CN-115461909-B - Electrochemical device and electronic device comprising same

CN115461909BCN 115461909 BCN115461909 BCN 115461909BCN-115461909-B

Abstract

An electrochemical device and an electronic device including the same. The electrochemical device comprises at least one bipolar current collector (10), wherein the bipolar current collector (10) is in sealing connection with an outer package (20), independent sealing cavities are formed on two sides of the bipolar current collector (10), each sealing cavity comprises an electrode assembly (30) and electrolyte, one side of the bipolar current collector (10) is electrically connected with the outermost positive electrode plate of the adjacent electrode assembly (30), and the other side of the bipolar current collector (10) is electrically connected with the outermost negative electrode plate of the adjacent electrode assembly (30). Through the introduction of the bipolar current collector (10) and the sealing design of the bipolar current collector (10) and the inner layer of the outer package (20), ion insulation among the liquid serial battery multi-electrode assemblies (30) is realized among the electrode assemblies (30), so that the reliability of the use of the high-output voltage battery and the effective output of electric energy are realized.

Inventors

ZHANG NAN
ZHANG YIBO
YAN KUN
HU QIAOSHU

Assignees

宁德新能源科技有限公司
宁德新能源科技有限公司

Dates

Publication Date: 20260421
Application Date: 20200630
Priority Date: 20200630

Claims (12)

1. An electrochemical device comprising a bipolar current collector and electrode assemblies, wherein the electrode assemblies are positioned at two sides of the bipolar current collector, and polarities of electrode assemblies at two sides, which are respectively close to an outermost pole piece of the bipolar current collector, are different; One side of the bipolar current collector is electrically connected with an outermost positive electrode plate of an adjacent electrode assembly, the other side of the bipolar current collector is electrically connected with an outermost negative electrode plate of the adjacent electrode assembly, one side of the positive electrode plate, which is electrically connected, is free of electrode active materials, and one side of the negative electrode plate, which is electrically connected, is free of electrode active materials, wherein the electrical connection means that the current collectors of the positive electrode plate or the negative electrode plate are respectively in physical contact with one side of the bipolar current collector to realize circuit connection; The bipolar current collector is connected with the external package, and independent sealing cavities are formed on two sides of the bipolar current collector, and each sealing cavity comprises an electrode assembly and electrolyte.
2. The electrochemical device of claim 1, wherein the electrolyte comprises an organic solvent.
3. The electrochemical device of claim 1, wherein the bipolar current collector further comprises a sealing region in sealing connection with the outer package, the sealing region comprising a sealing material having a melting point of 100 ℃ to 200 ℃.
4. The electrochemical device of claim 3, wherein the bipolar current collector comprises at least one of a Cu-Al composite current collector, a stainless steel foil current collector, or a polymeric conductive current collector; the sealing material includes at least one of polypropylene, polyester, or p-hydroxybenzaldehyde.
5. The electrochemical device according to claim 1, wherein the electron resistivity of the bipolar current collector in the Z direction is 1 x 10 -11 Ω -cm to 30 Ω -cm.
6. The electrochemical device according to claim 1, wherein the bipolar current collector water permeability M is 10 -3 g/(day·m 2 -Pa-3 mm or less.
7. The electrochemical device of claim 1, wherein the bipolar current collector has a thickness of 2mm to 100mm.
8. The electrochemical device according to claim 1, wherein a seal thickness T and a seal width W at a junction of the bipolar current collector and the exterior package satisfy T/w≤0.05, wherein T and W are in mm.
9. The electrochemical device of claim 8, having at least one of the following features: a. the electrochemical device comprises 2 to 3 bipolar current collectors; b. the sealing material has a melting point of 110 ℃ to 180 ℃; c. the electron resistivity of the bipolar current collector in the Z direction is 1 multiplied by 10 -5 omega cm to 5 omega cm; d. The water permeability M of the bipolar current collector is less than or equal to 10 -4 g/(day·m 2 Pa.3 mm); e. the bipolar current collector has a thickness of 5mm to 50mm; f. The seal thickness T and the seal width W are more than or equal to 0.02 and less than or equal to 0.04.
10. The electrochemical device of claim 9, having at least one of the following features: 1) The sealing material has a melting point of 120 ℃ to 160 ℃; 2) The electron resistivity of the bipolar current collector in the Z direction is 0.01Ω & cm to 0.10Ω & cm; 3) The bipolar current collector has a thickness of 5mm to 20mm.
11. The electrochemical device of claim 1, wherein the structure of the electrode assembly comprises at least one of a wound structure or a laminated structure.
12. An electronic device comprising the electrochemical device of any one of claims 1-11.

Description

Electrochemical device and electronic device comprising same Technical Field The present application relates to the field of electrochemistry, and in particular, to an electrochemical device and an electronic device including the same. Background The lithium ion battery has the advantages of high energy density, long cycle life, high nominal voltage, low self-discharge rate, small volume, light weight and the like, and has wide application in the consumer electronics field. With the recent rapid development of Electric Vehicles (EV) and mobile electronic devices, there is an increasing demand for batteries such as energy density, safety, and cycle performance, and the development of new lithium ion batteries with overall improved comprehensive performance is expected. In the existing lithium ion battery system, the limitation of an electrochemical system is limited, such as limited voltage difference of anode and cathode materials, limited oxidation-reduction resistance of electrolyte and the like, and the working voltage of the lithium ion battery is difficult to exceed 5V. However, in practical use, a large number of situations such as Electric Vehicles (EV), voltage transformers (PT), energy Storage Systems (ESS), etc. are required to use voltages exceeding 5V. Even in the mobile phone market, in order to meet the requirements of quick charge and the like, the open circuit voltage of the lithium ion battery is required to be increased. The scheme of the series connection method is that two lithium ion batteries are directly connected in series in the same packaging bag, but the problem that on one hand, the two lithium ion batteries are not subjected to ion insulation is generally solved, on the other hand, the battery is invalid due to the fact that battery voltage is increased, electrolyte is decomposed under the high-voltage condition, meanwhile, internal short circuit can occur between the two lithium ion batteries due to the voltage difference of pole pieces, the battery is invalid, on the other hand, the series connection method needs to weld different pole lugs of different lithium ion batteries to realize the series connection of the lithium ion batteries, the problem that the internal resistance of the lithium ion batteries is increased due to poor pole lug welding effect is solved, not only is the potential safety hazard greatly, but also the output of electric energy is not facilitated, meanwhile, the design of a plurality of pole lugs is led out, the fracture risk of the pole lugs is increased, and the production rate is reduced. Therefore, developing a new lithium ion battery with a serial structure to realize the use reliability of the battery with high output voltage and the effective output of electric energy becomes a problem to be solved by those skilled in the art. Disclosure of Invention The application provides an electrochemical device and an electronic device comprising the same, so as to realize the use reliability of a high-output voltage battery and the effective output of electric energy. The first aspect of the present application provides an electrochemical device comprising a bipolar current collector and electrode assemblies, wherein the electrode assemblies are positioned at two sides of the bipolar current collector, and polarities of electrode assemblies at two sides, which are respectively close to an outermost pole piece of the bipolar current collector, are different. In some embodiments of the present application, one side of the bipolar current collector is electrically connected to an outermost positive electrode tab of an electrode assembly adjacent thereto, and the other side of the bipolar current collector is electrically connected to an outermost negative electrode tab of an electrode assembly adjacent thereto. In some embodiments of the present application, the bipolar current collector is connected to an external package, and separate sealing cavities are formed on two sides of the bipolar current collector, wherein each sealing cavity contains an electrode assembly and electrolyte. In some embodiments of the application, the electrolyte comprises an organic solvent. In some embodiments of the application, the bipolar current collector further comprises a sealing region in sealing connection with the overpack, the sealing region comprising a sealing material having a melting point of 100 ℃ to 200 ℃. In some embodiments of the application, the bipolar current collector comprises at least one of a Cu-Al composite current collector, a stainless steel foil current collector, or a polymeric conductive current collector; the sealing material includes at least one of polypropylene (PP), polyester, or p-hydroxybenzaldehyde (PHBA). In some embodiments of the application, the bipolar current collector has an electron resistivity in the Z direction of 1 x 10 -11 Ω -cm to 30 Ω -cm. In some embodiments of the application, the bipolar current collector has a water permeab