CN104899461A - Method for calculating charge of nickel-hydrogen power battery pack - Google Patents

Abstract

The invention provides a method for calculating the charge of a nickel-hydrogen power battery pack. The method comprises the steps that the capacity Qt, the internal resistance Rt and the temperature Tt of the battery pack at the initial moment t and the internal resistance R(t+delta t), the temperature T(t+delta t) and the voltage U(t+delta t) of the battery pack at the moment (t+delta t) are acquired through a BMS, the current I of the battery pack in the period from the initial moment t to the moment (t+delta t) is acquired according to a certain frequency, the charge and discharge efficiency mu t of the battery pack at the moment t and the charge and discharge efficiency mu(t+delta t) of the battery pack at the moment (t+delta t) are searched out according to the table 1, the charge SOC(v_t+delta t), corresponding to the voltage U(t+delta t), of the battery pack is searched out according to the table 2, and the acquired data are substituted into a formula to obtain SOC(t+delta t) through calculation. According to the method, the charge of the battery pack at different moments can be calculated more accurately.

Description

A kind of computing method of Ni-MH power cell bag carrying capacity

Technical field

The present invention relates to a kind of computing method of Ni-MH power cell bag carrying capacity.

Background technology

Along with the growth of demographic and economic, the energy and environmental problem impel various countries to tap a new source of energy automobile, the energy saving and environment friendly vehicles.Hybrid vehicle energy-saving and environmental protection, have the wide market space and good development prospect.And the number of the carrying capacity of the power brick used in hybrid vehicle, be related to the overall usability of automobile.The true carrying capacity of power brick is used as important controling parameters always and is applied in Control Strategy for Hybrid Electric Vehicle and Full Vehicle System, and the calculating of the true carrying capacity of power brick relates to the impact of many factors as battery temperature, efficiency for charge-discharge etc., the computing method that all neither one accuracy rate is higher all the time.

Summary of the invention

The present invention aims to provide the computing method of the higher Ni-MH power cell bag carrying capacity of a kind of accuracy rate.

The present invention is realized by following scheme:

Computing method for Ni-MH power cell bag carrying capacity, carry out according to the following steps,

(I) by BMS management system, the capacity Q of the initial t of power brick is obtained _t, internal resistance R _t, temperature T _twith the internal resistance R of t+ Δ t _{t+ Δ t}, temperature T _{t+ Δ t}, voltage U _{t+ Δ t}, press certain frequency simultaneously and obtain power brick from initial t to the electric current I of t+ Δ t, find the efficiency for charge-discharge μ of the initial t of power brick according to table 1 _twith the efficiency for charge-discharge μ of t+ Δ t _{t+ Δ t}, find voltage U according to table 2 _{t+ Δ t}corresponding battery pack charge quantity SOC _{v_t+ Δ t};

Table 1

Table 2

(II) data are substituted into the SOC that formula (1) draws t+ Δ t power brick _{i_t+ Δ t},

${\mathrm{SOC}}_{i\_t+\mathrm{\Δ}t}=\left(\frac{Q_t+{\∫}_t^{t+\mathrm{\Δ}t}Idt\×\frac{{\mathrm{\μ}}_t+{\mathrm{\μ}}_{t+\mathrm{\Δ}t}}{2}}{Q}+K_1\×\frac{R_{t+\mathrm{\Δ}t}-R_t}{R_t}\right)\×100\%...\left(1\right)$

Wherein, Q is the rated capacity of power brick; K ₁for temperature adjustment factor, as temperature T _{t+ Δ t}≤ 0 DEG C or temperature T _{t+ Δ t}when>=45 DEG C, K ₁=0.5, as 0 DEG C of < temperature T _{t+ Δ t}during < 45 DEG C, K ₁=0.2;

(III) by SOC that step (II) calculates _{i_t+ Δ t}substitute into the final carrying capacity SOC that formula (2) calculates t+ Δ t power brick _{t+ Δ t},

SOC _t+Δt＝SOC _{i_t+Δt}+K ₂×(SOC _{v_t+Δt}-SOC _{i_t+Δt})……………………(2)

Wherein, K ₂for error coefficient, K ₂be 0.3;

(V) data of the initial t all data of t+ Δ t calculated as next carrying capacity, calculate the battery pack charge quantity in each moment successively by step (I) ~ (III).

Further, described acquisition power brick from initial t to the frequency of the electric current I of t+ Δ t be every 10 ~ 100 person of outstanding talent seconds.

The computing method of Ni-MH power cell bag carrying capacity of the present invention, consider the impact of efficiency for charge-discharge, internal resistance, also contemplate the error between carrying capacity that current integration method obtains and the SOC that open-circuit voltage method obtains simultaneously, make the carrying capacity SOC result that calculates more accurate, for researchist provides good data reference, how the serviceable life of power brick on hybrid vehicle is extended to research staff and improves usability, there is directive significance.

Embodiment

Below in conjunction with embodiment, the invention will be further described, but the present invention is not limited to the statement of embodiment.

embodiment 1

Computing method for Ni-MH power cell bag carrying capacity, carry out according to the following steps,

(I) by BMS management system, the capacity Q of the initial t of power brick is obtained _t, internal resistance R _t, temperature T _twith the internal resistance R of t+ Δ t _{t+ Δ t}, temperature T _{t+ Δ t}, voltage U _{t+ Δ t}, simultaneously by every 50 person of outstanding talent seconds frequency acquisition power brick from initial t to the electric current I of t+ Δ t, find the efficiency for charge-discharge μ of the initial t of power brick according to table 1 _twith the efficiency for charge-discharge μ of t+ Δ t _{t+ Δ t}, find voltage U according to table 2 _{t+ Δ t}corresponding battery pack charge quantity SOC _{v_t+ Δ t};

Table 1

Table 2

(II) data are substituted into the SOC that formula (1) draws t+ Δ t power brick _{i_t+ Δ t},

${\mathrm{SOC}}_{i\_t+\mathrm{\&Delta;}t}=\left(\frac{Q_t+{\&Integral;}_t^{t+\mathrm{\&Delta;}t}Idt\&times;\frac{{\mathrm{\&mu;}}_t+{\mathrm{\&mu;}}_{t+\mathrm{\&Delta;}t}}{2}}{Q}+K_1\&times;\frac{R_{t+\mathrm{\&Delta;}t}-R_t}{R_t}\right)\&times;100\%...\left(1\right)$

Wherein, Q is the rated capacity of power brick; K ₁for temperature adjustment factor, as temperature T _{t+ Δ t}≤ 0 DEG C or temperature T _{t+ Δ t}when>=45 DEG C, K ₁=0.5, as 0 DEG C of < temperature T _{t+ Δ t}during < 45 DEG C, K ₁=0.2;

(III) by SOC that step (II) calculates _{i_t+ Δ t}substitute into the final carrying capacity SOC that formula (2) calculates t+ Δ t power brick _{t+ Δ t},

SOC _t+Δt＝SOC _{i_t+Δt}+K ₂×(SOC _{v_t+Δt}-SOC _{i_t+Δt})……………………(2)

Wherein, K ₂for error coefficient, K ₂be 0.3;

(V) data of the initial t all data of t+ Δ t calculated as next carrying capacity, calculate the battery pack charge quantity in each moment successively by step (I) ~ (III).

Generally, it is all suitable for second every 10 ~ 100 persons of outstanding talent for obtaining power brick from initial t to the frequency of the electric current I of t+ Δ t.

Claims (2)

1. computing method for Ni-MH power cell bag carrying capacity, is characterized in that: carry out according to the following steps,

(I) by BMS management system, the capacity Q of the initial t of power brick is obtained _t, internal resistance R _t, temperature T _twith the internal resistance R of t+ Δ t _{t+ Δ t}, temperature T _{t+ Δ t}, voltage U _{t+ Δ t}, press certain frequency simultaneously and obtain power brick from initial t to the electric current I of t+ Δ t, find the efficiency for charge-discharge μ of the initial t of power brick according to table 1 _twith the efficiency for charge-discharge μ of t+ Δ t _{t+ Δ t}, find voltage U according to table 2 _{t+ Δ t}corresponding battery pack charge quantity SOC _{v_t+ Δ t};

Table 1

Table 2

(II) data are substituted into the SOC that formula (1) draws t+ Δ t power brick _{i_t+ Δ t},

${\mathrm{SOC}}_{t\_t+\mathrm{\&Delta;}t}=(\frac{Q_t+{\&Integral;}_t^{t+\mathrm{\&Delta;}t}Idt\&times;\frac{{\mathrm{\&mu;}}_t+{\mathrm{\&mu;}}_{t+\mathrm{\&Delta;}t}}{2}}{Q}+K_1\&times;\frac{{R_{t+\mathrm{\&Delta;t}}}_{}-R_t}{R_t})\&times;100\%\mathrm{...}\left(1\right)$

Wherein, Q is the rated capacity of power brick; K ₁for temperature adjustment factor, as temperature T _{t+ Δ t}≤ 0 DEG C or temperature T _{t+ Δ t}when>=45 DEG C, K ₁=0.5, as 0 DEG C of < temperature T _{t+ Δ t}during < 45 DEG C, K ₁=0.2;

(III) by SOC that step (II) calculates _{i_t+ Δ t}substitute into the final carrying capacity SOC that formula (2) calculates t+ Δ t power brick _{t_t+ Δ t},

SOC _t+Δt＝SOO _{i_t+Δt}+K ₂×(SOC _{v_t+Δt}-SOC _{i_t+Δt})…………………(2)

Wherein, K ₂for error coefficient, K ₂be 0.3;

(V) data of the initial t all data of t+ Δ t calculated as next carrying capacity, calculate the battery pack charge quantity in each moment successively by step (I) ~ (III).

2. the computing method of a kind of Ni-MH power cell bag carrying capacity as claimed in claim 1, is characterized in that: described acquisition power brick from initial t to the frequency of the electric current I of t+ Δ t for every 10 ~ 100 person of outstanding talent seconds.