CN-121984174-A - Battery equalization control system and control method

CN121984174ACN 121984174 ACN121984174 ACN 121984174ACN-121984174-A

Abstract

The invention discloses a battery equalization control method and a control system, which comprise the steps of obtaining standing time of a battery cluster, residual capacity of the battery cluster and monomer residual capacity and monomer voltage of each single battery in the battery cluster, executing an equalization algorithm based on the residual capacity when the standing time of the battery cluster reaches a first preset time and the residual capacity of the battery cluster is lower than a first preset value, controlling an equalization circuit according to parameters obtained by executing the equalization algorithm based on the residual capacity, executing a voltage-based equalization algorithm when the equalization algorithm based on the residual capacity judges that the equalization circuit does not need to work, and controlling the equalization circuit according to the parameters obtained by executing the equalization algorithm based on the voltage, so that the equalization efficiency of a battery equalization system and the service life of the battery cluster can be improved.

Inventors

DU FANGSUO
WANG ZHENG
WU HONGYU

Assignees

杭州协能科技股份有限公司

Dates

Publication Date: 20260505
Application Date: 20260325

Claims (10)

1. A battery equalization control method, comprising: obtaining standing time of a battery cluster, residual capacity of the battery cluster and monomer residual capacity and monomer voltage of each monomer battery in the battery cluster; when the standing time of the battery cluster reaches a first preset time and the residual electric quantity of the battery cluster is lower than a first preset value, executing an equalization algorithm based on the residual electric quantity, and controlling an equalization circuit according to parameters obtained by executing the equalization algorithm based on the residual electric quantity; and when the balance algorithm based on the residual electric quantity judges that the balance circuit does not need to work, executing a voltage-based balance algorithm, and controlling the balance circuit according to parameters obtained by executing the voltage-based balance algorithm.
2. The control method according to claim 1, wherein the equalization circuit includes an intra-group active equalization circuit and an inter-group active equalization circuit, each battery group includes a plurality of unit cells connected in series, the battery cluster includes at least two battery groups, The in-group active equalization circuit comprises a plurality of in-group active equalization units, and one in-group active equalization unit is connected between two adjacent single batteries in each battery group; The inter-group active equalization circuit comprises at least two inter-group active equalization units, and one inter-group active equalization unit is connected between the positive electrode and the negative electrode of each battery group.
3. The control method according to claim 2, wherein the remaining capacity-based equalization algorithm includes an intra-group active equalization algorithm based on remaining capacity and an inter-group active equalization algorithm based on remaining capacity, The parameters obtained by executing the active balancing algorithm in the group based on the residual electric quantity comprise the balancing direction of each active balancing unit in the group, the balancing duty ratio of each active balancing unit in the group in each balancing period and the balancing time of each active balancing unit in the group, The parameters obtained by executing the inter-group active equalization algorithm based on the residual electric quantity comprise an inter-group active equalization unit to be started and the starting time of the inter-group active equalization unit.
4. The control method according to claim 3, wherein the remaining power-based inter-group active equalization algorithm includes: Calculating the cluster average residual capacity of the whole battery cluster and the group average residual capacity of each battery group; calculating a first difference between the maximum group average remaining power and the group average remaining power of each battery pack and a second difference between the group average remaining power of each battery pack and the cluster average remaining power, and And determining a battery pack which needs to be subjected to inter-group active equalization according to the first difference value and the second difference value, and calculating the starting time of the corresponding inter-group active equalization unit.
5. The control method according to claim 4, wherein, And when the first difference value corresponding to the battery pack is higher than a second preset value or the second difference value is lower than a third preset value, determining that the battery pack needs inter-pack active equalization.
6. The control method of claim 2, wherein the voltage-based equalization algorithm comprises an intra-voltage-based active equalization algorithm and an inter-voltage-based active equalization algorithm, The parameters obtained by executing the voltage-based intra-group active equalization algorithm comprise the equalization direction of the intra-group active equalization units and the equalization duty ratio of the intra-group active equalization units in each equalization period; the parameters obtained by executing the inter-group active equalization algorithm based on the voltage comprise inter-group active equalization units which need to be started.
7. The control method of claim 6, wherein the voltage-based intra-group active equalization algorithm is updated every second preset time.
8. The control method of claim 6, wherein the voltage-based inter-group active equalization algorithm comprises: calculating the cluster average voltage of the whole battery cluster and the group average voltage of each battery group; calculating a third difference between the maximum group average voltage and the group average voltage of each battery group and a fourth difference between the group average voltage of each battery group and the cluster average voltage, and And determining a battery pack which needs to be subjected to inter-group active equalization according to the third difference value and the fourth difference value, and controlling the battery pack to be started for a third preset time.
9. The control method according to claim 8, wherein, And when the third difference value corresponding to the battery pack is higher than a fourth preset value or the fourth difference value is lower than a fifth preset value, determining that the battery pack needs inter-pack active equalization.
10. A battery equalization control system for performing the battery equalization control method according to any one of claims 1-9, the control system comprising: The sampling unit is used for obtaining the standing time of the battery cluster, the residual capacity of the battery cluster and the monomer residual capacity and the monomer voltage of each monomer battery in the battery cluster; An algorithm execution unit for executing a balance algorithm based on residual power or a balance algorithm based on voltage according to the signal sampled by the sampling unit to obtain corresponding parameters, and And the control unit is used for controlling the equalization circuit to execute corresponding equalization operation according to the parameters.

Description

Battery equalization control system and control method Technical Field The invention relates to the technical field of battery equalization, in particular to a battery equalization control system and a battery equalization control method. Background The lithium battery comprises a lithium battery cell, a lithium battery pack and a lithium battery cluster according to the packaging form. The inconsistency of the single batteries is gradually expanded along with the use of the battery pack, on one hand, the difference of the ageing rates of different single batteries is influenced by factors such as uneven temperature distribution of the use environment, difference of charge and discharge current distribution and the like, partial single batteries are accelerated to age, so that the capacity decay speed of the single batteries is faster than that of other batteries, and on the other hand, the small difference of initial parameters among the single batteries is continuously amplified along with the increase of the charge and discharge cycle times, so that the inconsistency of the parameters such as voltage, capacity, internal resistance and the like of each single battery is more remarkable. The inconsistency between the single cells can affect the overall performance of the battery pack, and also affect the service life of the single cells. In order to solve the above problems, various equalization schemes are proposed in the prior art, and the schemes are mainly divided into two major categories, namely active equalization and passive equalization. The core principle of the passive equalization mode is that the voltage of each single battery in the battery pack is monitored in real time through a voltage detection module, when the voltage of one or more single batteries is detected to be obviously higher than that of other single batteries, energy consumption elements (such as resistors) in an equalization circuit are controlled to be conducted, and redundant electric energy of the single battery with higher voltage is consumed in a heat energy mode until the voltages of the single batteries tend to be consistent. The active equalization mode is to identify the single battery with higher voltage and the single battery with lower voltage through the voltage detection module, and then directionally transfer the electric energy of the single battery with higher voltage to the single battery with lower voltage by using an energy transfer device (such as an inductor, a capacitor, a transformer and the like) in the active equalization circuit, so that the high-efficiency transfer and redistribution of the electric energy among different single batteries are realized, and the consistency of the battery pack is improved rapidly. However, the existing passive equalization scheme has lower efficiency and serious energy waste, while the active equalization scheme has higher efficiency, but has the problems of too slow equalization speed and higher cost. Based on this, a new battery equalization control system and control method have been proposed to solve the above-described problems. Disclosure of Invention In view of the foregoing, it is an object of the present invention to provide a battery equalization control system and control method, whereby the equalization efficiency of the battery equalization system and the service life of a battery cluster can be improved. According to one aspect of the invention, a battery equalization control method is provided, which comprises the steps of obtaining standing time of a battery cluster, residual capacity of the battery cluster and monomer residual capacity and monomer voltage of each monomer battery in the battery cluster, executing an equalization algorithm based on the residual capacity when the standing time of the battery cluster reaches a first preset time and the residual capacity of the battery cluster is lower than a first preset value, controlling an equalization circuit according to parameters obtained by executing the equalization algorithm based on the residual capacity, and executing a voltage-based equalization algorithm and controlling the equalization circuit according to the parameters obtained by executing the equalization algorithm based on the voltage when the equalization algorithm based on the residual capacity judges that the equalization circuit does not need to work. Optionally, the equalization circuit comprises an intra-group active equalization circuit and an inter-group active equalization circuit, each battery group comprises a plurality of single batteries connected in series, the battery cluster comprises at least two battery groups, the intra-group active equalization circuit comprises a plurality of intra-group active equalization units, one intra-group active equalization unit is connected between two adjacent single batteries in each battery group, the inter-group active equalization circuit comprises at least two inter-group active equ