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Part1. Characteristics of
lithium ion rechargeable battery |
| The major characteristics of lithium
ion rechargeable battery are described below. |
| 1
Charging characteristics |
Generally, lithium ion rechargeable
battery are charged at a constant voltage, a constant current
method. Fig. 1 shows charging characteristics of the prismatic
type (IMP340667AL-1).
The battery can be charged approximately to a capacity of 90%
of the rating after one hour, and about 99% after two hours. |
Fig. 1 |
| 2
Discharge load characteristics |
The discharge load characteristics
shown in Fig. 2 relate the prismetic type (IMP340667AL-1).
The greater the discharge current, the lower the discharge capacity
results; the capacity of discharge of 1C is 95% or more of the
capacity of 0.2C discharged. |
Fig. 2 |
| 3
Discharge temperature characteristics |
| Fig. 3 shows the 0.2C discharge temperature
curves for prismatic type (IMP340667AL-1). At the low temperature
dischage, the battery voltage drops and the discharge capacity
also decreases. However, even at -20Co,
a discharge capacity of about 90% of that at 20Co
is available. |
Fig. 3 |
| 4
Charge/discharge cycle characteristics |
| The charge/discharge cycle characteristics
of prismatic type (IMP340667AL-1) is shown in Fig. 4. When a
lithium ion rechargeable battery is charged and discharged cyclically,
the discharge capacity of the battery gradually decreases, because
of the deterioration of electrode materials, electrolyte, etc.
The degree of deterioration depends on ambient temperature during
charging and discharging. If a battery is charged at a higher
voltage than the allowable maximum voltage, the discharge capacity
may decrease excessively or battery safety may be jeopardized.
Be sure to maintain the allowable voltage and the temperature
ranges for charging and discharging. |
Fig. 4 |
| 5
Storage characteristics |
| Fig. 5, Fig. 6 and Fig. 7 show the
storage data for the prismatic type (IMP340847-1). Recovered
capacities (discharge capacities after recharging) vary depending
on storage period, ambient temperature, and battery voltage.
As battery voltage and ambient temperature are higher, recovery
capacities are decreased. Store battery within the ambient temperature
range of -20Co to 40Co.
If battery voltage or temperature is higher, battery performance
characteristics may deteriorate faster. If battery are stored
for a long time, they may be overdischarged due to self-discharge.
Consult NEC Mobile Energy Corporation before beginning long-term
storage. |
Fig. 5 |
Fig. 6 |
Fig. 7 |
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