CN-121983760-A - Electrode terminal fixing structure, battery comprising same, battery pack and automobile

Abstract

The invention relates to a fixing structure of an electrode terminal, a battery pack and an automobile comprising the fixing structure. The electrode terminal fixing structure includes a battery case having an open end portion on one side and a bottom portion formed with a through hole on the other side, an electrode terminal fixed to the bottom portion, and a terminal spacer interposed between the electrode terminal and the bottom portion. The electrode terminal includes a neck portion having a smaller cross section than the cross section of the through hole and inserted into the through hole, a head portion connected to one end portion of the neck portion, having a larger cross section than the cross section of the through hole, and extending along one side surface of the bottom portion, a protrusion portion connected to the other end portion of the neck portion, extending from the other side surface of the bottom portion in the axial direction of the battery case, an expanded diameter portion extending from the protrusion portion in the centrifugal direction, and a distal end surface provided at an end portion of the protrusion portion in the axial direction, the expanded diameter portion being a coupling member physically coupled to an outer peripheral surface of the protrusion portion.

Inventors

• Min Jianyu
• ZHAO MINQI
• JIN DUJUN
• JIN ZAIXIONG
• HuangFu Guangzhu

Assignees

• 株式会社LG新能源

Dates

Publication Date

20260505

Application Date

20221121

Priority Date

20211124

Claims (20)

1. 1. A fixing structure of an electrode terminal, the fixing structure of an electrode terminal comprising: A battery case having an open end portion at a first side, a bottom portion formed with a through hole at a second side opposite to the first side, and a cylindrical side wall, wherein the bottom portion is connected to an end portion of the cylindrical side wall and integrally formed with the cylindrical side wall; an electrode terminal fixed to the bottom, and A terminal pad sandwiched between the electrode terminal and the bottom, The electrode terminal includes: a neck portion having a cross section smaller than that of the through hole and inserted into the through hole; A head portion connected to one side end portion of the neck portion and configured to have a cross section larger than that of the through hole, and extending along one side surface of the bottom portion; A protrusion connected to the other side end of the neck portion and configured to extend from the other side surface of the bottom portion along an axial direction of the battery case; An expanded diameter portion arranged to extend from the protruding portion in a centrifugal direction, and A front end surface provided at an end portion of the protruding portion in the axial direction, Wherein the expanded diameter portion is a coupling member at an outer peripheral surface of the protruding portion.
2. 2. The fixing structure of an electrode terminal according to claim 1, Wherein the coupling member is physically coupled at an outer circumferential surface of the protruding portion.
3. 3. The fixing structure of an electrode terminal according to claim 1, Wherein the outer peripheral surface of the protruding part is provided with a connecting groove which is formed along the peripheral direction and is recessed toward the centripetal direction, and The coupling member is inserted into the coupling groove to be fixed.
4. 4. The fixing structure of an electrode terminal according to claim 3, Wherein the coupling groove has an external thread shape, the coupling member is a nut formed with an internal thread coupled with the external thread, or Wherein the coupling groove is an O-groove, and the coupling member is a C-ring inserted into the O-groove.
5. 5. The fixing structure of an electrode terminal according to claim 3, Wherein a surface of the coupling member facing the bottom portion includes a side wall surface gradually distant from the bottom portion as approaching an outer side in a radial direction.
6. 6. The fixing structure of an electrode terminal according to claim 5, Wherein the side wall surface is pressure-bonded to the terminal pad toward the bottom of the battery case in a state where the coupling member is coupled to the coupling groove.
7. 7. The fixing structure of an electrode terminal according to claim 1, further comprising: a first sealing coating layer formed at an interface between the terminal pad and the bottom of the battery case, and/or A second sealing coating covering an externally exposed interface between the coupling member and the terminal pad.
8. 8. The fixing structure of an electrode terminal according to claim 7, Wherein the first sealing coating comprises silicone, silicone acrylate, or polyamideimide.
9. 9. The fixing structure of an electrode terminal according to claim 7, Wherein the second sealing coating covers an externally exposed interface between the terminal pad and the bottom.
10. 10. The fixing structure of an electrode terminal according to claim 9, Wherein the second sealing coating comprises silicone, silicone acrylate, or polyamideimide.
11. 11. The fixing structure of an electrode terminal according to claim 1, Wherein the front end surface protrudes in the axial direction of the battery case from the enlarged diameter portion with reference to the bottom surface of the battery case.
12. 12. The fixing structure of an electrode terminal according to claim 1, Wherein the front end face includes a flat portion having a flat surface.
13. 13. The fixing structure of an electrode terminal according to claim 1, Wherein the front end surface is a welded region having a current collector.
14. 14. The fixing structure of an electrode terminal according to claim 1, The coupling member includes a first section that gradually moves away from the bottom of the battery case as the first section extends from the protruding portion in the centrifugal direction.
15. 15. The fixing structure of an electrode terminal according to claim 1, Wherein in the expanded diameter portion, a diameter of a cross section cut in a direction perpendicular to a central axis of the battery case gradually increases as it is distant from a bottom of the battery case.
16. 16. The fixing structure of an electrode terminal according to claim 1, Wherein the outer surface of the bottom portion is another electrode terminal having a polarity opposite to that of the electrode terminal.
17. 17. A battery, the battery comprising: An electrode assembly comprising a first electrode and a second electrode wound with a separator interposed therebetween, and having uncoated portions of the first electrode and uncoated portions of the second electrode extending from both side end portions of the electrode assembly to be exposed to the outside of the separator, and A battery case having an open end at a first side, and configured to receive the electrode assembly through the open end and to be electrically connected to the first electrode; The fixing structure of an electrode terminal according to any one of claims 1 to 16, the electrode terminal being provided through the through-hole in a manner not to contact an inner wall of the through-hole formed at the bottom of the battery case, and being electrically connected to the second electrode; A terminal pad sandwiched between the electrode terminal and the through hole, and A sealing body configured to seal an open end of the battery case so as to be able to be insulated from the battery case.
18. 18. The battery of claim 17, the battery further comprising: a second current collector bonded to the uncoated portion of the second electrode, Wherein at least a portion of the second current collector is welded to the front end face of the electrode terminal.
19. 19. The battery of claim 18, the battery further comprising: an insulator sandwiched between the second current collector and an inner peripheral surface of a bottom portion of the battery case and between an inner peripheral surface of a side wall of the battery case and the electrode assembly.
20. 20. A battery pack comprising a plurality of cells according to any one of claims 17 to 19.

Description

Electrode terminal fixing structure, battery comprising same, battery pack and automobile The present application is a divisional application of the application patent application with application number 202211452848.9 (application day 2022, 11, 21, entitled "fixing structure of electrode terminal," battery, battery pack, and automobile including the same "). Technical Field The invention relates to a fixing structure of an electrode terminal, a battery pack and an automobile comprising the fixing structure. Background In addition to portable devices, secondary batteries, which are highly convenient for application based on product groups and have electrical characteristics such as high energy density, are widely used in electric vehicles (EV, electric Vehicle) driven by electric driving sources, hybrid vehicles (HEV, hybrid ELECTRIC VEHICLE), plug-in Hybrid vehicles (PHEV, plug-in Hybrid ELECTRIC VEHICLE), and the like. Next, the electric vehicle includes EV, HEV, PHEV and the like. Such secondary batteries have the primary advantage of being able to greatly reduce the use of fossil fuels, and the advantage of not generating by-products at all with the use of energy, and thus are attracting attention as new energy sources for environmental protection and energy efficiency improvement. The types of secondary batteries that are widely used at present are lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries, and the like. The operating voltage of the secondary battery is about 2.5V-4.5V. Therefore, if a higher power voltage is required, a plurality of cells are sometimes connected in series to constitute a battery pack. Depending on the charge/discharge capacity required for the battery pack, a plurality of batteries may be connected in parallel to form the battery pack. Therefore, the number of batteries included in the battery pack and the electrical connection method can be designed in various ways according to the required power voltage and/or charge/discharge capacity. On the other hand, as the type of secondary battery cells, cylindrical, square and pouch batteries are disclosed. The cylindrical battery is configured by sandwiching a separator film as an insulator between an anode and a cathode, winding the separator film to form a jelly-roll-like electrode assembly, and inserting the jelly-roll-like electrode assembly together with an electrolyte into a battery case. Further, each of the anode and cathode may be connected to a strip-shaped electrode tab, which electrically connects the electrode assembly to an electrode terminal exposed to the outside. For reference, the anode terminal is a cap of a seal member that seals an opening of the battery case, and the cathode terminal is the battery case. However, according to the conventional cylindrical battery having such a structure, current is concentrated in the strip-shaped electrode tab joined to the uncoated portion of the anode and/or the uncoated portion of the cathode, and thus there are problems in that the resistance is large, heat generation is large, and the current collection efficiency is not high. The resistance and heat generation of the small cylindrical battery having the shape factor of 1865 or 2170 do not become a great problem. However, in the case of enlarging the form factor in order to apply the cylindrical battery to an electric vehicle, much heat is generated around the electrode tab during the rapid charge, and thus a problem of ignition of the cylindrical battery may occur. In order to solve such problems, a cylindrical battery (so-called Tab-less cylindrical battery) having a structure for improving the current collecting efficiency is disclosed, in which an anode uncoated portion and a cathode uncoated portion are respectively disposed at the upper and lower ends of a jelly-roll type electrode assembly, and a current collector is welded to such uncoated portion. Fig. 1 to 3 are diagrams showing a manufacturing process of the electrodeless ear cylindrical battery. Fig. 1 shows the structure of an electrode, fig. 2 shows the winding process of the electrode, and fig. 3 shows the process of welding a current collector to a bent surface of an uncoated portion. Fig. 4 is a sectional view of the electrodeless ear cylindrical battery cut along the length direction Y. Referring to fig. 1 to 4, the anode 10 and the cathode 11 have a structure in which an active material 21 is coated on a sheet-like current collector 20, and include an uncoated portion 22 on one long side along a winding direction X. As shown in fig. 2, the anode 10 and the cathode 11 are sequentially laminated together with two separation films 12 and then wound up in a direction X, thereby manufacturing an electrode assembly a. At this time, the uncoated portions of the anode 10 and the cathode 11 are arranged in opposite directions to each other. After the winding step, the uncoated portion 10a