CN109950661A - A device and method for simultaneously heating the inside and outside of a power battery pack - Google Patents
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- 238000010438 heat treatment Methods 0.000 title claims abstract description 153
- 238000000034 method Methods 0.000 title claims abstract description 40
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims abstract description 13
- 229910001416 lithium ion Inorganic materials 0.000 claims abstract description 13
- 238000005070 sampling Methods 0.000 claims description 36
- 230000010287 polarization Effects 0.000 claims description 33
- 230000005284 excitation Effects 0.000 claims description 30
- 230000002457 bidirectional effect Effects 0.000 claims description 18
- 230000006870 function Effects 0.000 claims description 14
- 239000003990 capacitor Substances 0.000 claims description 9
- 230000020169 heat generation Effects 0.000 claims description 6
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 238000001453 impedance spectrum Methods 0.000 claims description 3
- 238000007599 discharging Methods 0.000 claims 1
- 238000009826 distribution Methods 0.000 abstract description 8
- 230000000694 effects Effects 0.000 abstract description 6
- 239000012528 membrane Substances 0.000 abstract description 2
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 5
- 229910052744 lithium Inorganic materials 0.000 description 5
- 238000011217 control strategy Methods 0.000 description 2
- 230000007423 decrease Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000011149 active material Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 238000004146 energy storage Methods 0.000 description 1
- 230000003446 memory effect Effects 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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Abstract
一种动力电池组的内外部同时加热的装置及方法，涉及锂离子动力电池加热技术领域。本发明解决了现有动力电池组低温加热采用外部加热的方法存在加热温度分布不均，影响电池使用效果的问题。本发明首先进行电池电量的判断，在低电量时不启动自加热过程，避免电池过放。在电池电量充足时开始通过加热膜进行外部加热，并通过内部加热来对外部加热产生的温度的不均匀分布进行调整。内部加热首先将偶数组子电池组，每两组子电池组构成一个自加热单元，采用温度传感器采集所有自加热单元中一组子电池组的表面温度，并对采集的温度进行比较，仅对温度最低的组进行内部加热从而达到使温度均匀分布的目的。本发明适用于动力电池组预热。
A device and method for simultaneously heating the inside and outside of a power battery pack relate to the technical field of lithium-ion power battery heating. The invention solves the problem of uneven heating temperature distribution in the existing low-temperature heating method of the power battery pack using external heating, which affects the use effect of the battery. The present invention firstly judges the power of the battery, and does not start the self-heating process when the power is low, so as to avoid over-discharge of the battery. External heating by the heating membrane starts when the battery is sufficiently charged, and internal heating is used to adjust for the uneven distribution of temperature produced by the external heating. For internal heating, an even group of sub-battery packs, each of which constitutes a self-heating unit, uses a temperature sensor to collect the surface temperature of a group of sub-battery packs in all self-heating units, and compares the collected temperatures. The group with the lowest temperature is internally heated to achieve a uniform temperature distribution. The present invention is suitable for the preheating of power battery packs.
Description
技术领域technical field
本发明涉及锂离子动力电池加热技术领域。The invention relates to the technical field of lithium ion power battery heating.
背景技术Background technique
随着能源问题的产生，国家对新能源产业的大力支持，锂离子电池由于其能量密度大，自放电率低和无记忆效应等优点，成为重要的储能元件，在新能源电站，电动汽车等领域得到了广泛应用。With the emergence of energy problems and the country's strong support for the new energy industry, lithium-ion batteries have become an important energy storage element due to their advantages of high energy density, low self-discharge rate and no memory effect. In new energy power stations, electric vehicles and other fields have been widely used.
由于锂电池内部的结构及电化学性质，在低温下锂电池的充放电性能存在较大问题。低温下活性物质的活性降低，内部的扩散速率减小。使得锂离子电池内部阻抗在低温下大幅增加，输出功率减小，同时可用的电池容量也相应的减小。同时在低温下使用锂电池存在负极析锂等问题，使得锂电池的低温加热成为必要。而采用外部加热的方式存在温度分布不均匀的问题。Due to the internal structure and electrochemical properties of lithium batteries, the charge-discharge performance of lithium batteries at low temperatures has great problems. At low temperature, the activity of the active material decreases, and the diffusion rate inside decreases. The internal impedance of the lithium-ion battery is greatly increased at low temperatures, the output power is reduced, and the available battery capacity is correspondingly reduced. At the same time, the use of lithium batteries at low temperatures has problems such as lithium deposition in the negative electrode, which makes low-temperature heating of lithium batteries necessary. However, the method of external heating has the problem of uneven temperature distribution.
发明内容SUMMARY OF THE INVENTION
本发明是为了解决现有动力电池组低温加热采用外部加热的方法存在加热温度分布不均，影响电池使用效果的问题，提出了一种动力电池组的内外部同时加热的装置及方法。The present invention proposes a device and method for simultaneously heating the inside and outside of a power battery pack in order to solve the problem of uneven heating temperature distribution and affecting the use effect of the battery in the existing low-temperature heating method of the power battery pack using external heating.
本发明所述的一种动力电池组的内外部同时加热的装置，该装置应用于包括2N个子电池组的动力电池组，该装置包括加热膜1、2N个开关电路3、N个温度传感器4、双向DC/DC变换器5、采样电路6和控制单元7；The device for simultaneously heating the inside and outside of a power battery pack according to the present invention is applied to a power battery pack including 2N sub-battery packs. The device includes a heating film 1, 2N switching circuits 3, and N temperature sensors 4. , bidirectional DC/DC converter 5, sampling circuit 6 and control unit 7;
加热膜1设置在动力电池组的外侧，用于对动力电池组进行外部加热；所述加热膜1的加热功率控制信号输入端连接控制单元7的外部加热控制信号输出端；The heating film 1 is arranged on the outside of the power battery pack, and is used to externally heat the power battery pack; the heating power control signal input end of the heating film 1 is connected to the external heating control signal output end of the control unit 7;
排列位置以动力电池组内部空间中轴线对称的两个子电池组构成一个自加热单元，每个自加热单元内设置有一个温度传感器4，温度传感器4用于采集所属自加热单元中任意一个子电池组的表面温度信号，N个温度传感器4的温度信号输出端均连接控制单元7的温度信号输入端；Two sub-battery packs whose arrangement positions are symmetrical with the axis in the inner space of the power battery pack constitute a self-heating unit, each self-heating unit is provided with a temperature sensor 4, and the temperature sensor 4 is used to collect any sub-battery in the self-heating unit. The surface temperature signal of the group, the temperature signal output ends of the N temperature sensors 4 are all connected to the temperature signal input end of the control unit 7;
每个自加热单元中的一组子电池组的充放电信号输入输出端通过一个开关电路3连接双向DC/DC变换器5一侧的信号输入输出端，另一组子电池组的充放电信号输入输出端通过一个开关电路3连接双向DC/DC变换器5另一侧的信号输入输出端；2N个开关电路3的控制信号输入端都与控制单元7的开关控制信号输出端相连；The charge and discharge signal input and output terminals of a group of sub-battery packs in each self-heating unit are connected to the signal input and output terminals of one side of the bidirectional DC/DC converter 5 through a switch circuit 3, and the charge and discharge signals of the other group of sub-battery packs The input and output ends are connected to the signal input and output ends of the other side of the bidirectional DC/DC converter 5 through a switch circuit 3; the control signal input ends of the 2N switch circuits 3 are all connected with the switch control signal output end of the control unit 7;
采样电路6通过N个开关电路3分别与N个自加热单元中的一组子电池组相连，用于采集所连接的子电池组的电流、端电压和荷电状态；采样电路6的信号输出端连接控制单元7的采样信号输入端。The sampling circuit 6 is respectively connected with a group of sub-battery packs in the N self-heating units through N switch circuits 3, and is used to collect the current, terminal voltage and state of charge of the connected sub-battery packs; the signal output of the sampling circuit 6 The terminal is connected to the sampling signal input terminal of the control unit 7 .
一种动力电池组的内外部同时加热装置的加热控制方法，该方法是基于一种动力电池组的内外部同时加热的装置实现的，该方法的具体步骤为：A heating control method for simultaneously heating the inside and outside of a power battery pack, the method is realized based on a device for simultaneously heating the inside and outside of a power battery pack, and the specific steps of the method are:
步骤一、将某一组子电池组投入采样回路中，并采集该子电池组的荷电状态soc，并判断所述荷电状态soc是否大于设定的荷电状态阈值socset，若是，则执行步骤二、否则，电池组处于低电量状态，为了防止电池过放，不能进行自加热过程，重复执行步骤一，socset为正数；Step 1. Put a certain group of sub-battery packs into the sampling loop, and collect the state of charge soc of the sub-battery pack, and determine whether the state of charge soc is greater than the set state of charge threshold soc set , if so, then Perform step 2. Otherwise, the battery pack is in a low power state. In order to prevent the battery from being over-discharged, the self-heating process cannot be performed. Repeat step 1, and the soc set is a positive number;
步骤二、采集N个自加热单元内的温度T，判断N个自加热单元中的温度最低值Tmin是否小于温度阈值Tset，若是，则执行步骤三，否则，返回执行步骤一；其中，Tset为正数；Step 2: Collect the temperature T in the N self-heating units, and determine whether the minimum temperature value T min in the N self-heating units is less than the temperature threshold T set , if so, go to step three, otherwise, return to step one; wherein, T set is a positive number;
步骤三、控制加热膜1开始对动力电池组2进行外部加热；同时采集温度为最低值Tmin的自加热单元中一个子电池组的端电压U及电池电流I；Step 3: Control the heating film 1 to start externally heating the power battery pack 2; at the same time, collect the terminal voltage U and battery current I of a sub-battery pack in the self-heating unit whose temperature is the lowest value T min ;
步骤四、建立温度为最小值Tmin的一个子电池组的一阶戴维宁等效电路模型，利用步骤三采集的子电池组的端电压U及电池电流I，对所述子电池组的内部参数：欧姆内阻R0，极化内阻R1及极化电容C1进行辨识；Step 4: Establish a first-order Thevenin equivalent circuit model of a sub-battery pack whose temperature is the minimum value T min , and use the terminal voltage U and battery current I of the sub-battery pack collected in step 3 to determine the internal parameters of the sub-battery pack. : ohmic internal resistance R 0 , polarization internal resistance R 1 and polarization capacitance C 1 for identification;
步骤五、根据步骤四辨识的欧姆内阻R0，极化内阻R1及极化电容C1进行辨识，获得两组动力电池内部总阻抗与交变激励频率函数；Step 5, according to the ohmic internal resistance R 0 , the polarization internal resistance R 1 and the polarization capacitance C 1 identified in the step 4, to obtain the total internal impedance and the alternating excitation frequency function of the two groups of power batteries;
步骤六、利用步骤五获得的电池内部总阻抗与频率函数和产热率公式，获得温度为最小值Tmin的子电池组的最佳激励加热频率；Step 6, using the total internal impedance of the battery and the frequency function and the heat production rate formula obtained in Step 5 to obtain the optimal excitation heating frequency of the sub-battery pack whose temperature is the minimum value T min ;
步骤七、将温度为最小值Tmin的子电池组的最佳加热激励频率作为双向DC/DC变换器的最佳交变切换频率，使温度为最小值Tmin的子电池组所属自加热单元内的两组子电池组交变放电，实现对温度为最小值Tmin的子电池组进行激励加热，时间t1后，返回执行步骤一，其中，t1为正数。Step 7. Use the optimal heating excitation frequency of the sub-battery pack whose temperature is the minimum value T min as the optimum alternating switching frequency of the bidirectional DC/DC converter, so that the sub-battery pack whose temperature is the minimum value T min belongs to the self-heating unit The two sets of sub-battery packs inside are alternately discharged to realize excitation and heating of the sub-battery packs whose temperature is the minimum value T min . After time t1, return to step 1, where t1 is a positive number.
本发明采用内部加热和外部加热两种方式同时对动力电池组进行加热，实现了快速对动力电池组进行预热的效果。首先进行电池电量的判断，在低电量时不启动自加热过程，避免电池过放。在电池电量充足时开始通过加热膜进行外部加热，并通过内部加热来对外部加热产生的温度的不均匀分布进行调整。内部加热首先将偶数组子电池组，每两组子电池组构成一个自加热单元，由于对称的两块电池往往具有相似的温度特性，因此，位于同一自加热单元的两个电池组以动力电池组整体的中心轴空间对称。采用温度传感器采集所有自加热单元中一组子电池组的表面温度，并对采集的温度进行比较，仅对温度最低的组进行内部加热从而达到使温度均匀分布的目的。通过开关电路来使得温度最低的组与双向DC/DC变换器连接。并求取该组电池的最佳交变激励加热频率，将所述最佳加热频率作为双向DC/DC变换器的交变切换频率。The invention adopts two methods of internal heating and external heating to simultaneously heat the power battery pack, thereby realizing the effect of rapidly preheating the power battery pack. First, judge the battery power, and do not start the self-heating process when the battery is low to avoid over-discharge of the battery. External heating by the heating membrane starts when the battery is sufficiently charged, and internal heating is used to adjust for the uneven distribution of temperature produced by the external heating. For internal heating, firstly, even groups of sub-battery packs are formed into a self-heating unit. Since two symmetrical batteries often have similar temperature characteristics, the two battery packs located in the same self-heating unit are the same as the power battery. The central axis of the group as a whole is spatially symmetrical. A temperature sensor is used to collect the surface temperature of a group of sub-battery groups in all self-heating units, and the collected temperatures are compared, and only the group with the lowest temperature is internally heated to achieve the purpose of uniform temperature distribution. The group with the lowest temperature is connected to the bidirectional DC/DC converter through a switching circuit. And obtain the optimal alternating excitation heating frequency of the battery pack, and use the optimal heating frequency as the alternating switching frequency of the bidirectional DC/DC converter.
附图说明Description of drawings
图1是本发明所述的一种动力电池组的内外部同时加热的装置的结构示意图；1 is a schematic structural diagram of a device for simultaneously heating the inside and outside of a power battery pack according to the present invention;
图2是本发明所述动力电池组的内外部同时加热装置的加热控制方法的流程图；FIG. 2 is a flowchart of a heating control method of the internal and external simultaneous heating device of the power battery pack according to the present invention;
图3是具体实施方式四所述的的一阶戴维宁等效电路模型图。FIG. 3 is a diagram of a first-order Thevenin equivalent circuit model according to the fourth embodiment.
具体实施方式Detailed ways
以下将结合附图及实施例来详细说明本发明的实施方式，借此对本发明如何应用技术手段来解决技术问题，并达成相应技术效果的实现过程能充分理解并据以实施。本申请实施例以及实施例中的各个特征，在不相冲突前提下可以相互结合，所形成的技术方案均在本发明的保护范围之内。The embodiments of the present invention will be described in detail below with reference to the accompanying drawings and examples, so as to fully understand and implement the implementation process of how the present invention applies technical means to solve technical problems and achieve corresponding technical effects. The embodiments of the present application and the various features in the embodiments can be combined with each other under the premise of no conflict, and the formed technical solutions all fall within the protection scope of the present invention.
具体实施方式一：下面结合图1说明本实施方式，本实施方式所述的一种动力电池组的内外部同时加热的装置，该装置应用于包括2N个子电池组的动力电池组2，该装置包括加热膜1、2N个开关电路3、N个温度传感器4、双向DC/DC变换器5、采样电路6和控制单元7；Embodiment 1: This embodiment will be described below with reference to FIG. 1. The device for simultaneously heating the inside and outside of a power battery pack described in this embodiment is applied to a power battery pack 2 including 2N sub-battery packs. Including heating film 1, 2N switching circuits 3, N temperature sensors 4, bidirectional DC/DC converter 5, sampling circuit 6 and control unit 7;
加热膜1设置在动力电池组的外侧，用于对动力电池组进行外部加热；所述加热膜1的加热功率控制信号输入端连接控制单元7的外部加热控制信号输出端；The heating film 1 is arranged on the outside of the power battery pack, and is used to externally heat the power battery pack; the heating power control signal input end of the heating film 1 is connected to the external heating control signal output end of the control unit 7;
排列位置以动力电池组内部空间中轴线对称的两个子电池组构成一个自加热单元，每个自加热单元内设置有一个温度传感器4，温度传感器4用于采集所属自加热单元中任意一个子电池组的表面温度信号，N个温度传感器4的温度信号输出端均连接控制单元7的温度信号输入端；Two sub-battery packs whose arrangement positions are symmetrical with the axis in the inner space of the power battery pack constitute a self-heating unit, each self-heating unit is provided with a temperature sensor 4, and the temperature sensor 4 is used to collect any sub-battery in the self-heating unit. The surface temperature signal of the group, the temperature signal output ends of the N temperature sensors 4 are all connected to the temperature signal input end of the control unit 7;
每个自加热单元中的一组子电池组的充放电信号输入输出端通过一个开关电路3连接双向DC/DC变换器5一侧的信号输入输出端，另一组子电池组的充放电信号输入输出端通过一个开关电路3连接双向DC/DC变换器5另一侧的信号输入输出端；2N个开关电路3的控制信号输入端都与控制单元7的开关控制信号输出端相连；The charge and discharge signal input and output terminals of a group of sub-battery packs in each self-heating unit are connected to the signal input and output terminals of one side of the bidirectional DC/DC converter 5 through a switch circuit 3, and the charge and discharge signals of the other group of sub-battery packs The input and output ends are connected to the signal input and output ends of the other side of the bidirectional DC/DC converter 5 through a switch circuit 3; the control signal input ends of the 2N switch circuits 3 are all connected with the switch control signal output end of the control unit 7;
采样电路6通过N个开关电路3分别与N个自加热单元中的一组子电池组相连，用于采集所连接的子电池组的电流、端电压和荷电状态；采样电路6的信号输出端连接控制单元7的采样信号输入端。The sampling circuit 6 is respectively connected with a group of sub-battery packs in the N self-heating units through N switch circuits 3, and is used to collect the current, terminal voltage and state of charge of the connected sub-battery packs; the signal output of the sampling circuit 6 The terminal is connected to the sampling signal input terminal of the control unit 7 .
具体实施方式二：本实施方式对实施方式一所述的一种动力电池组的内外部同时加热的装置作进一步说明，采样电路6包括电流采样电路、电压采样电路和荷电状态采样电路，所述电流采样电路用于采集所连接的子电池组的电流，电压采样电路用于所连接的子电池组的端电压，荷电状态采样电路用于采集所连接的子电池组的荷电状态。Embodiment 2: This embodiment further describes a device for simultaneously heating the inside and outside of a power battery pack described in Embodiment 1. The sampling circuit 6 includes a current sampling circuit, a voltage sampling circuit and a state of charge sampling circuit. The current sampling circuit is used for collecting the current of the connected sub-battery group, the voltage sampling circuit is used for the terminal voltage of the connected sub-battery group, and the state of charge sampling circuit is used for collecting the state of charge of the connected sub-battery group.
具体实施方式三：结合图2说明本实施方式，本实施方式所述一种动力电池组的内外部同时加热装置的加热控制方法，该方法是基于具体实施方式所述的一种动力电池组的内外部同时加热的装置实现的，该方法的具体步骤为：Embodiment 3: This embodiment is described with reference to FIG. 2 . The heating control method for the simultaneous internal and external heating device of a power battery pack described in this embodiment is based on the power battery pack described in the specific embodiment. The internal and external heating device is realized, and the specific steps of the method are:
步骤一、将某一组子电池组投入采样回路中，并采集该子电池组的荷电状态soc，并判断所述荷电状态soc是否大于设定的荷电状态阈值socset，若是，则执行步骤二、否则，电池组处于低电量状态，为了防止电池过放，不能进行自加热过程，重复执行步骤一，socset为正数；Step 1. Put a certain group of sub-battery packs into the sampling loop, and collect the state of charge soc of the sub-battery pack, and determine whether the state of charge soc is greater than the set state of charge threshold soc set , if so, then Perform step 2. Otherwise, the battery pack is in a low power state. In order to prevent the battery from being over-discharged, the self-heating process cannot be performed. Repeat step 1, and the soc set is a positive number;
步骤二、采集N个自加热单元内的温度T，判断N个自加热单元中的温度最低值Tmin是否小于温度阈值Tset，若是，则执行步骤三，否则，返回执行步骤一；其中，Tset为正数；Step 2: Collect the temperature T in the N self-heating units, and determine whether the minimum temperature value T min in the N self-heating units is less than the temperature threshold T set , if so, go to step three, otherwise, return to step one; wherein, T set is a positive number;
步骤三、控制加热膜1开始对动力电池组2进行外部加热；同时采集温度为最低值Tmin的自加热单元中一个子电池组的端电压U及电池电流I；Step 3: Control the heating film 1 to start externally heating the power battery pack 2; at the same time, collect the terminal voltage U and battery current I of a sub-battery pack in the self-heating unit whose temperature is the lowest value T min ;
步骤四、建立温度为最小值Tmin的一个子电池组的一阶戴维宁等效电路模型，利用步骤三采集的子电池组的端电压U及电池电流I，对所述子电池组的内部参数：欧姆内阻R0，极化内阻R1及极化电容C1进行辨识；Step 4: Establish a first-order Thevenin equivalent circuit model of a sub-battery pack whose temperature is the minimum value T min , and use the terminal voltage U and battery current I of the sub-battery pack collected in step 3 to determine the internal parameters of the sub-battery pack. : ohmic internal resistance R 0 , polarization internal resistance R 1 and polarization capacitance C 1 for identification;
步骤五、根据步骤四辨识的欧姆内阻R0，极化内阻R1及极化电容C1进行辨识，获得两组动力电池内部总阻抗与交变激励频率函数；Step 5, according to the ohmic internal resistance R 0 , the polarization internal resistance R 1 and the polarization capacitance C 1 identified in the step 4, to obtain the total internal impedance and the alternating excitation frequency function of the two groups of power batteries;
步骤六、利用步骤五获得的电池内部总阻抗与频率函数和产热率公式，获得温度为最小值Tmin的子电池组的最佳激励加热频率；Step 6, using the total internal impedance of the battery and the frequency function and the heat production rate formula obtained in Step 5 to obtain the optimal excitation heating frequency of the sub-battery pack whose temperature is the minimum value T min ;
步骤七、将温度为最小值Tmin的子电池组的最佳加热激励频率作为双向DC/DC变换器的最佳交变切换频率，使温度为最小值Tmin的子电池组所属自加热单元内的两组子电池组交变放电，实现对度为最小值Tmin的子电池组进行激励加热，时间t1后，返回执行步骤一，其中，t1为正数。Step 7. Use the optimal heating excitation frequency of the sub-battery pack whose temperature is the minimum value T min as the optimum alternating switching frequency of the bidirectional DC/DC converter, so that the sub-battery pack whose temperature is the minimum value T min belongs to the self-heating unit The two groups of sub-battery packs inside are alternately discharged to realize excitation and heating of the sub-battery packs whose degree is the minimum value T min . After time t1, return to step 1, where t1 is a positive number.
本实施方式中，步骤一所述的将某一组子电池组投入采样回路中采集该子电池组的荷电状态soc的实现方法为控制2N个开关电路3中的一个开关电路闭合，实现采样电路对2N子电池组中的一组子电池组进行荷电状态进行采样，由于整个动力电池组内子电池组剩余电量基本相同，因此，只需要采集任意一组子电池组的荷电状态就可以判断出此时是否适合自加热，步骤三中若存在多组子电池组的温度均为最低值Tmin时，只需任意选择一组执行步骤二到步骤七即可，由于外部同时进行加热，加热时间t1后，所有子电池组的温度都会发生变化，同时，由于每个自加热单元中的两组子电池组的位置以电池组整体内部空间的中轴线成空间对称，因此，一个自加热单元的两组子电池组的表面温差很小，因此，只需要采用一个温度传感器采集一个自加热单元内的子电池组的温度就可以。步骤七中将温度为最小值Tmin的子电池组的最佳加热激励频率作为双向DC/DC变换器的最佳交变切换频率，使温度为最小值Tmin的子电池组所属自加热单元内的两组子电池组交变放电，实现对温度为最小值Tmin的子电池组进行激励加热。其具体过程为：控制单元将获得的子电池组的最佳加热激励频率作为最佳交变切换频率控制信号控制双向DC/DC变换器交变切换电流方向，控制单元同时控制与温度为最小值Tmin的子电池组所属的自加热单元的两个开关电路3闭合，实现双向DC/DC变换器与所属同温度为最小值Tmin的自加热单元的两个子电池组连接，继而实现对温度为最小值Tmin的子电池组进行激励加热。In this embodiment, the implementation method of putting a certain group of sub-battery packs into the sampling loop to collect the state of charge soc of the sub-battery pack described in step 1 is to control one of the 2N switch circuits 3 to close to realize sampling The circuit samples the state of charge of a group of sub-battery packs in the 2N sub-battery pack. Since the remaining power of the sub-battery packs in the entire power battery pack is basically the same, it is only necessary to collect the state of charge of any group of sub-battery packs. It is judged whether it is suitable for self-heating at this time. In step 3, if there are multiple groups of sub-battery packs whose temperature is the lowest value T min , it is only necessary to arbitrarily select a group to perform steps 2 to 7. Since the external heating is performed at the same time, After the heating time t1, the temperature of all the sub-battery packs will change. At the same time, since the positions of the two groups of sub-battery packs in each self-heating unit are spatially symmetrical with the central axis of the overall internal space of the battery pack, a self-heating unit The surface temperature difference between the two sub-battery packs of the unit is very small, so only one temperature sensor needs to be used to collect the temperature of the sub-battery pack in a self-heating unit. In step 7, the optimal heating excitation frequency of the sub-battery group whose temperature is the minimum value T min is used as the optimal alternating switching frequency of the bidirectional DC/DC converter, so that the sub-battery group whose temperature is the minimum value T min belongs to the self-heating unit The two sets of sub-battery packs inside are alternately discharged to realize excitation and heating of the sub-battery packs whose temperature is the minimum value T min . The specific process is as follows: the control unit uses the obtained optimal heating excitation frequency of the sub-battery group as the optimal alternating switching frequency control signal to control the direction of the alternating switching current of the bidirectional DC/DC converter, and the control unit simultaneously controls and the temperature is the minimum value. The two switch circuits 3 of the self-heating unit to which the sub-battery pack of T min belongs are closed, so that the bidirectional DC/DC converter is connected to the two sub-battery packs of the self-heating unit that belong to the same temperature as the minimum value T min , and then the temperature control is realized. Excitation heating is performed for the sub-battery with the minimum value Tmin .
具体实施方式四：结合图3说明本实施方式，本实施方式对实施方式三所述的一种动力电池组的内外部同时加热装置的加热控制方法作进一步说明，步骤四所述的一阶戴维宁等效电路模型包括欧姆内阻R0、极化电阻R1、极化电容C1和开路等效电压源UOC；Specific embodiment 4: This embodiment is described with reference to FIG. 3 . This embodiment further describes the heating control method of the internal and external simultaneous heating device of a power battery pack described in Embodiment 3. The first-order Thevenin described in step 4 The equivalent circuit model includes ohmic internal resistance R 0 , polarization resistance R 1 , polarization capacitance C 1 and open-circuit equivalent voltage source U OC ;
欧姆内阻R0的一端连接充电电源正极，欧姆内阻R0的另一端同时连接极化电容C1的一端和极化电阻R1的一端；极化电容C1的另一端同时与极化电阻R1的另一端和开路等效电压源UOC的正极，开路等效电压源UOC的负极连接充电电源负极。One end of the ohmic internal resistance R 0 is connected to the positive electrode of the charging power supply, and the other end of the ohmic internal resistance R 0 is connected to one end of the polarization capacitor C 1 and one end of the polarization resistor R 1 at the same time; the other end of the polarization capacitor C 1 is connected to the polarization capacitor C 1 at the same time. The other end of the resistor R1 is connected to the positive electrode of the open-circuit equivalent voltage source UOC , and the negative electrode of the open-circuit equivalent voltage source UOC is connected to the negative electrode of the charging power supply.
具体实施方式五：本实施方式对实施方式四所述的一种动力电池组的内外部同时加热装置的加热控制方法作进一步说明，一阶戴维宁等效电路模型的公式为：Embodiment 5: This embodiment further describes the heating control method for the simultaneous internal and external heating device of a power battery pack described in Embodiment 4. The formula of the first-order Thevenin equivalent circuit model is:
其中，R0为欧姆内阻，R1为极化内阻，C1为极化电容，UOC为锂离子电池开路电压,U是锂离子电池的端电压，s是复频率。Among them, R 0 is the ohmic internal resistance, R 1 is the polarization internal resistance, C 1 is the polarization capacitance, U OC is the open circuit voltage of the lithium-ion battery, U is the terminal voltage of the lithium-ion battery, and s is the complex frequency.
具体实施方式六：本实施方式对实施方式五所述的一种动力电池组的内外部同时加热装置的加热控制方法作进一步说明，步骤四中对子电池组的内部参数：欧姆内阻R0，极化内阻R1及极化电容C1进行辨识具体方法为：Specific embodiment 6: This embodiment further describes the heating control method of the internal and external simultaneous heating device of the power battery pack described in the fifth embodiment. In step 4, the internal parameters of the sub-battery pack are: ohmic internal resistance R 0 , the specific method for identifying the polarization internal resistance R 1 and the polarization capacitance C 1 is:
步骤四一、令将等效电路模型的公式化为差分形式，其中，x(k)为第k次采样得到的物理量值，x(k-1)为第k-1次采样得到的物理量值，所述物理量为Uoc(k)、U(k)或I(k)；Step 41. Order The equivalent circuit model is formulated into a differential form, where x(k) is the physical quantity obtained by the kth sampling, x(k-1) is the physical quantity obtained by the k-1th sampling, and the physical quantity is Uoc (k), U(k) or I(k);
UOC(K)-U(K)＝k1[UOC(K-1)-U(K-1)]+k2I(K)-k3I(K-1) (2)U OC (K)-U(K)=k 1 [U OC (K-1)-U(K-1)]+k 2 I(K)-k 3 I(K-1) (2)
其中， in,
Uoc(k)是k次采样动力电池的开路电压，U(k)是k次采样动力电池的端电压，I(K)是k次采样动力电池的电流，k-1代表第k-1次采样，T为采样间隔，两次采样间的时间，UOC(k-1)是k-1次采样动力电池的开路电压，U(k-1)是k-1次采样动力电池的端电压，I(k-1)是k-1次采样动力电池的电流；Uoc(k) is the open circuit voltage of the power battery sampled k times, U(k) is the terminal voltage of the power battery sampled k times, I(K) is the current of the power battery sampled k times, k-1 represents the k-1th time Sampling, T is the sampling interval, time between two samplings, U OC (k-1) is the open circuit voltage of the power battery sampled for k-1 times, U(k-1) is the terminal voltage of the power battery sampled for k-1 times , I(k-1) is the current of the power battery sampled for k-1 times;
步骤四二、由递推最小二乘法辨识出差分方程中的参数k1,k1,k3；则等效电路模型中的参数：Step 42: Identify the parameters k 1 , k 1 , k 3 in the difference equation by the recursive least squares method; then the parameters in the equivalent circuit model are:
具体实施方式七：本实施方式对实施方式六所述的一种适用于动力电池组的内外部同时加热方法作进一步说明，步骤五获得两组动力电池内部总阻抗与交变激励频率函数为：Embodiment 7: This embodiment further describes a method for simultaneous internal and external heating of a power battery pack described in Embodiment 6. In step 5, the total internal impedance and alternating excitation frequency function of the two groups of power batteries obtained are:
其中，ω＝2πf；f为锂离子动力电池的交变激励加热频率，j为虚数单位，R1(f)为电池的极化内阻随交变激励加热频率变化函数，C1(f)为电池的极化电容C1随交变激励加热频率变化函数，其中，C1(f)和R1(f)通过阻抗谱，进行拟合后获得。Among them, ω=2πf; f is the alternating excitation heating frequency of the lithium-ion power battery, j is an imaginary unit, R 1 (f) is the function of the polarization internal resistance of the battery with the alternating excitation heating frequency, C 1 (f) is the polarization capacitance C 1 of the battery as a function of the heating frequency of the alternating excitation, wherein C 1 (f) and R 1 (f) are obtained after fitting through the impedance spectrum.
具体实施方式八：本实施方式对实施方式七所述的一种适用于动力电池组的内外部同时加热方法作进一步说明，步骤五所述计算获得锂离子电池在当前温度环境下的最佳加热频率的具体方法为：Embodiment 8: This embodiment further describes a method for simultaneous internal and external heating of a power battery pack described in Embodiment 7. The calculation in step 5 obtains the optimal heating of the lithium-ion battery under the current temperature environment. The specific method of frequency is:
利用产热功率公式Utilize the heat generating power formula
获得产热功率Q与交变激励频率函数，其中，Re(Z(f))是对复数Z(f)取实部，△U为端电压U与开路电压UOC的差值；对产热功率公式展开获得：Obtain the heat generation power Q and the alternating excitation frequency function, where Re(Z(f)) is the real part of the complex number Z(f), △U is the difference between the terminal voltage U and the open circuit voltage U OC ; Expand the power formula to get:
对产热功率展开式求一阶导数和二阶导数，获得产热功率最大值，所述产热功率最大值对应的交变激励频率为动力电池的交变激励加热频率。The first-order derivative and the second-order derivative of the heat-generating power expansion formula are obtained to obtain the maximum heat-generating power, and the alternating excitation frequency corresponding to the maximum heat-generating power is the alternating-excitation heating frequency of the power battery.
具体实施方式九：本实施方式对实施方式三所述的一种适用于动力电池组的内外部同时加热方法作进一步说明，步骤一所述的中阈值socset的范围：0.1＜socset＜0.15。Embodiment 9: This embodiment further describes a method for simultaneous internal and external heating of a power battery pack described in Embodiment 3. The range of the middle threshold soc set in step 1 is: 0.1<soc set <0.15 .
具体实施方式十：本实施方式对实施方式三所述的一种电动汽车动力电池充电/加热控制方法作进一步说明，步骤二所述的温度阈值Tset的范围为5＜Tset＜10℃。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 10: This embodiment further describes a charging/heating control method for an electric vehicle power battery described in Embodiment 3. The temperature threshold Tset in Step 2 is in the range of 5< Tset <10°C.
具体实施方式十一：本实施方式对实施方式三所述的一种电动汽车动力电池充电/加热控制方法作进一步说明，步骤七所述的加热时间t1的范围为20s到40s。Embodiment 11: This embodiment further describes the charging/heating control method for an electric vehicle power battery described in Embodiment 3. The heating time t1 described in Step 7 ranges from 20s to 40s.
本发明采用内部加热和外部加热两种方式同时对动力电池组进行加热，实现了快速预热的效果。通过加热膜进行外部加热，通过双向DC/DC变换器实现组内电池间的交变激励充放电从而使得锂离子电池组内部加热。同时采用控制策略使得内部加热能够实现对外部加热所造成的温度的不均匀分布进行调整。也采用了控制策略避免了在电池电量低时电池进行自加热导致过放的可能性。The invention adopts two ways of internal heating and external heating to heat the power battery pack at the same time, and realizes the effect of rapid preheating. The heating film is used for external heating, and the bidirectional DC/DC converter is used to realize the alternating excitation charge and discharge between the batteries in the group, so that the lithium-ion battery group is heated inside. At the same time, the control strategy is adopted so that the internal heating can adjust the uneven temperature distribution caused by the external heating. A control strategy is also used to avoid the possibility of over-discharge due to self-heating of the battery when the battery power is low.
虽然本发明所揭露的实施方式如上，但所述的内容只是为了便于理解本发明而采用的实施方式，并非用以限定本发明。任何本发明所属技术领域内的技术人员，在不脱离本发明所揭露的精神和范围的前提下，可以在实施的形式上及细节上作任何的修改与变化，但本发明的专利保护范围，仍须以所附的权利要求书所界定的范围为准。Although the embodiments disclosed in the present invention are as above, the described contents are only the embodiments adopted to facilitate the understanding of the present invention, and are not intended to limit the present invention. Any person skilled in the art to which the present invention belongs, without departing from the spirit and scope disclosed by the present invention, can make any modifications and changes in the form and details of the implementation, but the scope of patent protection of the present invention, The scope as defined by the appended claims shall still prevail.
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