third electrode 14 is welded to form a third hard electrode 6. The third hard electrode 6 and the second hard electrode 3 are connected by a connecting branch 4, and a switching element 5 for controlling the opening and closing of the connecting branch 4 is provided on the connecting branch 4.

[0074] In this embodiment, an optional implementation is provided. The switching element 5 consists of a temperature switch. Specifically, the temperature switch comprises a normally open temperature switch 51 and a normally closed temperature switch 52 connected in series. Under normal operating conditions (i.e., normal battery usage), the normally open temperature switch 51 is open, and the normally closed temperature switch 52 is closed. When the battery is used under high power, high current, or other high-load conditions, or in harsh environments such as high temperatures, the battery temperature will continuously rise. This temperature increase will cause the normally open temperature switch 51 to close. Since the normally closed temperature switch 52 is closed, the connection branch 4 between the second hard tab 3 and the third hard tab 6 is connected, allowing the battery to self-discharge. This reduces the battery voltage and capacity, preventing further battery deterioration due to overheating, avoiding thermal runaway, and improving battery safety during use. When the normally open temperature switch 51 is closed, the temperature of the connecting branch 4 will continue to rise. The normally closed temperature switch 52 will open after reaching a certain temperature, thus disconnecting the connecting branch 4 and preventing it from continuing to heat up and melting. At this time, the battery is working normally. When the temperature of the switching element 5 drops to a certain temperature, the normally closed temperature switch 52 will close again, thus protecting the battery again. The pulse discharge achieved with temperature changes can better protect the battery and improve the safety of the battery during use.

[0075] In this embodiment, another optional implementation is also provided. The switching element 5 consists of a temperature sensor, a switch, and a control module. The temperature sensor is communicatively connected to the control module, and the switch is electrically connected to the control module. When the battery is in normal operating condition, the switch is in the open state. When the battery is used under high power, high current, or other high load conditions, or in harsh environments such as high temperature, the battery temperature will continuously rise. As the battery temperature rises, the temperature of the temperature sensor will also rise. The temperature sensor transmits temperature information to the control module. Based on the received temperature information, the control module controls the switch to close. At this time, the connection branch 4 between the second hard electrode 3 and the third hard electrode 6 is connected, and the battery self-discharges, thereby reducing the battery voltage and capacity, preventing further battery deterioration caused by overheating, avoiding thermal runaway, and improving battery safety during use. The control module receives the temperature information detected by the temperature sensor in real time. When the temperature rises significantly while the switch is closed, the control module controls the switch to open, disconnecting the connection branch 4 and preventing it from melting. When the temperature sensor detects a drop in temperature, the control module closes the switch again, thus protecting the battery once more. By implementing pulse discharge based on temperature changes, the battery is better protected, improving safety during battery use.

[0076] It should be noted that the connecting branch 4 is a conductive branch, used to realize the electrical connection between the second hard electrode 3 and the third hard electrode 6.

[0077] The battery with the above structure has a switching element 5 installed on the connecting branch 4 between the second hard tab 3 and the third hard tab 6 of the cell 1. The switching element 5 can control the opening and closing of the connecting branch 4. By controlling the connection of the connecting branch 4, the switching element 5 reduces the battery voltage and capacity, thereby preventing further battery deterioration caused by overheating, avoiding thermal runaway, and improving battery safety during use. Moreover, after the battery voltage drops, the switching element 5 can also control the connection branch 4 to disconnect, allowing the battery to operate normally and be used.

[0078] In some embodiments, the first hard tab 2 and the third hard tab 6 are positive tabs, and the second hard tab 3 is a negative tab. That is, the first current collector 111 and the third current collector 141 are positive current collectors, and the second current collector 121 is a negative current collector. With this configuration, when the battery is initially charging and the battery temperature is low, the positive and negative terminals of the external power supply are connected to the first hard tab 2 and the third hard tab 6, respectively. Current flows sequentially through the first hard tab 2, the third current collector 141, and the third hard tab 6. At this time, the third current collector 141 acts as a resistor, generating heat when the current passes through it, thereby raising the battery temperature and mitigating lithium plating during low-temperature charging.

[0079] In addition, the first hard electrode tab 2, the second hard electrode tab 3, and the third hard electrode tab 6 can be configured in other ways, for example, the first hard electrode tab 2 and the third hard electrode tab 6 are negative electrodes, and the second hard electrode tab 3 is a positive electrode tab.

[0080] Based on the above embodiments, the resistivity of the third current collector 141 is further 8*10⁻⁶. -7 ~1*10 -5 Ω·mm. During the initial charging of the battery composed of the first electrode 11, the second electrode 12, and the third electrode 14, the positive and negative terminals of the external power supply are connected to the first hard electrode tab 2 and the third hard electrode tab 6, respectively. At this time, the third current collector 141 acts as a resistor, generating heat. Thus, heat is generated under the action of the external circuit current, thereby improving the battery's heating efficiency and reducing lithium plating during subsequent charging. Maintaining the resistivity of the third current collector 141 within the aforementioned range enhances its heating efficiency as a resistor, thereby improving the efficiency of heating the battery from a low temperature to a suitable charging temperature, and ultimately improving the battery's charging efficiency. It also prevents the current collector or electrode tab from melting due to excessive resistivity. Typically, the resistivity of the first current collector 111 and the second current collector 121 is less than 8*10⁻⁶. -7In other words, the resistance of the first current collector 111 and the second current collector 121 is less than that of the third current collector 141. This reduces the battery impedance and energy loss during the charging and discharging process.

[0081] For example, the resistivity of the third current collector 141 can be: 8*10 -7 Ω·m, 8.1*10 -7 Ω·m, 8.5*10 -7 Ω·m, 9*10 -7 Ω·m, 1*10 -6 Ω·m, 2*10 -6 Ω·m, 5*10 -6 Ω·m, 8*10 -6 Ω·m, 9*10 -6 Ω·m, 9.5*10 -6 Ω·m, 1*10 -5 Ω·m, etc.

[0082] Furthermore, when a fourth electrode is installed alongside the second electrode 12, the resistivity of the fourth current collector can also be 8*10. -7 ~1*10 -5 Ω·m, which also allows for the heating of the battery during the initial stage of charging.

[0083] In some embodiments, the third current collector 141 is a metal current collector, an alloy current collector, or a composite current collector. That is, the material of the third current collector 141 is not limited, as long as the resistivity of the third current collector 141 is within 8*10⁻⁶. -7 ~1*10 -5 Within the Ω·mm range is sufficient; this setting can improve the heating efficiency of the battery during the initial charging stage.

[0084] In further embodiments, when the third current collector 141 is a metal current collector, it can be a metal such as aluminum; when the third current collector 141 is an alloy current collector, it can be stainless steel, nickel-chromium alloy foil, iron-nickel alloy foil, iron-chromium-aluminum alloy, aluminum-nickel-iron alloy, etc.; when the third current collector 141 is a composite current collector, it includes an aluminum foil and oxide layers disposed on both sides of the aluminum foil. The oxide layers are one or more of aluminum oxide, zirconium oxide, boron oxide, titanium oxide, nickel oxide, zinc oxide, gallium oxide, cerium oxide, tin oxide, antimony oxide, boron nitride, magnesium nitride, gallium nitride, and potassium nitride. The third current collector 141 can also be a polymer surface coated with aluminum foil (a sandwich structure composite film with an aluminum coating on the surface of a PET film), with the metal oxide layer formed on both sides of the aluminum foil, and the active material layer formed on the metal oxide layer on one side.

[0085] In addition, the first current collector can also be carbon paper, etc.

[0086] In some embodiments, the switching element 5 includes a normally open temperature switch 51 and a normally closed temperature switch 52 connected in series. The normally open temperature switch 51 is closed at a first temperature T1, the normally closed temperature switch 52 is open at a second temperature T2, and the normally closed temperature switch 52 is closed at a third temperature T3. Specifically, T1, T2, and T3 satisfy the condition: T2 > T3 > T1. When the battery is operating normally, the normally open temperature switch 51 is open and the normally closed temperature switch 52 is closed. However, when the battery is used under high power, high current, or other high load conditions, or in harsh environments such as high temperatures, the battery temperature will continuously rise, and the temperature of the normally open temperature switch 51 will also rise. When the normally open temperature switch 51 is at temperature T1, it is closed, while the normally closed temperature switch 52 is already closed. At this time, both switches connected in series in the connecting branch 4 are closed, and the connecting branch 4 is conductive, thus reducing the battery voltage and capacity. Since connecting branch 4 is in the conducting state, the temperature of normally closed temperature switch 52 will continue to rise. When the temperature of normally closed temperature switch 52 reaches temperature T2, it will be in the open state. At this time, connecting branch 4 is in the open state, and the number of normally closed temperature switches 52 on connecting branch 4 will decrease. When the temperature of normally closed temperature switch 52 drops to temperature T3, it will close again, and connecting branch 4 will be conducting again. During continuous battery operation, normally closed temperature switch 52 will repeat the above process, thereby achieving pulse discharge of the battery to ensure safety during battery use.

[0087] It should be noted that there is no limit to the number of normally open temperature switches 51 and normally closed temperature switches 52; one or more of each can be set.

[0088] Furthermore, by setting the normally open temperature switch 51 and normally closed temperature switch 52, the safety performance of the battery can be improved without affecting the chemical system. This method is applicable to various types of batteries and has little impact on the energy density of the battery.

[0089] It should also be noted that the connection method between the normally open temperature switch 51 and the normally closed temperature switch 52 and the second hard electrode 3 and the third hard electrode 6 is limited. For example, the connection can be achieved by wire connection, soldering, resistance soldering, laser soldering, or adhesive bonding.

[0090] It should also be noted that the normally open temperature switch 51, normally closed temperature switch 52 and connecting branch 4 can be located inside the battery, outside the battery, or connected between tabs of different polarities in the PACK or PCM protection board circuit.

[0091] In some embodiments, T1 satisfies: 70℃≤T1≤90℃. For example, T1 can be 70℃, 71℃, 72℃, 75℃, 80℃, 82℃, 85℃, 88℃, 89℃, 90℃, etc.

[0092] In some embodiments, T2 satisfies: 130℃≤T2≤180℃. For example, T2 can be 130℃, 131℃, 132℃, 135℃, 140℃, 150℃, 160℃, 170℃, 175℃, 177℃, 179℃, 180℃, etc.

[0093] In some embodiments, T3 satisfies: 100℃≤T3<130℃. For example, T3 can be 100℃, 101℃, 102℃, 105℃, 110℃, 115℃, 120℃, 125℃, 127℃, 129℃, etc.

[0094] By ensuring that T1, T2, and T3 are within the aforementioned range, it is possible to more flexibly control the battery discharge voltage and capacity, better prevent further battery deterioration caused by overheating, avoid battery thermal runaway, and improve battery safety during use.

[0095] In some embodiments, the normally open temperature switch 51 is disconnected at the fourth temperature T4. Based on the operation of the normally open temperature switch 51 and normally closed temperature switch 52, when the battery stops working, the temperatures of both normally open temperature switch 51 and normally closed temperature switch 52 will gradually decrease. When the temperature drops to T4, the normally open temperature switch 51, which is in the closed state, will open, thus disconnecting the connecting branch 4. This allows the normally open temperature switch 51 to open again when the battery is used next, restoring the normally open temperature switch 51 and normally closed temperature switch 52 on the connecting branch 4 to their initial state. This ensures that the switching element 5 can still protect the battery from thermal runaway during subsequent battery use.

[0096] Where T4 satisfies: T4≤50℃. For example, T4 can be 50℃, 49℃, 45℃, 42℃, 40℃, 35℃, 30℃, 25℃, etc.

[0097] In some embodiments, the third electrode 14 is located at the end of the stacked cell 1 in the stacking direction. Specifically, taking the first hard electrode 2 and the third hard electrode 6 as positive electrodes and the second hard electrode 3 as negative electrodes as examples. Under normal circumstances, the third current collector 141 located at the end of the stacked cell 1 is coated with an active material layer on only one side. Since the resistance of the third current collector 141 is greater than that of the first current collector 111 and the second current collector 121, and the third current collector 141 is connected to at least two third soft electrodes 143, when the battery with the above-mentioned current collector is discharged, compared with the third current collector 141 being located in the middle of the stacking direction of the stacked cell 1, the increase in battery impedance can be reduced, thereby ensuring battery performance.

[0098] It should be noted that the stacking direction of the first layer of the laminated cell refers to... Figure 7 The direction indicated by the double-headed arrow Z.

[0099] Furthermore, in one embodiment, a third active material layer 142 is disposed on the side of the third current collector 141 near the center of the stacked cell 1, while the third active material layer 142 is not disposed on the side of the third current collector 141 away from the center of the stacked cell 1. That is, the third active material layer 142 is disposed on only one side of the third current collector 141, and this side is the side closest to the center of the stacked cell 1. With this configuration, the resistivity of the third current collector 141 is approximately 8*10⁻⁶. -7 ~1*10 -5 In the Ω·m range, the battery composed of the first electrode 11, the second electrode 12 and the third electrode 14 has a third active material layer 142 on only one side of the third current collector 141, which can further reduce the increase in battery impedance and thus further improve battery performance.

[0100] Furthermore, in the stacking direction of the stacked cell 1, the third current collector 141 can also be located in the middle of the stacked cell 1, which can also solve the problem of lithium plating when the battery temperature is low during the initial stage of battery charging.

[0101] Based on the above embodiments, furthermore, in the stacking direction of the laminated cell 1, the electrodes located at both ends of the laminated cell 1 are third electrodes 14, and both the first electrode 11 and the third electrode 14 are positive electrodes. This further improves the heating efficiency when heating the battery.

[0102] It should be noted that the stacking direction of cell 1 refers to... Figure 7 The direction indicated by the double-headed arrow Z.

[0103] It should also be noted that there is no limit to the number of third electrodes 14 that can be set; one or more third electrodes 14 can be set.

[0104] In some embodiments, such as Figure 1 As shown, the first hard tab 2, the second hard tab 3, and the third hard tab 6 are disposed on the same side of the battery cell 1, and in the width direction of the battery, the second hard tab 3 is disposed between the first hard tab 2 and the third hard tab 6. Specifically, when the battery temperature is low, the positive and negative terminals of the external power supply are connected to the first hard tab 2 and the third hard tab 6, respectively. When the battery temperature rises to the target temperature, the positive and negative terminals of the external power supply are connected to the first hard tab 2 and the second hard tab 3, respectively. By disposing the second hard tab 3 between the first hard tab 2 and the third hard tab 6, the convenience of heating and charging the battery can be improved.

[0105] In some embodiments, the first hard electrode tab 2 and the second hard electrode tab 3 are disposed on the same side of the battery cell 1, and the first hard electrode tab 2 and the third hard electrode tab 6 are respectively disposed on different sides of the battery cell 1. For example, the first hard electrode tab 2 and the third hard electrode tab 6 can be disposed on adjacent sides of the battery cell 1, such as... Figure 3 or Figure 5 As shown; alternatively, the first hard tab 2 and the third hard tab 6 can be positioned on opposite sides of the battery cell 1. When the battery temperature is low, the positive and negative terminals of an external power supply are connected to the first hard tab 2 and the third hard tab 6 of the battery, respectively. The third current collector 141 of the first hard tab 2 and the third hard tab 6 will then act as a resistor to release heat. The resistance is positively correlated with the length of the resistor. That is, the greater the distance between the first hard tab 2 and the third hard tab 6, the greater the resistance when heating the battery, and the higher the heating efficiency of the battery. This arrangement can further improve the heating efficiency of the battery.

[0106] Based on the above embodiments, the first hard electrode tab 2 and the third hard electrode tab 6 are further disposed at opposite corners of the battery cell 1, similar to... Figure 3 The positions of the first hard electrode tab 2 and the third hard electrode tab 6 shown can further increase the distance between the first hard electrode tab 2 and the third hard electrode tab 6, and further increase the length of the third current collector 141 when heating the battery, so as to further improve the heating efficiency of the battery.

[0107] In some embodiments, a first insulating layer is provided on the end region of the first flexible tab 113 near the first current collector 111, and the size of the first insulating layer is D in the length direction of the first electrode 11, wherein D satisfies: 0.5mm≤D≤2mm; a second insulating layer is provided on the end region of the second flexible tab 123 near the end region of the second current collector 121, and the size of the second insulating layer is E in the length direction of the second electrode 1212, wherein E satisfies: 0.5mm≤E≤2mm; a third insulating layer is provided on the end region of the third flexible tab 143 near the end region of the third current collector 141, and the size of the third insulating layer is F in the length direction of the third electrode 14, wherein F satisfies: 0.5mm≤E≤2mm. Normally, the first soft tab 113, the second soft tab 123, and the third soft tab 143 are all die-cut from the first current collector 111 and the second current collector 121. When multiple first soft tabs 113 arranged in the stacking direction of the laminated cell 1 are welded into the first hard tab 2 of the battery, when multiple second soft tabs 123 arranged in the stacking direction of the laminated cell 1 are welded into the second hard tab 3 of the battery, and when multiple third soft tabs 143 arranged in the stacking direction of the laminated cell 1 are welded into the third hard tab 6 of the battery, the first soft tab 113 may contact the second current collector 121, and the second soft tab 123 may also contact the first soft tab 143. If the first current collector 111 comes into contact with the second current collector 121, the third flexible tab 143 may also come into contact with the second current collector 121, causing a short circuit in the battery. By providing a first insulating layer at the end of the first flexible tab 113 near the first current collector 111, a second insulating layer at the end of the second flexible tab 123 near the second current collector 121, and a third insulating layer at the end of the third flexible tab 143 near the third current collector 141, it is possible to prevent the first flexible tab 113 from contacting the second current collector 121, the second flexible tab 123 from contacting the first current collector 111, and the third flexible tab 143 from contacting the second current collector 121, thereby preventing a short circuit in the battery.

[0108] For example, the dimensions of the first insulating layer can be 0.5mm, 0.55mm, 0.7mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 1.9mm, 1.95mm, 2mm, etc.; the dimensions of the second insulating layer can be 0.5mm, 0.55mm, 0.7mm, 0.9mm, 1mm, 1.2mm, 1.5mm, 1.8mm, 1.9mm, 1.95mm, 2mm, etc.

[0109] It should be noted that the length direction of the first electrode 11 and the length direction of the second electrode 12 are as follows: Figure 2 The direction indicated by the double-headed arrow Y.

[0110] In some embodiments, a temperature sensor is provided on the battery surface to detect the battery temperature. Specifically, by providing the aforementioned temperature sensor, the battery temperature can be detected. During the initial stage of battery charging when the battery temperature is low, the battery is heated by connecting the positive and negative terminals of the external power supply to the terminals of the same polarity. The temperature sensor can conveniently monitor the battery temperature, and when the battery reaches the target temperature, the positive and negative terminals of the external power supply are connected to the terminals of different polarities, thus facilitating convenient and efficient battery charging.

[0111] Taking a battery with two positive tabs and one negative tab to form a three-tab structure as an example, the following embodiments and comparative examples are provided:

[0112] Example 1

[0113] A battery with a three-tab structure has two positive tabs and one negative tab, with the positive tab located on both sides of the negative tab. A special positive electrode with two soft tabs, the current collector of which is a 5μm thick stainless steel foil, and a positive electrode with one soft tab, the current collector of which is an 8μm aluminum foil, and a negative electrode with one soft tab are also included. A single-tab positive electrode, a separator 13, a single-tab negative electrode, and a separator 13 are sequentially stacked and assembled. Finally, a bitab positive electrode is assembled on the upper and lower surfaces of the stacked structure to form a battery core. Figure 7 As shown, after lamination, the negative electrode soft tabs overlap vertically, and the positive electrode soft tabs overlap, and aluminum tabs are transferred. After being placed into an aluminum-plastic film shell, encapsulation, electrolyte injection, formation, and sorting processes are performed. A 75°C normally open temperature switch 51 (internal resistance 4mΩ) and a 160°C normally closed temperature switch 52 (recovery temperature 110°C, internal resistance 4mΩ) are welded between the negative electrode tab of a qualified battery and the right positive electrode tab (soft tab transferred to hard tab). Figure 1 As shown, the welded batteries underwent hot box testing and charging heating testing.

[0114] Example 2:

[0115] Dual positive soft electrode tabs, one soft electrode tab on the top and one soft electrode tab on the bottom side. Figure 3 As shown, the other designs are the same as in Example 1.

[0116] Example 3

[0117] Dual positive soft electrode tabs, one soft electrode tab on the head and the other soft electrode tab on the middle of the side. Figure 5 As shown, the other designs are the same as in Example 1.

[0118] Example 4

[0119] The design features dual positive electrode tabs and a 5μm stainless steel current collector coated with an active material layer on both sides. This electrode is placed in the middle of the stacked core. Figure 8 As shown.

[0120] Example 5

[0121] In the structure of Example 1, a double positive electrode soft tab design is added. The current collector is made of 5μm stainless steel, and an active material layer is coated on both sides of the current collector, such as... Figure 9 As shown.

[0122] Comparative Example 1

[0123] The device features a bipolar tab structure with no third positive tab. There is no soldered temperature switch, and the positive current collector uses 8µm aluminum foil. Other design aspects are the same as in Example 1.

[0124] Comparative Example 2

[0125] The structure features a bipolar tab without a third positive tab. A temperature switch is soldered between the positive and negative electrodes. The positive current collector uses 8µm aluminum foil. Other design aspects are the same as in Example 1.

[0126] Comparative Example 3

[0127] The battery structure is the same as in Example 1, except that the positive electrode current collector uses 8µm aluminum foil, and the other materials are the same as in Example 1.

[0128] Comparative Example 4

[0129] The battery structure is the same as in Example 1, except that the normally open temperature switch 51 and the normally closed temperature switch 52 are not provided.

[0130] Table 1

[0131]

[0132]

[0133] A battery operation method is applicable to the aforementioned battery. Since this operation method is applicable to this battery, the beneficial effects of the battery operation method on the battery are described above and will not be repeated here.

[0134] The battery operation method includes a battery charging step and a battery discharging step. The battery charging step includes at least the following steps: S101: Before charging the battery, detect the battery temperature; S102: If the battery reaches the target temperature, charge the battery; S103: If the battery does not reach the target temperature, connect the positive and negative terminals of the external power supply to the two terminals of the same polarity of the battery respectively, heat the battery to the target temperature, and then connect the positive and negative terminals of the external power supply to the two terminals of different polarities of the battery to charge the battery.

[0135] Specifically, before charging the battery, a temperature sensor installed on the battery detects its temperature. When the battery temperature detected by the temperature sensor reaches the target temperature, the positive and negative terminals of the external power supply are connected to the two terminals of the battery with different polarities to charge the battery. When the battery temperature detected by the temperature sensor has not reached the target temperature, the positive and negative terminals of the external power supply are connected to the two terminals of the battery with the same polarity. At this time, the current collector connected to these two terminals acts as a resistor, which will cause the battery temperature to rise. The temperature sensor will monitor the battery temperature in real time. When the battery temperature rises to the target temperature, the positive and negative terminals of the external power supply are connected to the two terminals of the battery with different polarities to charge the battery.

[0136] It should be noted that the target temperature refers to the appropriate charging temperature for the battery, at which lithium deposition is less or even non-existent when charging the battery compared to low-temperature conditions.

[0137] In some embodiments, the battery discharge step includes at least the following steps:

[0138] S201: During battery discharge, the switching element 5 controls the connection branch 4 to open or close based on the temperature at which the switching element 5 is located; S202: When the temperature of the switching element 5 is at the first temperature, the switching element 5 controls the connection branch 4 to open; S203: When the temperature of the switching element 5 rises from the first temperature to the second temperature, the switching element 5 controls the connection branch 4 to close; S204: When the temperature of the switching element 5 drops from the second temperature to the third temperature, the switching element 5 controls the connection branch 4 to open; S205: Repeat S203 and S204 based on the battery temperature.

[0139] Specifically, when the battery discharges, especially under high loads such as high power and high current, or in harsh environments such as high temperature, a large amount of heat is often generated inside the battery, causing the battery temperature to rise further. When the temperature of the normally open temperature switch 51 reaches the first temperature, the normally open temperature switch 51 closes, and the connection branch 4 between the second hard electrode 3 and the third hard electrode 6 is connected. At this time, the battery self-discharges to reduce the battery voltage and prevent thermal runaway and other malfunctions. When the normally open temperature switch 51 and the normally closed temperature switch 51 are closed... With all temperature switches 52 closed, although the external power supply voltage decreases, the temperature of connecting branch 4 continues to rise. When the temperature of normally closed temperature switch 52 rises to the second temperature, it opens, and connecting branch 4 simultaneously disconnects. At this time, the external power supply operates normally. Since connecting branch 4 is not working, the temperature of normally closed temperature switch 52 decreases. When the temperature of normally closed temperature switch 52 drops to the third temperature, it closes again, and connecting branch 4 is reconnected, causing the battery to self-discharge again, further reducing the battery voltage. During battery operation, when the battery temperature rises, normally open temperature switch 51 and normally closed temperature switch 52 repeat the above process to achieve pulse discharge of the battery, ultimately enabling the battery to self-discharge at high temperatures. This reduces battery capacity, improves battery safety, and prevents the battery body from experiencing high-temperature thermal runaway.

[0140] The basic principles of this application have been described above with reference to specific embodiments. However, it should be noted that the advantages, benefits, and effects mentioned in this application are merely examples and not limitations, and should not be considered as essential features of each embodiment of this application. Furthermore, the specific details disclosed above are for illustrative and facilitative purposes only, and are not limitations. These details do not limit the application to the necessity of employing the aforementioned specific details for implementation.

[0141] The block diagrams of devices, apparatuses, devices, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As those skilled in the art will recognize, these devices, apparatuses, devices, and systems can be connected, arranged, and configured in any manner. Words such as “comprising,” “including,” “having,” etc., are open-ended terms meaning “including but not limited to,” and are used interchangeably with them. The terms “or” and “and” as used herein refer to the terms “and / or,” and are used interchangeably with them unless the context clearly indicates otherwise. The term “such as” as used herein refers to the phrase “such as but not limited to,” and is used interchangeably with it.

[0142] It should also be noted that in the apparatus, equipment, and methods of this application, the components or steps can be disassembled and / or recombined. These disassemblies and / or recombinations should be considered as equivalent solutions of this application.

[0143] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use this application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects without departing from the scope of this application. Therefore, this application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0144] It should be understood that the qualifiers “first,” “second,” “third,” “fourth,” “fifth,” and “sixth” used in the description of the embodiments of this application are only used to more clearly illustrate the technical solutions and are not intended to limit the scope of protection of this application.

[0145] The above description has been given for purposes of illustration and description. Furthermore, this description is not intended to limit the embodiments of this application to the forms disclosed herein. Although numerous exemplary aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A battery, characterized in that, It includes a stacked cell formed by alternating stacking of first and second electrodes, with a separator disposed between adjacent first and second electrodes; The first electrode includes a first current collector and a first active material layer located on at least one side of the first current collector; the second electrode includes a second current collector and a second active material layer located on at least one side of the second current collector. The first electrode includes a first flexible tab connected to the first current collector, and the second electrode includes a second flexible tab connected to the second current collector; The laminated cell also includes a third electrode, which includes a third current collector and at least two third flexible tabs connected to the third current collector; The third electrode has the same polarity as the first electrode. All the first soft electrodes and one of the third soft electrodes of each third electrode are welded together to form a first hard electrode. All the second soft electrodes are welded together to form a second hard electrode. The other third soft electrode of each third electrode is welded together to form a third hard electrode. The third hard electrode and the second hard electrode are connected by a connecting branch, and a switching element for controlling the opening and closing of the connecting branch is provided on the connecting branch. The switching element includes a normally open temperature switch and a normally closed temperature switch arranged in series. The normally open temperature switch is closed when the temperature is at a first temperature T1, the normally closed temperature switch is open when the temperature is at a second temperature T2, and the normally closed temperature switch is closed when the temperature is at a third temperature T3. Wherein, T1, T2, and T3 satisfy: T2 > T3 > T1.

2. The battery according to claim 1, characterized in that, The first hard electrode tab and the third hard electrode tab are positive electrode tabs, and the second hard electrode tab is a negative electrode tab.

3. The battery according to claim 1, characterized in that, The resistivity of the third current collector is 8. 10 -7 ~1 10 -5 Ω·m.

4. The battery according to claim 3, characterized in that, The third current collector is a metal current collector, an alloy current collector, or a composite current collector.

5. The battery according to claim 4, characterized in that, The third current collector is made of stainless steel, nickel-chromium alloy foil, iron-nickel alloy foil, iron-chromium-aluminum alloy, or aluminum-nickel-iron alloy; or, The third current collector is a polymer surface coated with a metal foil; or... The composite current collector includes an aluminum foil and an oxide layer disposed on both sides of the aluminum foil. The oxide layer is one or more of aluminum oxide, zirconium oxide, boron oxide, titanium oxide, nickel oxide, zinc oxide, gallium oxide, cerium oxide, tin oxide, and antimony oxide.

6. The battery according to claim 1, characterized in that, T1 satisfies: 70℃≤T1≤90℃; and / or, T2 satisfies: 130℃≤T2≤180℃; and / or, T3 satisfies: 100℃≤T3<130℃.

7. The battery according to claim 1, characterized in that, The normally open temperature switch is disconnected when the temperature is at the fourth temperature T4, where T4 satisfies: T4≤50℃.

8. The battery according to claim 3, characterized in that, In the stacking direction of the laminated battery cell, the third electrode is located at the end of the laminated battery cell.

9. The battery according to claim 8, characterized in that, The third current collector has a third active material layer on the side closer to the middle of the stacked cell, and the third current collector does not have the third active material layer on the side farther away from the middle of the stacked cell.

10. The battery according to claim 1, characterized in that, The first hard electrode tab, the second hard electrode tab, and the third hard electrode tab are disposed on the same side of the stacked cell, and in the width direction of the battery, the second hard electrode tab is disposed between the first hard electrode tab and the third hard electrode tab.

11. The battery according to claim 1, characterized in that, The first hard electrode tab and the second hard electrode tab are disposed on the same side of the laminated cell, and the first hard electrode tab and the third hard electrode tab are disposed on different sides of the laminated cell.

12. The battery according to claim 1, characterized in that, A first insulating layer is provided in the end region of the first soft electrode near the first current collector, and the size of the first insulating layer is D in the length direction of the first electrode, wherein D satisfies: 0.5mm≤D≤2mm; A second insulating layer is provided in the end region of the second soft electrode near the second current collector, and the dimension of the second insulating layer is E in the length direction of the second electrode, wherein E satisfies: 0.5mm≤E≤2mm; A third insulating layer is provided in the end region of the third soft electrode near the third current collector, and the dimension of the third insulating layer is F in the length direction of the third electrode, wherein F satisfies: 0.5mm≤F≤2mm.

13. The battery according to claim 1, characterized in that, A temperature sensor is installed on the surface of the battery to detect its temperature.

14. A battery operation method, characterized in that, The battery applicable to any one of claims 1-13, the battery operation method includes a battery charging step and a battery discharging step, wherein the battery charging step includes at least the following steps: S101: Before charging the battery, detect the temperature of the battery; S102: If the battery reaches the target temperature, then charge the battery; S103: If the battery does not reach the target temperature, connect the positive and negative terminals of the external power supply to the two identical terminals of the battery to heat the battery to the target temperature, and then connect the positive and negative terminals of the external power supply to the two different terminals of the battery to charge the battery. S201: During the battery discharge process, the switching element controls the switching on and off of the connecting branch according to the temperature at which the switching element is located; S202: When the temperature of the switching element is at the first temperature, the switching element controls the connection of the connecting branch; S203: When the temperature of the switching element rises from the first temperature to the second temperature, the switching element controls the connection branch to disconnect; S204: When the temperature of the switching element drops from the second temperature to the third temperature, the switching element controls the connection of the connecting branch; S205: Repeat S203 and S204 according to the temperature of the battery.

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