CN113782870A

CN113782870A - Electrochemical device and electric equipment

Info

Publication number: CN113782870A
Application number: CN202110956560.4A
Authority: CN
Inventors: 曹维毅; 丁宇; 严坤
Original assignee: Ningde Amperex Technology Ltd
Current assignee: Ningde Amperex Technology Ltd
Priority date: 2021-08-19
Filing date: 2021-08-19
Publication date: 2021-12-10
Anticipated expiration: 2041-08-19
Also published as: CN113782870B

Abstract

The present invention relates to an electrochemical device and an electric device, the electrochemical device including an electrode assembly, a heating assembly, and a housing, the electrode assembly including a first pole piece, the heating assembly including a heating portion and a first conductive member, the heating portion being located in the housing, the first conductive member including a first portion and a second portion, the first portion including a first connection region connected to the heating portion, the second portion protruding out of the housing, satisfying at least one of the following conditions (1) to (2): (1) the first portion further comprises a second connection region connected to the first pole piece; (2) the heating portion includes a third connection region connected to the first pole piece. Compared with the prior art in which the pole piece and the heating part are respectively connected with the conductive piece and are connected outside the shell, the use of the inactive conductive piece is reduced, the energy density of the electrochemical device is improved, the risk of connection falling is reduced, and the use reliability of the electrochemical device is improved. In addition, when the electric energy stored in the electrochemical device is used for heating, the energy loss of the conductive piece outside the shell can be effectively reduced.

Description

Electrochemical device and electric equipment

Technical Field

The application relates to the technical field of energy storage. And more particularly to an electrochemical device and an electric apparatus.

Background

It is well known that the use of lithium ion batteries is greatly affected by temperature. Generally, the charging capacity of the battery is reduced in a low-temperature environment, and the capacity cannot be fully exerted, particularly in cold winter, the phenomenon that the capacity of the battery active material is exerted and lost is more prominent, and the voltage platform is reduced, so that the energy density of the battery is lost; meanwhile, in a low-temperature environment, the electronic conductivity and the ionic conductivity of the lithium ion battery are reduced, and the dynamics is sharply reduced, so that lithium precipitation occurs in the high-rate charging process of the lithium ion battery, the battery interface is deteriorated, and serious potential safety hazards exist. There is a great interest in improving the low-temperature performance of lithium ion batteries by providing a heating sheet inside the battery for heating to improve the system dynamics. In order to connect the heating plate with the circuit, the heating plate is usually connected by a conductive member, and the portion of the conductive member extending out of the housing is connected with the circuit.

Disclosure of Invention

In view of the above, the present application provides an electrochemical device and an electric device to at least partially solve the problems of energy density loss and low reliability caused by the above connection method.

According to an aspect of the present application, there is provided an electrochemical device including an electrode assembly including a first pole piece, a heating assembly including a heating portion and a first conductive member, the heating portion being located within a case, the first conductive member including a first portion including a first connection region connected to the heating portion and a second portion protruding out of the case, satisfying at least one of the following conditions (1) to (2): (1) the first portion further comprises a second connection region connected to the first pole piece; (2) the heating portion includes a third connection region connected to the first pole piece. Compared with the traditional mode that the heating part and the pole pieces are respectively connected with the conductive pieces and connected outside the shell, on one hand, the use of inactive conductive pieces is reduced, and the energy density of the electrochemical device is improved; on the other hand, the risk of connection and shedding is reduced, and the use reliability of the electrochemical device is improved. Meanwhile, when the electric energy stored in the electrochemical device is used for heating, the energy loss of the conductive part outside the shell can be effectively reduced, and the utilization efficiency of the energy is improved.

In an alternative form, the first portion is located within the housing.

In an alternative mode, the first part is formed by integrally extending the second part, so that the structural strength of the first conductive member is ensured.

In an alternative form, the second portion is for connection to a first terminal of an external circuit.

In an alternative mode, the heating portion includes a fourth connection area connected to the first connection area, the first pole piece includes a fifth connection area connected to the second connection area, and the fourth connection area and the fifth connection area are located on the same side of the first conductive member. The heating part is positioned between the first conductive part and the first pole piece, so that heat generated by the heating part can be quickly transferred to the first pole piece, the heating rate of the electrode assembly is increased, and the low-temperature performance of the electrochemical device is improved.

In an alternative mode, the first pole piece further includes a sixth connection region connected to the third connection region, and the fourth connection region and the sixth connection region are located on the same side of the first conductive member.

In an alternative, at least one of the following conditions is satisfied: (a) the area S1 of the first connection region is 12-36 mm²(ii) a (b) The area S2 of the second attachment area is in the range of 12 to 36mm²(ii) a (c) The area S3 of the third linking area is in the range of 12 to 36mm²。

In an alternative, at least one of the following conditions is satisfied: (d) the first connection region includes at least one first connection point,the area of the single first connecting point is 0.6-2 mm²(ii) a (e) The second connecting area comprises at least one second connecting point, and the area of the second connecting point is 0.6-2 mm²(ii) a (f) The third connecting area comprises at least one third connecting point, and the area of the third connecting point is 0.6-2 mm²。

The areas and the number of the first connection region, the second connection region, the third connection region, the first connection point, the second connection point, and the third connection point may be reasonably selected according to the overcurrent capacity of the electrochemical device.

In an alternative manner, when only the condition (1) is satisfied, the following is satisfied: S1/S2 ranges from 1:1 to 1:3 or S2/S1 ranges from 1:1 to 1: 3; when only the condition (2) is satisfied, the following are satisfied: S1/S3 ranges from 1:1 to 1:3 or S3/S1 ranges from 1:1 to 1: 3; when the conditions (1) and (2) are satisfied at the same time, the following are satisfied: S1/(S2+ S3) ranges from 1:1 to 1:3 or (S2+ S3)/S1 ranges from 1:1 to 1: 3. By reasonably limiting the range of S1/S2 or S2/S1, S1/S3 or S3/S1, S1/(S2+ S3) or (S2+ S3)/S1, the area difference between the connecting areas is reduced, and the risk of connection falling off caused by stress concentration in the falling process is reduced.

In an alternative mode, the area S4 of the fourth connecting region is in the range of 12 to 36mm²。

In an alternative mode, the area S5 of the fifth linking area ranges from 12mm to 36mm²。

In an alternative mode, the area S6 of the sixth connecting region is in the range of 12 to 36mm²。

In an alternative mode, the fourth connecting area comprises at least one fourth connecting point, and the area of a single fourth connecting point is 0.6-2 mm². The number of the fourth connection points may be set according to an overcurrent capacity of the fourth connection region.

In an alternative mode, the fifth connecting area comprises at least one fifth connecting point, and the area of the single fifth connecting point is 0.6-2 mm². The number of the fifth connection points may be set according to an overcurrent capacity of the fifth connection region.

In an alternative form, the sixth connectionThe area comprises at least one sixth connecting point, and the area of a single sixth connecting point is 0.6-2 mm². The number of the sixth connection points may be set according to the overcurrent capacity of the sixth connection region.

In an alternative, when only the first connection region and the heating portion are connected and the fifth connection region and the second connection region are connected, S1/S5 ranges from 1:1 to 1:3 or S5/S1 ranges from 1:1 to 1: 3.

In an alternative manner, when only the first connection region and the heating portion are connected and the sixth connection region and the third connection region 221 are connected, the range of S1/S6 is 1:1 to 1:3 or the range of S6/S1 is 1:1 to 1: 3.

In an alternative manner, when the first connection region is connected to the heating portion, the fifth connection region is connected to the second connection region, and the sixth connection region is connected to the third connection region, S1/(S5+ S6) ranges from 1:1 to 1:3 or (S5+ S6)/S1 ranges from 1:1 to 1: 3.

In an alternative mode, the length d1 of the first connection region along the length direction of the first conductive member ranges from 1 mm to 20mm, wherein the length direction of the first conductive member is from the first portion to the second portion.

In an alternative mode, the length d2 of the second connection region along the length direction of the first conductive member is in a range of 1-20 mm.

In an alternative mode, the length d3 of the third connection region along the length direction of the first conductive member is in a range of 1-20 mm.

In an alternative mode, the length d4 of the fourth connection region along the length direction of the first conductive member is in a range of 1-20 mm.

In an alternative mode, the length d5 of the fifth connecting region along the length direction of the first conductive member is in a range of 1-20 mm.

In an alternative mode, the length d6 of the sixth connection region along the length direction of the first conductive member is in a range of 1-20 mm.

In an alternative, the area of the first connection region is equal to the area of the fourth connection region.

In an alternative, the area of the second attachment zone is equal to the area of the fifth attachment zone.

In an alternative, the area of the third attachment zone is equal to the area of the sixth attachment zone.

In an alternative mode, the first part of the first conductive member is provided with a second connecting region, the heating portion is simultaneously provided with a third connecting region, and the first pole piece is simultaneously provided with a fifth connecting region and a sixth connecting region, wherein the fifth connecting region is connected with the sixth connecting region.

In an alternative mode, the heating part includes a heating element and an insulating layer on a surface of the heating element. The heating element is used to generate heat to heat the electrode assembly. The insulating layer is used for insulating the local part of the heating element from the first pole piece and the first conductive piece, so that on one hand, the interference of the heating element on an electrochemical device system in the charging and discharging process can be reduced, and on the other hand, the risks of reduction of heating rate and deterioration of uniformity caused by direct contact of the local part of the heating element and the first pole piece can be reduced.

In an alternative, at least one of the following conditions is satisfied: (g) the heating element comprises at least one of a metallic material or a carbon material; (h) the insulating layer includes at least one of a polymer or an inorganic insulating material.

In an alternative, at least one of the following conditions is satisfied: (i) the metal material comprises at least one of nickel, titanium, copper, silver, gold, platinum, iron, cobalt, chromium, tungsten, molybdenum, aluminum, magnesium, potassium, sodium, calcium, strontium, barium, silicon, germanium, tin, lead, indium, zinc or stainless steel; (j) the carbon material comprises at least one of a carbon felt, a carbon film, carbon black, acetylene black, fullerene, a conductive graphite film, or a graphene film; (k) the polymer includes polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyetheretherketone, polyimide, polyamide, polyethylene glycol, polyamideimide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, polytetrafluoroethylene, polymethylene naphthalene, polyvinylidene fluoride, polyethylene naphthalate, polypropylene carbonate, poly (vinylidene fluoride-hexafluoropropylene), poly (vinylidene fluoride-co-chlorotrifluoroethylene), silicone, vinylon, polypropylene, anhydride-modified polypropylene, polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate, ethylene-acrylic acid copolymer, ethylene-vinyl alcohol copolymer, polyvinyl chloride, polystyrene, polyethernitrile, polyurethane, polyphenylene oxide, polyester, polyethylene terephthalate, polyethylene naphthalate, polyetheretherketone, poly (ethylene carbonate), poly (vinylidene fluoride-co-hexafluoropropylene), poly (vinylidene fluoride-co-chlorotrifluoroethylene), poly (vinylon-co-vinylon), poly (ethylene-vinyl acetate), ethylene-ethyl acrylate), ethylene-acrylic acid copolymer, ethylene-vinyl alcohol copolymer, polyvinyl chloride, polystyrene, polyethernitrile, polyurethane, polyphenylene oxide, polyester, poly (butylene terephthalate), poly (ethylene naphthalate), poly (ethylene carbonate), poly (ethylene), poly (butylene terephthalate), poly (ethylene), poly (butylene terephthalate), poly (ethylene, poly (butylene terephthalate), poly (ethylene), poly, At least one of polysulfone, amorphous alpha-olefin copolymer and derivatives thereof; (l) The inorganic insulating material comprises at least one of hafnium oxide, strontium titanate, tin oxide, cerium oxide, magnesium oxide, nickel oxide, calcium oxide, barium oxide, zinc oxide, zirconium dioxide, yttrium oxide, aluminum oxide, titanium dioxide, silicon dioxide, boehmite, magnesium hydroxide or aluminum hydroxide.

In an alternative, at least one of the following conditions is satisfied: (m) the electrochemical device further includes a separator and a second pole piece, the first pole piece, the separator and the second pole piece being wound to form a wound structure, the heating part being disposed at a central portion of the wound structure; (n) the heating assembly further includes a second conductive member connected to the heating part. The heating part is disposed at the center of the winding structure, so that the electrode assembly is heated more uniformly, and the temperature difference between the parts of the electrochemical device during heating can be further reduced.

According to an aspect of the embodiments of the present application, there is provided an electric device including the electrochemical device described above.

In an optional mode, the electric device further comprises a switch, a temperature sensor and a controller; the heating part is connected with the switch; the controller is respectively connected with the switch and the temperature sensor; the controller is used for controlling the switch to be closed when the temperature sensor detects that the temperature of the electrochemical device is smaller than a preset threshold value.

In an alternative, the preset threshold is 5 ℃.

The beneficial effect of this application is: the first part of the first conductive piece is electrically connected with the heating part and the first pole piece in the shell, and compared with the traditional mode that the heating part and the pole piece are respectively connected with the conductive piece and are connected outside the shell, on one hand, the use of inactive conductive pieces is reduced, and the energy density of the electrochemical device is improved; on the other hand, the risk of connection and shedding is reduced, and the use reliability of the electrochemical device is improved. Meanwhile, when the electric energy stored in the electrochemical device is used for heating, the energy loss of the conductive part outside the shell can be effectively reduced, and the utilization efficiency of the energy is improved.

Drawings

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.

FIG. 1 is a schematic view of an electrochemical device provided in an embodiment of the present application;

FIG. 2 is a cross-sectional view taken along line B-B of FIG. 1 according to an embodiment of the present application;

FIG. 3-1 is a cross-sectional view taken along line A-A of FIG. 1 according to an embodiment of the present application;

FIG. 3-2 is another cross-sectional view taken along line A-A of FIG. 1 according to an embodiment of the present application;

3-3 are further cross-sectional views taken along line A-A of FIG. 1 provided by embodiments of the present application;

FIGS. 3-4 are further cross-sectional views taken along line A-A of FIG. 1, as provided by embodiments of the present application;

FIG. 4-1 is an enlarged view of section D1 of FIG. 3-1 as provided by an embodiment of the present application;

FIG. 4-2 is an enlarged view of section D2 of FIG. 3-2 provided by an embodiment of the present application;

4-3 are enlarged views of section D3 of FIGS. 3-3 provided by embodiments of the present application;

4-4 are enlarged views of section D4 of FIGS. 3-4 provided by embodiments of the present application;

FIG. 5 is a cross-sectional view taken along line C-C of FIG. 1 according to an embodiment of the present application;

FIG. 6 is a surface temperature profile of an electrochemical device of example 3 provided in an example of the present application;

FIG. 7 is a circuit diagram of one implementation of a powered device provided by an embodiment of the present application;

fig. 8 is a block diagram of an electric device corresponding to fig. 7 provided in an embodiment of the present application;

fig. 9 is a circuit diagram of another implementation manner of an electric device provided by an embodiment of the present application;

fig. 10 is a block diagram of an electric device corresponding to fig. 9 according to an embodiment of the present application.

Detailed Description

In order to facilitate an understanding of the present application, the present application is described in more detail below with reference to the accompanying drawings and specific embodiments. It will be understood that when an element is referred to as being "secured to" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. The terms "vertical," "horizontal," "left," "right," "inner," "outer," and the like as used herein are for descriptive purposes only.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

Referring to fig. 1, 2 and 3-1, or 3-2, or 3-3, or 3-4, an electrochemical device 100 includes a case 1, a heating assembly 2, and an electrode assembly 3. The electrode assembly 3 is housed in the case 1, and part of the heating assembly 2 is housed in the case 1. The electrode assembly 3 is connected to the heating assembly 2, and the heating assembly 2 is used for heating the electrode assembly 3.

Referring to fig. 2 and 3-1, or fig. 3-2, or fig. 3-3, or fig. 3-4, for the case 1, the case 1 includes a receiving portion 11 and a sealing portion 12, the receiving portion 11 is used for receiving the electrode assembly 3 and a portion of the heating assembly 2, and a portion of the heating assembly 2 extends out of the case 1 from the sealing portion 12.

Referring to fig. 2 and 3-1, or fig. 3-2, or fig. 3-3, or fig. 3-4 for the heating assembly 2, the heating assembly 2 includes a first conductive member 21, a heating portion 22, and a second conductive member 23, the first conductive member 21 is connected to the heating portion 22, the second conductive member 23 is connected to the heating portion 22, and the first conductive member 21 and the second conductive member 23 are used for conducting the heating portion 22 to supply power to the heating portion 22. The heating part 22 is accommodated in the case 1, and the heating part 22 is used to heat the electrode assembly 3 to improve the low temperature performance of the electrode assembly 3.

Referring to fig. 2, the first conductive member 21 includes a first portion 211 and a second portion 212, the first portion 211 is connected to the heating portion 22, and the second portion 212 extends from the sealing portion 12 to the housing 1.

In some embodiments, referring to FIG. 3-1 and FIG. 4-1 for the first portion 211, the first portion 211 includes a first connection region 2111 and a second connection region 2112, the first connection region 2111 for connecting to the heating portion 22. The second connection region 2112 is for connection with the electrode assembly 3.

In some embodiments, the area S1 of the first connection region 2111 ranges from 12mm to 36mm²。

In some embodiments, the area S2 of the second attachment region 2112 ranges from 12 to 36mm²。

In some embodiments, the first connection region 2111 includes at least one first connection point (not shown), and the area of the single first connection point is 0.6-2 mm². The number of first connection points can be set according to the overcurrent capability of the first connection region 2111.

In some embodiments, the second connection region 2112 includes at least one second connection point (not shown), and the area of a single second connection point is 0.6-2 mm². The number of second connection points may be set according to the overcurrent capacity of the second connection region 2112.

In some embodiments, when it is satisfied that only the first connection region 2111 is connected to the heating portion 22 and the second connection region 2112 is connected to the electrode assembly 3, S1/S2 ranges from 1:1 to 1:3 or S2/S1 ranges from 1:1 to 1: 3. By properly defining the range of S1/S2 or S2/S1, the difference in area between the first attachment region 2111 and the second attachment region 2112 is reduced, reducing the risk of attachment detachment due to stress concentrations during a drop.

In some embodiments, the length d1 of the first connection region 2111 along the length direction L2 of the first conductive element 21 is in a range of 1 mm to 20mm, wherein the length direction L2 of the first conductive element 21 is from the first portion 211 to the second portion 212.

In some embodiments, the length d2 of the second connection region 2112 along the length direction L2 of the first conductive member 21 is in the range of 1-20 mm.

Referring to fig. 2, the second portion 212 can be used for connecting with an external circuit.

In some embodiments, referring to fig. 3-2 and 4-2 for the first portion 211, the first portion 211 includes a first connection region 2111, and the first connection region 2111 is used for connecting with the heating portion 22. As for the heating portion 22 described above, the heating portion 22 includes a third connection region 221 and a fourth connection region 222, the third connection region 221 is used for connection with the electrode assembly 3, and the fourth connection region 222 is connected with the first connection region 2111.

In some embodiments, the area S3 of the third connection region 221 ranges from 12mm to 36mm²。

In some embodiments, the area S4 of the fourth attachment area 222 ranges from 12mm to 36mm²。

In some embodiments, the third connection region 221 includes at least one third connection point (not shown), and the area of the single third connection point is 0.6-2 mm². The number of the third connection points may be set according to the overcurrent capacity of the third connection region 221.

In some embodiments, the fourth connecting region 222 includes at least one fourth connecting point (not shown), and the area of the single fourth connecting point is 0.6-2 mm². The number of the fourth connection points may be set according to the overcurrent capacity of the fourth connection region 222.

In some embodiments, when it is satisfied that only the first connection region 2111 is connected to the heating portion 22 and the third connection region 221 is connected to the electrode assembly 3, S1/S3 ranges from 1:1 to 1:3 or S3/S1 ranges from 1:1 to 1: 3. By properly defining the range of S1/S3 or S3/S1, the difference in area between the first connection region 2111 and the third connection region 221 is reduced, reducing the risk of connection drop-out during a drop due to stress concentration.

In some embodiments, referring to fig. 3-3 and 4-3 for the first portion 211, the first portion 211 includes a first connection region 2111 and a second connection region 2112, the first connection region 2111 being for connection to the heating portion 22. The second connection region 2112 is for connection with the electrode assembly 3. As for the heating portion 22 described above, the heating portion 22 includes a third connection region 221 and a fourth connection region 222, the third connection region 221 is used for connection with the electrode assembly 3, and the fourth connection region 222 is connected with the first connection region 2111. By connecting the first portion 211, the heating portion 22, and the electrode assembly 3 two by two, even if any of the connections between them is broken off, the conduction of the circuit can be maintained, thereby further improving the reliability of the connection.

In some embodiments, when the first connection region 2111 is connected to the heating portion 22, the second connection region 2112 is connected to the electrode assembly 3, and the third connection region 221 is connected to the electrode assembly 3, S1/(S2+ S3) ranges from 1:1 to 1:3 or (S2+ S3)/S1 ranges from 1:1 to 1: 3.

In some embodiments, the length d3 of the third connection region 221 along the length direction L2 of the first conductive member 21 ranges from 1 mm to 20 mm.

In some embodiments, the length d4 of the fourth connection region 222 along the length direction L2 of the first conductive member 21 is in the range of 1-20 mm.

It is noted that, in some embodiments, the area of the fourth connection region 222 is equal to the area of the first connection region 2111.

It is noted that referring to fig. 3-4 and 4-4, in some embodiments, the first conductive member 21 overlaps the heating portion 22. When the first portion 211 of the first conductive member 21 is provided with the second connection region 2112 and the heating portion 22 is provided with the third connection region 221, the projection of the second connection region 2112 on the electrode assembly 3 and the projection of the third connection region 221 on the electrode assembly 3 are connected in the thickness direction L3 of the electrode assembly 3. Wherein the thickness direction L3 of the electrode assembly 3 is from the first conductive member 21 to the heating part 22.

In some embodiments, referring to fig. 4-1, or fig. 4-2, or fig. 4-3, or fig. 4-4, the heating part 22 includes a heating element 221s and an insulating layer 222s on a surface of the heating element 221 s. The third connection region 221 of the heating part 22 is located at the heating element 221s, and the fourth connection region 222 of the heating part 22 is located at the heating element 221 s.

The third connection region 221 of the heating part 22 is connected to the electrode assembly 3, and in some embodiments, is connected by welding when the heating part 22 is connected to the electrode assembly 3.

The fourth connection region 222 of the heating portion 22 is connected to the first connection region 2111 of the first conductive member 21, and in some embodiments, is connected by welding when the heating portion 22 is connected to the first conductive member 21.

In some embodiments, electrochemical device 100 satisfies: the heating element 221s includes at least one of a metallic material or a carbon material, and/or the insulating layer 222s includes at least one of a polymer or an inorganic insulating material.

In some embodiments, electrochemical device 100 satisfies: (i) the metal material comprises at least one of nickel, titanium, copper, silver, gold, platinum, iron, cobalt, chromium, tungsten, molybdenum, aluminum, magnesium, potassium, sodium, calcium, strontium, barium, silicon, germanium, tin, lead, indium, zinc or stainless steel; (j) the carbon material comprises at least one of a carbon felt, a carbon film, carbon black, acetylene black, fullerene, a conductive graphite film, or a graphene film; (k) the polymer includes polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyetheretherketone, polyimide, polyamide, polyethylene glycol, polyamideimide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, polytetrafluoroethylene, polymethylene naphthalene, polyvinylidene fluoride, polyethylene naphthalate, polypropylene carbonate, poly (vinylidene fluoride-hexafluoropropylene), poly (vinylidene fluoride-co-chlorotrifluoroethylene), silicone, vinylon, polypropylene, anhydride-modified polypropylene, polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate, ethylene-acrylic acid copolymer, ethylene-vinyl alcohol copolymer, polyvinyl chloride, polystyrene, polyethernitrile, polyurethane, polyphenylene oxide, polyester, polyethylene terephthalate, polyethylene naphthalate, polyetheretherketone, polyimide, polyamide-imide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, polytetrafluoroethylene, polymethylene naphthalene, polyvinylidene fluoride, polyethylene naphthalate, polypropylene carbonate, polyethylene carbonate, At least one of polysulfone, amorphous alpha-olefin copolymer and derivatives thereof; (l) The inorganic insulating material includes at least one of hafnium oxide, strontium titanate, tin oxide, cerium oxide, magnesium oxide, nickel oxide, calcium oxide, barium oxide, zinc oxide, zirconium dioxide, yttrium oxide, aluminum oxide, titanium dioxide, silicon dioxide, boehmite, magnesium hydroxide, or aluminum hydroxide.

Referring to fig. 2, one end of the second conductive member 23 is connected to the heating portion 22, the other end of the second conductive member 23 extends out of the housing 1, and a portion of the second conductive member 23 extending out of the housing 1 is used for connecting to an external circuit. Wherein the second terminal of the external circuit is of opposite polarity to the first terminal. The second conductive member 23 may have the same structure as the first conductive member 21, and for the structure and function of each part of the second conductive member 23, reference may be made to the first conductive member 21, which is not described herein again.

Referring to fig. 3-1, or fig. 3-2, or fig. 3-3, or fig. 3-4 for the electrode assembly 3 described above, the electrode assembly 3 includes a first pole piece 31, a separator 32, and a second pole piece 33 stacked in this order. The thickness direction L3 of the electrode assembly 3 is from the second pole piece 33 to the first pole piece 31, or the thickness direction L3 of the electrode assembly 3 is from the first pole piece 31 to the second pole piece 33.

Wherein, the polarities of the first pole piece 31 and the second pole piece 33 are opposite. In some embodiments, the first pole piece 31 is a negative electrode and the second pole piece 33 is a positive electrode, or the first pole piece 31 is a positive electrode and the second pole piece 33 is a negative electrode.

The electrode assembly 3 includes a lamination stack in which a first pole piece 31, a separator 32, and a second pole piece 33 are sequentially stacked to form the lamination stack.

The electrode assembly 3 includes a winding structure, and referring to fig. 5, the first pole piece 31, the separator 32, and the second pole piece 33 are wound in a winding direction L1 to form the winding structure.

In some embodiments, along the winding direction L1, the winding start end 311s of the first electrode sheet 31 is located at the central portion 3a of the winding structure, the winding start end 311s of the first electrode sheet 31 includes the first current collector 3111, and the first current collector 3111 includes a copper foil or an aluminum foil, that is, the winding start end 311s of the first electrode sheet 31 is not provided with an active material layer, and the first electrode sheet 31 without an active material layer is also referred to as an empty foil area. The winding start end 311s of the first pole piece 31 is used for providing the heating portion 22 of the heating unit 2. The winding start end 311s of the first pole piece 31 is located at the central portion 3a of the winding structure, and the heating portion 22 of the heating assembly 2 is disposed at the central portion 3a of the winding structure, so that the heating portion 22 of the heating assembly 2 heats the electrode assembly 3 uniformly.

Referring to fig. 2 and fig. 3-1, or fig. 3-2, or fig. 3-3, or fig. 3-4, for the first pole piece 31 and the second pole piece 33, both the first pole piece 31 and the second pole piece 33 can be used to connect with the heating assembly 2, wherein the first pole piece 31 is connected with the first conductive member 21 in the heating assembly 2. The electrochemical device 100 further comprises a third conductive member 8, one end of the third conductive member 8 is connected to the second pole piece 33, the other end of the third conductive member 8 is available for connection to an external circuit, and the other end of the third conductive member 8 is also available for connection to the second conductive member 23.

Now, the connection between the first pole piece 31 and the first portion 211 will be described by taking the first pole piece 31 as an example. Referring to fig. 4-1, the first pole piece 31 includes a fifth connection region 311, and the fifth connection region 311 is connected to the second connection region 2112 of the first conductive member 21.

It is understood that referring to fig. 4-2, first pole piece 31 includes a sixth joint area 312, and sixth joint area 312 is connected to third joint area 221 of heating section 22.

Referring to fig. 4-3, the first pole piece 31 includes a fifth connection region 311 and a sixth connection region 312, the fifth connection region 311 is connected to the second connection region 2112 of the first conductive member 21, and the sixth connection region 312 is connected to the third connection region 221 of the heating portion 22.

It should be noted that, referring to fig. 4-4, in some embodiments, the first portion 211 of the first conductive member 21 is provided with the second connection region 2112, the heating portion 22 is provided with the third connection region 221, and when the first pole piece 31 is provided with the fifth connection region 311 and the sixth connection region 312, the fifth connection region 311 is connected to the sixth connection region 312.

It is worth noting that in some embodiments, the area of the fifth connection region 311 is equal to the area of the second connection region 2112.

It is noted that, in some embodiments, the area of the sixth connection region 312 is equal to the area of the third connection region 221.

It should be noted that, referring to fig. 4-1, or fig. 4-3, or fig. 4-4, in some embodiments, the fifth connection region 311 and the fourth connection region 222 are located on the same side of the first conductive member 21 along the thickness direction L3 of the electrode assembly 3.

It should be noted that, referring to fig. 4-2, or fig. 4-3, or fig. 4-4, in some embodiments, the sixth connection region 312 and the fourth connection region 222 are located on the same side of the first conductive member 21 along the thickness direction L3 of the electrode assembly 3.

In some embodiments, the area S5 of the fifth connecting region 311 is in the range of 12 to 36mm²。

In some embodiments, the area S6 of the sixth attachment area 312 ranges from 12mm to 36mm²。

In some embodiments, the fifth connecting region 311 includes at least one fifth connecting point (not shown), and the area of the single fifth connecting point is 0.6-2 mm². The number of the fifth connection points may be set according to the overcurrent capacity of the fifth connection region 311.

In some embodiments, the sixth connecting region 312 includes at least one sixth connecting point (not shown), and the area of the single sixth connecting point is 0.6-2 mm². The number of the sixth connection points may be set according to the overcurrent capacity of the sixth connection region 312.

In some embodiments, the length d5 of the fifth connection region 311 along the length direction L2 of the first conductive member 21 is in the range of 1-20 mm.

In some embodiments, the length d6 of the sixth connection region 312 along the length direction L2 of the first conductive member 21 is in a range of 1-20 mm.

In some embodiments, when it is sufficient that only first attachment region 2111 is attached to heating portion 22 and fifth attachment region 311 is attached to second attachment region 2112, S1/S5 ranges from 1:1 to 1:3 or S5/S1 ranges from 1:1 to 1: 3.

In some embodiments, when it is sufficient that only first attachment region 2111 is attached to heating portion 22 and sixth attachment region 312 is attached to third attachment region 221, S1/S6 ranges from 1:1 to 1:3 or S6/S1 ranges from 1:1 to 1: 3.

In some embodiments, when it is satisfied that the first connection region 2111 is connected to the heating portion 22, the fifth connection region 311 is connected to the second connection region 2112, and the sixth connection region 312 is connected to the third connection region 221 at the same time, S1/(S5+ S6) ranges from 1:1 to 1:3 or (S5+ S6)/S1 ranges from 1:1 to 1: 3.

To facilitate an understanding of the inventive concepts of the present application, specific electrochemical devices are listed below for reference. The examples and comparative examples were subjected to performance tests, and the relevant parameters of the examples and comparative examples and the results of the performance tests are shown in table 1 below.

The same structure as that of examples 1 to 9 and comparative example 1 includes an electrode assembly, a heating assembly, and a case, the electrode assembly includes a first pole piece, the first pole piece is a negative pole piece, a current collector of the negative pole piece is a copper foil, and the heating assembly includes a heating portion and a first conductive member. An electrode assembly is located within the housing. Wherein, the heating element in the heating part is made of pure nickel.

Examples 1 to 9 and comparative example 1 have the same structure including a heating part in a housing. Examples 1 to 5, examples 6 to 9 and comparative example 1 differ in that: the first conductive member of examples 1 to 5 was connected as shown in fig. 4 to 1, and the first connection region of the first conductive member was connected to the heating element by soldering, and the second connection region was connected to the copper foil by soldering; the first conductive member in the embodiment 6-9 is connected as shown in fig. 4-2, the first connection region of the first conductive member is connected to the heating element by soldering, and the third connection region of the heating portion is connected to the copper foil by soldering; comparative example 1 in which a copper foil and a heating element were each separately welded to a conductive member, both conductive members were protruded from a case and welded outside the case, and the area of the region of connection between the two conductive members was 12mm²。

S1 in table 1 corresponding to comparative example 1 indicates the area of a region where one conductive member is connected to the heating part, and S2 indicates the area of a region where the other conductive member is connected to the copper foil.

In examples 1 to 9 and comparative example 1, the length of the heating part was 77mm in the length direction of the electrode assembly, which corresponds to the length direction of the first conductive member as described above; the thickness of the heating part is 30 μm or 20 μm in the thickness direction of the electrode assembly; the width of the heating portion was 55.2mm in the width direction of the electrode assembly, which was perpendicular to the length direction of the electrode assembly, which was perpendicular to the thickness direction of the electrode assembly.

Testing the surface temperature difference of the lithium ion battery: the lithium ion battery surface temperature difference is the difference between the maximum temperature and the minimum temperature of the surface of the lithium ion battery after being heated in a heating mode, wherein the heating mode is that the surface of the lithium ion battery is heated for 60s at a current of 4.5A in an environment of-20 ℃, and then the difference between the maximum temperature and the minimum temperature of the surface of the lithium ion battery is measured after being heated for 35s at a current of 4.1A.

Drop test: and (3) taking 10 lithium ion batteries for a drop test, determining that the conductive connection between the copper foil and the heating element drops to be failure, and determining the number of the lithium ion batteries dropping to be failure. The drop test is to drop the lithium ion battery onto the surface of the steel plate freely from a position with a height of 1.8 meters, the drop is performed for 3 rounds, each 1 round drops for 6 times, each 1 round includes the thickness direction along the electrode assembly, two faces of the lithium ion battery respectively drop towards the steel plate, and 4 corners of the lithium ion battery respectively drop towards the steel plate.

TABLE 1

From table 1, the number of drop failures of the lithium ion batteries of examples 1 to 9 is significantly less than that of comparative example 1, which indicates that the connection mode of the conductive devices provided by the embodiments of the present application can significantly improve the reliability of the lithium ion batteries.

Meanwhile, the surface temperature difference of the lithium ion batteries of embodiments 1 to 9 is smaller than that of the lithium ion battery of comparative example 1, which indicates that the connection mode of the conductive piece provided by the embodiment of the present application can make the surface temperature difference of the lithium ion battery small when heating, because the conductive piece and the heating element are connected inside the battery, and the conductive piece and/or the heating element is connected with the copper foil of the negative electrode plate, the heat generated by the heating element is promoted to be transferred to the current collector of the electrode plate through the direct connection point, so that the temperature rise uniformity of the electrode assembly is improved.

From Table 1, from examples 1 to 4 and example 5, S1/S2 was measured at a temperature of 1: when the ratio of the number of the dropping failures of the lithium ion battery is 1 to 1:3, the number of the dropping failures of the lithium ion battery is smaller than that when the ratio of S1/S2 is 1:4, which shows that the dropping performance of the electrochemical device can be further improved by reasonably limiting the range of S1/S2.

The present application also shows the measurement of the temperature of the surface of the lithium ion battery in example 3. The measurement is shown in fig. 6, and the surface temperature difference of the electrochemical device of example 3 is 1 c from fig. 6.

The present embodiment also provides an embodiment of an electric device 200, as shown in fig. 7 and 8, the electric device 200 includes an electrochemical device 100, a switch 4, a temperature sensor 5, and a controller 6. For the specific structure and function of the electrochemical device 100, reference may be made to the above embodiments, and detailed description thereof is omitted.

The heating portion 22 is connected to the switch 4, and specifically, the heating portion 22 is connected to the switch 4 through the second conductive member 23. The controller 6 is respectively connected with the switch 4 and the temperature sensor 5, and the controller 6 is used for controlling the switch 4 to be closed when the temperature sensor 5 detects that the temperature of the electrochemical device 100 is less than a preset threshold value.

In some embodiments, the preset threshold is 5 ℃.

Referring to fig. 7 and 8, the first conductive member 21 of the heating element 2 in the electrochemical device 100 is connected to the first terminal 2001 of the electric device 200, the second conductive member 23 of the heating element 2 in the electrochemical device 100 is connected to the switch 4 and then connected to the second terminal 2002 of the electric device 200, and the polarities of the first terminal 2001 and the second terminal 2002 are opposite.

Referring to fig. 9 and 10, the second portion 212 of the first pole piece 31 of the electrode assembly 3 in the electrochemical device 100 is connected to the first terminal 2001 of the electric device 200, the second pole piece 33 of the electrode assembly 3 in the electrochemical device 100 is connected to the switch 7 and then connected to the second terminal 2002 of the electric device 200, or the second pole piece 33 of the electrode assembly 3 in the electrochemical device 100 is connected to the third terminal 2003 of the electric device 200 and then connected to the switch 7, and the third terminal 2003 and the first terminal 2001 have opposite polarities. The switch 7 is further connected to the controller 6, and the controller 6 is configured to control charging and discharging of the electrochemical device 100 through the switch 7.

It should be noted that the electric device 200 may be an energy storage product, a mobile phone, a tablet, an unmanned aerial vehicle, a single-wheel or two-wheel or more electric vehicle, or an electric cleaning tool. For example, in the above-described unmanned aerial vehicle, the electrochemical device 100 is mounted on the unmanned aerial vehicle, and the electrochemical device 100 is used to supply power to a flight system, a control system, an imaging system, and the like on the unmanned aerial vehicle.

It should be noted that the description of the present application and the accompanying drawings set forth preferred embodiments of the present application, however, the present application may be embodied in many different forms and is not limited to the embodiments described in the present application, which are not intended as additional limitations to the present application, but are provided for the purpose of providing a more thorough understanding of the present disclosure. Moreover, the above-mentioned technical features are combined with each other to form various embodiments which are not listed above, and all the embodiments are regarded as the scope described in the present specification; further, modifications and variations may occur to those skilled in the art in light of the foregoing description, and it is intended to cover all such modifications and variations as fall within the scope of the appended claims.

Claims

1. An electrochemical device comprising an electrode assembly, a heating assembly and a housing, the electrode assembly comprising a first pole piece,

the heating assembly includes a heating portion and a first conductive member, the heating portion is located in the housing, the first conductive member includes a first portion including a first connection region connected to the heating portion and a second portion protruding out of the housing, and the heating assembly satisfies at least one of the following conditions (1) to (2):

(1) the first portion further comprises a second connection region connected to the first pole piece;

(2) the heating portion includes a third connection region connected to the first pole piece.

2. The electrochemical device according to claim 1, wherein the heating portion includes a fourth connection region connected to the first connection region, the first pole piece includes a fifth connection region connected to the second connection region, and the fourth connection region and the fifth connection region are located on the same side of the first conductive member.

3. The electrochemical device according to claim 1, wherein at least one of the following conditions is satisfied:

(a) the area S1 of the first connection region is 12-36 mm²；

(b) The area S2 of the second attachment area is in the range of 12 to 36mm²；

(c) The area S3 of the third linking area is in the range of 12 to 36mm²。

4. The electrochemical device according to claim 3, wherein at least one of the following conditions is satisfied:

(d) the first connecting area comprises at least one first connecting point, and the area of each first connecting point is 0.6-2 mm²；

(e) The second connecting area comprises at least one second connecting point, and the area of the second connecting point is 0.6-2 mm²；

(f) The third connecting area comprises at least one third connecting point, and the area of the third connecting point is 0.6-2 mm²。

5. The electrochemical device according to claim 3,

when only the condition (1) is satisfied, satisfying: S1/S2 ranges from 1:1 to 1:3 or S2/S1 ranges from 1:1 to 1: 3;

when only the condition (2) is satisfied, satisfying: S1/S3 ranges from 1:1 to 1:3 or S3/S1 ranges from 1:1 to 1: 3;

when the condition (1) and the condition (2) are simultaneously satisfied, satisfying: S1/(S2+ S3) ranges from 1:1 to 1:3 or (S2+ S3)/S1 ranges from 1:1 to 1: 3.

6. The electrochemical device according to claim 1,

the heating part comprises a heating element and an insulating layer positioned on the surface of the heating element.

7. The electrochemical device according to claim 6, wherein at least one of the following conditions is satisfied:

(g) the heating element comprises at least one of a metallic material or a carbon material;

(h) the insulating layer includes at least one of a polymer or an inorganic insulating material.

8. The electrochemical device according to claim 7, wherein at least one of the following conditions is satisfied:

(i) the metal material comprises at least one of nickel, titanium, copper, silver, gold, platinum, iron, cobalt, chromium, tungsten, molybdenum, aluminum, magnesium, potassium, sodium, calcium, strontium, barium, silicon, germanium, tin, lead, indium, zinc or stainless steel;

(j) the carbon material comprises at least one of a carbon felt, a carbon film, carbon black, acetylene black, fullerene, a conductive graphite film, or a graphene film;

(k) the polymer includes polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyetheretherketone, polyimide, polyamide, polyethylene glycol, polyamideimide, polycarbonate, cyclic polyolefin, polyphenylene sulfide, polyvinyl acetate, polytetrafluoroethylene, polymethylene naphthalene, polyvinylidene fluoride, polyethylene naphthalate, polypropylene carbonate, poly (vinylidene fluoride-hexafluoropropylene), poly (vinylidene fluoride-co-chlorotrifluoroethylene), silicone, vinylon, polypropylene, anhydride-modified polypropylene, polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate, ethylene-acrylic acid copolymer, ethylene-vinyl alcohol copolymer, polyvinyl chloride, polystyrene, polyethernitrile, polyurethane, polyphenylene oxide, polyester, polyethylene terephthalate, polyethylene naphthalate, polyetheretherketone, poly (ethylene carbonate), poly (vinylidene fluoride-co-hexafluoropropylene), poly (vinylidene fluoride-co-chlorotrifluoroethylene), poly (vinylon-co-vinylon), poly (ethylene-vinyl acetate), ethylene-ethyl acrylate), ethylene-acrylic acid copolymer, ethylene-vinyl alcohol copolymer, polyvinyl chloride, polystyrene, polyethernitrile, polyurethane, polyphenylene oxide, polyester, poly (butylene terephthalate), poly (ethylene naphthalate), poly (ethylene carbonate), poly (ethylene), poly (butylene terephthalate), poly (ethylene), poly (butylene terephthalate), poly (ethylene, poly (butylene terephthalate), poly (ethylene), poly, At least one of polysulfone, amorphous alpha-olefin copolymer and derivatives thereof;

(l) The inorganic insulating material comprises at least one of hafnium oxide, strontium titanate, tin oxide, cerium oxide, magnesium oxide, nickel oxide, calcium oxide, barium oxide, zinc oxide, zirconium dioxide, yttrium oxide, aluminum oxide, titanium dioxide, silicon dioxide, boehmite, magnesium hydroxide or aluminum hydroxide.

9. The electrochemical device according to claim 1, wherein at least one of the following conditions is satisfied:

(m) the electrochemical device further includes a separator and a second pole piece, the first pole piece, the separator and the second pole piece being wound to form a wound structure, the heating part being disposed at a central portion of the wound structure;

(n) the heating assembly further includes a second conductive member connected to the heating part.

10. An electric device comprising the electrochemical apparatus according to any one of claims 1 to 9.

11. The powered device of claim 10, further comprising a switch, a temperature sensor, and a controller; the heating part is connected with the switch;

the controller is respectively connected with the switch and the temperature sensor;

the controller is used for controlling the switch to be closed when the temperature sensor detects that the temperature of the electrochemical device is smaller than a preset threshold value.

12. The consumer device according to claim 11, wherein the predetermined threshold is 5 ℃.