Battery life degradation curve acquisition method and device, intelligent device, and storage medium

Abstract

The application relates to the technical field of energy storage batteries, in particular to a battery life degradation curve acquisition method and device, an intelligent device and a storage medium, and aims to solve the technical problem of how to acquire a battery full-life cycle life degradation curve in a short time. For this purpose, the application comprises the following steps: controlling parallel samples to accelerate aging normal-temperature starting point discharge energy values based on high stress acceleration conditions; controlling the parallel samples to cycle and hang measurement to normal-temperature terminal point discharge energy values based on normal-temperature cycle conditions; acquiring normal-temperature discharge energy value sequences of normal-temperature cycle energy retention rate intervals corresponding to the parallel samples; and acquiring a battery life degradation curve based on all the normal-temperature discharge energy value sequences. The method can quickly acquire a full-life cycle life degradation curve of a battery actually measured under a normal-temperature working condition, and the life degradation curve can better reflect the actual trend of the battery in the later period, thereby providing strong data support for verifying whether a project life index is achieved.

Description

Technical Field

[0001] This application relates to the field of energy storage battery technology, specifically to a method, apparatus, smart device, and storage medium for obtaining battery life degradation curves. Background Technology

[0002] The energy storage industry is currently experiencing rapid growth, and lithium iron phosphate (LFP) batteries are seeing a rapid increase in their application share in the energy storage field due to their excellent advantages such as low cost, long lifespan, and safety and reliability. Furthermore, with technological advancements, the lifespan of LFP batteries for energy storage has significantly improved, with some companies claiming to have developed batteries with a lifespan of 12,000 cycles or even higher, achieving the same lifespan for both photovoltaic and energy storage.

[0003] However, this claimed lifespan is primarily based on predictions from a limited amount of actual measurement data. Whether the actual measured trend of the battery in its later stages will match the predicted value well is difficult to guarantee. Testing a high-lifespan battery to its end-of-life (e.g., 12,000 cycles with 70% energy retention) often requires more than five years, which is virtually impossible given the limited development cycles of battery development projects. Therefore, it is necessary to develop an accelerated testing method that can obtain the battery's full lifespan degradation curve in a shorter time, thus providing strong support for verifying whether the project's lifespan targets have been achieved.

[0004] Accordingly, there is a need in the field for a new technical solution that can accelerate the acquisition of battery life degradation curves throughout their entire life cycle to address the above problems. Summary of the Invention

[0005] In order to overcome the above-mentioned deficiencies, this application is made to solve, or at least partially solve, the technical problem of how to obtain the life degradation curve of the entire battery life cycle in a relatively short period of time.

[0006] In a first aspect, a method for obtaining a battery life degradation curve is provided, the method comprising: Based on preset high-stress acceleration conditions, each parallel sample is controlled to undergo cyclic testing, so that each parallel sample is accelerated to age to its corresponding room temperature starting discharge energy value. The room temperature starting discharge energy value is determined based on a preset room temperature cycle energy retention rate range that corresponds one-to-one with each parallel sample. Based on the ambient temperature cycling conditions corresponding to the ambient temperature cycling life index, each parallel sample is controlled to be cycled and tested until its corresponding ambient temperature endpoint discharge energy value, wherein the ambient temperature endpoint discharge energy value is determined based on the ambient temperature cycling energy retention rate range. During the cyclic testing process, the number of room temperature cycles for each parallel sample and the room temperature discharge energy value corresponding to each number of room temperature cycles are obtained, thus obtaining the room temperature discharge energy value sequence of the room temperature cycle energy retention rate range for each parallel sample. The battery life degradation curve is obtained based on the room temperature discharge energy value sequence within the room temperature cycle energy retention range.

[0007] In one technical solution of the above-mentioned method for obtaining battery life degradation curves, the method further includes: A first energy retention rate value is determined based on the high stress acceleration coefficient and the battery degradation trend curve, wherein the high stress acceleration coefficient is determined based on the high stress acceleration condition; Based on the first energy retention rate value, the second energy retention rate value corresponding to the battery life termination threshold, and the preset energy retention rate interval step size, all the room temperature cycle energy retention rate intervals are determined.

[0008] In one technical solution of the above-mentioned method for obtaining the battery life degradation curve, "determining the first energy retention rate value based on the high stress acceleration coefficient and the battery degradation trend curve" includes: Based on the high stress acceleration coefficient and the room temperature cycle life index, the high stress cycle life index corresponding to the high stress acceleration condition is determined. Based on the high-stress cycle life index, the lifespan of the high-stress battery under the high-stress acceleration condition is determined. The first energy retention rate value is determined based on the lifespan of the high-stress battery and the battery degradation trend curve.

[0009] In one technical solution of the above-mentioned method for obtaining the battery life degradation curve, "obtaining the battery life degradation curve based on the room temperature discharge energy value sequence within the room temperature cycle energy retention range" includes: Based on the right endpoints of each ambient temperature cycle energy retention rate interval in descending order, the ambient temperature discharge energy value sequences are sequentially spliced ​​together to obtain the full life cycle ambient temperature discharge energy value sequence. Based on the full life cycle room temperature discharge energy value sequence, the battery life degradation curve is obtained.

[0010] In one technical solution of the above-mentioned method for obtaining the battery life degradation curve, "obtaining the battery life degradation curve based on the full life cycle room temperature discharge energy value sequence" includes: The sequence number of each item in the full life cycle room temperature discharge energy value sequence is used as the horizontal axis of the battery life degradation curve. The normalized values ​​in the full life cycle room temperature discharge energy value sequence are used as the ordinate of the battery life degradation curve.

[0011] In one technical solution of the above-mentioned method for obtaining battery life degradation curves, the method further includes: Based on the initial true energy value of the battery and the right endpoint of each of the room temperature cycle energy retention rate intervals, the room temperature starting discharge energy value corresponding to the room temperature cycle energy retention rate interval is determined. Based on the initial true energy value of the battery and the left endpoint of each of the said room temperature cycle energy retention rate intervals, the room temperature endpoint discharge energy value corresponding to the said room temperature cycle energy retention rate interval is determined.

[0012] In one technical solution of the above-mentioned method for obtaining battery life degradation curves, the high-stress acceleration conditions include at least one of temperature conditions, rate conditions, and DOD conditions.

[0013] In a second aspect, a battery life degradation curve acquisition device is provided, the device comprising: The cyclic testing module is configured to perform the following operations: Based on preset high-stress acceleration conditions, each parallel sample is controlled to undergo cyclic testing, so that each parallel sample is accelerated to age to its corresponding room temperature starting discharge energy value. The room temperature starting discharge energy value is determined based on a preset room temperature cycle energy retention rate range that corresponds one-to-one with each parallel sample. Based on the ambient temperature cycling conditions corresponding to the ambient temperature cycling life index, each parallel sample is controlled to be cycled and tested until its corresponding ambient temperature endpoint discharge energy value, wherein the ambient temperature endpoint discharge energy value is determined based on the ambient temperature cycling energy retention rate range. The data acquisition module is configured to perform the following operations: during the cyclic testing process, acquire the number of room temperature cycles for each parallel sample and the room temperature discharge energy value corresponding to each number of room temperature cycles, and obtain the room temperature discharge energy value sequence of the room temperature cycle energy retention rate range corresponding to each parallel sample. The data processing module is configured to perform the following operations: obtain the battery life degradation curve based on the room temperature discharge energy value sequence within the room temperature cycle energy retention range.

[0014] In a third aspect, a smart device is provided, the smart device comprising at least one processor; and a memory communicatively connected to said at least one processor; The memory stores a computer program, which, when executed by the at least one processor, implements the method described in any of the above-described technical solutions for obtaining the battery life degradation curve.

[0015] In a fourth aspect, a storage medium stores a plurality of program codes, wherein when the computer program is executed by the at least one processor, it implements the method described in any one of the above-described technical solutions for obtaining the battery life degradation curve.

[0016] The above-mentioned technical solutions of this application have at least one or more of the following beneficial effects: the life degradation curve of the battery under normal temperature conditions can be obtained quickly, and since the life degradation curve is based entirely on the measured data, the life degradation curve can better reflect the actual trend of the battery in the later stage, and can provide strong data support for verifying whether the project life indicators of battery development have been achieved. Attached Figure Description

[0017] The disclosure of this application will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this application.

[0018] Figure 1 This is a schematic flowchart of the main steps of a method for obtaining a battery life degradation curve according to an embodiment of this application.

[0019] Figure 2 This is a schematic flowchart of the main steps of a method for determining the energy retention range during room temperature cycling according to an embodiment of this application.

[0020] Figure 3 This is an example graph of a battery degradation trend curve according to an embodiment of this application.

[0021] Figure 4 This is an example diagram showing all high-stress cycle ERR intervals, room temperature cycle ERR intervals, and the room temperature starting discharge energy value and room temperature ending discharge energy value corresponding to each room temperature cycle ERR interval according to an embodiment of this application.

[0022] Figure 5 This is an example diagram showing the energy value-cycle number corresponding to a room temperature discharge energy value sequence according to an embodiment of this application.

[0023] Figure 6 This is an example diagram of the energy value-cycle count curve and lifespan degradation curve of a battery throughout its entire lifespan, according to an embodiment of this application.

[0024] Figure 7 This is a main structural block diagram of a battery life degradation curve acquisition device according to another embodiment of this application.

[0025] Figure 8 This is a main structural block diagram of a smart device according to another embodiment of this application. Detailed Implementation

[0026] Some embodiments of this application are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application.

[0027] In the description of this application, "module" and "processor" can include hardware, software, or a combination of both. A module can include hardware circuitry, various suitable sensors, communication ports, memory, and may also include software components, such as program code, or a combination of software and hardware. A processor can be a central processing unit, microprocessor, image processor, digital signal processor, or any other suitable processor. The processor has data and / or signal processing capabilities. The processor can be implemented in software, in hardware, or a combination of both. Computer-readable storage media includes any suitable medium capable of storing program code, such as magnetic disks, hard disks, optical disks, flash memory, read-only memory, 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 terms "at least one A or B" or "at least one of A and B" have a similar meaning to "A and / or B" and can include only A, only B, or A and B. The singular terms "a" or "this" can also include plural forms.

[0028] See appendix Figure 1 , Figure 1 This is a schematic flowchart illustrating the main steps of a method for obtaining a battery life degradation curve according to an embodiment of this application. The method for obtaining a battery life degradation curve in this embodiment includes: Step S101: Based on the preset high-stress acceleration conditions, control each parallel sample to undergo cyclic testing, so that each parallel sample ages to its corresponding room-temperature starting discharge energy value. Step S102: Based on the ambient temperature cycling conditions corresponding to the ambient temperature cycling life index, control each parallel sample to be cycled and tested until its corresponding ambient temperature endpoint discharge energy value. Step S103: During the cyclic testing process, obtain the number of room temperature cycles for each parallel sample and the room temperature discharge energy value corresponding to each number of room temperature cycles, and obtain the room temperature discharge energy value sequence of the room temperature cycle energy retention rate range for each parallel sample. Step S104: Obtain the battery life degradation curve based on the room temperature discharge energy value sequence of the room temperature cycle energy retention range.

[0029] The technical solution proposed in this application is as follows: First, under high stress acceleration conditions, multiple sample batteries are accelerated to age to their corresponding preset energy retention rate (ERR); then, under normal temperature cycling conditions, each sample battery that has completed accelerated aging is subjected to cyclic charging and discharging tests within its corresponding normal temperature cycling energy retention rate range (normal temperature cycling ERR range); finally, the normal temperature cycling test data of all normal temperature cycling ERR ranges are integrated to quickly obtain the battery's measured full life cycle degradation curve under normal temperature conditions.

[0030] Before performing step S101, the ERR ranges for each ambient temperature cycle test must first be determined. (See Appendix) Figure 2 , Figure 2 This is a schematic flowchart illustrating the main steps of a method for determining the ERR range during ambient temperature cycling according to an embodiment of this application. The method for determining the ERR range during ambient temperature cycling in this embodiment includes: Step S201: Based on the high stress acceleration coefficient and the room temperature cycle life index, determine the high stress cycle life index corresponding to the high stress acceleration condition. Step S202: Determine the lifespan of the high-stress battery under high-stress acceleration conditions based on the high-stress cycle life index; Step S203: Determine the first energy retention rate value based on the high-stress battery lifespan and battery degradation trend curve; Step S204: Based on the first energy retention rate value, the second energy retention rate value corresponding to the battery life termination threshold, and the preset energy retention rate interval step size, determine the energy retention rate interval for all room temperature cycles.

[0031] In step S201, the high-stress acceleration conditions include at least one of temperature acceleration, rate acceleration, and DOD acceleration (Depth of Discharge). Based on the high-stress acceleration conditions, the high-stress acceleration coefficient relative to the normal temperature operating conditions (normal temperature cycling conditions) can be determined.

[0032] As an example, based on historical experience, the degradation trend (energy retention rate, ERR) of lithium iron phosphate batteries can be expressed by formula 1 - a*t. z The description is as follows, where z is the number of cycles, and a and t are set parameters. Those skilled in the art may determine the values ​​of a and t corresponding to different operating conditions based on the battery's operating temperature, rate, and DOD, etc. z is usually taken as 0.7, and a can be taken between [0.0004, 0.001] based on the room temperature cycle life index.

[0033] In this embodiment of the application, the nominal energy value of the type A lithium iron phosphate battery is 900Wh, and its initial actual energy value is 911Wh. Under normal temperature conditions (25℃_0.5P / 0.5P_0-100%SOC, that is, the normal temperature cycling conditions are: ambient temperature condition is 25℃, rate condition is 0.5P, and DOD condition is 0-100%SOC), when the life termination threshold corresponding to the end of life (EOL) of the type A lithium iron phosphate battery is set to 70%ERR, its normal temperature cycle life index is 12,000 cycles.

[0034] For type A lithium iron phosphate batteries, taking 0.0004 yields the following results: Figure 3 The degradation trend curve shown is represented by the horizontal axis as the number of cycles and the vertical axis as the energy retention rate (%).

[0035] In step S201, as an example, the preset high-stress acceleration conditions are 60℃_1P / 1P_0-100%SOC, that is, the ambient temperature condition is 60℃, the magnification condition is 1P, and the DOD condition is 0-100%SOC.

[0036] The high-stress acceleration factor can be obtained based on a small amount of measured data. Specifically, the measured termination threshold is set to 95% ERR. Charge-discharge tests are performed on two sets of batteries under normal temperature cycling conditions and high-stress acceleration conditions, respectively. The number of the first cycle (normal temperature cycling conditions) and the number of the second cycle (high-stress acceleration conditions) when the ERR value of the two sets of batteries reaches 95% are recorded. The ratio of the number of the first cycle and the number of the second cycle is the high-stress acceleration factor.

[0037] In this embodiment of the application, the high stress acceleration factor obtained based on a small amount of measured data is 3, the room temperature cycle life index is 12000 cycles, and the high stress cycle life index corresponding to the high stress acceleration condition is determined to be 12000 / 3 = 4000 cycles.

[0038] In step S202, the high-stress battery lifespan after 4000 cycles is first estimated based on a preset high-stress cycling strategy under high-stress acceleration conditions. As an example, the high-stress cycling strategy is: 60℃_1P / 1P_0-100%SOC, with a resting time of 20 minutes at each end of the charge and discharge cycle.

[0039] The time required for a Type A lithium iron phosphate battery to complete 4000 cycles is approximately one year. Therefore, it can be determined that the lifespan of a high-stress battery under high-stress acceleration conditions is 360 days.

[0040] In step S203, the time required to complete each cycle is first estimated based on the ambient temperature cycling strategy corresponding to the ambient temperature cycling conditions. As an example, the ambient temperature cycling strategy is: 25℃_0.5P / 0.5P_0-100%SOC, with a resting time of 20 minutes at each end of the charge and discharge cycle.

[0041] At this point, the time required for the Type A lithium iron phosphate battery to complete one cycle is approximately 4.8 hours, corresponding to the high-stress battery life obtained in step S202. Under the normal temperature cycling strategy, it can complete 1800 cycles in 360 days.

[0042] Combination Figure 3 The battery degradation trend curve shown indicates that the ERR value corresponding to 1800 cycles under normal temperature cycling conditions is the first energy retention rate (first ERR value). As an example, the first ERR value in this embodiment is 92%.

[0043] In step S204, a second energy retention rate value (second ERR value) is first obtained based on the battery's lifespan termination threshold, and the second ERR value is less than the first ERR value; then, based on a preset energy retention rate interval step size (ERR interval step size), the interval formed by the first ERR value and the second ERR value is divided into multiple continuous sub-ERR intervals; the multiple continuous sub-ERR intervals and the ERR interval from 100% ERR to the first ERR value together constitute the entire room temperature cycle ERR interval of this application.

[0044] As an example, the first ERR value is 92%, the second ERR value corresponding to the end-of-life threshold is 72%, and the ERR interval step size is 2% ERR. At this time, based on the step size of 2%, the [72%, 92%] interval can be divided into 11 consecutive sub-ERR intervals ([72%, 74%], [74%, 76%], ..., [90%, 92%]), plus the [92%, 100%] ERR interval, resulting in a total of 12 consecutive room temperature cycle ERR intervals.

[0045] Specifically, based on the battery's initial true energy value and the right endpoint of each room-temperature cycle ERR interval, the room-temperature starting discharge energy value corresponding to that room-temperature cycle ERR interval can be determined; based on the battery's initial true energy value and the left endpoint of each room-temperature cycle ERR interval, the room-temperature ending discharge energy value corresponding to that room-temperature cycle ERR interval can be determined. Furthermore, the room-temperature starting discharge energy value also serves as the stopping condition for high-stress accelerated aging.

[0046] like Figure 4 As shown, Figure 4 This is an example diagram illustrating all high-stress cycle ERR intervals, room temperature cycle ERR intervals, and the room temperature starting discharge energy value and room temperature ending discharge energy value corresponding to each room temperature cycle ERR interval, according to an embodiment of this application.

[0047] In the embodiments of this application, there are 12 consecutive room temperature cycle ERR intervals, corresponding to 12 parallel samples. The sequence number of each parallel sample and the corresponding room temperature cycle ERR interval range are as follows: Figure 4 As shown.

[0048] Parallel sample 1 (parallel sample 1) only has the room temperature cycling ERR range [92%, 100%], meaning it does not require cyclic testing under high stress acceleration conditions. Parallel samples 2 to 11 (parallel samples 2 to 12) have their own corresponding room temperature cycling ERR ranges and their own corresponding high stress cycling energy retention rate ranges (high stress cycling ERR ranges). The numerical range of the high stress cycling ERR range for each parallel sample is from 100% to the right endpoint of the corresponding room temperature cycling ERR range for each parallel sample.

[0049] Next, return Figure 1 The method for obtaining the battery life degradation curve is described in detail. In step S101, based on the high-stress cycling strategy corresponding to the high-stress acceleration conditions (60℃_1P / 1P_0-100% SOC, with a resting time of 20 minutes at each end of the charge and discharge), parallel samples 2 to parallel samples 12 are controlled to be cycled and observed to accelerate aging to the corresponding room temperature starting discharge energy value.

[0050] As an example, the room temperature starting discharge energy value corresponding to the accelerated aging of parallel sample 2 to the room temperature cycling ERR range [90%, 92%] is 838Wh; the room temperature starting discharge energy value corresponding to the accelerated aging of parallel sample 3 to the room temperature cycling ERR range [88%, 90%] is 820Wh; and the room temperature starting discharge energy value corresponding to the accelerated aging of parallel sample 12 to the room temperature cycling ERR range [70%, 72%] is 656Wh.

[0051] In step S102, for parallel sample 1 and each parallel sample that has completed step S101, based on the room temperature cycling strategy corresponding to the room temperature cycling conditions (25℃_0.5P / 0.5P_0-100%SOC, with a resting time of 20 minutes at each end of the charge and discharge), each parallel sample is controlled to be cycled and tested until the room temperature endpoint discharge energy value corresponding to each parallel sample is reached.

[0052] As an example, the discharge energy value at room temperature endpoint corresponding to the ERR range [92%, 100%] of parallel sample 1 after cyclic testing was 838Wh; the discharge energy value at room temperature endpoint corresponding to the ERR range [90%, 92%] of parallel sample 2 after cyclic testing was 820Wh; and the discharge energy value at room temperature endpoint corresponding to the ERR range [70%, 72%] of parallel sample 12 after cyclic testing was 638Wh.

[0053] It should be noted that testing can begin simultaneously for all parallel samples. Specifically, parallel control sample 1 can begin cyclic testing under normal temperature conditions, while parallel samples 2 through 12 can begin cyclic testing under high-stress acceleration conditions. Furthermore, after any parallel sample completes cyclic testing under high-stress acceleration conditions, it immediately transitions to cyclic testing within its corresponding normal temperature ERR range.

[0054] In step S103, during the cyclic testing process, the number of room temperature cycles for each parallel sample is recorded, and the discharge energy value (room temperature discharge energy value) corresponding to each room temperature cycle number is obtained through a DC power meter, thus obtaining the room temperature discharge energy value sequence of all parallel samples in the room temperature cycle ERR range.

[0055] The sequence of room temperature discharge energy values ​​corresponding to each parallel sample can be represented as {Wn(1),Wn(2),…,Wn(m),…,Wn(Nn)}, where n represents the serial number of the parallel sample, there are Nn data items in the parallel sample n, and Wn(m) is the m-th item in the room temperature discharge energy value sequence corresponding to the parallel sample n, that is, the room temperature discharge energy value with serial number m, 1≤m≤Nn.

[0056] As an example, the room temperature discharge energy value sequence corresponding to parallel sample 1 is {W1(1),W1(2),…,W1(m),…,W1(N1)}, and parallel sample 1 has N1 data items; the room temperature discharge energy value sequence corresponding to parallel sample 2 is {W2(1),W2(2),…,W2(m),…,W2(N2)}, and parallel sample 2 has N2 data items; the room temperature discharge energy value sequence corresponding to parallel sample 12 is {W12(1),W12(2),…,W12(m),…,W12(N12)}, and parallel sample 12 has N12 data items.

[0057] like Figure 5 As shown, Figure 5 (a) is an example graph showing the energy value-cycle number corresponding to the room temperature discharge energy value sequence of parallel sample 1. Figure 5 (b) is an example graph showing the energy value-cycle number corresponding to the room temperature discharge energy value sequence of parallel sample 2. Figure 5 (c) is an example graph of energy value-cycle number corresponding to the room temperature discharge energy value sequence of parallel sample 12, where the horizontal axis is the cycle number and the vertical axis is the discharge energy value (Energy / Wh).

[0058] In step S104, the room temperature discharge energy value sequences are first spliced ​​together in descending order of the right endpoints of each room temperature cycle ERR interval to obtain a full life cycle room temperature discharge energy value sequence.

[0059] In the embodiments of this application, the right endpoints of the room temperature cycle ERR intervals corresponding to parallel samples 1 to 12 decrease sequentially, and the room temperature discharge energy value sequences corresponding to parallel samples 1 to 12 are sequentially spliced ​​to obtain the full life cycle room temperature discharge energy value sequence {W1(1),W1(2),…,W1(m),…,W1(N1),W2(1),W2(2),…,W2(m),…,W2(N2),…,W12(1),W12(2),…,W12(m),…,W12(N12)}.

[0060] In the full life cycle room temperature discharge energy value sequence, there are a total of N1+N2+…+N12 data items. Among them, the first data item (W2(1)) of the room temperature discharge energy value sequence of parallel sample 2 becomes the N1+1 data item of the full life cycle room temperature discharge energy value sequence; the first data item (W3(1)) of the room temperature discharge energy value sequence of parallel sample 3 becomes the N1+N2+1 data item of the full life cycle room temperature discharge energy value sequence, and so on. The first data item (W12(1)) of the room temperature discharge energy value sequence of parallel sample 12 becomes the N1+N2+…+N11+1 data item of the full life cycle room temperature discharge energy value sequence.

[0061] The energy value-cycle number curves corresponding to the full life cycle room temperature discharge energy value sequence are as follows: Figure 6 As shown in (a), the horizontal axis represents the number of cycles, and the vertical axis represents the discharge energy value (Energy / Wh). After normalizing each item in the full life-cycle room-temperature discharge energy value sequence based on the battery's initial true energy value, the following can be obtained: Figure 6 (b) shows the battery life degradation curve expressed in terms of energy retention, where the horizontal axis represents the number of cycles and the vertical axis represents the energy retention (%).

[0062] It should be noted that those skilled in the art can set the values ​​of parameters such as high-stress acceleration conditions, battery life termination threshold, measured termination threshold, and ERR interval step size according to actual conditions. For example, for power batteries, the life termination threshold can be set to 80% ERR, and for energy storage batteries, it can be set to 70% ERR; the measured termination threshold of 95% ERR can be set to 96% ERR; the high-stress acceleration conditions can be set to 55℃_1.5P / 1.5P_0-100% SOC, or 55℃_1.0P / 1.0P_20% SOC-100% SOC; and the ERR interval step size can be set to 1% ERR, etc. Those skilled in the art will understand that, without departing from the technical solution of this application, adjustments to these preset parameters are all equivalent technical solutions and therefore will also fall within the protection scope of this application.

[0063] It should be noted that, considering that the method of this application includes a variety of actual measurement data, such as temperature, time, discharge energy value, etc., the terms "is", "to", "equal to", etc., which indicate an equal relationship, as used in this application can mean that the target value is exactly the same as the measured value; or that the target value is approximately equal to the measured value within the allowable deviation range.

[0064] In this embodiment, parallel samples 1 to 12 are set to start cyclic testing simultaneously. Based on the high-stress cyclic strategy and the room-temperature cyclic strategy, the longest cyclic testing time is for parallel sample 12, which takes approximately 1.6 years. Specifically, under high-stress accelerated conditions, it takes approximately 0.9 years (referencing approximately 4000 cycles corresponding to 72% ERR), and under room-temperature cyclic conditions, it takes approximately 0.6 years (referencing...). Figure 5 (c), approximately 1100 cycles). If the A-type lithium iron phosphate battery is cycled from 100% ERR to 70% ERR (end-of-life threshold) based on a room temperature cycling strategy, the required time is approximately 6 years (12000 cycles).

[0065] As can be seen from the above, the method of this application can quickly obtain the life degradation curve of the battery under normal temperature conditions for the entire life cycle. Since the life degradation curve is based entirely on the measured data, it can better reflect the actual trend of the battery in the later stage and provide strong data support for verifying whether the project life indicators of battery development have been achieved.

[0066] Furthermore, this application also provides a device for obtaining battery life degradation curves.

[0067] See Figure 7 , Figure 7 This is a main structural block diagram of a battery life degradation curve acquisition device according to another embodiment of this application. Figure 7As shown, the battery life degradation curve acquisition device 7 in this embodiment includes a cyclic testing module 71, a data acquisition module 72, and a data processing module 73.

[0068] The cyclic testing module 71 is configured to perform the following operations: based on preset high-stress acceleration conditions, control each parallel sample to perform cyclic testing, so that each parallel sample is accelerated to age to its corresponding room temperature starting discharge energy value, wherein the room temperature starting discharge energy value is determined based on a preset room temperature cycle energy retention rate range that corresponds one-to-one with each parallel sample.

[0069] The cyclic testing module 71 is also configured to perform the following operations: based on the ambient temperature cycling conditions corresponding to the ambient temperature cycling life index, control each parallel sample to be cyclically tested until its corresponding ambient temperature endpoint discharge energy value, wherein the ambient temperature endpoint discharge energy value is determined based on the ambient temperature cycling energy retention rate range.

[0070] The data acquisition module 72 is configured to perform the following operations: during the cyclic testing process, acquire the number of room temperature cycles for each parallel sample and the room temperature discharge energy value corresponding to each number of room temperature cycles, and obtain the room temperature discharge energy value sequence of the room temperature cycle energy retention rate range for each parallel sample.

[0071] The data processing module 73 is configured to perform the following operations: obtain the battery life degradation curve based on the sequence of room temperature discharge energy values ​​for the entire room temperature cycle energy retention range.

[0072] Furthermore, this application also provides a smart device.

[0073] In one embodiment of a smart device according to this application, the smart device may include at least one processor; and a memory communicatively connected to the at least one processor; wherein the memory stores a computer program, which, when executed by the at least one processor, implements the battery life degradation curve acquisition method described in any of the above embodiments. (See appendix) Figure 8 , Figure 8 The example illustrates a smart device 8 including a memory 81 and a processor 82, which are connected in communication via a bus.

[0074] Furthermore, this application also provides a storage medium.

[0075] In one embodiment of the storage medium according to this application, the storage medium may be configured to store a program for executing the battery life degradation curve acquisition method of the above-described method embodiments. This program may be loaded and run by a processor to implement the battery life degradation curve acquisition method. For ease of explanation, only the parts related to the embodiments of this application are shown; for specific technical details not disclosed, please refer to the method section of the embodiments of this application. The storage medium may be a storage device comprising various electronic devices. As an example, in the embodiments of this application, the storage medium is a non-transitory storage medium.

[0076] It should be noted that the method of this application is also applicable to non-lithium iron batteries. When non-lithium iron batteries can also undergo accelerated testing under high stress conditions, and the energy degradation trend curve determined theoretically or empirically can be used to obtain the ERR range for room temperature cycling, the life degradation curve of non-lithium iron batteries can also be obtained based on the method of this application.

[0077] It should be noted that although the steps in the above embodiments are described in a specific order, those skilled in the art will understand that in order to achieve the effect of this application, different steps do not necessarily have to be executed in such an order. They can be executed simultaneously (in parallel) or in other orders. These adjusted solutions are equivalent to the technical solutions described in this application and therefore will also fall within the protection scope of this application.

[0078] Those skilled in the art will understand that all or part of the processes in the method of the above-described embodiment can also be implemented by a computer program instructing related hardware. The computer program can be stored in a computer-readable storage medium, and when executed by a processor, it can implement the steps of the above-described method embodiments. The computer program includes computer program code, which can be in the form of source code, object code, executable file, or some intermediate form. The computer-readable storage medium can include any entity or device capable of carrying the computer program code, a medium, a USB flash drive, a portable hard drive, a magnetic disk, an optical disk, a computer memory, a read-only memory, a random access memory, an electrical carrier signal, a telecommunication signal, and a software distribution medium, etc.

[0079] The technical solution of this application has been described above with reference to one embodiment shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of this application is obviously not limited to these specific embodiments. Without departing from the principles of this 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 all fall within the scope of protection of this application.

Claims

1. A method for obtaining battery life degradation curves, characterized in that, The method includes: Based on the preset high-stress acceleration conditions, each parallel sample is controlled to undergo cyclic testing, so that each parallel sample is accelerated to age to its corresponding room temperature starting discharge energy value. The room temperature starting discharge energy value is determined based on the preset room temperature cycle energy retention rate range that corresponds one-to-one with each parallel sample. Based on the ambient temperature cycling conditions corresponding to the ambient temperature cycling life index, each parallel sample is controlled to be cycled and tested until its corresponding ambient temperature endpoint discharge energy value, wherein the ambient temperature endpoint discharge energy value is determined based on the ambient temperature cycling energy retention rate range. During the cyclic testing process, the number of room temperature cycles for each parallel sample and the room temperature discharge energy value corresponding to each number of room temperature cycles are obtained, thus obtaining the room temperature discharge energy value sequence of the room temperature cycle energy retention rate range for each parallel sample. The battery life degradation curve is obtained based on the room temperature discharge energy value sequence within the room temperature cycle energy retention range.

2. The method for obtaining battery life degradation curves according to claim 1, characterized in that, The method further includes: A first energy retention rate value is determined based on the high stress acceleration coefficient and the battery degradation trend curve, wherein the high stress acceleration coefficient is determined based on the high stress acceleration condition; Based on the first energy retention rate value, the second energy retention rate value corresponding to the battery life termination threshold, and the preset energy retention rate interval step size, all the ambient temperature cycle energy retention rate intervals are determined.

3. The method for obtaining battery life degradation curves according to claim 2, characterized in that, "Determining the first energy retention rate value based on the high stress acceleration coefficient and battery degradation trend curve" includes: Based on the high stress acceleration coefficient and the room temperature cycle life index, the high stress cycle life index corresponding to the high stress acceleration condition is determined. Based on the high-stress cycle life index, the lifespan of the high-stress battery under the high-stress acceleration condition is determined. The first energy retention rate value is determined based on the lifespan of the high-stress battery and the battery degradation trend curve.

4. The method for obtaining battery life degradation curves according to claim 1, characterized in that, "Obtaining the battery life degradation curve based on the room temperature discharge energy value sequence within the room temperature cycling energy retention range" includes: Based on the right endpoints of each ambient temperature cycle energy retention rate range in descending order, the ambient temperature discharge energy value sequences are sequentially spliced ​​together to obtain the full life cycle ambient temperature discharge energy value sequence. Based on the full life cycle room temperature discharge energy value sequence, the battery life degradation curve is obtained.

5. The method for obtaining battery life degradation curves according to claim 4, characterized in that, "Based on the full life cycle room temperature discharge energy value sequence, the battery life degradation curve is obtained" including: The sequence number of each item in the full life cycle room temperature discharge energy value sequence is used as the horizontal axis of the battery life degradation curve. The normalized values ​​in the full life cycle room temperature discharge energy value sequence are used as the ordinate of the battery life degradation curve.

6. The method for obtaining battery life degradation curves according to claim 1, characterized in that, The method further includes: Based on the initial true energy value of the battery and the right endpoint of each of the room temperature cycle energy retention rate intervals, the room temperature starting discharge energy value corresponding to the room temperature cycle energy retention rate interval is determined. Based on the initial true energy value of the battery and the left endpoint of each of the said room temperature cycle energy retention rate intervals, the room temperature endpoint discharge energy value corresponding to the said room temperature cycle energy retention rate interval is determined.

7. The method for obtaining battery life degradation curves according to claim 1, characterized in that, The high-stress acceleration conditions include at least one of the following: temperature conditions, magnification conditions, and DOD conditions.

8. A device for obtaining battery life degradation curves, characterized in that, The device includes: The cyclic testing module is configured to perform the following operations: Based on the preset high-stress acceleration conditions, each parallel sample is controlled to undergo cyclic testing, so that each parallel sample is accelerated to age to its corresponding room temperature starting discharge energy value. The room temperature starting discharge energy value is determined based on the preset room temperature cycle energy retention rate range that corresponds one-to-one with each parallel sample. Based on the ambient temperature cycling conditions corresponding to the ambient temperature cycling life index, each parallel sample is controlled to be cycled and tested until its corresponding ambient temperature endpoint discharge energy value, wherein the ambient temperature endpoint discharge energy value is determined based on the ambient temperature cycling energy retention rate range. The data acquisition module is configured to perform the following operations: during the cyclic testing process, acquire the number of room temperature cycles for each parallel sample and the room temperature discharge energy value corresponding to each number of room temperature cycles, and obtain the room temperature discharge energy value sequence of the room temperature cycle energy retention rate range corresponding to each parallel sample. The data processing module is configured to perform the following operations: obtain the battery life degradation curve based on the room temperature discharge energy value sequence within the room temperature cycle energy retention range.

9. A smart device, characterized in that, include: At least one processor; And, a memory communicatively connected to the at least one processor; The memory stores a computer program, which, when executed by the at least one processor, implements the battery life degradation curve acquisition method according to any one of claims 1 to 7.

10. A storage medium storing a plurality of program codes, characterized in that, The program code is adapted to be loaded and run by a processor to perform the battery life degradation curve acquisition method according to any one of claims 1 to 7.

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