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High heat-resistant Lithium-ion Capacitor

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What is a Lithium-ion capacitor?
What is a Lithium-ion capacitor?

Capacitors are power storage devices that are classified as secondary batteries.Various types of capacitors have been developed depending on the materials used, but there are generally two types of capacitors with large capacities: "Electric Double Layer Capacitors (EDLC)" and "Lithium-ion Capacitors".

キャパシタとは? 出力密度 エネルギー密度 表

Comparison of power density and energy density for power storage devices

Features

The feature of capacitors is that electricity goes in and out (charges/discharges) very quickly.Compared to well-known power storage devices (lithium-ion secondary batteries, lead-acid batteries, etc.), the energy density is inferior, but the power density is excellent, the performance deterioration due to repeated charging and discharging is small, and the life is long.

Performance comparison table

◎Excellent、〇Good、△Average

  •   Lithium-ion Battery EDLC Lithium-ion Capacitor
    (Conventional)
    Energy

    Power density


    Service life
    (number of
    charges/discharges)

    Operating
    temperature range (℃)
    -20〜60 -40〜70 -30〜70
    Operating voltage (V) 〜4.3 0〜2.7 2.2〜3.8
  • Lithium-ion Capacitor
    (JTEKT)
    〇⇒◎
    (Improved by
    increasing heat-
    resistance)
    〇⇒◎
    (Improved by
    increasing heat-
    resistance)

    -40〜85

    2.2〜3.8
JTEKT capacitors have significantly improved power density and service life due to the wide operating temperature range.
Principle and structure of Lithium-ion capacitors

Lithium-ion capacitor combines the positive electrode of EDLC and the negative electrode of a Lithium-ion secondary battery. This achieves higher energy density than general capacitors and higher safety than general Lithium-ion secondary batteries.

  •   Lithium-ion Battery EDLC Lithium-ion Capacitor
    (Conventional)
    Internal structure
    Click to enlarge

    Click to enlarge

    Click to enlarge
    Charge / discharge mechanism +:Lithium chemical reaction
    -:Lithium insertion / removal
    +:Electrolyte ion adsorption / desorption
    -:Electrolyte ion adsorption / desorption
    +:Electrolyte ion adsorption / desorption
    -:Lithium insertion / removal
    Features Energy (Wh/L) 200〜400 3〜6 10〜20
    Power density (W/kg) 500〜2,000 1,000〜4,500 1,000〜3,500
    Cycle life(cyc.) 1,000〜3,000 Over 100,000 Over 100,000
    Operating temperature limit (℃) -20〜60 -30〜70 -30〜60
  • Lithium-ion Capacitor
    (JTEKT)

    Click to enlarge
    +:Electrolyte ion adsorption / desorption
    -:Lithium insertion / removal
    13
    7,000
    Over 1 million
    -40〜85

There are two types of capacitors, a laminated type and a can type.JTEKT uses the laminated type (shown below).

Manufacturing method of Lithium-ion capacitor

Lithium-ion capacitors are manufactured in much the same process as Lithium-ion batteries.

General method for manufacturing lithium-ion capacitors

Glossary about electricity
Current (A) The number of electrons flowing per second
Voltage (V) The difference in potential between two points
Watt (W) Amount of electrical energy that can be output per second
Watt-hour (Wh) Total electrical energy
Internal resistance (mΩ) Resistance of energy storage devices
C-rate (C) A value that represents the ease of outputting power
Joule heat (J) Heat generated when a current flows through a conductor
Primary battery Batteries that can only be discharged (cannot be charged)
Secondary battery Rechargeable batteries (can be used repeatedly)
Float charging How to charge at a constant voltage
Power density (W/L, W/kg) Power by unit volume or mass
Energy density (Wh/L, Wh/kg) Electric energy by unit volume or mass
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