Basic Knowledge Of Electric Vehicle Charging
Basic Process Of Charging
We Know That Batteries Have Fixed Positive And Negative Poles, And Direct Current Is Needed For Charging, But The Power Grid Transmits Alternating Current, So What Should We Do?
The Function Of The Charger Is To Convert The Alternating Current Of The Grid Into Direct Current For Charging The Battery, And Adjust The Output Voltage Or Current. Look At Your Cell Phone Or Computer Charger, It’s Actually A Tiny Charger.
Slow Charging Process
Generally, New Energy Vehicles Have On-board Chargers. Due To Size And Cost Constraints, On-board Chargers Are Relatively Small And The Charging Speed Is Slow, So This Process Is Called Slow Charging.
During The Slow Charging Process, The Slow Charging Pile Provides Alternating Current For The Car, So It Is Also Called An Ac Slow Charging Pile.
Fast Charging Process
If The Charger Is Placed In The Charging Pile, It Is Not Limited By Size And Cost, And Multiple Charger Modules Are Stacked, The Charging Speed Will Be Very Fast. This Process Is Called Fast Charging.
During The Fast Charging Process, The Fast Charging Pile Provides Dc Power For The Car, So It Is Also Called A Dc Fast Charging Pile.
Not All New Energy Vehicles Can Perform Fast Charging And Slow Charging. Only Large Batteries Can Support Fast Charging, And Small Batteries Can Only Be Charged Slowly. Generally Speaking, Hybrid Vehicles Can Only Be Charged Slowly, And Pure Electric Vehicles Can Use Both. Of Course, There Are Exceptions.
Charging Speed
Generally, The Charging Power Is Used To Indicate The Charging Speed. The Higher The Power, The Faster The Charging Speed. The Calculation Formula Of The Power Is As Follows: Charging Power (p) = Voltage (u) × Current (i)
For Example, During Fast Charging: Voltage=350v, Current=200a, Then The Charging Power Is: 350×200=70000w=70kw (kw)
70kw Means That It Can Be Charged At 70 Degrees Per Hour. According To The Power, You Can Calculate How Much Electricity The Car Has Charged. The Formula Is As Follows: Charging Capacity (w) = Power (p) × Charging Time (t)
For Example: The Power Of The Household Slow Charging Pile Is Fixed At 7kw (kilowatt), And The Charging Time = 8 Hours, Then The Charging Capacity Is: 7×8=56kwh (kilowatt Hour)=56 Degrees
In The Same Way, The Time Required For Slow Charging Can Be Calculated:
For Example: Vehicle Battery = 70 Degrees, Household Slow Charging Pile Power = 7kw (kilowatt), Then The Time From Zero To Full Is: 70/7 = 10 Hours
Note: The Charging Power Of Fast Charging Is Constantly Changing, And The Power Gradually Decreases With The Increase Of Power; While The Charging Power Of Slow Charging Is Relatively Small And Basically Fixed, As Shown In The Figure.
Therefore, Calculating The Charging Capacity And Charging Time Through The Formula Is Only Suitable For Slow Charging, And It Is Difficult To Accurately Calculate The Fast Charging Time. The Next Article Will Introduce A Rough Estimation Method.
The Power Of Various Common Charging Piles
The Power Of The Charging Pile Above Is Only The Maximum Value. In The Actual Charging Process, The Power Will Be Affected By Many Factors.
At The Same Time, The Charging Power Of The Vehicle Itself Also Has A Maximum Limit. If The Maximum Charging Power Of The Vehicle Is 60kw, Even With A 120kw Charging Pile, The Maximum Power Can Only Be 60kw.
