Battery and electronic equipment

Abstract

The present disclosure provides a battery and an electronic device, the battery comprising: at least one negative current collector having a first surface and a second surface; the plurality of coating regions are positioned on the surface of the at least one negative electrode current collector; wherein the impedances of at least two coating areas in the plurality of coating areas are different, and the impedance of at least one coating area positioned on the first surface is different from the impedance of at least one coating area positioned on the second surface. According to the invention, the energy density and the conductivity speed of the battery can be balanced, and the cruising ability of high-power-consumption equipment is improved.

Description

Technical Field

[0001] The present disclosure relates to the field of electrochemical energy storage devices, and in particular to a battery and an electronic device. Background Art

[0002] Batteries are common electrochemical energy storage devices. However, it is usually difficult to balance the energy density and conductivity of batteries, making it difficult to balance the capacity and rate performance of batteries. This can lead to problems such as short battery life for high-power devices. Especially for XR devices (XR all-in-one devices), they usually involve multiple application scenarios (such as virtual reality (VR) scenarios, mixed reality (MR) scenarios, fast charging scenarios, etc.). Different application scenarios have different power consumption and different current requirements, and thus different rate performance requirements for batteries, which usually vary greatly. In order to meet the application of XR devices in various scenarios, when designing batteries, they are usually designed according to the rate requirements that can meet the application scenarios with the highest power consumption. However, this will reduce the capacity of the battery, resulting in problems such as short battery life for XR devices. Summary of the Invention

[0003] The present disclosure provides a battery and an electronic device to at least solve the problems existing in the prior art, such as the difficulty in balancing battery capacity and rate performance, and the short battery life of high-power consumption devices.

[0004] In a first aspect, an embodiment of the present disclosure provides a battery, comprising:

[0005] at least one negative electrode current collector, the at least one negative electrode current collector having a first surface and a second surface;

[0006] a plurality of coating regions located on a surface of the at least one negative electrode current collector;

[0007] The impedances of at least two of the plurality of coating areas are different, and the impedance of at least one coating area located on the first surface is different from the impedance of at least one coating area located on the second surface.

[0008] In a second aspect, an embodiment of the present disclosure provides an electronic device comprising the above-mentioned battery.

[0009] The batteries and electronic devices provided by the present disclosure have coating areas with lower impedance and higher conductivity speeds, which are conducive to ion shuttling and can maintain a higher rate performance of the battery (that is, increase the maximum allowable rate of the battery so that the battery can operate at a higher rate), meet the high power consumption (high current) requirements of devices such as XR all-in-one machines, and at the same time maintain a faster charging and discharging speed of the battery to ensure the fast charging performance of the battery; at the same time, the coating areas with higher impedance can maintain a higher capacity of the battery and improve the battery's battery life.

[0010] Therefore, the battery disclosed in the present invention has multiple coating areas, wherein the impedance and other properties of at least two coating areas are different, that is, their chemical systems are different, so that the battery has coating areas of multiple chemical systems. Through the multi-level chemical architecture design, the energy density and conductivity speed of the battery can be balanced, while improving the capacity and rate performance of the battery, and improving the battery life of high-power consumption equipment, so that the battery disclosed in the present invention can be applied to devices integrated with multiple application scenario modules to meet the application requirements of the device in different application scenarios and improve the battery life of the device. For example, it can meet the application requirements of XR devices in different application scenarios such as VR scenes, MR scenes, fast charging scenes, and improve the battery life of XR devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic structural diagram of a negative electrode sheet according to an embodiment of the present disclosure;

[0012] Figure 2 This is a schematic structural diagram of a negative electrode sheet according to another embodiment of the present disclosure;

[0013] Figure 3 This is a schematic structural diagram of a negative electrode sheet according to another embodiment of the present disclosure;

[0014] Figure 4 Schematic diagram of the structure of a wound battery cell according to an embodiment of the present disclosure;

[0015] Figure 5 This is a schematic structural diagram of a wound battery cell according to another embodiment of the present disclosure;

[0016] Figure 6 This is a schematic structural diagram of a laminated battery cell according to an embodiment of the present disclosure;

[0017] Figure 7 This is an atomic force microscope scan of a low-magnification, high-density graphite film applied to a coating area with relatively high impedance according to an embodiment of the present disclosure;

[0018] Figure 8 This is an atomic force microscope scan of a high-magnification, low-compaction-density graphite applied to a coating region with low impedance according to an embodiment of the present disclosure;

[0019] Figure 9 Schematic diagram of the equivalent model of impedance;

[0020] Figure 10 Schematic diagram of the parallel unit of Rfast and Cfast in the equivalent model of impedance;

[0021] Figure 11 Schematic diagram of the parallel unit of Rslow and Cslow in the equivalent model of impedance.

[0022] Explanation of the accompanying symbols: 1: negative electrode sheet; 10: negative electrode current collector; 11: coating area; 111: first coating area; 112: second coating area; 113: third coating area; 114: fourth coating area; 100: negative electrode tab; 101: first straight portion; 102: first bent portion; 2: positive electrode sheet; 200: positive electrode tab; 201: second straight portion; 202: second bent portion; 3: diaphragm; x, z: directions. DETAILED DESCRIPTION

[0023] To enable those skilled in the art to better understand the solutions of the present disclosure, the present disclosure is further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present disclosure. The examples are only used to explain the present disclosure and do not limit the scope of the present disclosure. Based on the embodiments of the present disclosure, all other implementations obtained by those of ordinary skill in the art without making any creative efforts are within the scope of protection of the present disclosure.

[0024] Batteries are common electrochemical energy storage devices, which mainly include components such as positive electrodes, separators and negative electrodes. During battery application, ions (such as lithium ions in lithium-ion batteries) are intercalated and deintercalated between the positive and negative electrodes to realize the battery's charge and discharge cycle process.

[0025] The energy density and conductivity of a battery are usually difficult to balance, making it difficult to strike a balance between the battery's capacity and rate performance, resulting in short battery life for high-power devices. This also places higher demands on the battery's fast-charging performance, which is positively correlated with the conductivity and negatively correlated with the battery's energy density, making it difficult to strike a balance between the battery's fast-charging performance and capacity.

[0026] Specifically, the conductivity rate (conductivity) is inversely proportional to the impedance of the electrode. The conductivity rate will affect the transmission speed of the battery's ions (such as lithium ions in lithium-ion batteries), and thus affect the current (rate) during the battery's operation, as well as the battery's charge and discharge speed. Therefore, the device's demand for high power consumption (the greater the power consumption, the greater the current) and battery fast charging performance is positively correlated with the conductivity rate, but is usually negatively correlated with the battery's capacity (energy density). For example: (1) The greater the battery's discharge power consumption (the greater the current, the higher the rate performance requirement for the battery), the smaller the battery's actual effective capacity (Real Capacity); (2) The faster the battery's charging speed is required, the smaller the energy density of the designed battery is usually, and the smaller the battery's basic capacity (Basic Capacity).

[0027] In general, batteries need to be discharged at a rate not exceeding their maximum allowable rate. The actual effective capacity of a battery is the capacity actually exerted by the battery under a certain rate working condition. It is affected by factors such as the basic capacity of the battery, the battery internal resistance (DCR), and the current (Current) during battery operation. For example, a battery using a conventional graphite negative electrode with only one chemical system (the batteries (Battery 1 to Battery 5) with these basic capacities in Table 1 can be prepared by conventional methods in the art) generally has the following pattern as shown in Table 1:

[0028] Table 1

[0029]

[0030] In Table 1, the basic capacity is the rated capacity of batteries 1 to 5 at a current rate of 0.2C.

[0031] It can be seen from Table 1 that as the rate (current) of the battery increases during operation, the capacity efficiency of the battery (the ratio of the actual effective capacity to the basic capacity) tends to decrease, that is, a large discharge current of the battery will lead to a decrease in the capacity efficiency; at the same time, in Table 1, the maximum allowable rates (maximum discharge rates) of battery 1, battery 2, battery 3, battery 4 and battery 5 increase in sequence. As the maximum allowable rate of the battery increases, its basic capacity also tends to decrease, that is, the greater the maximum allowable rate of the battery, the smaller its basic capacity (design capacity) is when designing the battery, which will also lead to a smaller actual effective capacity of the battery during operation.

[0032] The negative electrode sheet is an important component of the battery, which usually includes a negative electrode coating containing a negative electrode active material. The negative electrode coating includes a negative electrode active material. Among them, the conductivity rate of the negative electrode sheet and the battery is related to factors such as the compaction density of the negative electrode coating, the structure and properties of the negative electrode active material, and the negative electrode coating is also an important factor affecting the energy density and capacity of the battery. For example, the higher the compaction density of the negative electrode coating, the greater the energy density and basic capacity of the battery (the basic capacity of the battery and the energy density of the battery are usually positively correlated), but the higher compaction density is not conducive to the shuttle of ions in the negative electrode coating, making the negative electrode coating impedance large (poor conductivity speed), slow ion transmission speed, slow charging and discharging speed, thereby affecting the rate performance and fast charging performance of the battery, and vice versa.

[0033] Conventional negative electrode sheets are usually designed with the same chemical system, that is, the properties such as the compaction density and conductivity speed of each area of ​​the negative electrode coating are basically the same. However, for devices with different application scenarios, the power consumption of different application scenarios is usually different, and even varies greatly. In order to meet the power consumption requirements of each application scenario, when designing the battery, it is usually designed according to the rate required by the application scenario with the highest power consumption. However, this will reduce the capacity of the battery, and the adaptability between the performance such as the endurance and fast charging capability of each application scenario is poor.

[0034] Especially for XR devices (XR all-in-one), which usually involve multiple application scenarios such as VR scenarios, MR scenarios, and fast charging scenarios, different application scenarios have different power consumption and current requirements, and thus different requirements for battery rate performance, which are usually very different. For example, using a battery with a rated capacity of 5000mAH at a nominal rate of 0.2C, the operating current and rate requirements of XR devices in VR scenarios, MR scenarios, and fast charging scenarios are shown in Table 2:

[0035] Table 2

[0036]

[0037] In order to meet the application of XR devices in VR scenarios, MR scenarios, fast charging scenarios and other scenarios, batteries are usually designed at the maximum rate (for example, in the example shown in Table 2, the battery is designed according to the maximum rate ≥ 3C (that is, in the battery formula, the fast charging scenario is 100%, and other scenarios are 0%)). However, this will result in low energy density and basic capacity of the battery. For example, to ensure the high-rate performance of the battery, it is necessary to reduce the compaction density of the negative electrode coating to facilitate the shuttle of ions, reduce impedance, increase the conductivity speed, and achieve high-rate performance. However, the reduction in compaction density will reduce the energy density and basic capacity of the battery, resulting in problems such as short battery life of XR devices (the battery life of conventional XR devices in VR scenarios (low-power scenarios) is generally 2 to 2.5 hours, and the battery life in MR scenarios (high-power scenarios) is generally around 1 hour).

[0038] In view of this, the present disclosure provides a battery, such as Figures 1 to 6 As shown, the battery includes: at least one negative electrode current collector 10, the at least one negative electrode current collector 10 having a first surface and a second surface; a plurality of coating areas 11, located on the surface of the at least one negative electrode current collector 10; wherein, the impedance of at least two coating areas 11 among the plurality of coating areas 11 is different, and satisfies: the impedance of at least one coating area 11 located on the first surface is different from the impedance of at least one coating area 11 located on the second surface.

[0039] In this way, the coating area 11 with smaller impedance has a higher conductivity speed, which is conducive to ion shuttling, can maintain a larger rate performance of the battery, meet the high power consumption (large current) requirements of devices such as XR all-in-one machines, and at the same time maintain a faster charging and discharging speed of the battery to ensure the fast charging performance of the battery; at the same time, the coating area 11 with larger impedance can maintain a higher energy density of the battery, thereby increasing the capacity of the battery and improving the battery life.

[0040] Therefore, the negative electrode sheet 1 of the embodiment of the present disclosure has a coating area 11 of multiple chemical systems. Through the multi-level chemical architecture design, the energy density and conductivity speed of the battery can be balanced, and the capacity and rate performance of the battery can be improved. The battery life of high-power consumption equipment is improved, so that the battery can be applied to devices integrated with multiple application scenario modules to meet the application requirements of the device in different application scenarios and improve the battery life of the device. For example, it can meet the application requirements of XR devices in different application scenarios such as VR scenes, MR scenes, fast charging scenes, etc., and can improve the battery life of XR devices.

[0041] Specifically, among the multiple coating areas 11 of the above-mentioned battery, the impedances of some coating areas 11 may be different, the impedances of some coating areas 11 may be the same, or the impedances of every two coating areas 11 may be different (that is, the impedance of any coating area 11 is different from the impedance of any other coating area 11).

[0042] Specifically, for any negative electrode current collector 10 in the battery, there is at least one coating area 11 (i.e., one or more coating areas 11) on its surface. Specifically, there may be at least one coating area 11 on one side of the negative electrode current collector 10, or there may be at least one coating area 11 on both the front and back surfaces of the negative electrode current collector 10.

[0043] Specifically, the battery includes at least one negative electrode sheet 1 (i.e., one or more negative electrode sheets 1), each of which includes a negative electrode current collector 10 and a coating area (negative electrode coating) 11 located on the surface of the negative electrode current collector 10. For each negative electrode sheet 1, it includes at least one coating area 11 (i.e., one or more coating areas 11). Specifically, the coating area 11 may exist on one side surface of the negative electrode current collector 10 of the negative electrode sheet 1, or the coating area 11 may exist on both the front and back surfaces of the negative electrode current collector 10 of the negative electrode sheet 1.

[0044] Among them, on any negative electrode current collector 10 (that is, the negative electrode current collector 10 of any negative electrode sheet 1), when there are at least two coating areas 11 on its surface, the impedance of the coating areas 11 on the surface of the negative electrode current collector 10 can be the same (that is, the impedance of each coating area 11 is the same as the impedance of other coating areas 11), or the impedance of at least two coating areas 11 is different.

[0045] Specifically, if Figure 4 、 Figure 5 and Figure 6 As shown, the battery includes a cell, which includes a positive electrode sheet 2, a separator 3, and the aforementioned negative electrode sheet 1. The separator 3 is interposed between the positive electrode sheet 2 and the negative electrode sheet 1 to prevent contact and short circuit between the positive electrode sheet 2 and the negative electrode sheet 1. The embodiments of the present disclosure can use conventional positive electrode sheets 2 and separators 3 in the art, without particular limitation.

[0046] In some embodiments, as Figure 4 and Figure 5 As shown, the battery cell may be a wound battery cell, that is, the positive electrode sheet 2, the separator 3 and the negative electrode sheet 1 are stacked in sequence and then wound to form a battery cell with a wound structure.

[0047] Continue to refer Figure 4 and Figure 5 In the wound battery cell, the number of negative electrode sheet 1 is 1, and the negative electrode sheet 1 has a wound structure, that is, the negative electrode sheet 1 includes multiple first straight portions 101, and a first bent portion 102 connected between every two adjacent first straight portions 101, and the negative electrode sheet 1 is bent through the first bent portion 102 to form a wound structure; the number of positive electrode sheet 2 is 1, and the positive electrode sheet 2 has a wound structure, that is, the positive electrode sheet 2 includes multiple second straight portions 201, and a second bent portion 202 connected between every two adjacent second straight portions 201, and the positive electrode sheet 2 is bent through the second bent portion 202 to form a wound structure. Among them, multiple first straight portions 101 of the negative electrode sheet 1 and multiple second straight portions 201 of the positive electrode sheet 2 are stacked, and these first straight portions 101 and these second straight portions 201 are staggered and separated by the diaphragm 3, that is, each first straight portion 101 is separated from the second straight portion 201 by the diaphragm 3, and each second straight portion 201 is separated from the first straight portion 101 by the diaphragm 3.

[0048] In other embodiments, Figure 6 As shown, the above-mentioned battery cell can be a stacked battery cell, that is, the battery cell includes multiple positive electrode sheets 2 and multiple negative electrode sheets 1, these positive electrode sheets 2 and these negative electrode sheets 1 are arranged alternately and separated by a diaphragm 3, that is, each positive electrode sheet 2 is separated from the negative electrode sheet 1 by the diaphragm 3, each negative electrode sheet 1 is separated from the positive electrode sheet 2 by the diaphragm 3, and each positive electrode sheet 2 is separated from the negative electrode sheet 1 by the diaphragm 3.

[0049] Specifically, among the above-mentioned multiple coating areas 11, at least two coating areas are in direct contact with the negative electrode current collector 10, that is, there is no other coating structure between the coating area 11 and the negative electrode current collector 10, and the impedance of at least two coating areas 11 in direct contact with the negative electrode current collector 10 is different. For example, the impedance of at least one coating area 11 located on the first surface of the negative electrode current collector 10 and in direct contact with the negative electrode current collector 10 is different from the impedance of at least one coating area 11 located on the second surface of the negative electrode current collector 10 and in direct contact with the negative electrode current collector 10.

[0050] In some embodiments, each of the plurality of coating regions 11 (all coating regions in the battery) is in direct contact with the negative electrode current collector 10 .

[0051] In one embodiment of the present disclosure, Figures 1 to 3 As shown, the first surface and the second surface can be the surfaces of the opposite sides of the same negative electrode current collector 10 (i.e., the negative electrode current collector 10 of the same negative electrode sheet 1), that is, one side surface of the negative electrode current collector 10 is the first surface, and the other side surface is the second surface. On the negative electrode current collector 10, there is at least one coating area 11 on its first surface, that is, the number of the coating area 11 on the first surface can be one (e.g., Figure 1 as shown) or multiple (as shown Figure 2 and Figure 3 As shown), there is at least one coating area 11 on the second surface, that is, the number of the coating area 11 on the second surface can be one (as shown Figure 1 as shown) or multiple (as shown Figure 2 and Figure 3 As shown), and the impedance of at least one coating area 11 on the first surface is different from the impedance of at least one coating area 11 on the second surface, there may be at least one such negative electrode current collector 10 (negative electrode sheet 1) in the battery.

[0052] Continue to refer Figures 1 to 3 On at least one negative electrode current collector 10 having a first surface and a second surface opposite to each other, each coating area 11 is in direct contact with the negative electrode current collector 10, that is, the coating area 11 located on the first surface is in direct contact with the first surface of the negative electrode current collector 10, and the coating area 11 located on the second surface is in direct contact with the second surface of the negative electrode current collector 10.

[0053] In general, if Figures 1 to 3 As shown, at least one negative electrode current collector 10 having a first surface and a second surface relative to each other may have an even number of coating areas 11, the number of coating areas 11 located on the first surface is the same as the number of coating areas 11 located on the second surface, and the coating areas 11 located on the first surface and the coating areas 11 located on the second surface correspond one to one, and the projections of the two corresponding coating areas 11 on the negative electrode current collector 10 at least partially overlap.

[0054] For example, Figure 1 As shown, at least one negative electrode current collector 10 (negative electrode sheet 1) in the above battery satisfies the following conditions: there are two coating areas 11 on the surface of the negative electrode current collector 10, one of which is a first coating area 111 located on the first surface, and the other coating area 11 is a second coating area 112 located on the second surface, and the projection of the first coating area 111 on the negative electrode current collector 10 and the projection of the second coating area 112 on the negative electrode current collector 10 at least partially overlap (as shown in FIG. Figure 1 As shown, the two are substantially completely overlapped), the impedance of the first coating area 111 is greater than the impedance of the second coating area 112, that is, the negative electrode sheet 1 containing the negative electrode current collector 10 is a dual-chemical structure design.

[0055] For example, Figure 2 As shown, at least one negative electrode current collector 10 (negative electrode sheet 1) in the above-mentioned battery satisfies: there are four coating areas 11 on the surface of the negative electrode current collector 10, wherein the number of coating areas 11 located on the first surface is two, namely, a first coating area 111 and a third coating area 113, and the number of coating areas 11 located on the second surface is two, namely, a second coating area 112 and a fourth coating area 114, the first coating area 111 and the second coating area 112 correspond to each other (that is, the projection of the first coating area 111 on the negative electrode current collector 10 and the projection of the second coating area 112 on the negative electrode current collector 10 at least partially overlap), and the third coating area 113 and the fourth coating area 114 correspond to each other (that is, the projection of the third coating area 113 on the negative electrode current collector 10 and the projection of the fourth coating area 114 on the negative electrode current collector 10 at least partially overlap).

[0056] For example, Figure 3 As shown, at least one negative electrode current collector 10 (negative electrode sheet 1) in the above-mentioned battery satisfies: there are six coating areas 11 on the surface of the negative electrode current collector 10, wherein three coating areas 11 are located on the first surface, and the other three coating areas 11 are located on the second surface, and the three coating areas 11 located on the first surface correspond to the three coating areas 11 located on the second surface one by one, which will not be repeated.

[0057] In another embodiment of the present disclosure, the battery includes a plurality of negative electrode sheets 1, and accordingly, the battery includes a plurality of negative electrode current collectors 10, and the above-mentioned first surface and second surface are respectively the surfaces of different negative electrode current collectors 10, that is, the first surface is the surface of one or several negative electrode current collectors (such as the first negative electrode current collector described below) 10 in the battery, and the second surface is the surface of another one or several other negative electrode current collectors (such as the second negative electrode current collector described below) 10 in the battery.

[0058] In some specific embodiments, the at least one negative electrode current collector 10 includes at least one first negative electrode current collector and at least one second negative electrode current collector (that is, the battery includes at least one first negative electrode current collector and at least one second negative electrode current collector), the surface of the first negative electrode current collector is provided with at least two coating areas 11, the impedance of the coating areas 11 on the first negative electrode current collector is the same, the surface of the second negative electrode current collector is provided with at least two coating areas 11, the impedance of the coating areas 11 on the second negative electrode current collector is the same, and the impedance of the coating areas 11 on the first negative electrode current collector is different from that of the coating areas 11 on the second negative electrode current collector. That is, the negative electrode sheet 1 in the battery includes at least one first negative electrode sheet containing the first negative electrode current collector and at least one second negative electrode sheet containing the second negative electrode current collector, the impedance of the coating area 11 in the first negative electrode sheet is different from that of the coating area 11 in the second negative electrode sheet, that is, the chemical structures of the first negative electrode sheet and the second negative electrode sheet are different, so that the battery includes multiple negative electrode sheets 1 with different chemical structures, which is conducive to constructing a multi-level chemical structure, balancing the energy density and conductivity rate of the battery, and adapting to devices with multiple application scenarios.

[0059] For example, in the above-mentioned laminated battery cell, part of the negative electrode sheets 1 is the first negative electrode sheet, and another part of the negative electrode sheet 1 is the second negative electrode sheet.

[0060] In other embodiments, among the multiple negative electrode sheets 1 in the laminated battery cell, at least one negative electrode sheet 1 has at least two coating areas 11 with different impedances. For example, the laminated battery cell includes Figures 1 to 3 At least two of the negative electrode sheets shown, that is, the stacked battery cell includes multiple negative electrode sheets 1 with a multi-level chemical structure design, so that the stacked battery cell has coating areas 11 with more chemical systems (that is, the impedance and other properties of these coating areas 11 are different), further constructing a multi-level chemical structure, balancing the energy density and conductivity speed of the battery, and adapting to equipment with a variety of application scenarios.

[0061] Specifically, if Figures 1 to 6 As shown, the negative electrode sheet 1 further includes at least one negative electrode tab 100 connected to the negative electrode current collector 10. The negative electrode tab 100 can be arranged at the end of the negative electrode current collector 10 in the length direction, or on one side or two opposite sides in the width direction of the negative electrode current collector 10. The negative electrode tab 100 can be arranged in a single-sided tab (such as Figure 1 As shown), center-mounted tabs (as shown Figure 2 As shown) or multi-pole (as Figure 3 The negative electrode tab 100 may be welded to the negative electrode current collector 10 or extended outward from the negative electrode current collector 10 .

[0062] In some embodiments, in a battery, at least one negative electrode current collector 10 satisfies the following requirements: the negative electrode tab 100 on the negative electrode current collector 10 is arranged at the end in the length direction of the negative electrode current collector 10, and there are coating areas 11 on the surfaces of opposite sides of the negative electrode current collector 10, wherein one coating area 11 is continuously arranged on one side surface of the negative electrode current collector, and the other coating area 11 is continuously arranged on the other side surface of the negative electrode current collector 10, that is, in the battery, the negative electrode tab 100 of one negative electrode sheet 1 (that is, the negative electrode tab 100 on one negative electrode current collector 10) may be arranged in such a manner, or the negative electrode tabs 100 of multiple negative electrode sheets 1 may all be arranged in such a manner, for example, the negative electrode tabs 100 on all negative electrode sheets 1 (that is, the negative electrode tabs 100 on all negative electrode current collectors 10) may all be arranged in such a manner.

[0063] For example, in Figure 1 In the negative electrode sheet 1 shown, the negative electrode tab 100 is arranged at the end in the length direction of the negative electrode current collector 10. The negative electrode sheet 1 has two coating areas 11, one coating area 11 (the first coating area 111) is continuously arranged on the first surface, and the other coating area 11 (the second coating area 112) is continuously arranged on the second surface.

[0064] Illustratively, in the battery, the negative electrode tab 100 on at least one negative electrode sheet 1 is arranged in a single-sided tab manner, that is, the number of the negative electrode tab 100 is one, which is arranged at one end of the negative electrode current collector 10 in the length direction.

[0065] In other embodiments, at least one negative electrode current collector 10 satisfies the following requirements: the negative electrode tab 100 on the negative electrode current collector 10 is arranged on one side or on two opposite sides in the width direction of the negative electrode current collector 10, and in the length direction of the negative electrode current collector 10, there is a coating area 11 on both opposite sides of each negative electrode tab 100, that is, in the battery, the negative electrode tab 100 of one negative electrode sheet 1 (that is, the negative electrode tab 100 on one negative electrode current collector 10) can be arranged in this manner, or the negative electrode tabs 100 of multiple negative electrode sheets 1 can all be arranged in this manner, for example, the negative electrode tabs 100 on all negative electrode sheets 1 (that is, the negative electrode tabs 100 on all negative electrode collectors 10) can all be arranged in this manner.

[0066] For example, if Figure 2 and Figure 3 As shown, the negative electrode tabs 100 are disposed on one side or two opposite sides of the negative electrode current collector 10 in the width direction, and in the length direction of the negative electrode current collector 10 , there are coating regions 11 on two opposite sides of each negative electrode tab 100 .

[0067] For example, Figure 2As shown, the negative electrode tab 100 is arranged in a central tab configuration, that is, there is one negative electrode tab 100, which is arranged on one side in the width direction of the negative electrode current collector 10 and located in the middle of the side of the negative electrode current collector 10 (that is, located in the middle of the length direction of the negative electrode current collector 10). In the length direction of the negative electrode current collector 10, the first coating area 111 and the third coating area 113 on the first surface are respectively located on opposite sides of the negative electrode tab 100, and the second coating area 112 and the fourth coating area 114 on the second surface are respectively located on opposite sides of the negative electrode tab 100.

[0068] For example, Figure 3 As shown, the negative electrode tabs 100 are arranged in a multi-tab arrangement, that is, multiple negative electrode tabs 100 are provided on the negative electrode sheet 1, and these negative electrode tabs 100 are arranged on one side in the width direction of the negative electrode current collector 10, and these negative electrode tabs 100 are distributed along the length direction of the negative electrode current collector 10. In the length direction of the negative electrode current collector 10, there are coating areas 11 on two opposite sides of each negative electrode tab 100 (the number of negative electrode tabs 100 on the negative electrode sheet 1 is at least two, and the number of coating areas 11 is at least six). It should be noted that Figure 3 The arrangement of multiple tabs in the negative electrode sheet 1 is merely shown for example. The number of negative electrode tabs 100 is not limited to two, but may be more.

[0069] Specifically, in every two coating areas 11 with different impedances, the difference △R between the impedance of the coating area 11 with larger impedance (such as the first coating area 111) and the impedance of the coating area 11 with smaller impedance (such as the second coating area 112) can be greater than or equal to 5ohm, for example, greater than or equal to 10ohm, or greater than or equal to 15ohm, or greater than or equal to 20ohm, etc., which is beneficial to improving the capacity and rate performance of the battery, and is particularly suitable for XR all-in-one machines, meeting their application requirements in different application scenarios such as VR scenes, MR scenes, and fast charging scenes, and can improve the battery life of the XR all-in-one machine.

[0070] Specifically, the impedance of the above-mentioned coating area 11 (such as the first coating area 111 and / or the second coating area 112, etc.) can be between 2.7ohm and 56ohm. The impedance of the above-mentioned coating area 11 is, for example, 2.7ohm, 2.77ohm, 3ohm, 5ohm, 10ohm, 15ohm, 20ohm, 25ohm, 30ohm, 35ohm, 40ohm, 45ohm, 50ohm, 55ohm, 55.5ohm, 56ohm or a range consisting of any two of them.

[0071] The present disclosure can measure the impedance of the coating area 11 by conventional methods in the art. For example, taking the impedance of the coating area 11 on the first surface as an example, the test process may include: (1) removing the coating area 11 on the second surface of the negative electrode 1, retaining the coating area 11 on the first surface to be tested, and obtaining a test sample; (2) cutting the test sample into a test piece with a width of w1 and a length of L; (3) using a clamp with a width of 25 mm to clamp the test piece on opposite sides of the width direction, leaving a test area with a width of w2 in the middle of the clamp, that is, leaving a test area with a width of w2 and a length of L, and using a constant current source (current I) to perform the test, with the current flowing from the width side of the test area; (4) measuring the voltage drop ΔU, and calculating the impedance R of the coating area 11 according to R=ΔU / I. Wherein, w1 can be 15 mm, L can be 20 mm, w2 can be 10 mm, and the current I can be 0.1 A.

[0072] Specifically, the coating area 11 is the negative electrode active material layer (negative electrode coating) of the negative electrode sheet 1 , which includes a negative electrode active material. The negative electrode active material may include negative electrode active materials such as graphite and / or silicon-based materials.

[0073] In the multiple coating areas 11 of the above-mentioned battery, the types and compositions of the negative electrode active materials in different coating areas 11 can be the same or different. For example, the negative electrode active materials in every two coating areas 11 in the battery are the same (for example, both are graphite); or, the negative electrode active materials in at least two coating areas 11 are different, for example, the negative electrode active material in at least one coating area 11 is graphite, the negative electrode active material in at least one coating area 11 is a mixture of graphite and silicon-based materials, or the negative electrode active materials in at least two coating areas 11 are respectively a mixture of graphite and silicon-based materials, but the ratio (such as mass ratio) of graphite and silicon-based materials in each two coating areas 11 is different.

[0074] Generally, for any two coating regions 11 with different impedances, one or more of their compaction density, particle size of the negative electrode active material therein, and composition of the negative electrode active material are different.

[0075] For example, in any two coating regions 11 with different impedances, the negative electrode active material in one coating region 11 includes graphite and a silicon-based material, while the negative electrode active material in the other coating region 11 is graphite; or, in any two coating regions 11 with different impedances, the negative electrode active material in each coating region 11 includes graphite and a silicon-based material, respectively, and the content of the silicon-based material in one coating region 11 is different from the content of the silicon-based material in the other coating region 11. The impedance of the silicon-based material is greater than that of graphite. Therefore, generally, the content of the silicon-based material in the coating region 11 with higher impedance is greater than that in the coating region 11 with lower impedance.

[0076] However, the embodiments of the present disclosure are not limited to this. In other embodiments, the types of negative electrode active materials in any two coating areas 11 with different impedances may also be the same, for example, both are graphite, but their compaction density and / or average particle size of the negative electrode active material and other conditions are different, so that the impedances of the two coating areas 11 are different.

[0077] In some embodiments, in any two coating areas 11 with different impedances, the compaction density of the coating area 11 with larger impedance is greater than the compaction density of the coating area 11 with smaller impedance. In this way, the compaction density of the coating area 11 with larger impedance is smaller, which is conducive to the shuttle of ions in the coating area 11, thereby improving the battery rate performance and fast charging performance, while the compaction density of the coating area 11 with larger impedance is larger, which is conducive to ensuring a higher energy density and capacity of the battery and improving the battery life.

[0078] Among them, in any two coating areas 11 with different impedances, the difference between the compaction density of the coating area 11 with larger impedance (such as the first coating area 111) and the compaction density of the coating area 11 with smaller impedance (such as the second coating area 112) can be 0.01-0.5 g / cm 3 , for example 0.01 g / cm 3 , 0.05g / cm 3 , 0.1g / cm 3 , 0.2g / cm 3 , 0.3g / cm 3 , 0.4g / cm 3 , 0.5g / cm 3 Or a range consisting of any two of them. This is conducive to further improving the capacity and rate performance of the battery, and is especially suitable for XR all-in-one machines, meeting their application needs in different application scenarios such as VR scenes, MR scenes, fast charging scenes, etc., and can improve the battery life of XR all-in-one machines.

[0079] In some embodiments, among the plurality of coating regions 11, at least one coating region 11 located on the first surface (such as the first coating region 111) has a compaction density of ρ1, 0.5 g / cm 3 ≤ρ1≤3.5g / cm 3 , ρ1 is, for example, 0.5 g / cm 3 , 0.8g / cm 3 , 1g / cm 3 , 1.3g / cm 3 , 1.5g / cm 3 , 2.1g / cm 3 , 2.5g / cm 3 , 3g / cm 3 , 3.5g / cm 3or a range consisting of any two thereof, at least one coating area 11 located on the second surface (such as the second coating area 112) has a compaction density of ρ2, 0.4 g / cm 3 ≤ρ2≤3g / cm 3 , ρ2 is, for example, 0.4 g / cm 3 , 0.7g / cm 3 , 1g / cm 3 , 1.2g / cm 3 , 1.5g / cm 3 , 1.8g / cm 3 , 2g / cm 3 , 2.5g / cm 3 , 3g / cm 3 or any two of them, ρ1>ρ2 (the difference between ρ1 and ρ2 can be 0.01~0.5g / cm 3 ), which is conducive to further improving the capacity and rate performance of the battery, and is especially suitable for XR all-in-one machines, meeting the application needs of different application scenarios such as VR scenes, MR scenes, and fast charging scenes, and can improve the battery life of XR all-in-one machines.

[0080] For example, in Figure 2 In the negative electrode sheet 1 shown, at least one of the following conditions (a) and (b) is satisfied: (a) the impedance of the first coating area 111 is greater than the impedance of the second coating area 112, and the compaction density of the first coating area 111 is greater than the compaction density of the second coating area 112; (b) the impedance of the third coating area 113 is greater than the impedance of the fourth coating area 114, and the compaction density of the third coating area 113 is greater than the compaction density of the fourth coating area 114.

[0081] Specifically, in Figure 2 In the negative electrode sheet 1 shown, the impedance (compaction density) of each of the first coating region 111 , the second coating region 112 , the third coating region 113 , and the fourth coating region 114 may be different.

[0082] In the embodiment of the present disclosure, the compaction density of each coating area 11 can be measured by conventional methods in the art, and there is no particular limitation on this.

[0083] In some embodiments, in any two coating regions 11 with different impedances, the average particle size of the negative electrode active material in the coating region 11 with larger impedance (such as the first coating region 111) may be larger than the average particle size of the negative electrode active material in the coating region 11 with smaller impedance (such as the second coating region 112).

[0084] Specifically, in any two coating areas 11 with different impedances, the difference between the average particle size of the negative electrode active material in the coating area 11 with larger impedance (such as the first coating area 111) and the average particle size of the negative electrode active material in the coating area 11 with smaller impedance (such as the second coating area 112) can be 5 to 45 μm, for example, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm or a range consisting of any two of them.

[0085] In some embodiments, among the above-mentioned multiple coating areas 11, the average particle size of the negative electrode active material in at least one coating area 11 located on the first surface (such as the first coating area 111) is d1, 30μm≤d1≤50μm, d1 is, for example, 30μm, 35μm, 40μm, 45μm, 50μm or a range consisting of any two thereof, and the average particle size of the negative electrode active material in at least one coating area 11 located on the second surface (such as the second coating area 112) is d2, 5μm≤d2≤35μm, d2 is, for example, 5μm, 10μm, 15μm, 20μm, 25μm, 30μm, 35μm or a range consisting of any two thereof, d1>d2 (the difference between d1 and d2 can be 5~45μm).

[0086] In specific implementation, an atomic force microscope can be used to scan the coating area 11, and the area of ​​the scanning area can be 100 to 300 μm. 2 , such as 100μm 2 , 200μm 2 or 300 μm 2 , to measure the average particle size of the negative electrode active material in the coating area 11.

[0087] Taking the negative electrode active material in the negative electrode coating as graphite as an example, generally, the graphite in the coating area 11 (such as the first coating area 111) with larger impedance is low-rate graphite (such as Figure 7 The low-rate high-density graphite shown in FIG1 is a low-rate graphite having a low maximum allowable rate. For example, the maximum allowable rate of the battery using the low-rate graphite is about 1C (i.e., the battery can be discharged at a rate of 0 to 1C). The graphite in the coating area 11 (such as the second coating area 112) with low impedance can be a high-rate graphite (such as Figure 8 The high-rate, low-compacted-density graphite shown in FIG. 4 is a graphite having a relatively high rate, i.e., a battery using this high-rate graphite has a relatively high maximum allowable rate, for example, about 3.5C (i.e., the battery can be discharged at a rate of 0 to 3.5C). Conventional low-rate and high-rate graphites in the art can be used in the present disclosure without particular limitation.

[0088] Specifically, in addition to the negative electrode active material, the negative electrode coating (each coating area 11) generally also includes a conductive agent and a binder. The embodiments of the present disclosure can adopt conventional conductive agents and binders in the field. For example, the conductive agent includes one or more of conductive carbon black (SP), acetylene black, carbon nanotubes, and graphene, and the binder may include one or more of polyvinylidene fluoride (PVDF), styrene-butadiene rubber (SBR), carboxymethyl cellulose, etc.

[0089] In the above-mentioned battery, at least one negative electrode current collector 10 has coating areas 11 on both sides of its opposite surfaces, and the thickness of the coating area 11 on one side of the surface can be the same as or different from the thickness of the coating area 11 on the other side. Relatively speaking, when the thickness of the coating areas 11 on the two opposite sides of the negative electrode current collector 10 is different, it is more conducive to winding.

[0090] Generally, the ratio of the volume of each of the plurality of coating regions 11 to the total volume of the plurality of coating regions 11 in the battery (ie, the sum of the volumes of all coating regions 11 in the battery) may be greater than or equal to 20%.

[0091] For example, the number of negative electrode sheets 1 in the battery is 1, which is Figures 1 to 3 For the negative electrode sheet 1 shown in any one of the figures, the ratio of the volume of each coating area 11 in the multiple coating areas 11 of the negative electrode sheet 1 to the total volume of all coating areas 11 in the negative electrode sheet 1 (also the total volume of the negative electrode coating in the negative electrode sheet 1) can be greater than or equal to 20%.

[0092] For example, the negative electrode 1 in the battery is Figure 1 In the negative electrode sheet 1 shown, the ratio of the volume of the first coating area 111 to the total volume of the negative electrode coating is greater than or equal to 20%, the ratio of the volume of the second coating area 112 to the total volume of the negative electrode coating is greater than or equal to 20%, and the total volume of the negative electrode coating = the volume of the first coating area 111 + the volume of the second coating area 112; or, the negative electrode sheet 1 in the battery is as follows Figure 2 In the negative electrode sheet 1 shown, the ratio of the volume of the first coating area 111 to the total volume of the negative electrode coating is greater than or equal to 20%, the ratio of the volume of the second coating area 112 to the total volume of the negative electrode coating 11 is greater than or equal to 20%, the ratio of the volume of the third coating area 113 to the total volume of the negative electrode coating 11 is greater than or equal to 20%, and the ratio of the volume of the fourth coating area 114 to the total volume of the negative electrode coating 11 is greater than or equal to 20%. The total volume of the negative electrode coating = the volume of the first coating area 111 + the volume of the second coating area 112 + the volume of the third coating area 113 + the volume of the fourth coating area 114.

[0093] The volume of each coating region 11 is related to the product of the area of ​​the coating region 11 and the thickness of the coating region 11. The area of ​​the coating region 11 refers to the surface area of ​​the coating region 11 (also the area of ​​the projection of the coating region 11 on the negative electrode current collector 10). For example, Figures 1 to 3 As shown, for any coating area 11, it is a relatively flat film structure, and its surface is basically flat, that is, the thickness of each area of ​​the coating area 11 is basically the same, and the cross-section of the coating area 11 parallel to the thickness direction (third direction z) of the coating area 11 is, for example, basically rectangular or square, etc. At this time, the volume of the coating area 11 is basically equal to the product of the area of ​​the coating area 11 and the thickness of the coating area 11.

[0094] Specifically, for any two coating regions 11 with different impedances, their volumes may be the same or different, that is, the ratio of their volumes to the total volume of the plurality of coating regions 11 in the battery may be the same or different. For example, in Figure 1 In the negative electrode sheet 1 shown, the volume of the first coating area 111 and the volume of the second coating area 112 can be the same or different.

[0095] For devices that integrate modules for multiple application scenarios, the power consumption of different application scenarios is different, and the rate requirements for the battery are different. By designing coating areas 11 with different impedances in the battery, the rate requirements of each application scenario can be adapted. Generally, the application ratios of various application scenarios of the device are different. Therefore, the volume ratio of the coating area 11 in the battery that adapts to the rate requirements of the application scenario (that is, the ratio of the coating area 11 to the total volume of all coating areas 11 in the battery) can be adjusted accordingly to better meet the rate requirements of various application scenarios of the device, while taking into account maintaining the battery's high capacity and other performance.

[0096] In addition, in any two coating regions 11 with different impedances, the thickness of one coating region 11 may be the same as or different from the thickness of the other coating region 11 .

[0097] Furthermore, among any two coating regions 11 with different impedances, the area of ​​one coating region 11 may be the same as or different from the area of ​​the other coating region 11 .

[0098] By coordinating the thickness and area of ​​the coating area 11, the volume ratio requirement of the coating area 11 in the battery can be met, while facilitating the manufacture of the electrode sheet and the battery. For example, for a negative electrode sheet 1 (e.g., Figure 1For the negative electrode sheet 1 shown in FIG, when manufacturing the negative electrode sheet 1, the coating areas on the two opposite sides of the negative electrode collector 10 can be made the same (i.e., the areas of the first coating area 111 and the second coating area 112 are the same). On this basis, by adjusting the thickness of the coating areas 11 on the two opposite sides of the negative electrode collector 10, the volume ratio requirements of the coating areas 11 on the two opposite sides can be met, and the processing of the negative electrode sheet 1 is facilitated. For the negative electrode sheet 1 with more coating areas 11 (such as Figure 2 The negative electrode sheet 1 or the negative electrode sheet 1 with the middle tab arrangement shown Figure 3 The multi-tab negative electrode sheet 1 shown can have the same thickness for coating regions 11 of varying impedance. Furthermore, the areas of these coating regions 11 (specifically, their coating lengths on the negative electrode current collector 10) can be adjusted to meet their respective volume requirements. Consequently, the disclosed embodiments also offer advantages such as flexible manufacturing of the negative electrode sheet 1, which in turn facilitates both negative electrode sheet 1 and battery manufacturing.

[0099] During specific implementation, the volume proportion of each coating area 11 can be adjusted according to the proportion of each application scenario of equipment such as the XR all-in-one machine. Specifically, the volume of each coating area 11 can be adjusted by adjusting parameters such as the thickness thereof, thereby adjusting its volume proportion in the battery (that is, the ratio of the volume of the coating area 11 to the total volume of all coating areas 11 in the battery).

[0100] For example, for XR all-in-one devices, the application ratio k of VR scenes (low power consumption scenes) is usually about 70%, and the application ratio of MR scenes (high power consumption scenes) is usually about (1-k). In order to adapt to user habits, the following can be adopted: Figure 1 The negative electrode sheet 1 of the dual chemical structure design is shown, and the thickness of the first coating area 111 is H1=H0×k, and the thickness of the second coating area 112 is H2=H0×(1-k)+H0, where H0 can be 40μm to 60μm, for example, about 50μm.

[0101] Specifically, if Figures 4 to 6 As shown, the positive electrode sheet 2 may include a positive electrode current collector and a positive electrode active material layer located on the surface of the positive electrode current collector. The positive electrode sheet 2 also includes a positive electrode tab 200. The positive electrode tab 200 may be arranged in a single-sided tab, a central tab, or multiple tabs.

[0102] For example, Figure 4 As shown, both the positive electrode tab 200 and the negative electrode tab 100 are arranged in a single-sided tab configuration.

[0103] For example, Figure 5 As shown, both the positive electrode tab 200 and the negative electrode tab 100 are arranged in a multi-tab manner.

[0104] Among them, when the negative electrode tab 100 of the negative electrode sheet 1 is a multi-tab arrangement (such as Figure 5 As shown in the figure, when a plurality of negative electrode tabs 100 are provided on the negative electrode sheet 1, in the wound battery cell, the projections of these negative electrode tabs 100 along the thickness direction of the battery cell (also the thickness direction of the negative electrode sheet 1 and the positive electrode sheet 2) basically overlap, that is, in the cross section of the battery cell parallel to the thickness direction of the battery cell, the centers of these negative electrode tabs 100 are basically on the same straight line.

[0105] In some embodiments, as Figures 1 to 3 As shown, when the negative electrode sheet 1 and the positive electrode sheet 2 are not wound to form a wound structure battery cell, the length direction of the negative electrode sheet 1 and the length direction of the positive electrode sheet 2 are parallel to the first direction x, the width direction of the negative electrode sheet 1 and the width direction of the positive electrode sheet 2 are parallel to the second direction, and the thickness direction of the negative electrode sheet 1 and the thickness direction of the positive electrode sheet 2 are parallel to the third direction z; after forming the wound battery cell, the negative electrode sheet 1 and the positive electrode sheet 2 both form a wound structure. At this time, as shown in FIG. Figure 4 and Figure 5 As shown, the width direction of the battery cell is parallel to the first direction x, the length direction of the battery cell is parallel to the second direction, and the thickness direction of the battery cell is parallel to the third direction z.

[0106] Specifically, the battery may be a lithium-ion battery.

[0107] The embodiment of the present disclosure further provides an electronic device, including the above-mentioned battery, which has the same advantages as the above-mentioned negative electrode sheet 1 and will not be described in detail.

[0108] Specifically, the device of the embodiment of the present disclosure can be an XR all-in-one machine, a mobile phone, a tablet, a drone, an electric car and other devices.

[0109] Specifically, the devices of the embodiments of the present disclosure are particularly suitable for devices with multiple application scenarios, such as XR all-in-one devices, which have VR scenarios, MR scenarios, and fast charging scenarios. The battery of the embodiments of the present disclosure can meet the battery life and fast charging requirements of devices with multiple application scenarios such as XR all-in-one devices.

[0110] The present disclosure is further introduced below in conjunction with impedance models of different chemical architectures.

[0111] like Figure 9 、 Figure 10 and Figure 11 As shown, in the equivalent impedance model, the parallel unit of Rfast and Cfast (such as Figure 10 As shown) represents the polarization impedance (resistance Rfast represents the impedance effect, capacitance Cfast represents the transient change trend), the parallel unit of Rslow and Cslow (as shown) Figure 11The ohmic resistance (ESR) is represented by the diffusion resistance, the parallel connection of Rfast and Cfast, and the parallel connection of Rslow and Cslow in series to characterize the DC resistance of the current. Different chemical structure designs of the negative electrode sheet 1 or battery cell have different ESR systems.

[0112] Specifically, in the prior art, batteries are usually designed with a single chemical structure, that is, the negative electrode sheet 1 thereof is designed with a single chemical structure, that is, the negative electrode sheet 1 thereof has only a coating area 11 of one chemical system, and the negative electrode sheet 1 is, for example, a 3.5C graphite negative electrode (that is, the maximum allowable rate of the battery using the 3.5C graphite negative electrode is 3.5C) or a 1C graphite negative electrode (that is, the maximum allowable rate of the battery using the 1C graphite negative electrode is 1C). For batteries using this single chemical structure design, regardless of whether the negative electrode tab 100 is arranged in a single-sided tab, a central tab, or a multi-tab (including a wound battery cell formed by a negative electrode sheet 1 using multiple negative electrode tabs 100, or a stacked battery cell having multiple negative electrode sheets 1 and multiple negative electrode tabs 100), it has only one ohmic impedance (ESR) system (such as Figure 9 As shown), the battery operates at a single rate. As mentioned above, when the battery is designed with a single rate (for example, designed with a maximum allowable rate of 3.5C, or designed with a maximum rate of 1C), it is difficult to balance its energy density and conductivity speed, and it is difficult to take into account both the capacity and the rate performance of the battery. For example, the battery with a maximum allowable rate of 3.5C has good rate performance, but its capacity is low, which makes the endurance of high-power devices such as XR all-in-one machines poor; while the battery with a maximum allowable rate of 1C has a higher capacity but poor rate performance and cannot meet the needs of high power consumption and fast charging.

[0113] In the embodiment of the present disclosure, the battery is designed with a multi-level chemical structure, that is, at least two coating areas 11 in the battery have different impedances, different conductivity speeds, and corresponding different rates, so that the battery has at least two ESR systems.

[0114] For example, in a wound cell, for a negative electrode tab 100 arranged in a single-sided tab manner, the negative electrode sheet 1 (eg Figure 1 As shown), it has two coating areas 11 (respectively, a first coating area 111 and a second coating area 112). The impedance of the two coating areas 11 is different, and there are two ESR systems (respectively, ESR1 and ESR2); in the wound battery cell, for the negative electrode tab 100 with a central tab arrangement (as shown in FIG. Figure 2As shown), it has four coating areas 11 (respectively, a first coating area 111, a second coating area 112, a third coating area 113 and a fourth coating area 114). When the impedances of two of the four coating areas 11 are different, the battery has four ESR systems (respectively, ESR1, ESR2, ESR3 and ESR4); in a battery cell with more coating areas 11 with different impedances, for example, for a wound battery cell formed by a negative electrode sheet 1 with a multi-electrode arrangement of the negative electrode tab 100 or a laminated battery cell with multiple coating areas 11 with different impedances ( Figure 9 The impedance system of the equivalent model corresponding to the multi-pole ear or stack in the battery is shown in FIG1 ), wherein the impedance of each two coating areas 11 in the n coating areas 11 are different (n is an integer). At this time, the wound battery cell or the stacked battery cell has n ESR systems (ESR1, ESR2...ESRn respectively), so that the battery has n ESR systems.

[0115] The disclosed embodiments design a multi-level chemical architecture for the battery. During the battery application process, the battery can operate at an adaptive rate according to the application scenario to meet the power consumption requirements of each application scenario, while also improving the battery capacity and enhancing the endurance of the device.

[0116] For example, in adopting Figure 1 In the wound battery cell formed by the negative electrode sheet 1 shown, the second coating area 112 is designed with a maximum allowable rate of 3.5C (that is, the second coating area 112 is the same as the negative electrode coating 11 of the 3.5C graphite negative electrode in the above-mentioned prior art), and the first coating area 111 is designed with a maximum allowable rate of 1C (that is, the first coating is the same as the negative electrode coating 11 of the 1C graphite negative electrode in the above-mentioned prior art). The battery formed by this battery cell has both the high rate performance of the 3.5C graphite negative electrode and the high capacity performance of the 1C graphite negative electrode, which meets the high power consumption and fast charging requirements of high-power consumption equipment with different application scenarios, and can also improve the endurance of high-power consumption equipment.

[0117] In the description of the present disclosure, terms such as "first" and "second" are used only for descriptive purposes, such as distinguishing between components to more clearly illustrate / explain the technical solution, and cannot be understood as indicating or implying the number of the indicated technical features or the order with substantial significance.

[0118] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A battery, characterized in that: include: at least one negative electrode current collector, the at least one negative electrode current collector having a first surface and a second surface; a plurality of coating regions located on a surface of the at least one negative electrode current collector; The impedances of at least two of the plurality of coating areas are different, and the impedance of at least one coating area located on the first surface is different from the impedance of at least one coating area located on the second surface.

2. The battery according to claim 1, characterized in that The first surface and the second surface are surfaces on two opposite sides of the same negative electrode current collector.

3. The battery according to claim 1, characterized in that The battery includes a plurality of negative electrode current collectors, and the first surface and the second surface are surfaces of different negative electrode current collectors.

4. The battery according to claim 1 or 3, characterized in that The battery includes at least one first negative electrode current collector and at least one second negative electrode current collector, the surface of the first negative electrode current collector is provided with at least two coating areas, the impedance of the coating areas on the first negative electrode current collector is the same, the surface of the second negative electrode current collector is provided with at least two coating areas, the impedance of the coating areas on the second negative electrode current collector is the same; the impedance of the coating area on the first negative electrode current collector is different from that of the coating area on the second negative electrode current collector.

5. The battery according to any one of claims 1 to 3, characterized in that: In any two coating regions with different impedances, the compaction density of the coating region with a larger impedance is greater than the compaction density of the coating region with a smaller impedance.

6. The battery according to claim 5, characterized in that In any two coating areas with different impedances, the difference in compaction density between the coating area with larger impedance and the coating area with smaller impedance is 0.01 to 0.5 g / cm 3 .

7. The battery according to claim 5, characterized in that Among the plurality of coating areas, at least one coating area located on the first surface has a compaction density of ρ1,0.5 g / cm 3 ≤ρ1≤3.5g / cm 3 , the compacted density of at least one of the coating areas located on the second surface is ρ2, 0.4 g / cm 3 ≤ρ2≤3g / cm 3 ,ρ1>ρ2.

8. The battery according to any one of claims 1 to 3, characterized in that: In any two coating regions with different impedances, the average particle size of the negative electrode active material in the coating region with a larger impedance is larger than the average particle size of the negative electrode active material in the coating region with a smaller impedance.

9. The battery according to claim 8, characterized in that In any two coating regions with different impedances, the difference between the average particle size of the negative electrode active material in the coating region with larger impedance and the average particle size of the negative electrode active material in the coating region with smaller impedance is 5 to 45 μm.

10. The battery according to claim 8, characterized in that Among the multiple coating areas, the average particle size of the negative electrode active material in at least one coating area located on the first surface is d1, 30μm≤d1≤50μm, and the average particle size of the negative electrode active material in at least one coating area located on the second surface is d2, 5μm≤d2≤35μm, d1>d2.

11. The battery according to claim 1, characterized in that The coating region includes a negative electrode active material, and the negative electrode active material includes graphite and / or silicon-based materials.

12. The battery according to claim 11, characterized in that In any two coating regions with different impedances, the negative electrode active material in one coating region includes graphite and silicon-based material, and the negative electrode active material in the other coating region is graphite; Alternatively, in any two coating areas with different impedances, the negative electrode active material in each coating area includes graphite and a silicon-based material, respectively, and the content of the silicon-based material in one coating area is different from that in the other coating area.

13. The battery according to any one of claims 1 to 3, characterized in that: The number of the coating areas located on the first surface is the same as the number of the coating areas located on the second surface, and the coating areas located on the first surface correspond to the coating areas located on the second surface in a one-to-one manner.

14. The battery according to any one of claims 1 to 3, characterized in that: In any two coating regions with different impedances, the thickness of one coating region is different from the thickness of the other coating region; And / or, in any two coating regions with different impedances, the area of ​​one coating region is different from the area of ​​the other coating region.

15. The battery according to any one of claims 1 to 3, characterized in that: The coating area is provided on two opposite surfaces of at least one of the negative electrode current collectors, and the thickness of the coating area on one surface is different from the thickness of the coating area on the other surface of the two opposite surfaces.

16. The battery according to any one of claims 1 to 3, characterized in that: The ratio of the volume of each coating area to the total volume of the plurality of coating areas is greater than or equal to 20%.

17. The battery according to any one of claims 1 to 3, characterized in that: The battery further includes at least one negative electrode tab connected to the negative electrode current collector; Wherein, at least one of the negative electrode current collectors satisfies the following conditions: the negative electrode tabs on the negative electrode current collector are arranged at the ends in the length direction of the negative electrode current collector, and the coating areas exist on the surfaces of opposite sides of the negative electrode current collector, wherein one of the coating areas is continuously arranged on one side of the negative electrode current collector, and the other coating area is continuously arranged on the other side of the negative electrode current collector; Alternatively, at least one of the negative electrode current collectors satisfies the following conditions: the negative electrode tabs on the negative electrode current collector are arranged on one side or on two opposite sides in the width direction of the negative electrode current collector, and the coating area exists on two opposite sides of each of the negative electrode tabs in the length direction of the negative electrode current collector.

18. The battery according to any one of claims 1 to 3, characterized in that: The battery is a lithium-ion battery.

19. An electronic device, characterized in that: A battery comprising the battery according to any one of claims 1 to 18.

20. The electronic device according to claim 19, wherein The electronic device is an XR all-in-one device.

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