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JP-7855467-B2 - Electrodes, electrode groups, secondary batteries, battery packs, and vehicles

JP7855467B2JP 7855467 B2JP7855467 B2JP 7855467B2JP-7855467-B2

Inventors

  • 原田 康宏
  • 深谷 太郎
  • 吉田 頼司
  • 山下 泰伸
  • 村田 芳明
  • 高見 則雄

Assignees

  • 株式会社東芝

Dates

Publication Date
20260508
Application Date
20220914

Claims (12)

  1. An active material-containing layer comprising a first side and a second side on the opposite side in a first direction intersecting the first side, and containing an electrode active material, The current collector comprises an active material supporting portion that supports the active material-containing layer, and an active material non-supporting portion adjacent to the active material-supporting portion and the first side, where the active material-containing layer is not provided. An electrode having a surface with a plurality of ridges and a plurality of grooves along the first direction, wherein the relationship a < b is satisfied between a first pitch a , which is the average value of the distance between adjacent pairs of ridges in the surface with a plurality of ridges along the first side, and a second pitch b, which is the average value of the distance between adjacent pairs of ridges in the surface with a plurality of ridges along the second side.
  2. The electrode according to claim 1, wherein, with respect to the average length X of the first length of the first side and the second length of the second side, the first pitch a is within the range of 0.01X ≤ a ≤ 0.1X, and the second pitch b is within the range of 0.05X ≤ b ≤ 0.5X.
  3. The electrode according to claim 1 or 2, wherein the ridges and grooves are arranged to radiate outwards from the first side to the second side.
  4. The electrode according to claim 1 or 2, wherein the electrode active material contains a metal oxide, and the active material-containing layer has a density of 2.3 g/ cm³ or more and 3.5 g/ cm³ or less.
  5. The electrode according to claim 1 or 2, wherein the active material-containing layer has a main surface area of 150 cm² or more and 500 cm² or less.
  6. Multiple positive electrodes, Multiple negative electrodes, A group of electrodes comprising, The negative electrode is the electrode described in claim 1 or 2. An electrode group having a stacked structure in which the positive electrode and the negative electrode are stacked.
  7. The electrode group according to claim 6, A secondary battery comprising an electrolyte.
  8. A battery pack comprising the secondary battery described in claim 7.
  9. External terminals for power supply, The battery pack according to claim 8, further comprising a protection circuit.
  10. The device comprises multiple secondary batteries, The battery pack according to claim 8, wherein the secondary batteries are electrically connected in series, parallel, or a combination of series and parallel.
  11. A vehicle equipped with the battery pack described in claim 8.
  12. The vehicle according to claim 11, comprising a mechanism for converting the kinetic energy of the vehicle into regenerative energy.

Description

Embodiments of the present invention relate to electrodes, electrode groups, secondary batteries, battery packs, and vehicles. In recent years, rechargeable batteries such as lithium-ion batteries have been increasingly incorporated into battery-powered devices such as smartphones, vehicles, stationary power supplies, robots, and drones. Furthermore, to enable prolonged use of these devices, there is a demand for higher capacity single cells. Recently, oxides containing niobium and titanium have been used as negative electrode active materials to increase charging capacity and enable rapid charging. For example, titanium niobium oxide, represented as Nb₂TiO₃₆ , has a high theoretical capacity exceeding 380 mAh/g. While niobium titanium oxide has high capacity, on the other hand, electrodes using niobium titanium oxide as the active material require a large amount of conductive additive to ensure conductivity. Furthermore, a large amount of binder is used to prevent electrode collapse due to the expansion and contraction of niobium titanium oxide during battery charging and discharging. Increasing the capacity per unit volume of electrodes with a large amount of electrode composite material other than the active material can be achieved by increasing the electrode density. Increasing the capacity per unit weight of a single cell can be achieved by increasing the electrode area. Therefore, energy density can be improved by increasing electrode density and expanding electrode area. Japanese Patent Publication No. 2001-76711Japanese Patent Publication No. 2012-174434Japanese Patent Publication No. 2013-73690 A partially cutaway plan view schematically showing an example of an electrode according to the embodiment.A conceptual diagram showing an example of a cross-sectional shape of a part of the electrode according to the embodiment, which is determined by a three-dimensional laser displacement meter.A conceptual diagram showing an example of another cross-sectional shape of the electrode according to the embodiment, as determined by a three-dimensional laser displacement meter.A plan view schematically showing one step in the manufacturing of an electrode according to the embodiment.A plan view schematically showing other steps in the manufacturing of an electrode according to the embodiment.A schematic cross-sectional view showing an example of an electrode group according to the embodiment.An exploded perspective view schematically showing another example of the electrode group according to the embodiment.A schematic partial cutaway perspective view showing an example of a secondary battery according to the embodiment.An enlarged cross-sectional view of section E of the secondary battery shown in Figure 8.A schematic perspective view showing an example of a battery pack according to this embodiment.An exploded perspective view schematically showing an example of a battery pack according to this embodiment.A block diagram showing an example of the electrical circuit of the battery pack shown in Figure 11.A partially transparent view schematically showing an example of a vehicle according to the embodiment.A schematic diagram showing an example of a control system for the electrical system in a vehicle according to this embodiment. In batteries using negative electrode active materials containing niobium titanium oxide, the negative electrode contains a large amount of additives such as conductive agents and binders, resulting in a high electrode density. Therefore, batteries using niobium titanium oxide suffer from poor electrolyte permeability due to the large electrode surface area. This not only increases the time required to impregnate the electrodes with electrolyte during manufacturing, but also leads to uneven electrolyte distribution within the electrodes, potentially causing a decrease in battery performance. Furthermore, in battery cells containing niobium titanium oxide, the volume change (expansion and contraction) of the electrodes during charging and discharging can push the electrolyte out, potentially reducing input/output performance and lifespan. For these reasons, methods to improve the electrolyte permeability of electrodes and batteries containing niobium titanium oxide are needed. The embodiments will be described below with reference to the drawings as appropriate. Common components throughout the embodiments will be denoted by the same reference numerals, and redundant explanations will be omitted. Furthermore, each figure is a schematic diagram intended to illustrate the embodiments and facilitate understanding; their shapes, dimensions, and ratios may differ from those of the actual device. These can be appropriately modified based on the following description and known technology. (First embodiment) According to the first embodiment, an electrode is provided. The electrode comprises an active material-containing layer containing an electrode active material and a current collector.