Pole piece, battery and electric equipment

Abstract

The invention discloses a pole piece, a battery and electric equipment, the pole piece comprises an electrode and a thermoelectric material, and the thermoelectric material is distributed in the whole area or partial area of the electrode. The thermoelectric material is arranged in the pole piece, so that the risk of lithium precipitation during battery charging can be reduced, and the service life of the battery is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a pole piece, a battery and an electrical device. Background Art

[0002] Lithium-ion batteries are widely used in energy storage and electric vehicles due to their high energy density, high average output voltage, high output power, low self-discharge, excellent cycle performance, fast charge and discharge, wide operating temperature range, and long service life. Among them, long charging time is the main obstacle to the further development of lithium-ion batteries. To this end, lithium-ion battery manufacturers are actively developing batteries with super fast charging capabilities from the aspects of battery design and battery management.

[0003] Among them, a key factor limiting the fast charging of lithium ions is the uneven temperature distribution at different locations of the fast-charging battery. The current density generated at different locations of the negative electrode is different. The high-temperature area will be fully charged first due to its high temperature and low impedance. In addition, when the charging end is about to be fully charged, a large charging current will be generated toward the low-temperature area, which makes it easy for the central area to precipitate lithium. On the one hand, the deposited lithium metal reacts with the electrolyte to consume the active lithium of the positive electrode. On the other hand, the continued growth of lithium metal can easily pierce the diaphragm and cause serious safety problems. At present, the market mainly controls the temperature of the battery through liquid cooling or direct cooling, but this method can only regulate the temperature distribution on the surface of the battery. There is still a large temperature difference inside the battery, which will still cause lithium precipitation. Summary of the invention

[0004] The purpose of the present invention is to provide a pole piece, a battery and an electrical device to solve the problem of lithium deposition during battery charging.

[0005] To achieve the purpose of the present invention, the present invention provides the following technical solutions:

[0006] In a first aspect, the present invention provides a pole piece, comprising an electrode and a thermoelectric material, wherein the thermoelectric material is distributed in the entire region or a partial region of the electrode.

[0007] In one embodiment, the pole piece includes a first end and a second end opposite to each other in a first direction, and a middle area between the first end and the second end, the first direction is the length direction of the pole piece, and the thermoelectric material is located at least one of the first end, the second end and the middle area.

[0008] In one embodiment, the first end and the middle area are spaced apart, and the second end and the middle area are spaced apart.

[0009] In one embodiment, taking the center line of the active material layer in the first direction as a reference, the thermoelectric material is symmetrical with respect to the center line.

[0010] In one embodiment, the dimensions of the first end and the second end in the first direction are independently 1 mm-10 mm, and the dimension of the middle area in the first direction is 5 mm-20 mm.

[0011] In one embodiment, the thermoelectric material includes one or more of NaPb20SbTe22, Bi2Te3, and CsBi4Te6.

[0012] In one embodiment, the electrode includes an active material layer, and the thermoelectric material includes a first thermoelectric material, and the first thermoelectric material is distributed in the entire region or a part of the region of the active material layer.

[0013] In one embodiment, the electrode includes a current collector, the thermoelectric material includes a second thermoelectric material, and the second thermoelectric material is distributed in the entire region or a partial region of the current collector.

[0014] In one embodiment, the electrode includes an active material layer, and the mass ratio of the thermoelectric material to the active material layer is 1%-5%.

[0015] In a second aspect, the present invention provides a battery, comprising a pole piece as described in any embodiment of the first aspect.

[0016] In a third aspect, the present invention provides an electrical device comprising the battery described in the second aspect.

[0017] The pole piece provided by the present invention comprises an electrode and a thermoelectric material. The thermoelectric material can generate a reverse current flowing from a low temperature zone to a high temperature zone when a large temperature difference is generated inside the battery, which can partially offset the original current discharged from the high temperature zone to the low temperature zone, reduce the occurrence of lithium plating problems, and increase the life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention 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 some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 is a cross-sectional view of an active material layer of an embodiment;

[0020] Figure 2 is a cross-sectional view of a current collector of an embodiment;

[0021] Figure 3 is a cross-sectional view of a pole piece of an embodiment.

[0022] Description of reference numerals:

[0023] 100-pole piece, 10-active material layer, 11-active material, 12-first thermoelectric material, 20-first end, 30-second end, 40-middle region, 50-current collector, 51-substrate, 52-second thermoelectric material, 60-pole ear;

[0024] a-first direction, b-midline. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that when a component is said to be "fixed to" another component, it can be directly on the other component or there can be a central component. When a component is said to be "connected to" another component, it can be directly connected to the other component or there can be a central component at the same time.

[0027] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used in the present invention includes any and all combinations of one or more of the related listed items.

[0028] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0029] refer to Figure 1 and Figure 3 , Figure 1 is a cross-sectional view of the active material layer 10 taken along the first direction a.

[0030] The present invention provides a pole piece 100, comprising an electrode and a thermoelectric material, wherein the thermoelectric material is distributed in the entire region or a partial region of the electrode.

[0031] The thermoelectric material is distributed in the whole area or a part of the area of ​​the electrode, which means that the thermoelectric material is coated on the whole area or a part of the area of ​​the electrode, and / or the thermoelectric material is doped in the whole area or a part of the area of ​​the electrode.

[0032] Thermoelectric materials can generate a reverse current flowing from the low-temperature area to the high-temperature area when a large temperature difference occurs inside the battery, which will partially offset the original current discharging from the high-temperature area to the low-temperature area, reduce the occurrence of lithium plating problems, and increase the life of the battery.

[0033] refer to Figure 1 and Figure 3 In one embodiment, the pole piece 100 includes a first end 20 and a second end 30 opposite to each other in a first direction a, and a middle region 40 between the first end 20 and the second end 30, the first direction a being the length direction of the pole piece 100, and the thermoelectric material is located at least one of the first end 20, the second end 30 and the middle region 40. Optionally, the thermoelectric material is located at the first end 20, the second end 30 and the middle region 40.

[0034] When the thermoelectric material only exists in the middle area 40, since the first end 20 and the second end 30 are high temperature areas and the middle area 40 is a low temperature area, when the thermoelectric material only exists in the middle area 40, current will still be generated flowing from the low temperature area to the high temperature area, which has a good effect on improving the lithium plating problem.

[0035] When the thermoelectric material only exists at the first end 20 and / or the second end 30, since the current exists in the entire area of ​​the electrode, the first end 20 and the second end 30 will still generate reverse current, which still has a certain improvement effect on the lithium plating problem.

[0036] The thermoelectric material may be uniformly distributed throughout the electrode, or may be non-uniformly distributed throughout the electrode.

[0037] The thermoelectric material is located in a partial area of ​​the electrode, and the partial area may also be the area between the first end 20 and the middle area 40, the area between the second end 30 and the middle area 40, and any other possible local area. There is current in all areas of the electrode, so adding thermoelectric material in any area can generate reverse current to offset the current, reduce the temperature difference generated inside the battery, and improve the lithium precipitation problem.

[0038] In one embodiment, the electrode further includes a tab 60, and the tab 60 is connected to the first end 20 and / or the second end 30. The tab 60 can be in the form of a full tab 60, a multi-tab 60, or a single tab 60, etc., without limitation.

[0039] The pole tabs 60 may be in the form of same-side pole tabs 60 , different-side pole tabs 60 , symmetrical pole tabs 60 , or asymmetrical pole tabs 60 , without limitation.

[0040] The welding method of the tab 60 includes but is not limited to resistance welding, ultrasonic welding, FTT welding and laser welding, etc., and is not limited thereto.

[0041] The first end 20 and the second end 30 of the pole piece 100 correspond to the high temperature area that is easily generated during charging, and the middle area 40 corresponds to the low temperature area during charging. The thermoelectric material can generate a current flowing from the low temperature area to the high temperature area, offsetting the current flowing from the high temperature area to the low temperature area, reducing the occurrence of lithium deposition problems, and improving the life of the battery. Among them, when the thermoelectric material is distributed at the first end 20, the second end 30 and the middle area 40, the current flowing from the low temperature area to the high temperature area is more obvious, the offset effect of the current flowing from the original high temperature area to the low temperature area is better, and the improvement effect on the lithium deposition problem is better.

[0042] refer to Figure 1 In one embodiment, the first end 20 and the middle area 40 are spaced apart, and the second end 30 and the middle area 40 are spaced apart.

[0043] In one embodiment, taking the center line b of the pole piece 100 in the first direction a as a reference, the thermoelectric material is symmetrical with respect to the center line b.

[0044] The thermoelectric material is symmetrically arranged in the electrode, which can make the thermoelectric material produce a reverse current flowing from the low temperature area to the high temperature area, which has the same offsetting effect on the current discharged from the high temperature area to the low temperature area, and has a better effect on improving the lithium plating problem and increasing the life of the battery.

[0045] In one embodiment, the dimensions of the first end 20 and the second end 30 in the first direction a are independently 1 mm to 10 mm, and the dimension of the middle area 40 in the first direction a is 5 mm to 20 mm.

[0046] The size of the first end 20 in the first direction a may range from 2mm to 9mm, 3mm to 8mm, or 4mm to 7mm. Specifically, the size of the first end 20 in the first direction a may range from 1mm to 2mm, 3mm to 4mm, 7mm to 8mm, 9mm to 10mm without limitation.

[0047] The size of the second end 30 in the first direction a may range from 2mm to 9mm, 3mm to 8mm, or 4mm to 7mm. Specifically, the size of the second end 30 in the first direction a may range from 1mm to 2mm, 3mm to 4mm, 7mm to 8mm, 9mm to 10mm without limitation.

[0048] The size of the middle area 40 in the first direction a ranges from 8mm to 16mm, 10mm to 14mm, and 11mm to 13mm. Specifically, the size of the middle area 40 in the first direction a can be 5mm, 8mm, 10mm, 11mm, 13mm, 14mm, 16mm, and 20mm without limitation.

[0049] The lengths of the first end 20, the second end 30 and the middle area 40 are restricted so that the distribution position of the thermoelectric material corresponds to the high temperature zone and the middle area 40 when the battery is charged. The current generated from the low temperature zone to the high temperature zone can better offset the current flowing from the original high temperature zone to the low temperature zone, which helps to reduce the probability of lithium plating problems and increase the life of the battery.

[0050] In one embodiment, the thermoelectric material includes one or more of NaPb20SbTe22, Bi2Te3, and CsBi4Te6.

[0051] In one embodiment, the thermoelectric material may further include one or more of Sb2Te3 and Bi2Se.

[0052] Thermoelectric materials can generate a reverse current flowing from the low-temperature area to the high-temperature area when a large temperature difference occurs inside the battery, which will partially offset the original current discharging from the high-temperature area to the low-temperature area, reduce the occurrence of lithium plating problems, and increase the life of the battery.

[0053] In one embodiment, the electrode includes an active material layer 10 , the active material layer 10 includes an active material 11 , and the thermoelectric material includes a first thermoelectric material 12 , which is distributed in the entire region or a portion of the active material layer 10 .

[0054] The first thermoelectric material 12 may be uniformly distributed in the entire area of ​​the active material layer 10 , or may be non-uniformly distributed in the entire area of ​​the active material layer 10 .

[0055] The first thermoelectric material 12 may be distributed in a partial area of ​​the active material layer 10, and the partial area may be at least one of the first end 20, the second end 30 and the middle area 40, or may be an area between the first end 20 and the middle area 40, an area between the second end 30 and the middle area 40, and any other possible local area.

[0056] In one embodiment, the first end 20 and the middle region 40 are spaced apart, the second end 30 and the middle region 40 are spaced apart, and the first thermoelectric material 12 is symmetrical relative to the middle line b in the first direction a of the pole piece 100 .

[0057] The first thermoelectric material 12 may be doped with the active material 11 and then coated to form the active material layer 10 having the first thermoelectric material 12 , or may be directly coated on the surface of the active material layer 10 .

[0058] In one embodiment, when the electrode sheet 100 is a negative electrode sheet, the active material 11 includes a negative electrode active material, a conductive agent and a binder, the conductive agent includes one or more of graphite, carbon black, acetylene black, graphene, carbon fiber, C60 (carbon 60) and carbon nanotubes, without limitation; the type of binder includes one or more of polyvinylidene chloride, soluble polytetrafluoroethylene, styrene-butadiene rubber, hydroxypropyl methylcellulose, methyl cellulose, carboxymethyl cellulose, polyvinyl alcohol, acrylonitrile copolymer, sodium alginate, chitosan and chitosan derivatives, without limitation; the negative electrode material may be a carbon-based negative electrode material or a non-carbon-based negative electrode material, the carbon-based negative electrode material includes at least one of a graphite material and a non-graphite material without limitation; wherein the graphite material includes at least one of natural graphite or artificial graphite without limitation; the non-graphite material includes at least one of a hard carbon material or a soft carbon material without limitation; the non-carbon-based negative electrode material may be a titanium-based material, a tin-based material, a silicon-based material, or a nitride without limitation.

[0059] In one embodiment, when the pole piece 100 is a positive pole piece, the active material 11 includes a positive active material, a conductive agent and a binder. The positive active material can be a phosphate positive active material and a ternary positive active material. In a specific embodiment, it includes one or more of lithium cobalt oxide, lithium manganese oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxyphosphate, fluorolithium vanadium phosphate, lithium titanate, lithium nickel cobalt manganese oxide, and lithium nickel cobalt aluminum oxide. This application does not specifically limit these materials, and suitable materials can be selected according to actual application requirements. The types of conductive agents and binders are similar to those of the aforementioned pole piece 100, and the content of the binder in the positive active layer is 2wt%-4wt%.

[0060] refer to Figure 2 and Figure 3 The electrode includes a current collector 50 , and the thermoelectric material includes a second thermoelectric material 52 . The second thermoelectric material 52 is distributed in the entire region or a partial region of the current collector 50 .

[0061] The second thermoelectric material 52 may be uniformly distributed in the entire area of ​​the current collector 50 , or may be non-uniformly distributed in the entire area of ​​the current collector 50 .

[0062] In one embodiment, the current collector 50 includes a substrate 51, the substrate 51 includes a foil and a material layer, the material layer is arranged on the foil, the second thermoelectric material 52 can be doped in the material layer, or can be directly coated on the surface of the foil, and the second thermoelectric material 52 can also be directly coated on the surface of the material layer.

[0063] In one embodiment, the current collector 50 is used to prepare a pole piece 100 , and the current collector 50 includes a first end 20 and a second end 30 opposite to each other in a first direction a, and a middle area 40 located between the first end 20 and the second end 30 , and the first direction a is the length direction of the pole piece 100 .

[0064] The second thermoelectric material 52 may be distributed in a partial area of ​​the current collector 50 , and the partial area may be at least one of the first end 20 , the second end 30 , and the middle area 40 , or may be an area between the first end 20 and the middle area 40 , an area between the second end 30 and the middle area 40 , or any other possible local area.

[0065] In one embodiment, the first end 20 and the middle region 40 are spaced apart, the second end 30 and the middle region 40 are spaced apart, and the second thermoelectric material 52 is symmetrical relative to the middle line b of the first direction a of the pole piece 100 .

[0066] The second thermoelectric material 52 is set at specific positions on the current collector 50, namely the first end 20, the second end 30 and the middle area 40. The first end 20 and the second end 30 correspond to the high temperature area that is easily generated during charging, and the middle area 40 corresponds to the low temperature area during charging. The second thermoelectric material 52 can generate a current flowing from the low temperature area to the high temperature area, offsetting the current flowing from the high temperature area to the low temperature area, reducing the occurrence of lithium plating problems, and improving the life of the battery.

[0067] When the electrode sheet 100 is a negative electrode sheet, the foil includes but is not limited to any one of copper foil, composite copper foil, and carbon-coated copper foil.

[0068] When the electrode sheet 100 is a positive electrode sheet, the foil includes but is not limited to any one of aluminum foil, composite aluminum foil, and carbon-coated aluminum foil.

[0069] The material layer may further include a conductive material. The second thermoelectric material 52 is mixed with the conductive material and then disposed on the foil.

[0070] The current collector 50 includes a second thermoelectric material 52. The second thermoelectric material 52 can generate a reverse current flowing from the low temperature area to the high temperature area when a large temperature difference occurs inside the battery, which will partially offset the original current discharged from the high temperature area to the low temperature area, reduce the occurrence of lithium plating problems, and increase the life of the battery.

[0071] refer to Figure 3 The present invention provides a pole piece 100 , wherein an active material layer 10 is stacked on a current collector 50 .

[0072] In one embodiment, the pole piece 100 includes a first thermoelectric material 12 and a second thermoelectric material 52, and the first thermoelectric material 12 and the second thermoelectric material 52 are located at at least one of the first end 20, the second end 30 and the middle area 40. The positions of the first thermoelectric material 12 and the second thermoelectric material 52 may overlap or may not overlap without limitation.

[0073] In one embodiment, the pole piece 100 includes a first thermoelectric material 12 or a second thermoelectric material 52 , and the first thermoelectric material 12 or the second thermoelectric material 52 is located at at least one of the first end 20 , the second end 30 , and the middle region 40 .

[0074] The electrode 100 includes a first thermoelectric material 12 and / or a second thermoelectric material 52. The thermoelectric material can generate a reverse current flowing from the low-temperature area to the high-temperature area when a large temperature difference occurs inside the battery, which will partially offset the original current discharged from the high-temperature area to the low-temperature area, reduce the occurrence of lithium plating problems, and increase the life of the battery.

[0075] In one embodiment, the electrode includes an active material layer 10, and the mass ratio of the thermoelectric material to the active material layer 10 is 1%-5%.

[0076] The thermoelectric material is all the thermoelectric materials in the electrode 100, which is the sum of the first thermoelectric material 12 and the second thermoelectric material 52. When the active material layer 10 is not doped with the first thermoelectric material 12, the active material layer 10 is an active material layer 10 without the first thermoelectric material 12. When the active material layer 10 is doped with the first thermoelectric material 12, the active material layer 10 is an active material layer 10 with the first thermoelectric material 12. The mass ratio of the thermoelectric material to the active material layer 10 of the electrode can be 1%, 2%, 3%, 4%, 5%, without limitation.

[0077] Thermoelectric materials can generate a reverse current from the low temperature zone to the high temperature zone when a large temperature difference is generated inside the battery, which will partially offset the current discharged from the original high temperature zone to the low temperature zone, reduce the occurrence of lithium plating problems, and improve the life of the battery. When the mass ratio of the thermoelectric material to the active material layer 10 of the electrode is 1%-5%, the reverse current generated by the thermoelectric material can partially or even completely offset the current generated from the original high temperature zone to the low temperature zone; when the mass ratio of the thermoelectric material to the active material layer 10 of the electrode is less than 1%, the reverse current generated by the thermoelectric material has little effect on the current generated from the original high temperature zone to the low temperature zone, and lithium plating will still occur; when the mass ratio of the thermoelectric material to the active material layer 10 of the electrode is greater than 5%, the reverse current generated by the thermoelectric material is too large, which may cause lithium plating problems.

[0078] The present invention provides a battery, comprising a separator and the pole piece 100 in any one of the aforementioned embodiments.

[0079] The separator may be any one of a woven membrane, a nonwoven membrane (nonwoven fabric), a microporous membrane, a composite membrane, a rolled membrane, etc., without limitation.

[0080] The battery also includes a shell, and the diaphragm and the pole piece 100 are accommodated in the shell. The shell is a material with high structural strength, and can be specifically made of metal materials, high-strength plastics, ceramics, etc. Metal materials such as aluminum, aluminum alloys, magnesium alloys, iron and iron alloys. The shell can be an integrated structure, that is, the bottom plate and the side plate are an integrated structure made by an integrated molding process. The integrated molding process can be specifically stamping, casting, etc., without limitation. The shell can also be a split structure, and the side plate and the bottom plate can be connected and fixed by welding, bonding, clamping, screwing, etc.

[0081] The present invention provides an electrical device, comprising a battery in any of the above embodiments. The electrical device may be a mobile device, a car, a laptop computer, etc., without limitation.

[0082] The technical solution of the present invention is described in detail below through specific embodiments. In Examples 1 to 3 and Comparative Example 1, the thermoelectric material is provided only in the negative electrode sheet.

[0083] Example 1

[0084] This embodiment provides a negative electrode sheet, the mass ratio of the thermoelectric material to the active material layer of the electrode is 1%, and the thermoelectric material is distributed at the first end, the second end and the middle area of ​​the negative electrode sheet.

[0085] Example 2

[0086] This embodiment provides a negative electrode sheet, the mass ratio of the thermoelectric material to the active material layer of the electrode is 3%, and the thermoelectric material is distributed at the first end, the second end and the middle area of ​​the negative electrode sheet.

[0087] Example 3

[0088] This embodiment provides a negative electrode sheet, in which the mass ratio of the thermoelectric material to the active material layer of the electrode is 3%, and the thermoelectric material is evenly distributed in the negative electrode sheet.

[0089] Comparative Example 1

[0090] This embodiment provides a negative electrode sheet, which does not include thermoelectric material.

[0091] The capacity retention rates of the batteries provided in Examples 1 to 3 and Comparative Example 1 after cycling are shown in Table 1 below, and the thermoelectric material is the first thermoelectric material and / or the second thermoelectric material.

[0092] Table 1

[0093]

[0094] Referring to Table 1, comparing Examples 1 to 3 with Comparative Example 1, when the thermoelectric material is doped into the negative electrode of the battery, the capacity retention rates of the batteries of Examples 1 to 3 after 500 cycles, 1000 cycles and 1500 cycles are all greater than the capacity retention rate of the battery of Comparative Example 1, indicating that adding thermoelectric materials to the battery electrode can improve the lithium plating problem caused by the current generated from the high temperature zone to the low temperature zone of the battery during the charging process, thereby increasing the life of the battery.

[0095] Comparing Example 1 and Example 2, when the mass ratio of the thermoelectric material to the active material layer of the electrode increases from 1% to 3%, the capacity retention rate of the battery in Example 1 after 500 cycles, 1000 cycles and 1500 cycles is lower than that of the battery in Example 2, indicating that when the mass ratio of the thermoelectric material to the active material layer of the electrode is between 1% and 5%, as the mass ratio of the thermoelectric material increases, the reverse current generated by the thermoelectric material will offset the current generated from the original high temperature zone to the low temperature zone, thereby further reducing the risk of lithium plating and improving the life of the battery.

[0096] Comparing Example 2 and Example 3, when the mass ratio of the thermoelectric material to the active material layer of the electrode is the same, the thermoelectric material in Example 2 is located at the first end, the second end and the middle area of ​​the negative electrode sheet, and the thermoelectric material in Example 3 is uniformly distributed in the electrode. The capacity retention rate of the battery in Example 2 after 500 cycles, 1000 cycles and 1500 cycles is greater than the capacity retention rate of the battery in Example 3, indicating that the distribution of the thermoelectric material in a specific position has a better effect on the capacity retention of the battery. This is because when the content of the thermoelectric material is the same, doping the first end, the second end and the middle area of ​​the negative electrode sheet with the thermoelectric material can produce a more obvious current flowing from the low temperature zone to the high temperature zone, and has a better offset effect on the current flowing from the high temperature zone to the low temperature zone, thereby reducing the probability of lithium plating problems and increasing the life of the battery.

[0097] In summary, when the battery is charging, it will generate a current flowing from the high-temperature area to the low-temperature area. After the thermoelectric material is doped in the battery's electrode, it can generate a reverse current flowing from the low-temperature area to the high-temperature area, which can partially offset the original current from the high-temperature area to the low-temperature area, reduce the occurrence of lithium plating problems, and increase the life of the battery.

[0098] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship of terms such as "center", "up", "down", "left", "right", "vertical", "horizontal", "inside" and "outside" are based on the orientation or positional relationship described in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0099] What is disclosed above is only a preferred embodiment of the present invention, and it certainly cannot be used to limit the scope of rights of the present invention. Ordinary technicians in this field can understand that all or part of the processes of the above embodiment and equivalent changes made according to the claims of the present invention still fall within the scope covered by the present invention.

Claims

1. A pole piece, characterized in that: The invention comprises an electrode and a thermoelectric material, wherein the thermoelectric material is distributed in the whole area or a part of the area of ​​the electrode.

2. The pole piece according to claim 1, characterized in that: The pole piece includes a first end and a second end opposite to each other in a first direction, and a middle area between the first end and the second end. The first direction is the length direction of the pole piece. The thermoelectric material is located at least one of the first end, the second end and the middle area.

3. The pole piece according to claim 2, characterized in that: The first end and the middle area are spaced apart, and the second end and the middle area are spaced apart.

4. The pole piece according to claim 3, characterized in that: Taking the center line of the pole piece in the first direction as a reference, the thermoelectric material is symmetrical relative to the center line.

5. The pole piece according to claim 2, characterized in that: The dimensions of the first end and the second end in the first direction are independently 1 mm to 10 mm, and the dimension of the middle area in the first direction is 5 mm to 20 mm.

6. The pole piece according to claim 1, characterized in that: The thermoelectric material includes one or more of NaPb20SbTe22, Bi2Te3, and CsBi4Te6.

7. The pole piece according to claim 1, characterized in that: The electrode includes an active material layer, and the thermoelectric material includes a first thermoelectric material distributed in the entire region or a partial region of the active material layer.

8. The pole piece according to claim 1, characterized in that: The electrode includes a current collector, and the thermoelectric material includes a second thermoelectric material, which is distributed in the entire region or a partial region of the current collector.

9. The pole piece according to any one of claims 1 to 8, characterized in that: The electrode comprises an active material layer, and the mass ratio of the thermoelectric material to the active material layer is 1%-5%.

10. A battery, characterized in that: A pole piece comprising any one of claims 1 to 9.

11. An electrical device, characterized in that: Comprising the battery as claimed in claim 10.

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