Charging control method for energy storage battery

Abstract

The invention relates to the technical field of battery management, in particular to an energy storage battery charging control method, which comprises the following steps: acquiring a battery temperature T1, a minimum charging temperature T0 of a battery, a battery residual capacity C, a charging pile output power Pu and a charging voltage U; if T1 is greater than T0, allowing the charging pile to charge the battery, and obtaining the heating power P1 of the battery when the battery is charged at the current temperature; obtaining the average electricity consumption power P0 when the BMS works within a preset time period before charging; re-estimating the electricity utilization power P2 of the BMS, and calculating the charging power Pm according to the Pu, the P2, the P1 and the P0; and estimating the charging time t = C / (Pm / U). The heating condition of the battery and the actual electricity utilization condition of the BMS in the charging process are comprehensively considered, the calculated charging power Pm better conforms to the actual condition, and the estimated charging time is more accurate.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management, and in particular to a charging control method for an energy storage battery. Background Art

[0002] The battery management system, BMS, is an important component of the electric vehicle power battery system. It is necessary to perform operations such as battery state estimation, charging control, parameter detection and thermal management. When performing thermal management on the battery, it is necessary to determine the intensity of active heating or heat dissipation based on the temperature distribution information in the battery pack and the charging and discharging requirements, so that the battery can work at the most suitable temperature as much as possible and give full play to the battery's performance. When charging the battery, the BMS estimates the battery charging time based on the battery and its own power consumption, but under different working conditions, the actual power consumption of the BMS and the battery is also changing, resulting in inaccurate judgment of the charging time, affecting the accuracy of data presentation. Summary of the invention

[0003] The present invention provides a method for controlling charging of an energy storage battery, so as to solve the problem of inaccurate estimation of charging time of the battery in the prior art.

[0004] A method for controlling charging of an energy storage battery of the present invention adopts the following technical solution: A method for controlling charging of an energy storage battery comprises the following steps: S100, obtaining the battery temperature T1, the battery's minimum charging temperature T0, the battery's remaining capacity C, the charging pile output power Pu, and the charging voltage U; S200, if T1 is greater than T0, the charging pile is allowed to charge the battery, and the heat generation power P1 of the battery when charging at the current temperature is obtained; S300, obtaining the average power consumption P0 of the BMS during operation in a preset time period before charging; S400, re-estimating the power consumption P2 of the BMS, and calculating the charging power Pm based on Pu, P2, P1 and P0; S500, estimating charging time t=C / (Pm / U).

[0005] Furthermore, step S200 further includes: If T1 is not greater than T0, the charging pile supplies power to the BMS, and the BMS heats the battery until the battery temperature is greater than T0. The charging pile is allowed to charge the battery and obtain the charging heat power P1 of the battery at the current temperature.

[0006] Furthermore, step S200 further includes: Get the battery internal resistance R1 at the current battery temperature; Get the charging current I1; Calculate the heat generation power of the battery when charging at the current temperature P1=R1*I1 2 .

[0007] Further, step S300 includes: Get the real-time power of BMS at multiple time points within the preset time period before charging; The average power consumption P0 is obtained by calculating the average value of multiple real-time powers.

[0008] Further, step S400 includes: S410, obtaining an average heat generation power P8 of the battery when discharging at the current temperature; S420, obtaining an energy efficiency ratio η of the BMS for heat dissipation of the battery; S430, obtaining the inherent power consumption P of the BMS in the standby state 固 ; S440, obtaining the working status of the BMS within a preset time period before charging; S441, if the BMS is in standby mode within the preset time period before charging, P2=P 固 +P1 / η; S442, if the BMS is in a heat dissipation state within the preset time period before charging, P2=P0-P8 / η+P1 / η; S443, if the BMS is in a heating state within the preset time period before charging, P2=P0-P1 / η; S450, calculating charging power Pm=Pu-P2-P1.

[0009] Further, step S410 includes: Obtain the average operating current I2 of the battery within a preset time period before charging; Get the internal resistance R2 of the battery; Calculate the average heat generation power of the battery when discharging at the current temperature P8=R2*I2 2 .

[0010] The beneficial effects of the present invention are as follows: the energy storage battery charging control method of the present invention comprehensively considers the heating of the battery during the charging process and the actual power consumption of the BMS, the calculated charging power Pm is more in line with the actual situation, and the estimated charging time is also more accurate.

[0011] Furthermore, by obtaining the working status and actual output power of the BMS before charging and inferring its actual output power in the subsequent charging process, the power Pm actually used by the charging pile to charge the battery can be calculated, which is more accurate when estimating the charging time. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0013] Figure 1 A schematic diagram of a flow chart of an embodiment of a method for controlling charging of an energy storage battery according to the present invention; Figure 2 It is a flow chart of step S400 in an embodiment of a method for controlling charging of an energy storage battery of the present invention. DETAILED DESCRIPTION

[0014] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0015] An embodiment of a method for controlling charging of an energy storage battery according to the present invention is as follows: Figure 1 to Figure 2 As shown, the following steps are included: S100, obtaining the battery temperature T1, the battery's minimum charging temperature T0, the battery's remaining capacity C, the charging pile output power Pu, and the charging voltage U; S200, if T1 is greater than T0, the charging pile is allowed to charge the battery, and the heat generation power P1 of the battery when charging at the current temperature is obtained; S300, obtaining the average power consumption P0 of the BMS during operation in a preset time period before charging; S400, re-estimating the power consumption P2 of the BMS, and calculating the charging power Pm based on Pu, P2, P1 and P0; S500, estimating charging time t=C / (Pm / U).

[0016] The allowable charging range of the battery includes the optimal charging temperature range. Taking lithium batteries as an example, under normal circumstances, the optimal charging temperature is between 20°C and 45°C. The battery has good rate characteristics and small capacity attenuation. The allowable charging temperature range is between 0°C and 45°C. In this embodiment, the minimum charging temperature T0 of the battery can be the lowest value of the allowable charging temperature range of the battery. When T1 is greater than T0, the charging pile is allowed to charge the battery to avoid damage to the battery caused by charging at low temperatures. Obtain the heat generation power P1 of the battery when charging at the current temperature, and calculate the power of the BMS when dissipating heat for the battery; calculate the average power consumption P0 of the BMS when working in the preset time period before charging; it can be judged what kind of working state the BMS is in before charging the battery, and estimate the power consumption P2 of the BMS in the next charging process of the battery based on the previous working state of the BMS, which can more accurately reflect the power consumption of the BMS in the actual working state, and calculate the charging power Pm by combining the output power Pu of the charging pile, the power consumption P2 of the BMS, the heat generation power P1 of the battery when charging at the current temperature, and the average power consumption P0 of the BMS when working in the preset time period before charging; the charging power Pm refers to the power consumed by the part of the charging pile actually used for charging the battery. Taking into account the heating of the battery during the charging process and the actual power consumption of the BMS, the calculated charging power Pm is more in line with the actual situation, and the estimated charging time is also more accurate.

[0017] In this embodiment, step S200 further includes: If T1 is not greater than T0, the charging pile supplies power to the BMS, and the BMS heats the battery until the battery temperature is greater than T0. The charging pile is allowed to charge the battery and obtain the charging heat power P1 of the battery at the current temperature.

[0018] When T1 is not greater than T0, heat the battery first to avoid charging at low temperature which may affect the battery life.

[0019] In this embodiment, step S200 further includes: Get the battery internal resistance R1 at the current battery temperature; Get the charging current I1; Calculate the heat generation power of the battery when charging at the current temperature P1=R1*I1 2 .

[0020] The internal resistance of the battery will have different values ​​at different temperatures. This internal resistance value can be given by the battery manufacturer. It can usually be obtained through testing during the production process. The corresponding battery internal resistance value is obtained according to the current temperature of the battery, and combined with the charging current, the heat power of the battery when charging at the current temperature can be obtained. The heat power reflects the degree of heat generated by the battery when it is charging.

[0021] In this embodiment, step S300 includes: Get the real-time power of BMS at multiple time points within the preset time period before charging; The average power consumption P0 is obtained by calculating the average value of multiple real-time powers.

[0022] The preset time period can be 5 minutes to 10 minutes, starting from the acquisition of the charging signal and working backwards. The real-time power of the BMS is generally recorded in the control module of the car and can be directly obtained. The real-time power is obtained every 1 minute to 2 minutes and the average value is calculated to reduce the impact of the instantaneous power change of the BMS on the obtained results.

[0023] In this embodiment, step S400 includes: S410, obtaining an average heat generation power P8 of the battery when discharging at the current temperature; S420, obtaining an energy efficiency ratio η of the BMS for heat dissipation of the battery; S430, obtaining the inherent power consumption P of the BMS in the standby state 固 ; S440, obtaining the working status of the BMS within a preset time period before charging; S441, if the BMS is in standby mode within the preset time period before charging, P2=P 固 +P1 / η; S442, if the BMS is in a heat dissipation state within the preset time period before charging, P2=P0-P8 / η+P1 / η; S443, if the BMS is in a heating state within the preset time period before charging, P2=P0-P1 / η; S450, calculating charging power Pm=Pu-P2-P1.

[0024] Among them, η is the ratio of the heat dissipated by the battery to the electric energy consumed by the BMS. This ratio is measured experimentally by the battery and the BMS during the simulation process, reflecting the efficiency of the BMS in dissipating the heat of the battery. Based on this energy efficiency ratio, the power required for the BMS to dissipate the heat generated during the battery charging process can be calculated. The BMS has a standby state, a heat dissipation state, and a heating state. In the standby state, the temperature of the battery is within the normal operating temperature range. The BMS only monitors the battery without heating or dissipating the heat. In this state, only the inherent power consumption P of the BMS is consumed. 固 That is, P 固It is the power consumption of other modules of BMS except the thermal management module. In the heat dissipation state or heating state, BMS needs to dissipate heat or heat the battery, and the output power must be greater than its inherent power consumption. If the BMS is in standby state before charging, then during the charging process, the BMS only needs its inherent power consumption plus the power required to dissipate the heat generated during the battery charging process. If the BMS was previously in a heat dissipation state, it means that the battery temperature increases with the increase of working time, and the car may be in a driving state. The BMS dissipates heat from the battery to keep it within the normal working temperature range. By obtaining the average heat generation power P8 when the battery is discharged at the current temperature, the power consumed by the BMS to dissipate the heat generated by the battery during the previous preset time period is calculated as P8 / η. In the subsequent charging process, the battery will only increase in temperature due to charging. The actual power consumption P2 of the BMS needs to be obtained by subtracting the power consumed by the BMS to dissipate the heat generated in the battery working state in the previous preset time period from the average power consumption P0 of the BMS during the preset time period before charging, which is P8 / η, and adding the power P1 / η required to dissipate the heat generated during the battery charging process. If the BMS was previously in a heating state, it means that the battery temperature is low, the car may be in a parking state and the external environment temperature is low. The BMS heats the battery to keep it within the normal working temperature range. In the following charging process, since the battery will also generate heat due to charging, the actual power consumption P2 of the BMS can be obtained by subtracting the power P1 / η required to dissipate the heat generated during the battery charging process from the average power consumption P0 of the BMS during the preset time period before charging, that is, during the charging process, due to the heat generated by the battery itself, the BMS will reduce its actual output power accordingly. During the charging process of the battery by the charging pile, the battery itself generates heat and consumes part of the energy, and the BMS monitors the battery and dissipates heat and also consumes part of the energy. Therefore, the charging power Pm actually used to charge the battery is the output power Pu of the charging pile minus the power consumption P2 of the BMS and the heat generation power P1 of the battery when charging at the current temperature.

[0025] By obtaining the working status and actual output power of the BMS before charging and inferring its actual output power in the subsequent charging process, it is possible to calculate the power Pm actually used by the charging pile to charge the battery, which is also more accurate when estimating the charging time.

[0026] In some other embodiments, the input-output ratio of the BMS is obtained, and the input power of the BMS is calculated based on the actual output power of the BMS. When calculating the charging power Pm, the input power of the BMS and the heat generation power P1 of the battery when charging at the current temperature are subtracted from the output power Pu of the charging pile to obtain a more accurate charging power Pm.

[0027] In this embodiment, step S410 includes: Obtain the average operating current I2 of the battery within a preset time period before charging; Get the internal resistance R2 of the battery; Calculate the average heat generation power of the battery when discharging at the current temperature P8=R2*I2 2 .

[0028] The real-time working current of the battery is generally recorded in the control module of the car and can be directly obtained. Multiple real-time working current values ​​are obtained within a preset time period, and the average working current is obtained by calculation. If the battery is not discharged within the preset time period before charging, that is, the car is parked, and the battery is cooled by the BMS due to the increase in the external ambient temperature, then I2 is 0, and the corresponding P8 is also 0.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for controlling charging of an energy storage battery, characterized in that: The following steps are involved: S100, obtaining the battery temperature T1, the battery's minimum charging temperature T0, the battery's remaining capacity C, the charging pile output power Pu, and the charging voltage U; S200, if T1 is greater than T0, the charging pile is allowed to charge the battery, and the heat generation power P1 of the battery when charging at the current temperature is obtained; S300, obtaining the average power consumption P0 of the BMS during operation in a preset time period before charging; S400, re-estimating the power consumption P2 of the BMS, and calculating the charging power Pm based on Pu, P2, P1 and P0; S500, estimating charging time t=C / (Pm / U).

2. A method for controlling charging of an energy storage battery according to claim 1, characterized in that: Step S200 also includes: If T1 is not greater than T0, the charging pile supplies power to the BMS, and the BMS heats the battery until the battery temperature is greater than T0. The charging pile is allowed to charge the battery and obtain the charging heat power P1 of the battery at the current temperature.

3. A method for controlling charging of an energy storage battery according to claim 2, characterized in that: Step S200 also includes: Get the battery internal resistance R1 at the current battery temperature; Get the charging current I1; Calculate the heat generation power of the battery when charging at the current temperature P1=R1*I1 2 .

4. The energy storage battery charging control method according to claim 1, characterized in that: Step S300 includes: Get the real-time power of BMS at multiple time points within the preset time period before charging; The average power consumption P0 is obtained by calculating the average value of multiple real-time powers.

5. The energy storage battery charging control method according to claim 1, characterized in that: Step S400 includes: S410, obtaining an average heat generation power P8 of the battery when discharging at the current temperature; S420, obtaining an energy efficiency ratio η of the BMS for heat dissipation of the battery; S430, obtaining the inherent power consumption P of the BMS in the standby state 固 ; S440, obtaining the working status of the BMS within a preset time period before charging; S441, if the BMS is in standby mode within the preset time period before charging, P2=P 固 +P1 / η; S442, if the BMS is in a heat dissipation state within the preset time period before charging, P2=P0-P8 / η+P1 / η; S443, if the BMS is in a heating state within the preset time period before charging, P2=P0-P1 / η; S450, calculating charging power Pm=Pu-P2-P1.

6. A method for controlling charging of an energy storage battery according to claim 5, characterized in that: Step S410 includes: Obtain the average operating current I2 of the battery within a preset time period before charging; Get the internal resistance R2 of the battery; Calculate the average heat generation power of the battery when discharging at the current temperature P8=R2*I2 2 .

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