Battery pack temperature acquisition method and device, storage medium and vehicle

Abstract

The invention relates to the technical field of battery temperature, and particularly provides a battery pack temperature obtaining method and device, a storage medium and a vehicle, and the battery pack temperature obtaining method comprises the steps: carrying out the grid division of a target cell, and obtaining a plurality of grid units; constructing a first heat conservation equation of each grid unit, and constructing a second heat conservation equation of the peripheral component; obtaining the temperature of each grid unit based on the first heat conservation equation and the second heat conservation equation; through thermal resistance and specific heat capacity parameters of the battery cell and peripheral components, the temperatures of different positions of the battery cell are accurately estimated by using a heat conservation and heat conduction method, the accuracy of acquiring the temperature of the battery cell is improved, the temperature of the battery cell is controlled according to the highest temperature or the lowest temperature of the battery cell, and the reliability of the battery cell is improved. The temperature of the battery cell can be in a reasonable temperature range, and the safety performance and the service life of the battery pack are improved.

Description

Technical Field

[0001] The present application relates to the field of battery temperature technology, and in particular to a method, device, storage medium and vehicle for obtaining the temperature of a battery pack. Background Art

[0002] At present, the temperature sensor of the battery pack is usually arranged above the battery cell, and can only accurately measure the temperature above the battery cell. In addition, considering the cost, the arrangement points of the temperature sensor are limited, resulting in the temperature sensor being unable to directly and accurately measure the temperature at different positions of the battery cell.

[0003] The temperature of the battery cell has an important impact on the lithium deposition and safe use of the battery cell, but the existing technology is often unable to accurately obtain the temperature at different positions of the battery cell. It is usually necessary to perform thermal management on the battery pack based on the highest or lowest temperature of the battery cell. When the temperature of the battery cell exceeds the specified threshold, the performance of the battery pack will decline, the life of the battery pack will be shortened, and even safety hazards will be caused.

[0004] Accordingly, the art needs a new battery pack temperature acquisition solution to solve the above problems. Summary of the invention

[0005] In order to overcome the above-mentioned defects, the present application is proposed to solve or at least partially solve the technical problem of accurately obtaining the temperature of the battery cell.

[0006] In a first aspect, a method for obtaining the temperature of a battery pack is provided, wherein the battery pack includes a target battery cell and a peripheral component, wherein the peripheral component is in contact with the target battery cell, and the method includes:

[0007] Dividing the target battery cell into a grid to obtain a plurality of grid units;

[0008] Constructing a first heat conservation equation for each of the grid units, and constructing a second heat conservation equation for the peripheral components;

[0009] Based on the first heat conservation equation and the second heat conservation equation, the temperature of each of the grid cells at the current moment is obtained.

[0010] In a technical solution of the above-mentioned method for obtaining the temperature of the battery pack, after obtaining the temperature of each of the grid units, the method further includes:

[0011] The grid cell with the highest or lowest temperature is taken as the target grid;

[0012] Dividing the target grid again to obtain a plurality of sub-units;

[0013] A heat conservation equation for each of the sub-units is constructed, and based on the heat conservation equation for each of the sub-units, the temperature of each of the sub-units at the current moment is obtained.

[0014] In a technical solution of the temperature acquisition method of the battery pack, the first heat conservation equation is constructed based on at least one of the following factors: heat change of each grid unit, heat generation of each grid unit, convection heat transfer between mutually contacting grid units, and convection heat transfer between mutually contacting peripheral components and the grid units;

[0015] The second heat conservation equation is constructed based on at least one of the following factors: heat change of the peripheral components, convective heat transfer between the peripheral components in contact with each other, convective heat transfer between the peripheral components and the environment, and convective heat transfer between the peripheral components in contact with each other and the grid units.

[0016] In a technical solution of the above-mentioned method for obtaining the temperature of the battery pack, the first heat conservation equation is expressed according to the following formula:

[0017]

[0018] Among them, Q partM Represents the heat change of grid unit M; C part represents the specific heat capacity of the target battery cell; ΔT partM represents the temperature difference between two samplings of grid cell M, ΔT partM =T partM -T partM ′,T partM Represents the temperature of grid cell M at the current moment, T partM ′ represents the temperature of the grid unit M at the last moment; I represents the current of the target battery cell; R represents the resistance of the target battery cell; h A Indicates the convective heat transfer coefficient of the water cooling plate; T cool Indicates the temperature of the water cooling plate at the current moment; T 外围 Indicates the temperature of the peripheral components at the current moment; R 外围 represents the thermal resistance of the peripheral components; T partN Represents the temperature of grid cell N at the current moment; R part represents the thermal resistance of the target battery cell.

[0019] In a technical solution of the above-mentioned method for obtaining the temperature of the battery pack, the second heat conservation equation is expressed according to the following formula:

[0020]

[0021] Among them, Q 外围aIndicates the heat change of peripheral component a; C 外围a Indicates the specific heat capacity of the peripheral component a; ΔT 外围a Indicates the temperature difference between two samples of peripheral component a, ΔT 外围a =T 外围a -T 外围a ′,T 外围a represents the temperature of peripheral component a at the current moment, T 外围a ' represents the temperature of peripheral component a at the last moment; T partM Represents the temperature of grid cell M at the current moment; R 外围a Represents the thermal resistance of peripheral components a; T amb Indicates the current ambient temperature; R amb Represents ambient thermal resistance; T 外围b Indicates the temperature of peripheral component b at the current moment.

[0022] In a technical solution of the temperature acquisition method of the battery pack, the peripheral components include a top plate, a partition, a pad and a bottom plate, the top plate is arranged on the top of the target battery cell, the bottom plate is arranged on the bottom of the target battery cell, the pad is arranged between the target battery cell and the bottom plate, and the partition is in contact with the side surface of the target battery cell; the method further includes:

[0023] Determine the heat change of each of the peripheral components according to the specific heat capacity of each of the peripheral components, the temperature of the peripheral components at a current moment, and the temperature of the peripheral components at a previous moment;

[0024] Determine the convective heat exchange between the bottom plate and the contacting bottom plate according to the temperature of the bottom plate, the temperature of the bottom plate and the thermal resistance of the bottom plate at a current moment;

[0025] Determine the convective heat exchange between the top plate and the grid unit in contact with the top plate according to the temperature of the grid unit in contact with the top plate at a current moment, the temperature of the top plate, and the thermal resistance of the top plate;

[0026] Determine the convective heat transfer between the partition and all the mesh units in contact with the partition according to the temperature of all the mesh units in contact with the partition at the current moment, the temperature of the partition and the thermal resistance of the partition;

[0027] Determine the convective heat transfer between the pad and the contacting mesh unit according to the temperature of the mesh unit in contact with the pad at the current moment, the temperature of the pad, and the thermal resistance of the pad;

[0028] According to the temperature of the top plate, the temperature of the partition plate, the temperature of the bottom plate, the ambient temperature and the ambient thermal resistance at the current moment, the convective heat exchange between the top plate, the partition plate and the bottom plate and the environment is determined respectively.

[0029] In a technical solution of the temperature acquisition method of the above-mentioned battery pack, the battery pack includes a battery cell module, the battery cell module includes multiple battery cells, the top view of the battery cell module is a rectangle, and the battery cells located at the four corners of the rectangle are used as the target battery cells.

[0030] In a second aspect, a smart device is provided, comprising at least one processor; and a memory communicatively connected to the at least one processor; wherein a computer program is stored in the memory, and when the computer program is executed by the at least one processor, the method described in any one of the technical solutions of the above-mentioned battery pack temperature acquisition method is implemented.

[0031] In a third aspect, a computer-readable storage medium is provided, wherein a plurality of program codes are stored therein, wherein the program codes are suitable for being loaded and run by a processor to execute the method described in any one of the technical solutions of the above-mentioned method for obtaining the temperature of the battery pack.

[0032] In a fourth aspect, a vehicle is provided, comprising a battery pack and the smart device described in the above technical solution, wherein the battery pack comprises a target battery cell and peripheral components, wherein the peripheral components are in contact with the target battery cell, and the smart device is used to obtain the temperature of the battery pack.

[0033] The above one or more technical solutions of the present application have at least one or more of the following beneficial effects:

[0034] In implementing the technical solution of the temperature acquisition method of the battery pack provided in the present application, the target battery cell is gridded to obtain multiple grid units; a first heat conservation equation is constructed for each grid unit, and a second heat conservation equation for peripheral components is constructed; based on the first heat conservation equation and the second heat conservation equation, the temperature of each grid unit is obtained; through the thermal resistance and specific heat capacity parameters of the battery cell and peripheral components, the temperature at different positions of the battery cell is accurately estimated by utilizing the heat conservation and heat conduction methods, thereby improving the accuracy of the battery cell temperature acquisition; the battery cell temperature is controlled according to the maximum or minimum temperature of the battery cell, so that the battery cell temperature can be within a reasonable temperature range, thereby improving the safety performance and service life of the battery pack. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The disclosure of the present application will become easier to understand with reference to the accompanying drawings. It is easy for those skilled in the art to understand that these drawings are only for illustrative purposes and are not intended to limit the scope of protection of the present application. Among them:

[0036] Figure 1 is a flowchart of main steps of a method for obtaining the temperature of a battery pack according to an embodiment of the present application;

[0037] Figure 2 is a schematic diagram of the structure of peripheral components of a target battery cell according to an embodiment of the present application;

[0038] Figure 3 is a flowchart of further steps of a method for obtaining the temperature of a battery pack according to an embodiment of the present application;

[0039] Figure 4 This is a schematic flow chart of the main steps of a method for obtaining the minimum temperature of a battery pack according to an embodiment of the present application;

[0040] Figure 5 is a schematic flow chart of steps of a method for acquiring a target battery cell according to an embodiment of the present application;

[0041] Figure 6 is a schematic diagram of temperature distribution simulation of a target battery cell during the charging and discharging process according to an embodiment of the present application;

[0042] Figure 7 is a schematic diagram of dividing a target battery cell grid into nine grid units according to an embodiment of the present application;

[0043] Figure 8 is a schematic diagram of low temperature area grid division according to an embodiment of the present application;

[0044] Fig. 9 is a schematic diagram of a module of a device for acquiring a target battery cell according to an embodiment of the present application;

[0045] Fig.10 It is a schematic diagram of the main structure of a smart device according to an embodiment of the present application.

[0046] Reference numerals:

[0047] 201: top plate; 202: water cooling plate; 203: partition plate; 204: bottom plate; 205: pad; 206: temperature sensor; 1001: memory; 1002: processor. DETAILED DESCRIPTION

[0048] Some embodiments of the present application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present application and are not intended to limit the protection scope of the present application.

[0049] In the description of the present application, "module" and "processor" may include hardware, software or a combination of the two. A module may include hardware circuits, various suitable sensors, communication ports, memory, and may also include software parts, such as program code, or a combination of software and hardware. The processor may be a central processing unit, a microprocessor, an image processor, a digital signal processor or any other suitable processor. The processor has data and / or signal processing functions. The processor may be implemented in software, hardware or a combination of the two. Computer-readable storage media include any suitable medium that can store program code, such as a disk, a hard disk, an optical disk, a flash memory, a read-only memory, a random access memory, etc. The term "A and / or B" means all possible combinations of A and B, such as only A, only B or A and B. The term "at least one A or B" or "at least one of A and B" has a similar meaning to "A and / or B" and may include only A, only B or A and B. The singular terms "one" and "the" may also include plural forms.

[0050] The relevant user personal information that may be involved in the various embodiments of this application is strictly in accordance with the requirements of laws and regulations, following the principles of legality, legitimacy and necessity, based on the reasonable purposes of business scenarios, to process the personal information that users actively provide during the use of products / services or generated due to the use of products / services, as well as the personal information obtained with the user's authorization.

[0051] The user personal information processed by this application will vary depending on the specific product / service scenario, and shall be based on the specific scenario in which the user uses the product / service, and may involve the user's account information, device information, driving information, vehicle information or other related information. This application will treat the user's personal information and its processing with a high degree of diligence.

[0052] This application attaches great importance to the security of user personal information and has taken reasonable and feasible security protection measures that meet industry standards to protect user information and prevent personal information from being accessed, disclosed, used, modified, damaged or lost without authorization.

[0053] See attached Figure 1 and attached Figure 2 , Figure 1 is a flow chart of the main steps of a method for obtaining the temperature of a battery pack according to an embodiment of the present application. Figure 2 is a schematic diagram of the peripheral components structure of a target battery cell according to an embodiment of the present application. The battery pack may include multiple battery cells and peripheral components in the pack, such as Figure 2As shown, a water-cooling plate 202, a partition 203, a top plate 201, a pad 205 and a bottom plate 204 are arranged around the target battery cell of the embodiment of the present application, and the water-cooling plate 202 is arranged between adjacent single battery cells; the top plate 201 is arranged at the top of the target battery cell, the bottom plate 204 is arranged at the bottom of the target battery cell, the pad 205 is arranged between the target battery cell and the bottom plate 204, the partition 203 is in contact with the side surface of the target battery cell, and a temperature sensor 206 is also arranged on the top of the target battery cell.

[0054] In one embodiment, the partition 203 may be configured as an aluminum partition.

[0055] In one embodiment, the pad 205 is foam placed in the box of the battery pack. The pad 205 can be set as an integrated structure that fully covers the contact surface with the target battery cell and the contact surface with the bottom plate 204, or it can be set as an integrated structure smaller than the contact surface with the target battery cell and the contact surface with the bottom plate 204, or it can be set as multiple sub-pads.

[0056] The following combination Figure 2 The structure of the present application introduces a method for obtaining the temperature of a battery pack, which mainly includes the following steps S101 to S103.

[0057] Step S101: grid-dividing the target battery cell to obtain a plurality of grid units.

[0058] The target battery cell is the battery cell whose temperature is to be obtained, which may refer to any one or more battery cells in the battery pack.

[0059] In an optional embodiment, the battery cells located at the edge of the battery pack are generally more affected by the external ambient temperature, and the temperature of the battery cells is easily too high or too low compared to other battery cells in the pack. In this case, the battery cells at the edge of the battery pack can be used as target cells.

[0060] Furthermore, when the top view of the battery cell module in the battery pack is a rectangle, the battery cells located at the four corners of the rectangle are taken as target battery cells.

[0061] In an optional embodiment, when the target battery cell is meshed, it can be meshed with uniform area or meshed with non-uniform area. Figure 2 The square shell battery cells can be evenly divided into multiple grid units.

[0062] Step S102: constructing a first heat conservation equation for each of the grid units, and constructing a second heat conservation equation for the peripheral components.

[0063] In this embodiment, the first heat conservation equation is constructed based on at least one of the following factors: heat change of each grid unit, heat generation of each grid unit, convective heat transfer between mutually contacting grid units, and convective heat transfer between mutually contacting peripheral components and grid units;

[0064] In one embodiment, the heat change of each cell grid unit is determined according to the specific heat capacity of the target cell, the temperature of each grid unit at the current moment, and the temperature of each grid unit at the last sampling moment;

[0065] Obtaining the current of the target battery cell and the resistance of the target battery cell, and determining the heat generation of each grid cell according to the current of the target battery cell and the resistance of the target battery cell and the number of grid cells;

[0066] For each grid unit, the convective heat transfer between the grid units in contact with each other is determined according to the thermal resistance of the target battery cell, the temperature of the grid unit at the current moment, and the temperatures of other grid units in contact with the grid unit;

[0067] For each grid unit, the convective heat transfer between the grid unit and the water cooling plate 202 is determined according to the temperature of the water cooling plate 202 at the current moment, the temperature of the grid unit, and the convective heat transfer coefficient of the water cooling plate 202:

[0068] For each grid unit, the convective heat exchange between the mutually contacting peripheral components and the grid unit is determined according to the temperature of the grid unit at the current moment, the temperature of the peripheral components contacted by the grid unit, and the thermal resistance of the peripheral components.

[0069] In one embodiment, the first heat conservation equation is expressed according to the following formula:

[0070]

[0071] Among them, Q partM Represents the heat change of grid unit M; C part Indicates the specific heat capacity of the target battery cell; ΔT partM represents the temperature difference between two samplings of grid cell M, ΔT partM =T partM -T partM ′,T partM Represents the temperature of grid cell M at the current moment, T partM ′ represents the temperature of the grid unit M at the last moment; I represents the current of the target cell; R represents the resistance of the target cell; h A represents the convection heat transfer coefficient of the water cooling plate 202; T cool Indicates the temperature of the water cooling plate 202 at the current moment; T 外围 Indicates the temperature of the peripheral components at the current moment; R 外围 Represents the thermal resistance of peripheral components; TpartN Represents the temperature of grid cell N at the current moment; R part Indicates the thermal resistance of the target cell.

[0072] In this embodiment, the second heat conservation equation is constructed based on at least one of the following factors: heat change of peripheral components, convective heat transfer between mutually contacting peripheral components, convective heat transfer between peripheral components and the environment, and convective heat transfer between mutually contacting peripheral components and grid units.

[0073] In one embodiment, the heat change of each peripheral component is determined based on the specific heat capacity of each peripheral component, the temperature of the peripheral component at a current moment, and the temperature of the peripheral component at a previous moment;

[0074] Determine the convective heat transfer between the bottom plate 204 and the contacting bottom plate 205 according to the temperature of the bottom plate 205, the temperature of the bottom plate 204 and the thermal resistance of the bottom plate 204 at the current moment;

[0075] Determine the convective heat transfer between the top plate 201 and the contacting grid unit according to the temperature of the grid unit in contact with the top plate 201 at the current moment, the temperature of the top plate 201 and the thermal resistance of the top plate 201;

[0076] Determine the convective heat transfer between the partition 203 and all the mesh units in contact with the partition 203 according to the temperature of all the mesh units in contact with the partition 203 at the current moment, the temperature of the partition 203 and the thermal resistance of the partition 203;

[0077] Determine the convective heat transfer between the pad 205 and the contacting mesh unit according to the temperature of the mesh unit in contact with the pad 205 at the current moment, the temperature of the pad 205 and the thermal resistance of the pad 205;

[0078] According to the temperature of the top plate 201, the temperature of the partition plate 203, the temperature of the bottom plate 204, the ambient temperature and the ambient thermal resistance at the current moment, the convective heat exchange between the top plate 201, the partition plate 203 and the bottom plate 204 and the environment is determined respectively.

[0079] In one embodiment, the second heat conservation equation is expressed according to the following formula:

[0080]

[0081] Among them, Q 外围a Indicates the heat change of peripheral component a; C 外围a Indicates the specific heat capacity of the peripheral component a; ΔT 外围a Indicates the temperature difference between two samples of peripheral component a, ΔT 外围a =T 外围a -T 外围a ′,T 外围arepresents the temperature of peripheral component a at the current moment, T 外围a ' represents the temperature of peripheral component a at the last moment; T partM Represents the temperature of grid cell M at the current moment; R 外围a Represents the thermal resistance of peripheral components a; T amb Indicates the current ambient temperature; R amb Represents ambient thermal resistance; T 外围b Indicates the temperature of peripheral component b at the current moment.

[0082] Step S103: Based on the first heat conservation equation and the second heat conservation equation, obtain the temperature of each of the grid cells at the current moment.

[0083] In this embodiment, the first heat conservation equation and the second heat conservation equation are solved simultaneously to obtain the temperature of each grid unit at the current moment, and the grid unit with the highest / lowest temperature among the grid units is selected. Through the battery management system (BMS), thermal management is performed on the target battery cell according to the temperature of the grid unit with the highest / lowest temperature, so that the battery cell temperature can be within a reasonable temperature range, thereby improving the safety performance and service life of the battery pack.

[0084] See attached Figure 3 , Figure 3 1 is a further step flow chart of a method for obtaining the temperature of a battery pack according to an embodiment of the present application. Based on the method described in steps S101 to S103 above, after obtaining the temperature of each grid unit, the method of the embodiment of the present application further includes:

[0085] Step S301: taking the grid unit with the highest or lowest temperature as the target grid;

[0086] In this embodiment, the target grid is one or more grid cells with the lowest or lowest temperature;

[0087] Step S302: mesh the target grid again to obtain multiple sub-units;

[0088] In this embodiment, when the target grid is meshed again, it can be meshed with uniform area or meshed with non-uniform area.

[0089] In one implementation, the target grid may be evenly gridded into 9 sub-cells.

[0090] Step S303: construct the heat conservation equation of each sub-unit, and based on the heat conservation equation of each sub-unit, obtain the temperature of each sub-unit at the current moment.

[0091] In this embodiment, the heat conservation equation of each subunit is constructed based on at least one of the following factors: heat change of each subunit, heat generation of each subunit, convective heat transfer between each subunit in contact with each other and the grid unit, and convective heat transfer between each subunit in contact with each other and peripheral components.

[0092] The subunit with the highest / lowest temperature is selected from each subunit, and the target battery cell is thermally managed based on the temperature of the subunit with the highest / lowest temperature through the BMS, so that the battery cell temperature can be within a reasonable temperature range, thereby improving the safety performance and service life of the battery pack.

[0093] In an application scenario according to an embodiment of the present application, the lowest temperature of the battery pack is obtained, and the temperature of the battery pack is controlled by the lowest temperature. At this time, the battery cell at the lowest temperature point needs to be selected as the target battery cell for calculation;

[0094] See attached Figure 4 , Figure 4 FIG. 1 is a flow chart of the main steps of a method for obtaining the minimum temperature of a battery pack according to an embodiment of the present application. Figure 4 As shown, the method for obtaining the minimum temperature of a battery pack in the embodiment of the present application mainly includes the following steps S401 to S408.

[0095] Step S401: obtaining a target battery cell, and dividing the target battery cell into grids to obtain a plurality of grid units;

[0096] In the present embodiment, the battery cell near the side shell of the battery pack is the battery cell with the lowest temperature. Therefore, the battery cell near the side shell of the battery pack can be selected as the target battery cell; it should be noted that in the present embodiment, the battery cell near the side shell of the battery pack is identified as the battery cell with the lowest temperature only as an example of application scenario, and is not a limitation of the present embodiment. In actual applications of the implementation methods of the present application, the battery cell near the side shell of the battery pack is easily higher or lower than other battery cells in the pack, and the temperature of any one or more battery cells in the battery pack can be obtained according to actual needs.

[0097] In one embodiment, see the attached Figure 5 , Figure 5 FIG. 1 is a schematic flow chart of steps of a method for obtaining a target battery cell according to an embodiment of the present application. Figure 5 As shown, the method for obtaining the target battery cell includes:

[0098] Step S501: performing temperature distribution simulation on the battery pack;

[0099] Step S502: determining the area where the lowest temperature point of the battery pack is located based on the temperature distribution simulation result;

[0100] Step S503: taking the single cell with the lowest temperature in the area where the lowest temperature point is located as the target cell.

[0101] See attached Figure 6 , Figure 6 FIG. 1 is a schematic diagram of a temperature distribution simulation of a target battery cell during a charging and discharging process according to an embodiment of the present application. Figure 6 As shown, during the charge and discharge process, the lower left corner and the lower right corner of the single cell are the lowest temperature distribution points of the single cell. In the battery pack, the temperature sensor 206 is usually arranged directly above the single cell, and the lowest temperature of the single cell cannot be accurately estimated. Therefore, the present application divides the single cell into grids, and uses the thermal resistance and specific heat capacity parameters, the law of heat conservation and heat conduction to accurately estimate the lowest temperature of the single cell.

[0102] In this embodiment, Figure 2 As shown, a peripheral structure including a water-cooling plate 202, a partition 203, a top plate 201, two pads 205 and a bottom plate 204 is arranged around the target battery cell, and the water-cooling plate 202 is arranged between adjacent single battery cells; the top plate 201 is arranged at the top of the target battery cell, the bottom plate 204 is arranged at the bottom of the target battery cell, the two pads 205 are arranged between the target battery cell and the bottom plate 204, the partition 203 is in contact with the side surface of the target battery cell, and the temperature sensor 206 is arranged at the top of the target battery cell.

[0103] See Appendix 7, Figure 7 is a schematic diagram of dividing a target cell grid into nine grid units according to an embodiment of the present application. In this embodiment, the target cell is evenly grid-divided into nine grid units of the same size;

[0104] Step S402: constructing a first heat conservation equation for each grid unit;

[0105] In this embodiment, based on the specific heat capacity of the target battery cell, the temperature of each grid unit at the current moment and the temperature of each grid unit at the previous sampling moment, the current of the target battery cell, the resistance of the target battery cell, the number of grid units, the thermal resistance of the target battery cell, the temperature of other grid units in contact at the current moment, the temperature of the water-cooling plate 202 at the current moment, the convection heat transfer coefficient of the water-cooling plate 202, the temperature of the peripheral components in contact at the current moment, and the thermal resistance of the peripheral components, a first heat conservation equation for each grid unit is constructed;

[0106] The heat conservation equation for the first grid cell is as follows:

[0107]

[0108] Among them, Q part1 Indicates the heat change of the first grid unit; C partIndicates the specific heat capacity of the target battery cell; ΔT part1 represents the temperature difference between two samplings of the first grid cell, ΔT part1 =T part1 -T part1 ′,T part1 Represents the temperature of the first grid cell at the current moment, T part1 ′ represents the temperature of the first grid unit at the last moment; I represents the current of the target battery cell; R represents the resistance of the target battery cell; h A represents the convection heat transfer coefficient of the water cooling plate 202; T cool Indicates the temperature of the water cooling plate 202 at the current moment; T al Indicates the temperature of the partition 203 at the current moment; R al represents the thermal resistance of the partition 203; T up Indicates the temperature of the top plate 201 at the current moment; R up represents the thermal resistance of the top plate 201; T part2 Represents the temperature of the second grid cell at the current moment; R parth Indicates the horizontal thermal resistance inside the battery cell; T part4 Represents the temperature of the fourth grid cell at the current moment; R partv Indicates the thermal resistance in the vertical direction inside the battery cell.

[0109] The heat conservation equation for the second grid cell is as follows:

[0110]

[0111] Among them, Q part2 Indicates the heat change of the second grid unit; ΔT part2 represents the temperature difference between two samplings of the second grid cell, ΔT part2 =T part2 -T part2 ′,T part2 ′ represents the temperature of the second grid unit at the last moment; T part3 represents the temperature of the third grid cell at the current moment; T part5 Indicates the temperature of the third grid cell at the current moment.

[0112] The heat conservation equation for the third grid cell is as follows:

[0113]

[0114] Among them, Q part3 Indicates the heat change of the third grid unit; ΔT part3 represents the temperature difference between two samplings of the third grid cell, ΔT part3 =T part3 -Tpart3 ′,T part3 ′ represents the temperature of the third grid cell at the last moment; T part6 Indicates the temperature of the sixth grid cell at the current moment.

[0115] The heat conservation equation for the fourth grid cell is as follows:

[0116]

[0117] Among them, Q part4 Indicates the heat change of the fourth grid unit; ΔT part4 represents the temperature difference between two samplings in the fourth grid cell, ΔT part4 =T part4 -T part4 ′,T part4 ′ represents the temperature of the fourth grid cell at the last moment; T part7 Indicates the temperature of the seventh grid cell at the current moment.

[0118] The heat conservation equation for the fifth grid cell is as follows:

[0119]

[0120] Among them, Q part5 Indicates the heat change of the fifth grid cell; ΔT part5 represents the temperature difference between two samplings in the fifth grid cell, ΔT part5 =T part5 -T part5 ′,T part5 ′ represents the temperature of the fifth grid cell at the last moment; T part8 Indicates the temperature of the eighth grid cell at the current moment.

[0121] The heat conservation equation for the sixth grid cell is as follows:

[0122]

[0123] Among them, Q part6 Indicates the heat change of the sixth grid unit; ΔT part6 represents the temperature difference between two samplings in the sixth grid cell, ΔT part6 =T part6 -T part6 ′,T part6 ′ represents the temperature of the sixth grid cell at the last moment; T part9 Indicates the temperature of the sixth grid cell at the current moment.

[0124] The heat conservation equation for the seventh grid cell is as follows:

[0125]

[0126] Among them, Q part7 Indicates the heat change of the seventh grid unit; ΔT part7 represents the temperature difference between two samplings in the seventh grid cell, ΔT part7 =T part7 -T part7 ′,T part7 ′ represents the temperature of the seventh grid cell at the last moment; T base1 Indicates the temperature of the first pad at the current moment; R base1 represents the thermal resistance of the first pad.

[0127] The heat conservation equation for the eighth grid cell is as follows:

[0128]

[0129] Among them, Q part8 Indicates the heat change of the eighth grid unit; ΔT part8 represents the temperature difference between two samplings in the eighth grid cell, ΔT part8 =T part8 -T part8 ′,T part8 ' represents the temperature of the eighth grid cell at the previous moment.

[0130] The heat conservation equation for the ninth grid cell is as follows:

[0131]

[0132] Among them, Q part9 Indicates the heat change of the ninth grid unit; ΔT part9 Indicates the temperature difference between two samplings of the ninth grid cell, ΔT part9 =T part9 -T part9 ′,T part9 ′ represents the temperature of the ninth grid cell at the last moment; T base2 Indicates the temperature of the second pad at the current moment; R base2 represents the thermal resistance of the second pad.

[0133] Step S403: constructing a second heat conservation equation for the peripheral components;

[0134] In this embodiment, a second heat conservation equation for each peripheral component is constructed based on the specific heat capacity of each peripheral component, the temperature of each peripheral component at the current moment, the temperature of each peripheral component at the previous moment, the thermal resistance of each peripheral component, the temperature of the mesh unit in contact at the current moment, the ambient temperature at the current moment, and the ambient thermal resistance;

[0135] The heat conservation equation of the top plate 201 is:

[0136]

[0137] Among them, Q up Indicates the heat change of the top plate 201; C up represents the specific heat capacity of the top plate 201; ΔT up Indicates the temperature difference between two samplings of the top plate 201, ΔT up =T up -T up ′,T up ' represents the temperature of the top plate 201 at the last moment; R ambup represents the thermal resistance between the environment and the top plate 201.

[0138] The heat conservation equation of the partition 203 is:

[0139]

[0140] Among them, Q al Indicates the heat change of the partition 203; C al represents the specific heat capacity of the partition 203; ΔT al represents the temperature difference between two samples of the partition 203, ΔT al =T al -T al ′,T al ' represents the temperature of the partition 203 at the last moment; R ambal Represents the thermal resistance between the environment and the partition 203.

[0141] The heat conservation equation for the first pad is:

[0142]

[0143] Among them, Q base1 Indicates the heat change of the first pad; C base1 represents the specific heat capacity of the first pad; ΔT base1 Indicates the temperature difference between two samples of the first pad, ΔT base1 =T base1 -T base1 ′,T base1 ' represents the temperature of the first pad at the last moment; Rdown represents the thermal resistance of the base plate 204 .

[0144] The heat conservation equation of the second pad is:

[0145]

[0146] Among them, Q base2 Indicates the heat change of the second pad; C base2 represents the specific heat capacity of the second pad; ΔT base2 Indicates the temperature difference between two samples of the second pad, ΔT base2 =T base2 -T base2 ′,T base2 ' represents the temperature of the second pad at the previous moment.

[0147] The heat conservation equation of the bottom plate 204 is:

[0148]

[0149] Among them, Q down Indicates the heat change of the bottom plate 204; C down represents the specific heat capacity of the bottom plate 204; ΔT base2 represents the temperature difference between two samplings of the bottom plate 204, ΔT down =T down -T down ′,T down represents the temperature of the bottom plate 204 at the current moment, T base2 ' represents the temperature of the bottom plate 204 at the last moment.

[0150] Step S404: Acquire the temperature of the temperature sensor 206, and obtain the temperature of each grid unit at the current moment based on the temperature of the temperature sensor 206, the first heat conservation equation, and the second heat conservation equation.

[0151] In this embodiment, the temperature collected by the temperature sensor 206 is the temperature of the second grid unit. Therefore, the temperature collected by the temperature sensor 206 can be used to correct the temperature of the second grid unit: T part2 =T NTC

[0152] Among them, T NTC It is the temperature collected by the temperature sensor 206 at the current moment.

[0153] Step S405: re-dividing the grid unit with the lowest temperature among the grid units at the current moment into a grid to obtain a plurality of sub-units;

[0154] In this embodiment, if Figure 8 As shown, the seventh grid unit and the ninth grid unit are the grid units with the lowest temperature. In order to accurately calculate the lowest temperature value of the target battery cell, the seventh grid unit and the ninth grid unit are meshed again. When the seventh grid unit and the ninth grid unit are meshed again, they can be meshed with uniform area or meshed with uneven area.

[0155] In one implementation, see Appendix 8, Figure 8 is a schematic diagram of low temperature area grid division according to an embodiment of the present application, such as Figure 8 As shown, the seventh grid unit and the ninth grid unit can be divided into three parallel sub-units, and the two sub-units close to the bottom plate 204 are the sub-units with the lowest temperature of the target battery cell.

[0156] Step S406: constructing a heat conservation equation for the target battery cell minimum temperature subunit, and obtaining the temperature of the target battery cell minimum temperature subunit at the current moment based on the heat conservation equation for the target battery cell minimum temperature subunit;

[0157] In this embodiment, the heat conservation equations of the first lowest temperature subunit and the second lowest temperature subunit are constructed.

[0158] The heat conservation equation for the first lowest temperature subunit is:

[0159]

[0160] Among them, Q low1 Indicates the heat change of the first lowest temperature subunit; ΔT low1 Indicates the temperature difference between two samples of the first lowest temperature subunit, ΔT low1 =T low1 -T low1 ′,T low1 Indicates the temperature of the first lowest temperature subunit at the current moment, T low1 Indicates the temperature of the first lowest temperature subunit at the previous moment.

[0161] The heat conservation equation for the second lowest temperature subunit is:

[0162]

[0163] Among them, Q low2 Indicates the heat change of the second lowest temperature subunit; ΔT low2 Indicates the temperature difference between two samples of the second lowest temperature subunit, ΔT low2 =T low2 -T low2 ′,T low2 Indicates the temperature of the second lowest temperature subunit at the current moment, T low2' represents the temperature of the second lowest temperature subunit at the previous moment.

[0164] Step S407: selecting the temperature of the subunit with the lowest temperature in the subunit with the lowest temperature of the target battery cell at the current moment as the lowest temperature of the battery pack at the current moment.

[0165] Step S408: Performing thermal management on the target battery cell through the BMS according to the lowest temperature.

[0166] See Appendix 9, Fig. 9 is a schematic diagram of a module of a temperature acquisition device for a battery pack according to an embodiment of the present application, such as Fig. 9 As shown, another aspect of the present application further provides a battery pack temperature acquisition device, comprising:

[0167] A grid unit division module 901 is used to divide the target battery cell into grids to obtain a plurality of grid units;

[0168] A heat conservation equation construction module 902 is used to construct a first heat conservation equation for each of the grid units and to construct a second heat conservation equation for the peripheral components;

[0169] The grid unit temperature acquisition module 903 is used to obtain the temperature of each of the grid units at the current moment based on the first heat conservation equation and the second heat conservation equation.

[0170] It should be pointed out that although the various steps in the above embodiments are described in a specific order, those skilled in the art can understand that in order to achieve the effect of the present application, different steps do not have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders. These adjusted schemes are equivalent to the technical schemes described in this application, and therefore will also fall within the scope of protection of this application.

[0171] It is understood by those skilled in the art that all or part of the processes in the method for implementing the above-mentioned embodiment of the present application can also be completed by instructing the relevant hardware through a computer program, and the computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable storage medium may include: any entity or device, medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory, random access memory, electrical carrier signal, telecommunication signal and software distribution medium, etc. that can carry the computer program code.

[0172] Another aspect of the present application also provides a computer-readable storage medium. In an embodiment of a computer-readable storage medium according to the present application, the computer-readable storage medium can be configured to store a program for executing the temperature acquisition method of the battery pack of the above-mentioned method embodiment, and the program can be loaded and run by the processor to implement the temperature acquisition method of the above-mentioned battery pack. For ease of explanation, only the parts related to the embodiment of the present application are shown. For specific technical details not disclosed, please refer to the method part of the embodiment of the present application. The computer-readable storage medium can be a storage device formed by various electronic devices. Optionally, the computer-readable storage medium in the embodiment of the present application is a non-temporary computer-readable storage medium.

[0173] Another aspect of the present application further provides a smart device. Specifically, the smart device may refer to a battery management system (BMS) in a battery pack.

[0174] In an embodiment of an intelligent device according to the present application, the intelligent device may include at least one processor; and a memory connected to the at least one processor in communication; wherein a computer program is stored in the memory, and when the computer program is executed by the at least one processor, the method described in any of the above embodiments is implemented. The intelligent device described in the present application may include a driving device, a smart car, a robot, and the like. Fig.10 , Fig.10 Schematically shows that the memory 1001 and the processor 1002 are connected to each other through a bus.

[0175] In some embodiments of the present application, the smart device may further include at least one sensor, which is used to sense information. The sensor is connected to any type of processor mentioned in the present application. Optionally, the smart device may also include an autonomous driving system, which is used to guide the smart device to drive itself or assist in driving. The processor communicates with the sensor and / or the autonomous driving system to complete the method described in any of the above embodiments. (The electronic device described in the present application may be, but is not limited to, a mobile phone, a tablet computer, a desktop, a laptop, a handheld computer, a notebook computer, a vehicle-mounted device, an ultra-mobile personal computer (UMPC), a netbook, a personal digital assistant (PDA), an augmented reality (AR)\virtual reality (VR) device, etc., and the embodiments of the present application are not limited to this.)

[0176] So far, the technical solution of the present application has been described in conjunction with an embodiment shown in the accompanying drawings, but it is easy for those skilled in the art to understand that the protection scope of the present application is obviously not limited to these specific embodiments. Without departing from the principles of the present application, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present application.

Claims

1. A method for obtaining the temperature of a battery pack, characterized in that: The battery pack includes a target battery cell and a peripheral component, wherein the peripheral component is in contact with the target battery cell, and the method includes: Dividing the target battery cell into a grid to obtain a plurality of grid units; Constructing a first heat conservation equation for each of the grid units, and constructing a second heat conservation equation for the peripheral components; Based on the first heat conservation equation and the second heat conservation equation, the temperature of each of the grid cells at the current moment is obtained.

2. The method according to claim 1, characterized in that After obtaining the temperature of each of the grid units, the method further includes: The grid cell with the highest or lowest temperature is taken as the target grid; Dividing the target grid again to obtain a plurality of sub-units; A heat conservation equation for each of the sub-units is constructed, and based on the heat conservation equation for each of the sub-units, the temperature of each of the sub-units at the current moment is obtained.

3. The method according to claim 1, characterized in that The first heat conservation equation is constructed based on at least one of the following factors: heat change of each of the grid units, heat generation of each of the grid units, convective heat transfer between mutually contacting grid units, and convective heat transfer between mutually contacting peripheral components and the grid units; The second heat conservation equation is constructed based on at least one of the following factors: heat change of the peripheral components, convective heat transfer between the peripheral components in contact with each other, convective heat transfer between the peripheral components and the environment, and convective heat transfer between the peripheral components in contact with each other and the grid units.

4. The method according to claim 3, characterized in that The first heat conservation equation is expressed according to the following formula: Among them, Q partM Represents the heat change of grid unit M; C part represents the specific heat capacity of the target battery cell; ΔT partM represents the temperature difference between two samplings of grid cell M, ΔT partM =T partM -T partM ′,T partM Represents the temperature of grid cell M at the current moment, T partM ' represents the temperature of the grid unit M at the last moment; I represents the current of the target battery cell; R represents the resistance of the target battery cell; h A Indicates the convective heat transfer coefficient of the water cooling plate; T cool Indicates the temperature of the water cooling plate at the current moment; T 外围 Indicates the temperature of the peripheral components at the current moment; R 外围 represents the thermal resistance of the peripheral components; T partN Represents the temperature of grid cell N at the current moment; R part represents the thermal resistance of the target battery cell.

5. The method according to any one of claims 3 or 4, characterized in that The second heat conservation equation is expressed according to the following formula: Among them, Q 外围a Indicates the heat change of peripheral component a; C 外围a Indicates the specific heat capacity of the peripheral component a; ΔT 外围a Indicates the temperature difference between two samples of peripheral component a, ΔT 外围a =T 外围a -T 外围a ′,T 外围a represents the temperature of peripheral component a at the current moment, T 外围a ' represents the temperature of peripheral component a at the last moment; T partM Represents the temperature of grid cell M at the current moment; R 外围a Represents the thermal resistance of peripheral components a; T amb Indicates the current ambient temperature; R amb Represents ambient thermal resistance; T 外围b Indicates the temperature of peripheral component b at the current moment.

6. The method according to claim 3, characterized in that The peripheral component includes a top plate, a partition, a pad and a bottom plate, wherein the top plate is arranged on the top of the target battery cell, the bottom plate is arranged on the bottom of the target battery cell, the pad is arranged between the target battery cell and the bottom plate, and the partition contacts the side surface of the target battery cell; The method further comprises: Determine the heat change of each of the peripheral components according to the specific heat capacity of each of the peripheral components, the temperature of the peripheral components at a current moment, and the temperature of the peripheral components at a previous moment; Determine the convective heat exchange between the bottom plate and the contacting bottom plate according to the temperature of the bottom plate, the temperature of the bottom plate and the thermal resistance of the bottom plate at a current moment; Determine the convective heat exchange between the top plate and the grid unit in contact with the top plate according to the temperature of the grid unit in contact with the top plate at a current moment, the temperature of the top plate, and the thermal resistance of the top plate; Determine the convective heat transfer between the partition and all the mesh units in contact with the partition according to the temperature of all the mesh units in contact with the partition at the current moment, the temperature of the partition and the thermal resistance of the partition; Determine the convective heat transfer between the pad and the contacting mesh unit according to the temperature of the mesh unit in contact with the pad at the current moment, the temperature of the pad, and the thermal resistance of the pad; According to the temperature of the top plate, the temperature of the partition plate, the temperature of the bottom plate, the ambient temperature and the ambient thermal resistance at the current moment, the convective heat exchange between the top plate, the partition plate and the bottom plate and the environment is determined respectively.

7. The method according to claim 1, characterized in that The battery pack includes a battery cell module, the battery cell module includes a plurality of battery cells, the top view of the battery cell module is a rectangle, and the battery cells located at the four corners of the rectangle are used as the target battery cells.

8. A smart device, characterized in that: include: at least one processor; and, a memory communicatively coupled to the at least one processor; The memory stores a computer program, and when the computer program is executed by the at least one processor, the method for obtaining the temperature of the battery pack according to any one of claims 1 to 7 is implemented.

9. A computer-readable storage medium storing a plurality of program codes, characterized in that: The program code is suitable for being loaded and run by a processor to execute the method for obtaining the temperature of a battery pack according to any one of claims 1 to 7.

10. A vehicle, characterized in that: The vehicle comprises a battery pack and the smart device according to claim 8, wherein the battery pack comprises a target battery cell and a peripheral component, wherein the peripheral component is in contact with the target battery cell, and the smart device is used to obtain the temperature of the battery pack.

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