計算 battery impedence

Origin

一顆電池被拉載後，會產生電流及電壓如下圖，
如何計算其電池內阻呢
其公式為
R = |delta(V) / delta(I)|

公式推導如下：

V1 = 10 - I1R --- 左圖
V2 = 10 - I2R --- 右圖

===>>>

10 = V1 + I1R
10 = V2 + I2R

===>>>

V1 + I1R = V2 + I2R

===>>>

V1 - V2 = -I1R + I2R

===>>>

V1 - V2 = R (-I1 + I2)

===>>>

R = (V1 - V2) / (-I1 + I2)
R = |delta(V) / delta(I)|

---

Conclusion

R = |delta(V) / delta(I)|