Fundamental Characteristics of Stationary Lithium-Ion Secondary Cells and a Cell-Voltage-Equalizing Circuit

Individual Cell Equalization for Series Connected Lithium-Ion Batteries

“…The disadvantage of this equalization scheme is that the stored energy in the inductor is transferred to the weaker cell only in the (1 − D)T s duty cycle. The equalization time and efficiency of this equalization scheme are therefore poor for practical battery equalization applications in a smart battery management system (SBMS) [6]- [11]. Battery equalization control should be implemented to restrict the charge-discharge current to the allowable cell limitations in the battery string.…”

“…This enables additional charging capacity for the entire battery string [4]. Complete cell voltage balancing is performed using a bi-directional dc-dc converter based on the Cûk converter [9], [11]. This unit can be designed to operate at the DICM or DCVM to obtain soft switching in MOSFET switches [11]- [15].…”

“…Complete cell voltage balancing is performed using a bi-directional dc-dc converter based on the Cûk converter [9], [11]. This unit can be designed to operate at the DICM or DCVM to obtain soft switching in MOSFET switches [11]- [15]. The discontinuous conducting mode of a Cûk converter is generally of used in applications of the power factor correction technology [16]- [18] and the maximum power point tracker of PV panels [15], [19].…”

“…The aforementioned analysis and design method of the uni-directional Cûk converter operated at DCVM can not be totally adopted for the battery equalization application due to the alternating characteristics of the cell voltage balancing process in the charge/discharge of battery string [3], [4], [7]- [9]. The continuous and discontinuous inductor current modes of the bi-directional Cûk converter application for cell voltage balancing control of lithium-ion battery strings were investigated in literatures [11] and [20], [21], respectively. The main contribution of this paper is the first application of the bi-directional Cûk converter operating at DCVM in the design and analysis of the individual cell equalization control of the lithium-ion battery strings.…”

“…The consideration and experience for the cell balanc-Copyright c 2006 The Institute of Electronics, Information and Communication Engineers ing control system of a lithium ion battery string are summarized as follows [8], [11], [21]:…”