Battery and battery operation method

Abstract

The invention provides a battery and a battery operation method, the battery comprises a winding cell formed by winding a first pole piece, a diaphragm and a second pole piece, the first pole piece comprises a first current collector and a first active material layer arranged on at least one side of the first current collector, and the first active material layer is provided with a first groove; the first current collector is partially exposed in the first groove; the second pole piece comprises a second current collector and a second active substance layer arranged on at least one side of the second current collector, the second active substance layer is provided with a second groove, and the second current collector is partially exposed in the second groove; a first tab connected with the first current collector is arranged in the first groove, and a second tab connected with the second current collector is arranged in the second groove; the first pole piece further comprises a first extension part formed by extending outwards from the first current collector, and / or the second pole piece further comprises a second extension part formed by extending outwards from the second current collector. According to the arrangement, lithium precipitation of the battery can be slowed down when the battery is charged at low temperature.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a battery and a battery operation method. Background Art

[0002] In the field of batteries, especially lithium-ion batteries, due to their high energy density and good charge and discharge cycle capabilities, they have been widely used in mobile phones, laptops, electric vehicles and other fields. However, charging lithium-ion batteries at low temperatures will cause lithium deposition at the negative electrode of lithium-ion batteries. Lithium deposition in lithium-ion batteries will increase the internal resistance of the battery, shorten the cycle life, and limit the fast charging capacity.

[0003] In addition, the safety issues caused by battery thermal runaway are mainly because when the battery is under high load such as high power and high current or when the battery is used in a relatively harsh environment such as high temperature, a large amount of heat is often generated inside the battery, and the battery temperature rises further. When the battery temperature rise cannot be suppressed or eliminated, the chemical system inside the battery will further deteriorate, and the internal materials will be destroyed, resulting in thermal runaway, which will cause battery fires, explosions and other accidents. Among them, the higher the pass rate of the battery in the hot box test, the better the safety performance of the battery. Summary of the invention

[0004] In view of this, the present 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. The present application also provides a battery operation method applicable to the above-mentioned battery.

[0005] In order to achieve the above objectives, this application provides the following technical solutions:

[0006] A battery, comprising a wound cell formed by winding a first pole piece, a separator and a second pole piece, wherein:

[0007] The first pole piece includes a first current collector and a first active material layer disposed on at least one side of the first current collector, the first active material layer is provided with a first groove, and the first current collector is partially exposed in the first groove;

[0008] The second pole piece includes a second current collector and a second active material layer disposed on at least one side of the second current collector, the second active material layer is provided with a second groove, and the second current collector is partially exposed to the second groove;

[0009] A first electrode tab connected to the first current collector is disposed in the first groove, and a second electrode tab connected to the second current collector is disposed in the second groove;

[0010] The first pole piece further includes a first extension portion extending outward from the first current collector, and / or the second pole piece further includes a second extension portion extending outward from the second current collector.

[0011] Optional,

[0012] At least one first extension portion is provided, and at least one first extension portion is welded to form a third pole lug of the wound battery core, the third pole lug is connected to the second pole lug via a connecting branch, and a switching piece for controlling the connection branch to be turned on and off is provided on the connecting branch; and / or,

[0013] At least one second extension portion is provided, and at least one second extension portion is welded to form a fourth pole ear of the wound battery core. The fourth pole ear and the first pole ear are connected through a connecting branch, and a switching piece for controlling the connection branch to be turned on and off is provided on the connecting branch.

[0014] Optionally, the first pole tab and the third pole tab are positive pole tabs, and the second pole tab is a negative pole tab.

[0015] Optionally, in the height direction of the wound battery cell, the first pole tab and the third pole tab have the same height.

[0016] Optional,

[0017] The first current collector includes a first single-sided region with the first active material layer disposed on one side, and a first double-sided region with the first active material layer disposed on both sides, and the first extension portion is located in the first single-sided region and / or the first double-sided region; and / or,

[0018] The second current collector includes a second single-sided region with the second active material layer disposed on one side, and a second double-sided region with the second active material layer disposed on both sides, and the second extension portion is located in the second single-sided region and / or the second double-sided region.

[0019] Optionally, the switch comprises a normally open temperature switch and a normally closed temperature switch arranged in series, wherein:

[0020] The normally open temperature switch is closed at a first temperature T1, the normally closed temperature switch is opened at a second temperature T2, and the normally closed temperature switch is closed when at a 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 at a fourth temperature T4, wherein T4 satisfies: T4≤50°C.

[0026] Optionally, in the length direction of the first pole piece, the length of the first current collector is L1, and the minimum distance between adjacent first extension portions is L2, wherein L1 and L2 satisfy the following relationship: 100 mm ≤ L2 ≤ L1 / 2.

[0027] Optionally, in the length direction of the first pole piece, the first pole ear is arranged in the middle of the first pole piece, and the first extension portion is arranged at the end of the first pole piece.

[0028] Optionally, in the width direction of the first pole piece, an insulating layer is provided in the end region of the first extension portion close to the current collector, and a size D of the insulating layer satisfies: 0.5 mm≤D≤2 mm.

[0029] Optionally, the first pole tab, the second pole tab and the third pole tab are arranged on the same side of the wound battery cell, and in the width direction of the battery, the second pole tab is arranged between the first pole tab and the third pole tab.

[0030] Optionally, the first pole tab and the second pole tab are arranged on the same side of the wound battery cell, and the third pole tab and the first pole tab are arranged on different sides of the wound battery cell.

[0031] Optionally, a temperature sensor for detecting the temperature of the battery is disposed on the surface of the battery.

[0032] A battery operation method, applicable to any of the above batteries, the battery operation method comprising a battery charging step and a battery discharging step, the battery charging step at least comprising the following steps:

[0033] S101: Before charging the battery, detecting the temperature of the battery;

[0034] S102: If the battery reaches the target temperature, charging the battery;

[0035] S103: If the battery has not reached the target temperature, the positive and negative electrodes of the external power source are respectively connected to the two tabs of the battery with the same polarity, and after the battery is heated to the target temperature, the positive and negative electrodes of the external power source are respectively connected to the two tabs of the battery with different polarities to charge the battery.

[0036] Optionally, the battery discharging step includes at least the following steps:

[0037] S201: During the battery discharging process, the switch component controls the connection branch circuit according to the temperature of the switch component;

[0038] S202: When the temperature of the switch is at a first temperature, the switch controls the connection branch to be connected;

[0039] S203: When the temperature of the switch component rises from the first temperature to the second temperature, the switch component controls the connection branch to be disconnected;

[0040] S204: When the temperature of the switch component drops from the second temperature to a third temperature, the switch component controls the connection branch to be connected;

[0041] S205: Repeat S203 and S204 according to the temperature of the battery.

[0042] The battery provided by the present application, on the basis of the battery being provided with the first pole ear and the second pole ear, the first current collector extends outward to form the first extension part, and / or the second current collector extends outward to form the second extension part, the first extension part forms the pole ear with the same polarity as the first pole ear, and the second extension part forms the pole ear with the same polarity as the second pole ear, that is, at least one of the first pole ear and the second pole ear is provided with at least two, so that in the initial stage of charging the battery, when the battery temperature is low, the positive and negative poles of the external power supply are respectively connected to the two pole ears with the same polarity of the battery, at this time, the pole ears with the same polarity act as resistors, and the resistors will heat up and the temperature of the battery will rise under the action of the external power supply, and the temperature of the battery will rise, and when it rises to a suitable temperature, the positive and negative poles of the external power supply are respectively connected to the two pole ears with different polarities of the battery to realize charging of the battery. With such a configuration, when the battery is charged at a low temperature, the lithium precipitation of the battery can be slowed down to avoid the increase of the internal resistance of the battery, improve the cycle life of the battery, and improve the fast charging capacity.

[0043] The battery provided in the present application realizes discharge at high temperature by setting a temperature idle switch between the pole ears with opposite polarities, thereby reducing the battery energy and reducing the risk of the battery catching fire at high temperature, thereby improving the safety performance of the battery during use and improving the pass rate of the battery in the hot box test. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0045] Figure 1A schematic diagram of the structure of a battery cell provided by the prior art;

[0046] Figure 2 is a schematic structural diagram of the first pole piece in an unfolded state;

[0047] Figure 3 is a schematic diagram of the structure of the second pole piece in an unfolded state;

[0048] Figure 4 Schematic diagram of the structure of the first pole piece in the unfolded state in another embodiment.

[0049] Figure 5 Schematic diagram of the battery structure.

[0050] exist Figure 1-Figure 5 middle:

[0051] 1-battery core, 2-first pole ear, 3-second pole ear, 4-connecting branch, 5-switching piece, 6-insulating layer, 7-first extension part, 8-third pole ear;

[0052] 11-first pole piece, 12-second pole piece, 13-diaphragm, 51-normally open temperature switch, 52-normally closed temperature switch;

[0053] 111 - first current collector, 112 - first active material layer, 113 - first groove, 121 - second current collector, 122 - second active material layer, 123 - second groove. DETAILED DESCRIPTION

[0054] The present application provides a battery and a battery operation method applicable to the battery.

[0055] 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 ordinary technicians in this field without creative work are within the scope of protection of this application.

[0056] like Figures 1 to 5 As shown, the embodiment of the present application provides a battery, wherein the battery can be a lithium-ion battery, a nickel-hydrogen battery, a lead-acid battery, etc. The battery includes a wound battery cell 1 formed by winding a first pole piece 11, a separator 13 and a second pole piece 12.

[0057] Among them, the first pole piece 11 includes a first current collector 111 and a first active material layer 112 arranged on at least one side of the first current collector 111, the first active material layer 112 has a first groove 113, the first current collector 111 is partially exposed to the first groove 113, and a first pole ear 2 connected to the first current collector 111 is arranged in the first groove 113, that is, the first pole ear 2 is welded to the first current collector 111 exposed in the first groove 113; correspondingly, the second pole piece 12 includes a second current collector 121 and a second active material layer 122 arranged on at least one side of the second current collector 121, the second active material layer 122 has a second groove 123, the second current collector 121 is partially exposed to the second groove 123, and a second pole ear 3 connected to the second current collector 121 is arranged in the second groove 123, that is, the second pole ear 3 is welded to the second current collector 121 exposed in the second groove 123. Such a configuration can increase the cross-sectional area of ​​the first pole tab 2 and the second pole tab 3 , so that when the battery is charged using the first pole tab 2 disposed in the first groove 113 and the second pole tab 3 disposed in the second groove 123 , the charging efficiency of the battery can be improved.

[0058] Further, the first pole piece 11 further includes a first extension portion 7 extending outward from the first current collector 111, and / or the second pole piece 12 further includes a second extension portion extending outward from the second current collector 121. The first extension portion 7 will form a pole ear with the same polarity as the first pole ear 2, and correspondingly, the second extension portion will form a pole ear with the same polarity as the second pole ear 3. In other words, at least one of the positive pole ear and the negative pole ear of the battery is provided with at least two, so that in the initial stage of charging the battery, when the battery temperature is low, the positive and negative poles of the external power source are respectively connected to the two pole ears of the battery with the same polarity. At this time, the pole ears with the same polarity act as resistors. Under the action of the external power source, the resistor will heat up and the temperature of the battery will rise. When it rises to a suitable temperature, the positive and negative poles of the external power source are respectively connected to the two pole ears of the battery with different polarities to realize charging of the battery.

[0059] It should be noted that the first pole tab 2 and the second pole tab 3 are not limited here. The first pole tab 2 can be a positive pole tab, and the second pole tab 3 is a negative pole tab. Of course, the first pole tab 2 can also be a negative pole tab, and the second pole tab 3 is a positive pole tab.

[0060] For example, in the length direction of the first pole piece 11, the first pole lug 2 is arranged in the middle of the first pole piece 11, and in the length direction of the second pole piece 12, the second pole lug 3 is arranged in the middle of the second pole piece 12. Such an arrangement enables the current to flow to various positions of the pole piece more efficiently when charging the battery, so that the lithium ion migration reaction occurs quickly between the first active material layer 112 and the second active material layer 122, thereby improving the charging efficiency. As an example, the length direction of the first pole piece 11 is Figure 2 In the direction indicated by the double-headed arrow X1, the length direction of the second pole piece 12 is Figure 2 The direction is indicated by the double-headed arrow X2.

[0061] It should be noted that the second extension portion is not shown in the figure, and the second extension portion has a similar structure to the first extension portion 7 .

[0062] In the battery of the above structure, on the basis of the first pole ear 2 and the second pole ear 3 being provided in the battery, the first current collector 111 extends outward to form the first extension part 7, and / or the second current collector 121 extends outward to form the second extension part, the first extension part 7 forms a pole ear with the same polarity as the first pole ear 2, and the second extension part forms a pole ear with the same polarity as the second pole ear 3, that is, at least one of the first pole ear 2 and the second pole ear 3 is provided with at least two, so that in the initial stage of charging the battery, when the battery temperature is low, the positive and negative poles of the external power supply are respectively connected to the two pole ears with the same polarity of the battery, at this time, the pole ears with the same polarity act as resistors, and the resistors will heat up and the temperature of the battery will rise under the action of the external power supply, and then the positive and negative poles of the external power supply are respectively connected to the two pole ears with different polarities of the battery to realize charging of the battery. With such a configuration, when the battery is charged at a low temperature, the lithium deposition of the battery can be slowed down to avoid the increase of the internal resistance of the battery, improve the cycle life of the battery, and improve the fast charging capacity.

[0063] In some embodiments, at least one first extension portion 7 is provided, and at least one first extension portion 7 is welded to form a third pole lug 8 of the wound battery cell 1, the third pole lug 8 is connected to the second pole lug 3 via a connecting branch 4, and a switching piece 5 for controlling the on / off of the connecting branch 4 is provided on the connecting branch 4; and / or, at least one second extension portion is provided, and at least one second extension portion is welded to form a fourth pole lug of the wound battery cell 1, the fourth pole lug is connected to the first pole lug 2 via a connecting branch 4, and a switching piece 5 for controlling the on / off of the connecting branch 4 is provided on the connecting branch 4. That is to say, when two positive pole ears are provided and one negative pole ear is provided, a connecting branch 4 is provided between one of the positive pole ears and the negative pole ear, and a switch 5 is provided on the connecting branch 4; when two positive pole ears are provided and one negative pole ear is provided, a connecting branch 4 is provided between one of the negative pole ears and the positive pole ear, and a switch 5 is provided on the connecting branch 4; when multiple positive pole ears and multiple negative pole ears are provided, a connecting branch 4 is provided between one of the positive pole ears and one of the negative pole ears, and a switch 5 is provided on the connecting branch 4. Of course, the number of positive pole ears and negative pole ears is not limited here, and multiple positive pole ears and negative pole ears can be provided. Moreover, the number of connecting branches 4 is not limited here, and one or more connecting branches 4 can be provided. It should be noted that the following description takes the example of setting a connecting branch 4 between the second pole ear 3 and the third pole ear as an example.

[0064] In this embodiment, an optional implementation is provided, in which the switch 5 is composed of a temperature switch. Furthermore, the temperature switch is a normally open temperature switch 51 and a normally closed temperature switch 52 arranged in series. Under normal temperature conditions, that is, when the battery is in normal use, the normally open temperature switch 51 is in an open state, and the normally closed temperature switch 52 is in a closed state. When the battery is under high loads such as high power and high current, or when the battery is used in a relatively harsh environment such as high temperature, the temperature of the battery will continue to rise, and the temperature rise of the normally open temperature switch 51 will cause the normally open temperature switch 51 to close. Since the normally closed temperature switch 52 is in a closed state, the connecting branch 4 connected between the second pole lug 3 and the third pole lug 8 is connected at this time, and the battery is self-discharged, thereby reducing the voltage and capacity of the battery, avoiding further deterioration of the battery caused by the temperature rise of the battery, avoiding thermal runaway of the battery, and improving the safety of the battery when in use. When the normally open temperature switch 51 is in the closed state, the temperature of the connecting branch 4 will continue to rise, and the normally closed temperature switch 52 will be disconnected after reaching a certain temperature, so that the connecting branch 4 is disconnected to prevent the connecting branch 4 from continuing to heat up and to prevent the connecting branch 4 from being melted. At this time, the battery works normally and discharges outward; when the temperature of the switching element 5 drops to a certain temperature, the normally closed temperature switch 52 will be closed again, so that the battery can be protected again, so that the battery can achieve pulse discharge as the temperature changes, which can better protect the battery and improve the safety of the battery during use.

[0065] In this embodiment, another optional implementation is also provided, the switch 5 is composed of a temperature sensor, a switch and a control module, wherein the temperature sensor is communicatively connected to the control module, the switch is electrically connected to the control module, wherein the battery is in a normal working state and the switch is in a disconnected state. When the battery is under high load such as high power and high current or the battery is used in a relatively harsh environment such as high temperature, the temperature of the battery will continue to rise. As the temperature of the battery rises, the temperature of the temperature sensor will also rise. The temperature sensor transmits the temperature information to the control module, and the control module controls the switch to close according to the received temperature information. At this time, the connecting branch 4 connected between the second pole ear 3 and the third pole ear 8 is connected, and the battery self-discharges, thereby reducing the voltage and capacity of the battery, avoiding further deterioration of the battery caused by the battery temperature rise, avoiding thermal runaway of the battery, and improving the safety of the battery when in use. The control module receives the temperature information detected by the temperature sensor in real time. When the temperature rises high when the switch is in a closed state, when the temperature detected by the temperature sensor is high, the control module controls the switch to open, so that the connecting branch 4 is disconnected, and the connecting branch 4 is prevented from being fused. When the temperature detected by the temperature sensor drops, the control module controls the switch to close again, so that the battery can be protected again. As the temperature changes, the battery can be pulse discharged, which can better protect the battery and improve the safety of the battery during use.

[0066] It should be noted that the connecting branch 4 is a conductive branch, which is used to achieve electrical connection between the first pole tab 2 and the second pole tab 3 .

[0067] It should also be noted that the fourth pole lug is not shown in the figure, and the structure of the fourth pole lug is similar to that of the third pole lug 8 .

[0068] The battery of the above structure is provided with a switch 5 on the connecting branch 4 between the second pole lug 3 and the third pole lug 8 of the battery cell 1, and / or a switch 5 is provided on the connecting branch 4 between the first pole lug 2 and the fourth pole lug, and the switch 5 can control the connecting branch 4. The switch 5 controls the connecting branch 4 to reduce the voltage and capacity of the battery, thereby avoiding further deterioration of the battery caused by the temperature rise of the battery, avoiding thermal runaway of the battery, and improving the safety of the battery when in use. Moreover, after the battery voltage is reduced, the connecting branch 4 can also be disconnected by controlling the switch 5 to allow the battery to work and be used normally.

[0069] In some embodiments, the first pole tab 2 is a positive pole tab, the second pole tab 3 is a negative pole tab, at least two first pole tabs 2 are provided, and one second pole tab 3 is provided. That is to say, at least two positive pole tabs are provided, and one negative pole tab is provided. With such a configuration, when the battery is charged at an early stage and the battery temperature is low, the positive and negative poles of the external power source are connected to the two positive pole tabs respectively, and the current flows through one positive pole tab, the positive current collector and the other pole tab in sequence. At this time, the positive current collector acts as a resistor, and generates heat when the current passes through, thereby increasing the temperature of the battery to alleviate lithium precipitation when the battery is charged at a low temperature.

[0070] In addition, the first electrode tab 2 and the second electrode tab 3 may also be arranged in other ways, for example, at least two negative electrode tabs are arranged and one positive electrode tab is arranged.

[0071] On the basis of the above embodiment, further, the first current collector 111 includes at least aluminum material. Since the resistivity of aluminum is much greater than that of copper, and resistance and resistivity are positively correlated, the resistance of aluminum is greater than that of copper under the same shape, so when the battery temperature is low at the initial stage of charging, the positive electrode and the negative electrode of the external power supply are respectively connected to the two positive electrode tabs, so that the positive electrode current collector acts as a resistor, and the resistance of the positive electrode current collector is large, and the heating efficiency is high, so that the battery can be raised to a suitable temperature more efficiently, thereby avoiding lithium precipitation during the charging process of the battery.

[0072] In some embodiments, the first pole tab 2 and the third pole tab 8 are at the same height in the height direction of the wound battery cell 1. That is, the first pole tab 2 and the third pole tab 8 are ensured to be in the same plane, so that the structural strength of the battery during subsequent packaging can be ensured, and the aesthetics of the battery can be improved, so as to facilitate the setting of the connecting branch 4.

[0073] Correspondingly, when the second current collector 121 extends outward to form a second extension portion, and the second extension portion forms a fourth pole tab, the second pole tab 3 and the fourth pole tab have the same height in the height direction of the wound battery cell 1 .

[0074] In some embodiments, the first current collector 111 includes a first single-sided region with a first active material layer 112 on one side, and a first double-sided region with the first active material layer 112 on both sides, and the first extension 7 is located in the first single-sided region and / or the first double-sided region; and / or, the second current collector 121 includes a second single-sided region with a second active material layer 122 on one side, and a second double-sided region with the second active material layer 122 on both sides, and the second extension is located in the second single-sided region and / or the second double-sided region. In other words, the first extension 7 can be arranged in the first single-sided region or in the first double-sided region, and one or more first extensions 7 can be arranged; correspondingly, the second extension can be arranged in the second single-sided region or in the second double-sided region, and one or more second extensions can be arranged. And it is necessary to ensure that after the wound battery cell 1 is wound, in the height direction of the battery cell 1, multiple first extensions 7 are arranged in an overlapping manner, and multiple second extensions are arranged in an overlapping manner, so as to facilitate the subsequent arrangement of the third pole ear 8 or the fourth pole ear.

[0075] In some embodiments, the switch 5 includes a normally open temperature switch 51 and a normally closed temperature switch 52 which are arranged in series, wherein: the normally open temperature switch 51 is closed when it is at a first temperature T1, the normally closed temperature switch 52 is opened when it is at a second temperature T2, and the normally closed temperature switch 52 is closed when it is at a third temperature T3, wherein: T1, T2 and T3 satisfy: T2>T3>T1. Specifically, when the battery is working normally, the normally open temperature switch 51 is in an open state and the normally closed temperature switch 52 is in a closed state, and when the battery is under high load such as high power and high current or the battery is used in a relatively harsh environment such as high temperature, the temperature of the battery will continue to 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, the normally open temperature switch 51 is closed, and the normally closed temperature switch 52 itself is in a closed state. At this time, the two switches connected in series on the connecting branch 4 are both in a closed state, and the connecting branch 4 is turned on, then the voltage and capacity of the battery will decrease; Since the connecting branch 4 is in the conducting state, the temperature of the normally closed temperature switch 52 will continue to rise. When the temperature of the normally closed temperature switch 52 is at the temperature T2, the normally closed temperature switch 52 will be in the disconnected state. At this time, the connecting branch 4 is in the disconnected state, and the number of normally closed temperature switches 52 on the connecting branch 4 will decrease. When the temperature of the normally closed temperature switch 52 drops to the temperature T3, the normally closed temperature switch 52 will be closed again. At this time, the connecting branch 4 will be turned on again. When the battery continues to work, the normally closed temperature switch 52 will repeat the above process, thereby realizing the pulse discharge of the battery. To ensure the safety of the battery during use.

[0076] It should be noted that the number of normally open temperature switches 51 and normally closed temperature switches 52 is not limited here, and one or more of each can be provided.

[0077] In addition, by providing the normally open temperature switch 51 and the normally closed temperature switch 52, the safety performance of the battery can be improved without affecting the chemical system. This is applicable to various types of batteries and has little effect on the energy density of the battery.

[0078] 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 first pole ear 2 and the second pole ear 3 is limited. For example, the electrical connection can be achieved by connecting with a wire, by welding methods such as soldering, resistance welding, laser welding, etc., or by bonding with electrical adhesive.

[0079] It should also be noted that the normally open temperature switch 51, the normally closed temperature switch 52 and the connecting branch 4 can be located inside the battery or outside the battery, and can also be connected between the poles of different polarities in the PACK or PCM protection board circuit.

[0080] In some embodiments, T1 satisfies: 70° C. ≤ T1 ≤ 90° C. For example, T1 may be 70° C., 71° C., 72° C., 75° C., 80° C., 82° C., 85° C., 88° C., 89° C., 90° C., and the like.

[0081] In some embodiments, T2 satisfies: 130° C. ≤ T2 ≤ 180° C. For example, T2 may be 130° C., 131° C., 132° C., 135° C., 140° C., 150° C., 160° C., 170° C., 180° C., 185° C., 187° C., 189° C., 190° C., and the like.

[0082] In some embodiments, T3 satisfies: 100° C. ≤ T3 < 130° C. For example, T3 may be 100° C., 101° C., 102° C., 105° C., 110° C., 115° C., 120° C., 125° C., 127° C., 129° C., and the like.

[0083] Here, ensuring that T1, T2 and T3 are within the above range can more flexibly control the battery discharge voltage and capacity, better avoid further deterioration of the battery caused by battery temperature rise, avoid thermal runaway of the battery, and further improve the safety of the battery during use.

[0084] In some embodiments, the normally open temperature switch 51 is disconnected when the temperature is at the fourth temperature T4. Based on the operation of the normally open temperature switch 51 and the normally closed temperature switch 52, when the battery stops working, the temperature of the normally open temperature switch 51 and the normally closed temperature switch 52 will gradually decrease. When the temperature decreases to the temperature T4, the normally open temperature switch 51 in the closed state will be disconnected, so that the connecting branch 4 will be disconnected, so that the normally open temperature switch 51 will be disconnected when the battery is used next time, so that the normally open temperature switch 51 and the normally closed temperature switch 52 set on the connecting branch 4 will return to the initial state, so that the switch 5 can still protect the battery from thermal runaway when the battery is used subsequently.

[0085] Wherein T4 satisfies: T4≤50° C. For example, T4 may be 50° C., 49° C., 45° C., 42° C., 40° C., 35° C., 30° C., 25° C., and the like.

[0086] In some embodiments, in the length direction of the first pole piece 11, the length of the first current collector 111 is L1, and the minimum distance between adjacent first extensions 7 is L2, wherein L1 and L2 satisfy: 100mm≤L2≤L1 / 2. Specifically, when the battery temperature is low before charging the battery, the positive and negative electrodes of the external power source need to be connected to the two first pole tabs 2 of the battery. At this time, the first current collector 111 is used as a resistor to generate heat. When the resistivity of the first current collector 111 is constant, the greater the distance between the two adjacent first extensions 7, the greater the resistance of the first current collector 111 between the adjacent first extensions 7. Here, it is ensured that the distance between the adjacent first extensions 7 in the length direction of the first current collector 111 is within the above range, which can improve the heating efficiency when heating the battery, and can improve the charging efficiency of the battery while alleviating the lithium deposition when the battery temperature is low and charging.

[0087] In some embodiments, in the length direction of the first pole piece 11, the first pole lug 2 is arranged in the middle of the first pole piece 11, and the first extension portion 7 is arranged at the end of the first pole piece 11. Specifically, when multiple first extension portions 7 are provided, and the first extension portion 7 is arranged at the end of the first pole piece 11, optionally, the first extension portions 7 are respectively arranged at both ends of the length direction of the first pole piece 11, and in order to improve the charging speed of the battery, the first pole lug 2 is usually arranged in the middle of the first pole piece 11, so that when the battery is charged at a low temperature, the first extension portion 7 is respectively located at both ends of the first pole piece 11, so that the longer the distance between the first extension portion 7 and the first pole lug 2, the greater the resistance during charging, so as to further improve the heating efficiency of the battery.

[0088] It should be noted that the length direction of the first pole piece 11 refers to Figure 2 The direction is indicated by the double-headed arrow X1.

[0089] In some embodiments, in the width direction of the first pole piece 11, an insulating layer 6 is provided at the end region of the first extension portion 7 close to the current collector, and the size D of the insulating layer 6 satisfies: 0.5mm≤D≤2mm. Generally, in order to improve the charging efficiency of the first pole tab 2 and the heating efficiency of the battery in the initial charging stage, a plurality of first extension portions 7 are provided, and then the pole tab of the battery is formed by welding the plurality of first extension portions 7 together. Since the first extension portion 7 is usually formed by die-cutting the current collector, when the plurality of first extension portions 7 are welded into the pole tab of the battery, the first extension portion 7 may contact the current collector with the opposite polarity thereof. By providing the insulating layer 6 at the end of the first extension portion 7 close to the current collector, the first extension portion 7 can be prevented from contacting the current collector with the opposite polarity thereof, so as to prevent the battery from short-circuiting.

[0090] Illustratively, the size of the insulating layer 6 may be 0.5 mm, 0.55 mm, 0.7 mm, 0.9 mm, 1 mm, 1.2 mm, 1.5 mm, 1.8 mm, 1.9 mm, 1.95 mm, 2 mm, and the like.

[0091] In some embodiments, the first pole tab 2, the second pole tab 3, and the third pole tab 8 are arranged on the same side of the battery cell 1, and in the width direction of the battery, the second pole tab 3 is arranged on both sides of the first pole tab 2 and the third pole tab 8. Specifically, when the battery temperature is low, the positive and negative poles of the external power source are connected to the first pole tab 2 and the third pole tab 8, and when the battery is heated to the target temperature, the positive and negative poles of the external power source are respectively connected to the first pole tab 2 and the second pole tab 3 of the battery. Here, by arranging the first pole tab 2, the second pole tab 3, and the third pole tab 8 on the same side of the battery cell 1, and arranging the second pole tab 3 on both sides of the first pole tab 2 and the third pole tab 8, the convenience of heating and charging the battery can be improved.

[0092] It should be noted that the width direction of the battery refers to Figure 5 The direction indicated by the double-headed arrow X3.

[0093] In some embodiments, the first pole tab 2 and the second pole tab 3 are arranged on the same side of the battery cell 1, and the third pole tab 8 and the first pole tab 2 are arranged on different sides of the battery cell 1. That is to say, the first pole tab 2 and the third pole tab 8 are arranged on both sides of the length direction of the battery cell 1. Before charging the battery, when the battery temperature is low, the positive and negative electrodes of the external power source are respectively connected to the first pole tab 2 and the third pole tab 8 to heat the battery. The first pole tab 2 and the third pole tab 8 are arranged on different sides of the battery cell 1, so that the length of the first current collector 111 between the first pole tab 2 and the third pole tab 8 can be increased to increase the resistance when heating the battery, thereby improving the heating efficiency of the battery.

[0094] In some embodiments, a temperature sensor (not shown in the figure) for detecting the battery temperature is provided on the surface of the battery. Specifically, by providing the above-mentioned temperature sensor, the temperature of the battery can be detected, so that when the battery temperature is low at the initial stage of battery charging, the positive and negative electrodes of the external power source are connected to the battery's pole lugs with the same polarity to heat the battery, and the temperature sensor can detect the battery's temperature to conveniently monitor the battery's temperature, so that when the battery is heated to the target temperature, the positive and negative electrodes of the external power source are connected to the battery's pole lugs with different polarities to conveniently and efficiently charge the battery.

[0095] In some embodiments, the positive electrode sheet preparation method is as follows: Coat the lithium cobalt oxide active material layer on both sides of the aluminum foil, the coating length of one side is 1200mm, the gap is 26mm, the length L3 of the other side is 1067mm, the gap is 159mm, and the overall length is L1=1226mm. Clean the groove at a distance of 128mm from the head, with a width of 10mm. Then die-cut the first extension part 7 at a distance of L2=790mm from the edge of the groove, and successively produce four first extension parts 7 as shown in FIG. Figure 4 As shown. The positive electrode sheet is prepared by slitting and rolling, and then welding the pole ear at the groove. The preparation method of the negative electrode sheet is a conventional preparation method. The positive electrode sheet, the negative electrode sheet and the separator 13 are wound according to the process. After winding, the first extension part 7 is welded to form the third pole ear 8, and then the packaging, liquid injection, sealing, and formation processes are performed to prepare a three-pole ear battery.

[0096] Further, the temperature control switch welding method is as follows: 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 in series between the third tab 8 and the negative tab of the qualified battery. Figure 5 As shown. The welded battery is subjected to hot box test and charging heating test.

[0097] A battery operating method is applicable to the above-mentioned battery. Since the operating method is applicable to the battery, the beneficial effects brought by the battery operating method are shown in the above-mentioned contents and will not be described in detail here.

[0098] The battery operation method includes a battery charging step and a battery discharging step, and the battery charging step includes at least the following steps: S101: before charging the battery, detecting the temperature of the battery; S102: if the battery reaches the target temperature, charging the battery; S103: if the battery does not reach the target temperature, connecting the positive and negative electrodes of the external power source to two tabs of the battery with the same polarity, respectively, heating the battery to the target temperature, and then connecting the positive and negative electrodes of the external power source to two tabs of the battery with different polarities, respectively, to charge the battery.

[0099] Specifically, before charging the battery, the temperature of the battery is detected by a temperature sensor arranged on the battery; when the battery temperature detected by the temperature sensor reaches the target temperature, the positive and negative electrodes of the external power supply are connected to two pole ears of the battery with different polarities to charge the battery; when the battery temperature detected by the temperature sensor does not reach the target temperature, the positive and negative electrodes of the external power supply are connected to two pole ears of the battery with the same polarity. At this time, the current collector connected to the two pole ears acts as a resistor, so that the temperature of the battery will increase, and the temperature sensor will detect the temperature of the battery in real time. When the battery temperature rises to the target temperature, the positive and negative electrodes of the external power supply are connected to the two pole ears of the battery with different polarities to charge the battery.

[0100] It should be noted that the target temperature refers to the battery being at a suitable charging temperature. At this temperature, less or even no lithium deposition occurs when the battery is charged compared to charging under low temperature conditions.

[0101] In some embodiments, the battery discharging step includes at least the following steps: S201: During the battery discharging process, the switch 5 controls the connection of the connecting branch 4 according to the temperature of the switch 5; S202: When the temperature of the switch 5 is at a first temperature, the switch 5 controls the connection of the connecting branch 4; S203: When the temperature of the switch 5 rises from the first temperature to the second temperature, the switch 5 controls the connection branch 4 to be disconnected; S204: When the temperature of the switch 5 drops from the second temperature to the third temperature, the switch 5 controls the connection branch 4 to be connected; S205: Repeat S203 and S204 according to the temperature of the battery.

[0102] Specifically, when the battery is discharging, especially when the battery is under high load such as high power and high current or when the battery is used in a relatively harsh environment such as high temperature, a large amount of heat is often generated inside the battery, and the battery temperature further increases. The increase in the battery temperature will increase the temperature of the normally open temperature switch 51. When the normally open temperature switch 51 rises to the first temperature, the normally open temperature switch 51 is closed, and the connecting branch 4 connected between the first pole ear 2 and the second pole ear 3 is turned on. At this time, the battery self-discharges to reduce the battery voltage to avoid thermal runaway and other faults of the battery. When the normally open temperature switch 51 rises to the first temperature, the normally open temperature switch 51 is closed, and the connecting branch 4 connected between the first pole ear 2 and the second pole ear 3 is turned on. At this time, the battery self-discharges to reduce the battery voltage to avoid thermal runaway and other faults of the battery. When the switch 51 and the normally closed temperature switch 52 are both in the closed state, although the voltage of the external power supply is reduced, the temperature of the connecting branch 4 will continue to rise. When the temperature of the normally closed temperature switch 52 rises to the second temperature, the normally closed temperature switch 52 is disconnected, and the connecting branch 4 is disconnected synchronously. At this time, the external power supply is working normally. Since the connecting branch 4 is not working, the temperature of the normally closed temperature switch 52 will drop. When the temperature of the normally closed temperature switch 52 drops to the third temperature, the normally closed temperature switch 52 will be closed again. At this time, the connecting branch 4 is turned on again, and the battery self-discharges again, reducing the battery voltage again. During the operation of the battery, when the battery temperature rises, the normally open temperature switch 51 and the normally closed temperature switch 52 will repeat the above process to realize pulse discharge of the battery, and finally realize self-discharge of the battery at high temperature, so as to reduce the battery capacity and improve the battery safety while the battery body will not cause high-temperature thermal runaway.

[0103] The basic principles of the present application are described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, effects, etc. mentioned in the present application are only examples and not limitations, and it cannot be considered that these advantages, strengths, effects, etc. are required by each embodiment of the present application. In addition, the specific details disclosed above are only for the purpose of illustration and ease of understanding, not for limitation, and the above details do not limit the present application to being implemented by adopting the above specific details.

[0104] The block diagrams of the devices, apparatuses, equipment, and systems involved in this application are only illustrative examples and are not intended to require or imply that they must be connected, arranged, and configured in the manner shown in the block diagram. As will be appreciated by those skilled in the art, these devices, apparatuses, equipment, and systems can be connected, arranged, and configured in any manner. Words such as "including", "comprising", "having", etc. are open words, referring to "including but not limited to", and can be used interchangeably with them. The words "or" and "and" used here refer to the words "and / or" and can be used interchangeably with them, unless the context clearly indicates otherwise. The words "such as" used here refer to the phrase "such as but not limited to", and can be used interchangeably with them.

[0105] It should also be noted that in the apparatus, device and method of the present application, each component or each step can be decomposed and / or recombined. Such decomposition and / or recombination should be regarded as equivalent solutions of the present application.

[0106] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

[0107] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly explain the technical solutions and cannot be used to limit the scope of protection of the present application.

[0108] The above description has been given for the purpose of illustration and description. In addition, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although multiple example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, changes, additions and sub-combinations thereof.

Claims

1. A battery, characterized in that: A wound battery cell is formed by winding a first pole piece, a diaphragm and a second pole piece, wherein: The first pole piece includes a first current collector and a first active material layer disposed on at least one side of the first current collector, the first active material layer is provided with a first groove, and the first current collector is partially exposed in the first groove; The second pole piece includes a second current collector and a second active material layer disposed on at least one side of the second current collector, the second active material layer is provided with a second groove, and the second current collector is partially exposed to the second groove; A first electrode tab connected to the first current collector is disposed in the first groove, and a second electrode tab connected to the second current collector is disposed in the second groove; The first pole piece further includes a first extension portion extending outward from the first current collector, and / or the second pole piece further includes a second extension portion extending outward from the second current collector.

2. The battery according to claim 1, characterized in that At least one first extension portion is provided, and at least one first extension portion is welded to form a third pole lug of the wound battery core, the third pole lug is connected to the second pole lug via a connecting branch, and a switching piece for controlling the connection branch to be turned on and off is provided on the connecting branch; and / or, At least one second extension portion is provided, and at least one second extension portion is welded to form a fourth pole ear of the wound battery core. The fourth pole ear and the first pole ear are connected through a connecting branch, and a switching piece for controlling the connection branch to be turned on and off is provided on the connecting branch.

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

4. The battery according to claim 3, characterized in that In the height direction of the wound battery core, the first pole tab and the third pole tab have the same height.

5. The battery according to claim 2, characterized in that The first current collector includes a first single-sided region with the first active material layer disposed on one side, and a first double-sided region with the first active material layer disposed on both sides, and the first extension portion is located in the first single-sided region and / or the first double-sided region; and / or, The second current collector includes a second single-sided region with the second active material layer disposed on one side, and a second double-sided region with the second active material layer disposed on both sides, and the second extension portion is located in the second single-sided region and / or the second double-sided region.

6. The battery according to claim 2 or 3, characterized in that: The switch comprises a normally open temperature switch and a normally closed temperature switch arranged in series, wherein: The normally open temperature switch is closed at a first temperature T1, the normally closed temperature switch is opened at a second temperature T2, and the normally closed temperature switch is closed when at a third temperature T3, wherein: T1, T2 and T3 satisfy: T2>T3>T1.

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

8. The battery according to claim 6, characterized in that The normally open temperature switch is disconnected at a fourth temperature T4, wherein T4 satisfies: T4≤50°C.

9. The battery according to claim 3, characterized in that In the length direction of the first pole piece, the length of the first current collector is L1, and the minimum distance between adjacent first extension portions is L2, wherein L1 and L2 satisfy the following relationship: 100 mm ≤ L2 ≤ L1 / 2.

10. The battery according to claim 1, characterized in that In the length direction of the first pole piece, the first pole ear is arranged in the middle of the first pole piece, and the first extension portion is arranged at the end of the first pole piece.

11. The battery according to claim 1, characterized in that In the width direction of the first pole piece, an insulating layer is disposed in the end region of the first extension portion close to the current collector, and a size D of the insulating layer satisfies: 0.5 mm ≤ D ≤ 2 mm.

12. The battery according to claim 3, characterized in that The first pole tab, the second pole tab and the third pole tab are arranged on the same side of the wound battery cell, and in the width direction of the battery, the second pole tab is arranged between the first pole tab and the third pole tab.

13. The battery according to claim 3, characterized in that The first pole tab and the second pole tab are disposed on the same side of the wound battery core, and the third pole tab and the first pole tab are disposed on different sides of the wound battery core.

14. The battery according to claim 2 or 3, characterized in that: A temperature sensor for detecting the temperature of the battery is arranged on the surface of the battery.

15. A battery operation method, characterized in that: Applicable to the battery according to any one of claims 1 to 14, the battery operation method comprises a battery charging step and a battery discharging step, and the battery charging step comprises at least the following steps: S101: Before charging the battery, detecting the temperature of the battery; S102: If the battery reaches the target temperature, charging the battery; S103: If the battery has not reached the target temperature, the positive and negative electrodes of the external power source are respectively connected to the two tabs of the battery with the same polarity, and after the battery is heated to the target temperature, the positive and negative electrodes of the external power source are respectively connected to the two tabs of the battery with different polarities to charge the battery.

16. The battery operation method according to claim 15, characterized in that: The battery discharging step comprises at least the following steps: S201: During the battery discharging process, the switch component controls the connection branch circuit according to the temperature of the switch component; S202: When the temperature of the switch is at a first temperature, the switch controls the connection branch to be connected; S203: When the temperature of the switch component rises from the first temperature to the second temperature, the switch component controls the connection branch to be disconnected; S204: When the temperature of the switch component drops from the second temperature to a third temperature, the switch component controls the connection branch to be connected; S205: Repeat S203 and S204 according to the temperature of the battery.

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