A method, device and equipment for acquiring the demand of internal resistance of an electric cell
By acquiring historical data of cells from the same system, performing curve fitting and temperature rise calculation, the problem of being unable to predict the internal resistance of new cells in battery selection was solved, achieving accurate prediction of cell internal resistance and improving selection efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- BEIJING ELECTRIC VEHICLE
- Filing Date
- 2023-01-05
- Publication Date
- 2026-06-26
Smart Images
Figure CN115932396B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery cell technology, and in particular to a method, apparatus and equipment for obtaining the internal resistance requirement of a battery cell. Background Technology
[0002] Lithium-ion batteries, as a clean energy source with high energy density, have become a core component of new energy vehicles. With the development of new energy vehicles, the requirements for fast charging time and charging rates are increasing, leading to higher battery heat generation. To maintain a suitable battery operating temperature, one approach is to improve the thermal management system to enhance heat dissipation; another is to fundamentally reduce the internal resistance of the battery cells.
[0003] In the initial design phase of a thermal management system, it's necessary to estimate the battery's heat generation power to match the vehicle's energy flow and the liquid cooling system's heat exchange capacity. Cell internal resistance, as a key cell parameter, significantly impacts heat generation power. Reducing cell internal resistance effectively controls battery heat generation power, allowing for the matching of suitable cooling plates. With a fixed contact area between the cooling plate and the cell, lower cell internal resistance leads to reduced heat generation power, placing less emphasis on the cooling capacity of the cooling plate. This benefits the distribution of energy flow throughout the vehicle, reduces energy load, effectively controls battery temperature, and achieves optimal battery performance. With the development of new energy vehicles, charging times are becoming increasingly shorter, meaning charging currents are increasing. To reduce heat generation power, cells with lower internal resistance need to be selected during the initial cell selection phase to meet project requirements.
[0004] During battery charging, the internal resistance of the battery cell varies at different charging rates. Typically, the internal resistance data is obtained from actual testing. In the early stages of developing a new battery cell, it is necessary to estimate the internal resistance and heat generation power required to meet the charging rate. Since high-current, high-rate charging is a long-standing trend, the charging rates have already exceeded those of past development projects. However, there is a lack of test data for newly developed cells. Therefore, there is a lack of a method to estimate the internal resistance of new cells of different specifications within the same battery system based on existing data from similar cells, thus hindering battery selection and ensuring compliance with selection requirements. Summary of the Invention
[0005] The technical objective of this application is to provide a method, apparatus, and device for obtaining the internal resistance requirements of battery cells, so as to solve the problem that it is currently difficult to predict the internal resistance of newly developed battery cells when selecting batteries, making battery selection more difficult.
[0006] To address the aforementioned technical problems, embodiments of this application provide a method for obtaining the required internal resistance of a battery cell, comprising:
[0007] Obtain historical data of battery cells of the same system as the target battery cell, wherein the historical data includes at least: charging rate and corresponding heat generation power;
[0008] Based on the historical data, the pre-selected heating power corresponding to the target charging rate of the target battery cell is obtained;
[0009] Based on the pre-selected heating power, obtain the cell temperature corresponding to the target charging rate;
[0010] When the cell temperature is lower than the temperature limit of the target cell, the pre-selected heating power is determined to be the target heating power corresponding to the target charging rate;
[0011] Based on the target heating power, the required internal resistance value corresponding to the target battery cell is obtained.
[0012] Specifically, in the method described above, obtaining the pre-selected heating power corresponding to the target charging rate of the target battery cell based on the historical data includes:
[0013] Based on the historical data, a curve is fitted, and the first expression corresponding to the fitted curve is obtained;
[0014] The pre-selected heating power is obtained based on the target charging rate and the first expression.
[0015] Specifically, in the method described above, obtaining the cell temperature corresponding to the target charging rate based on the pre-selected heating power includes:
[0016] The temperature change power of the battery cell is obtained based on the pre-selected heating power and the heat exchange power of the hot and cold plates;
[0017] The energy of temperature change of the battery cell is obtained based on the temperature change power and the predetermined charging time of the battery.
[0018] The cell temperature rise is obtained based on the energy of the cell temperature change and the temperature rise-related parameters.
[0019] The cell temperature is obtained based on the cell temperature rise and the cell charging temperature.
[0020] Specifically, in the method described above, the temperature rise-related parameters include: the specific heat capacity of the battery cell, the mass of the battery cell, and the number of battery cells connected in series.
[0021] Preferably, the method described above, after obtaining the cell temperature corresponding to the target charging rate based on the heating power and the pre-selected heating power, further includes:
[0022] When the cell temperature is greater than or equal to the temperature limit, the pre-selected heating power is downgraded to obtain the processed pre-selected heating power, and the process returns to the step of obtaining the cell temperature corresponding to the target charging rate based on the heating power and the pre-selected heating power.
[0023] Another embodiment of this application also provides a processing apparatus, including:
[0024] The first processing module is used to acquire historical data of cells of the same system as the target cell. The historical data includes at least: charging rate and corresponding heat generation power.
[0025] The second processing module is used to obtain the pre-selected heating power corresponding to the target charging rate of the target cell based on the historical data.
[0026] The third processing module is used to obtain the cell temperature corresponding to the target charging rate based on the pre-selected heating power.
[0027] The fourth processing module is used to determine the pre-selected heating power as the target heating power corresponding to the target charging rate when the cell temperature is less than the temperature limit of the target cell.
[0028] The fifth processing module is used to obtain the internal resistance requirement value corresponding to the target battery cell based on the target heating power.
[0029] Another embodiment of this application provides an apparatus including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of a method for obtaining the internal resistance requirement of a battery cell as described above.
[0030] Another embodiment of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of a method for obtaining the internal resistance requirement of a battery cell as described above.
[0031] Compared with the prior art, the method, apparatus, and device for obtaining the internal resistance requirement of a battery cell provided in this application have at least the following beneficial effects:
[0032] This application predicts the heat generation power of a target battery cell at a target charging rate based on historical data of battery cells in the same system. After determining that the predicted heat generation power meets the actual requirements, the internal resistance requirement of the battery cell is obtained based on the heat generation power. This fills the current technical gap that the internal resistance of the battery cell cannot be known in the early stage of battery cell design, which helps to reduce the difficulty of battery cell selection and improve the efficiency of battery cell development. Attached Figure Description
[0033] Figure 1 This is one of the flowcharts illustrating the method for obtaining the internal resistance requirement of a battery cell in this application;
[0034] Figure 2 This is the second flowchart illustrating the method for obtaining the internal resistance requirement of the battery cell in this application;
[0035] Figure 3 This is a schematic diagram of the processing device in this application. Detailed Implementation
[0036] To make the technical problems, technical solutions, and advantages of this application clearer, a detailed description will be provided below in conjunction with the accompanying drawings and specific embodiments. In the following description, specific details such as particular configurations and components are provided merely to aid in a comprehensive understanding of the embodiments of this application. Therefore, those skilled in the art should understand that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this application. Furthermore, for clarity and brevity, descriptions of known functions and structures have been omitted.
[0037] It should be understood that the phrase "one embodiment" or "an embodiment" throughout the specification means that a specific feature, structure, or characteristic related to the embodiment is included in at least one embodiment of this application. Therefore, "in one embodiment" or "in an embodiment" appearing throughout the specification does not necessarily refer to the same embodiment. Furthermore, these specific features, structures, or characteristics can be combined in any suitable manner in one or more embodiments.
[0038] In the various embodiments of this application, it should be understood that the sequence number of each process described below does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.
[0039] It should be understood that the term "and / or" in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.
[0040] In the embodiments provided in this application, it should be understood that "B corresponding to A" means that B is associated with A, and B can be determined based on A. However, it should also be understood that determining B based on A does not mean determining B solely based on A; B can also be determined based on A and / or other information.
[0041] See Figure 1 A preferred embodiment of this application provides a method for obtaining the internal resistance requirement of a battery cell, comprising:
[0042] Step S101: Obtain historical data of cells from the same system as the target cell. The historical data includes at least: charging rate and corresponding heat generation power.
[0043] Step S102: Obtain the pre-selected heating power corresponding to the target charging rate of the target battery cell based on the historical data;
[0044] Step S103: Obtain the cell temperature corresponding to the target charging rate based on the pre-selected heating power;
[0045] Step S104: When the cell temperature is less than the temperature limit of the target cell, the pre-selected heating power is determined to be the target heating power corresponding to the target charging rate;
[0046] Step S105: Based on the target heating power, obtain the internal resistance requirement value corresponding to the target battery cell.
[0047] In one specific embodiment of this application, when developing a new battery cell, the technician needs to determine at least one of the following based on functional requirements: the system corresponding to the target battery cell, the target charging rate, the temperature limit, the heat exchange power of the hot and cold plates, the battery cell mass, the number of battery cells connected in series, the battery cell capacity, the battery cell specific heat capacity, and the charging time. Since the heat output of the target battery cell cannot be directly known, in order to obtain the heat output corresponding to the target charging rate, historical data of other battery cells in the same system after actual testing is first obtained. This historical data includes at least the correspondence between charging rate and heat output. Based on the historical data, the pre-selected heat output corresponding to the target charging rate is predicted and obtained. Then, based on the pre-selected heat output and the aforementioned predetermined parameters, the highest temperature that the target battery cell can reach when charging at the target charging rate, i.e., the battery cell temperature, can be predicted. By judging the battery cell temperature and the predetermined temperature limit, it can be determined whether the current pre-selected heat output meets the battery cell selection requirements. When the battery cell temperature is less than the temperature limit, it can be determined that the pre-selected heat output meets the battery cell selection requirements, and thus the pre-selected heat output can be determined as the target heat output. Then, based on the preset relationship between heat output and internal resistance, the internal resistance requirement value corresponding to the target battery cell can be obtained through the target heat output, thereby completing the battery cell selection.
[0048] In summary, this application predicts the heat generation power of a target battery cell at a target charging rate based on historical data of battery cells in the same system. After determining that the predicted heat generation power meets the actual requirements, the internal resistance requirement of the battery cell is obtained based on the heat generation power. This fills the current technical gap that the internal resistance of the battery cell cannot be known in the early stage of battery cell design, which helps to reduce the difficulty of battery cell selection and improve the efficiency of battery cell development.
[0049] It should be noted that the relationship between heating power and internal resistance in this embodiment is expressed as follows:
[0050] R = Q t / I 2 / n
[0051] Q t =P t *t
[0052] P t =P n -P w
[0053] Where R is the internal resistance of the battery cell; Q t I represents the energy generated by the temperature change of the battery cell; n represents the charging current; t represents the number of battery cells connected in series; and P represents the charging time. t Power is the power generated by temperature change; P w P is the heat exchange power of the hot and cold plates; n This refers to the heating power.
[0054] It should also be noted that the historical data mentioned above may include at least one of the following: the system corresponding to the battery cell, temperature limit, heat exchange power of the hot and cold plates, battery cell mass, number of battery cells connected in series, battery cell capacity, battery cell specific heat capacity, and charging time, so as to help technicians determine the relevant parameters of the target battery cell.
[0055] Specifically, in the method described above, obtaining the pre-selected heating power corresponding to the target charging rate of the target battery cell based on the historical data includes:
[0056] Based on the historical data, a curve is fitted, and the first expression corresponding to the fitted curve is obtained;
[0057] The pre-selected heating power is obtained based on the target charging rate and the first expression.
[0058] In one specific embodiment of this application, when obtaining the pre-selected heating power based on historical data, it is preferable to perform curve fitting based on the historical data, and obtain a first expression for the curve based on the fitted curve, for example: P n =f(C y ), where P n For heating power, C y The target charging rate is then calculated by substituting it into the first expression, which contains historical data.
[0059] See Figure 2 Specifically, in the method described above, obtaining the cell temperature corresponding to the target charging rate based on the pre-selected heating power includes:
[0060] Step S201: Based on the pre-selected heating power and the heat exchange power of the hot and cold plates, the temperature change power of the battery cell is obtained;
[0061] Step S202: Based on the temperature change power and the predetermined battery charging time, the cell temperature change energy is obtained.
[0062] Step S203: Obtain the cell temperature rise based on the cell temperature change energy and temperature rise-related parameters;
[0063] Step S204: Obtain the cell temperature based on the cell temperature rise and the cell charging temperature.
[0064] In another embodiment of this application, when obtaining the cell temperature based on the pre-selected heating power, it is preferable to obtain the cell temperature change rate based on the pre-selected heating power and the heat exchange power of the hot and cold plates, wherein P t =P n -P w P n The pre-selected heating power is determined by multiplying the temperature change rate by the charging time to obtain the cell temperature change energy of the target cell, where Q... t =P t *t. The temperature rise of the target cell during charging can be obtained by combining the energy of the cell's temperature change with relevant temperature rise parameters. These parameters include the cell's specific heat capacity, mass, and the number of cells connected in series. Therefore, the expression for obtaining the cell's temperature rise based on the energy of the temperature change and these parameters can be expressed as: ΔT = Q t / CM / n, where C is the specific heat capacity of the battery cell; M is the mass of the battery cell, specifically the mass of a single cell; and n is the number of cells connected in series. The cell temperature can be obtained by summing the cell's charging temperature and the temperature rise during battery charging.
[0065] Preferably, the method described above, after obtaining the cell temperature corresponding to the target charging rate based on the heating power and the pre-selected heating power, further includes:
[0066] When the cell temperature is greater than or equal to the temperature limit, the pre-selected heating power is downgraded to obtain the processed pre-selected heating power, and the process returns to the step of obtaining the cell temperature corresponding to the target charging rate based on the pre-selected heating power.
[0067] In another embodiment of this application, after obtaining the cell temperature, if it is determined that the cell temperature is greater than or equal to a temperature limit, it can be determined that if the cell is developed using the current pre-selected heating power, it is likely to result in the developed cell exceeding the design requirements. Therefore, cell development cannot be based on the current pre-selected heating power. Instead, the pre-selected heating power is appropriately adjusted by multiplying it by a preset coefficient, and the steps described above for obtaining the cell temperature corresponding to the target charging rate based on the pre-selected heating power are repeated. The determination is then made again based on the cell temperature and the temperature limit. This helps ensure that the final target heating power corresponds to the cell internal resistance requirement, which meets the cell selection requirements.
[0068] In one specific embodiment, the charging time, heat generation efficiency, etc. corresponding to the charging rate of the same battery cell include stage values corresponding to the state of charge stage during the charging process of the battery cell. When performing various calculations based on charging time, heat generation efficiency, etc. in the above steps, the corresponding stage values are first obtained according to different state of charge stages, and the final required value is obtained from all the stage values.
[0069] See Figure 3 Another embodiment of this application also provides a processing apparatus, including:
[0070] The first processing module 301 is used to acquire historical data of cells of the same system as the target cell. The historical data includes at least: charging rate and corresponding heat generation power.
[0071] The second processing module 302 is used to obtain the pre-selected heating power corresponding to the target charging rate of the target cell based on the historical data.
[0072] The third processing module 303 is used to obtain the cell temperature corresponding to the target charging rate based on the pre-selected heating power.
[0073] The fourth processing module 304 is used to determine the pre-selected heating power as the target heating power corresponding to the target charging rate when the cell temperature is less than the temperature limit of the target cell.
[0074] The fifth processing module 305 is used to obtain the internal resistance requirement value corresponding to the target battery cell based on the target heating power.
[0075] Specifically, in the apparatus described above, the second processing module includes:
[0076] The first processing unit is used to perform curve fitting based on the historical data and obtain the first expression corresponding to the fitted curve.
[0077] The first processing unit is configured to obtain the pre-selected heating power based on the target charging rate and the first expression.
[0078] Specifically, in the apparatus described above, the third processing module includes:
[0079] The third processing unit is used to obtain the temperature change power of the battery cell based on the pre-selected heating power and the heat exchange power of the hot and cold plates.
[0080] The fourth processing unit is used to obtain the cell temperature change energy based on the temperature change power and the predetermined battery charging time.
[0081] The fifth processing unit is used to obtain the cell temperature rise based on the energy of the cell temperature change and temperature rise-related parameters;
[0082] The sixth processing unit is used to obtain the cell temperature based on the cell temperature rise and the cell charging temperature.
[0083] Specifically, in the device described above, the temperature rise-related parameters include: the specific heat capacity of the battery cell, the mass of the battery cell, and the number of battery cells connected in series.
[0084] Preferably, the apparatus as described above further includes:
[0085] The sixth processing module is used to downgrade the pre-selected heating power when the cell temperature is greater than or equal to the temperature limit, obtain the processed pre-selected heating power, and return to execute the step of obtaining the cell temperature corresponding to the target charging rate based on the heating power and the pre-selected heating power.
[0086] The processing apparatus of this application is an apparatus corresponding to the embodiment of the method for obtaining the internal resistance requirement of the battery cell described above. All implementation means in the above method embodiment are applicable to the embodiment of this apparatus and can achieve the same technical effect.
[0087] Another embodiment of this application provides an apparatus including a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of a method for obtaining the internal resistance requirement of a battery cell as described above.
[0088] Another embodiment of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of a method for obtaining the internal resistance requirement of a battery cell as described above.
[0089] Furthermore, reference numerals and / or letters may be repeated in different examples within this application. Such repetition is for the purpose of simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or settings discussed.
[0090] It should also be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion.
[0091] The above description is the preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principles described in this application, and these improvements and modifications should also be considered within the scope of protection of this application.
Claims
1. A method for obtaining the required internal resistance of a battery cell, characterized in that, include: Obtain historical data of battery cells of the same system as the target battery cell, wherein the historical data includes at least: charging rate and corresponding heat generation power; Based on the historical data, the pre-selected heating power corresponding to the target charging rate of the target battery cell is obtained; Based on the pre-selected heating power, the cell temperature corresponding to the target charging rate is obtained; When the cell temperature is lower than the target cell temperature limit, the pre-selected heating power is determined to be the target heating power corresponding to the target charging rate; Based on the target heating power, the required internal resistance value corresponding to the target battery cell is obtained; After obtaining the cell temperature corresponding to the target charging rate based on the heating power and the pre-selected heating power, the method further includes: When the cell temperature is greater than or equal to the temperature limit, the pre-selected heating power is downgraded to obtain the processed pre-selected heating power, and the process returns to the step of obtaining the cell temperature corresponding to the target charging rate based on the heating power and the pre-selected heating power.
2. The method according to claim 1, characterized in that, The step of obtaining the pre-selected heating power corresponding to the target charging rate of the target battery cell based on the historical data includes: Based on the historical data, a curve is fitted, and the first expression corresponding to the fitted curve is obtained; The pre-selected heating power is obtained based on the target charging rate and the first expression.
3. The method according to claim 1, characterized in that, The step of obtaining the cell temperature corresponding to the target charging rate based on the pre-selected heating power includes: The temperature change power of the battery cell is obtained based on the pre-selected heating power and the heat exchange power of the hot and cold plates; The energy of temperature change of the battery cell is obtained based on the temperature change power and the predetermined charging time of the battery. The cell temperature rise is obtained based on the energy of the cell temperature change and the temperature rise-related parameters. The cell temperature is obtained based on the cell temperature rise and the cell charging temperature.
4. The method according to claim 3, characterized in that, The temperature rise-related parameters include: the specific heat capacity of the battery cell, the mass of the battery cell, and the number of battery cells connected in series.
5. A processing apparatus, characterized in that, include: The first processing module is used to acquire historical data of cells of the same system as the target cell. The historical data includes at least: charging rate and corresponding heat generation power. The second processing module is used to obtain the pre-selected heating power corresponding to the target charging rate of the target cell based on the historical data. The third processing module is used to obtain the cell temperature corresponding to the target charging rate based on the pre-selected heating power. The fourth processing module is used to determine the pre-selected heating power as the target heating power corresponding to the target charging rate when the cell temperature is less than the temperature limit of the target cell. The fifth processing module is used to obtain the internal resistance requirement value corresponding to the target battery cell based on the target heating power; The sixth processing module is used to downgrade the pre-selected heating power when the cell temperature is greater than or equal to the temperature limit, obtain the processed pre-selected heating power, and return to execute the step of obtaining the cell temperature corresponding to the target charging rate based on the heating power and the pre-selected heating power.
6. A device, characterized in that, It includes a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the computer program, when executed by the processor, implements the steps of a method for obtaining the internal resistance requirement of a battery cell as described in any one of claims 1 to 4.
7. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium, which, when executed by a processor, implements the steps of a method for obtaining the internal resistance requirement of a battery cell as described in any one of claims 1 to 4.