CN105445663B - The detection method and device of cell degradation degree - Google Patents

Abstract

The invention discloses a method and a device for detecting the aging degree of a battery. Wherein, the detection method of battery aging includes: testing the first battery to obtain the first battery parameters, wherein the first battery is a brand new battery; testing the second battery to obtain the second battery parameters, wherein the second battery It is a fully aged battery; the third battery is tested to obtain the third battery parameter, wherein the third battery is the battery to be tested, the first battery, the second battery and the third battery are the same battery, and the aging of the third battery The degree is different from the aging degree of the second battery; and calculating the aging degree of the third battery using the first battery parameter, the second battery parameter and the third battery parameter. The invention solves the problem of inaccurate detection of battery aging degree in the prior art, and further achieves the effect of accurately detecting the battery aging degree.

Description

Method and device for detecting battery aging degree

technical field

The invention relates to the field of measurement, in particular to a method and device for detecting the aging degree of a battery.

Background technique

Lithium-ion batteries have the advantages of long cycle life, large specific capacity, low self-discharge rate, and no memory characteristics, and have become a hotspot in battery research. In practical applications, it is often necessary to detect the aging degree of lithium-ion batteries. Lithium-ion batteries whose aging level has reached or is close to the life limit should be replaced in time, otherwise, it may cause danger to the entire application.

The aging degree of the battery is often marked by the State of Health (hereinafter referred to as SOH) of the battery. SOH is defined as the ratio of the actual capacity of the battery to the nominal capacity. The traditional method of measuring battery SOH is the full discharge method, which requires the battery to be fully charged and discharged to measure the actual capacity of the battery, which is not only time-consuming, but also the measurement method itself aggravates the aging of the battery.

The method of SOH estimation using internal resistance measurement includes the direct discharge method and the like. The direct discharge method has high requirements on the equipment, and it is difficult to distinguish the ohmic internal resistance and the polarization internal resistance in the measurement results. In fact, the internal resistance of the battery is divided into ohmic internal resistance and polarization internal resistance, and the ohmic internal resistance can directly reflect the aging level of the battery. At the same time, the internal resistance parameters measured by the direct discharge method are also affected by the state of charge (SOC) of the battery, and the response to the aging degree is not accurate enough.

Aiming at the problem of inaccurate detection of battery aging degree in related technologies, no effective solution has been proposed yet.

Contents of the invention

The main purpose of the present invention is to provide a battery aging degree detection method and device to solve the problem of inaccurate detection of battery aging degree in the prior art.

According to one aspect of the present invention, a method for detecting battery aging is provided.

The method for detecting the battery aging degree according to the present invention includes: testing the first battery to obtain the first battery parameter, wherein the first battery is a brand new battery; testing the second battery to obtain the second battery parameter, wherein , the second battery is a fully aged battery; the third battery is tested to obtain a third battery parameter, wherein the third battery is a battery to be tested, the first battery, the second battery and the The third battery is the same battery, and the aging degree of the third battery is different from the aging degree of the second battery; and using the first battery parameter, the second battery parameter and the third battery parameter to calculate the aging degree of the third battery.

Further, testing the first battery to obtain the first battery parameters includes: performing a mixed pulse capability characteristic test on the first battery to obtain the functional relationship U ₁ =f ₁ (SOC ₁ ) and the functional relationship r ₁ =f ₂ (SOC ₁ ), where U ₁ is the open circuit voltage of the first battery, SOC ₁ is the state of charge of the first battery, r ₁ is the ohmic internal resistance of the first battery, and the first The battery parameters include the functional relationship U ₁ =f ₁ (SOC ₁ ) and the functional relationship r ₁ =f ₂ (SOC ₁ ), and the second battery is tested to obtain the second battery parameters including: The battery performs the mixed pulse capability characteristic test, and obtains the functional relationship r ₂ =f ₂ (SOC ₂ ), wherein, SOC ₂ is the battery state of charge of the second battery, and r ₂ is the ohmic voltage of the second battery. The second battery parameter includes the functional relationship r ₂ =f ₂ (SOC ₂ ), and the third battery is tested to obtain the third battery parameter includes: performing the mixed pulse capability characteristic on the third battery Test to obtain the ohmic internal resistance r _3x and open circuit voltage U _3x of the third battery, and calculate the aging degree of the third battery by using the first battery parameter, the second battery parameter and the third battery parameter _It includes: calculating the battery state of charge SOC _3x =f _{1 -1} (U _3x ) of the ^third battery corresponding to the open circuit voltage U _3x according to the functional relationship U 1 =f ₁ (SOC ₁ ); according to the function The relationship r ₁ =f ₂ (SOC ₁ ) calculates the ohmic resistance r _1x =f ₂ (SOC _3x ) of the first battery at the battery state of charge SOC _3x and the ohmic resistance at the preset battery state of charge SOC ₀ Ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ); according to the functional relationship r ₂ =f ₂ (SOC ₂ ), calculate the ohmic internal resistance r of the second battery under the preset battery state of charge SOC _{0 20} =f ₂ (SOC ₀ ); and according to the ohmic internal resistance r _3x , the ohmic resistance r _1x =f ₂ (SOC _3x ), the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) and the Ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) calculates the aging degree of the third battery.

Further, according to the ohmic internal resistance r _3x , the ohmic internal resistance r _1x =f ₂ (SOC _3x ), the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) and the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) Calculating the aging degree of the third battery includes: according to the ohmic internal resistance r _3x , the ohmic resistance r _1x =f ₂ (SOC _3x ) and the ohmic internal resistance r ₁₀ =f ₂ ( SOC ₀ ) calculating the ohmic internal resistance r ₃₀ of the third battery at the preset battery state of charge SOC ₀ ; and according to the ohmic internal resistance r ₃₀ , the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) and the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) to calculate the aging degree of the third battery.

Further, according to the formula Calculate said ohmic internal resistance r ₃₀ ; and according to the formula Calculate the aging degree D of the third battery.

According to another aspect of the present invention, a device for detecting the aging degree of a battery is provided.

The detection device for battery aging degree according to the present invention includes: a first test unit, used to test the first battery to obtain first battery parameters, wherein, the first battery is a brand new battery; a second test unit, used for The second battery is tested to obtain the second battery parameters, wherein the second battery is a completely aged battery; the third test unit is used to test the third battery to obtain the third battery parameters, wherein the The third battery is the battery to be tested, the first battery, the second battery and the third battery are the same battery, and the aging degree of the third battery is different from the aging degree of the second battery; And a calculation unit, configured to calculate the aging degree of the third battery by using the first battery parameter, the second battery parameter and the third battery parameter.

Further, the first test unit includes: a first test subunit, configured to perform a mixed pulse capability characteristic test on the first battery to obtain the functional relationship U ₁ =f ₁ (SOC ₁ ) and the functional relationship r ₁ = f ₂ (SOC ₁ ), wherein, U ₁ is the open circuit voltage of the first battery, SOC ₁ is the battery state of charge of the first battery, r ₁ is the ohmic internal resistance of the first battery, and the The first battery parameter includes the functional relationship U ₁ =f ₁ (SOC ₁ ) and the functional relationship r ₁ =f ₂ (SOC ₁ ), and the second test unit includes: a second test subunit for testing The second battery performs the mixed pulse capability characteristic test, and obtains the functional relationship r ₂ =f ₂ (SOC ₂ ), wherein, SOC ₂ is the battery state of charge of the second battery, and r ₂ is the second The ohmic internal resistance of the battery, the second battery parameter includes the functional relationship r ₂ =f ₂ (SOC ₂ ), the third test unit includes: a third test subunit, used to test the third battery The characteristic test of the mixed pulse capability obtains the ohmic internal resistance r _3x and the open circuit voltage U _3x of the third battery, and the calculation unit includes: a first calculation subunit, which is used for according to the functional relationship U ₁ =f ₁ (SOC ₁ ) Calculate the battery state of charge SOC _3x =f ₁ ^-1 (U _3x ) of the third battery corresponding to the open circuit voltage U _3x ; the second calculation subunit is used to calculate according to the functional relationship r ₁ = f ₂ (SOC ₁ ) calculates the ohmic resistance r _1x =f ₂ (SOC _3x ) of the first battery at the battery state of charge SOC _3x and the ohmic internal resistance r at the preset battery state of charge SOC _{0 10} =f ₂ (SOC ₀ ); a third calculation subunit, configured to calculate the charge of the second battery under the preset battery state of charge SOC ₀ according to the functional relationship r ₂ =f ₂ (SOC ₂ ). Ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ); and a fourth calculation subunit, configured to use the ohmic internal resistance r _3x , the ohmic resistance r _1x =f ₂ (SOC _3x ), the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) and the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) calculate the aging degree of the third battery.

Further, the fourth calculation subunit includes: a first calculation module, configured to calculate according to the ohmic internal resistance r _3x , the ohmic resistance r _1x =f ₂ (SOC _3x ) and the ohmic internal resistance r ₁₀ = f ₂ (SOC ₀ ) calculates the ohmic internal resistance r ₃₀ of the third battery at the preset battery state of charge SOC ₀ ; and a second calculation module, configured to use the ohmic internal resistance r ₃₀ , the The ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) and the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) calculate the aging degree of the third battery.

Further, the first calculation module is used for according to the formula Calculating the ohmic internal resistance r ₃₀ ; and the second calculation module is used according to the formula Calculate the aging degree D of the third battery.

In the present invention, the first battery is tested to obtain the first battery parameters, wherein the first battery is a brand new battery; the second battery is tested to obtain the second battery parameters, wherein the second battery It is a fully aged battery; the third battery is tested to obtain a third battery parameter, wherein the third battery is a battery to be tested, and the first battery, the second battery and the third battery are the same battery, and the aging degree of the third battery is different from the aging degree of the second battery; and the third battery parameter is calculated using the first battery parameter, the second battery parameter and the third battery parameter. The aging degree of the battery. By testing the new battery and the fully aged battery, and then calculate the aging degree of the battery to be tested based on the battery parameters of the new battery and the battery parameters of the completely aged battery, it is realized that the battery to be tested does not need to be charged and discharged, and the battery due to discharge is avoided. The response to the degree of aging caused by the influence of the state of charge of the battery is not accurate enough, and the parameter test of the new battery and the completely aged battery can calibrate the parameters of the battery to be tested, making the test result more accurate and solving the problem of the existing technology The problem of inaccurate detection of the aging degree of the battery is solved, and the effect of accurately detecting the aging degree of the battery is achieved.

Description of drawings

The accompanying drawings constituting a part of this application are used to provide further understanding of the present invention, and the schematic embodiments and descriptions of the present invention are used to explain the present invention, and do not constitute an improper limitation of the present invention. In the attached picture:

FIG. 1 is a flow chart of a method for detecting battery aging according to an embodiment of the present invention; and

Fig. 2 is a schematic diagram of a detection device for battery aging degree according to an embodiment of the present invention.

Detailed ways

In order to enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is an embodiment of a part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first" and "second" in the description and claims of the present invention and the above drawings are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having", as well as any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product or device comprising a sequence of steps or elements is not necessarily limited to the expressly listed instead, may include other steps or elements not explicitly listed or inherent to the process, method, product or apparatus.

In the case of no conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and examples.

Example 1

According to the embodiment of the present invention, a method embodiment that can be implemented or executed by the device embodiment of the present application is provided. It should be noted that the steps shown in the flow chart of the accompanying drawings can be executed in a program such as a set of computer-executable instructions computer system, and although a logical order is shown in the flowcharts, in some cases the steps shown or described may be performed in an order different from that shown or described herein.

According to an embodiment of the present invention, a method for detecting the degree of battery aging is provided. The method for detecting the degree of battery aging provided by the embodiment of the present invention is described in detail below:

FIG. 1 is a flow chart of a method for detecting battery aging according to an embodiment of the present invention. As shown in FIG. 1 , the method mainly includes the following steps S102 to S108:

S102: Test the first battery to obtain first battery parameters, wherein the first battery is a brand-new battery, that is, test a brand-new battery to obtain battery parameters of the brand-new battery, which are called first battery parameters.

S104: Test the second battery to obtain the second battery parameters, wherein the second battery is a fully aged battery, that is, test the fully aged battery to obtain the battery parameters of the fully aged battery, which is called the second battery parameter .

S106: Test the third battery to obtain the third battery parameters, wherein the third battery is the battery to be tested, the first battery, the second battery and the third battery are the same battery, and the aging degree of the third battery is the same as that of the second battery The aging degree of the battery is different, that is, the battery parameter of the battery to be tested is obtained by testing the battery to be tested which is the same type as the first battery and the second battery, which is called the third battery parameter.

S108: Using the first battery parameter, the second battery parameter and the third battery parameter to calculate the aging degree of the third battery, that is, based on the battery parameters of the new battery and the battery parameters of the completely aged battery as a reference basis, combined with the tested battery parameters to be Test the relevant parameters of the battery, and calculate the aging degree of the battery to be tested.

The method for detecting the battery aging degree provided by the embodiment of the present invention, by testing a brand new battery and a completely aged battery, and then calculating the aging degree of the battery to be tested based on the battery parameters of the brand new battery and the battery parameters of the completely aged battery, realizes In order to avoid the need to charge and discharge the battery to be tested, it avoids the inaccurate response to the aging degree caused by the discharge being affected by the state of charge of the battery, and the parameter test of the brand new battery and the completely aged battery can be used to test the parameters of the battery Calibration makes the detection result more accurate, solves the problem of inaccurate detection of battery aging degree in the prior art, and then achieves the effect of accurately detecting the battery aging degree.

Among them, in the embodiment of the present invention, the battery is mainly tested by using the hybrid pulse power characteristic (Hybrid Pulse PowerCharacteristic, hereinafter referred to as HPPC), as follows:

The first battery is tested to obtain the first battery parameters mainly as follows: the mixed pulse capability characteristic test is performed on the first battery to obtain the functional relationship U ₁ =f ₁ (SOC ₁ ) and the functional relationship r ₁ =f ₂ (SOC ₁ ) , wherein, U ₁ is the open circuit voltage of the first battery, SOC ₁ is the battery state of charge of the first battery, r ₁ is the ohmic internal resistance of the first battery, and the first battery parameters include the functional relationship U ₁ =f ₁ (SOC ₁ ) and the functional relationship r ₁ =f ₂ (SOC ₁ ), specifically, the following steps 1-1 to 1-5 can be used to test the first battery:

Step 1-1, discharge the first battery with a constant current of 1C until the discharge voltage limit of the first battery.

Step 1-2, let the battery stand for 1 hour.

Step 1-3, charging the first battery with a constant current of 1C until the charging voltage limit of the first battery. Record the charging time t (hours) of the battery, then the initial capacity of the battery is:

_Cnew ＝1C×t

Steps 1-4, let the battery stand for an hour.

In steps 1-5, the first battery is discharged at a constant current of 1C until SOC ₁ =0.9, and a Hybrid Pulse Power Characteristic (Hybrid Pulse Power Characteristic, hereinafter referred to as HPPC) test is performed on the first battery. After standing still for 5 minutes, the battery was discharged at a constant current of 1C until SOC ₁ =0.8, and HPPC test was performed on the battery. The subsequent test process can be analogized, that is, the HPPC test is performed on the battery every 0.1SOC ₁ until the first battery reaches the discharge limit.

Then, the parameter identification is carried out on the HPPC test data of the first battery, and the values of the battery open circuit voltage U ₁ and the ohmic internal resistance r ₁ at different SOC ₁ can be obtained, and the values of the battery open circuit voltage U ₁ and The functional relationship between resistance r ₁ and different SOC ₁ is U ₁ =f ₁ (SOC ₁ ), and the functional relationship r ₁ =f ₂ (SOC ₁ ).

The second battery is tested to obtain the second battery parameters mainly as follows: the second battery is tested for the mixed pulse capability characteristics, and the functional relationship r ₂ =f ₂ (SOC ₂ ), wherein, SOC ₂ is the battery charge of the second battery electric state, r ₂ is the ohmic internal resistance of the second battery, and the second battery parameters include the functional relationship r ₂ =f ₂ (SOC ₂ ), specifically, the following steps 2-1 to 2-4 can be adopted for the first battery carry out testing:

Step 2-1, cyclically charge and discharge the fully aged second battery (the second battery may be a battery that has completed the above steps 1-1 to 1-5). The specific process is as follows: first, charge the second battery with a constant current of 0.5C until it reaches the charging voltage limit; then stand still for 0.5 hours; then discharge the second battery with a constant current of 1C until it reaches the discharge voltage limit; then stand still for 0.5 hours. Record the battery capacity Q during charging and discharging. This process is repeated several times until Q=0.8Q ₀ , where Q ₀ is the nominal capacity of the second battery.

Step 2-2, fully charge the second battery with a constant current of 1C until the second battery reaches the charging voltage limit.

Step 2-3, let the second battery stand for 1 hour.

Step 2-4, discharge the second battery with a constant current of 1C until the SOC ₂ of the second battery = 0.5, and let it stand for 1 hour. The cells were then subjected to HPPC testing.

Then, the parameter identification is performed on the HPPC test data of the second battery, and the values of battery open circuit voltage U ₂ and ohmic internal resistance r ₂ at different SOC ₂ can be obtained, and the values of battery open circuit voltage U ₂ and ohmic internal resistance r 2 can be obtained by interpolation The functional relationship between resistance r ₂ and different SOC ₂ is U ₂ =f ₁ (SOC ₂ ), and the functional relationship is r ₂ =f ₂ (SOC ₂ ), where U ₂ is the open circuit voltage of the second battery.

The third battery is tested, and the parameters of the third battery are obtained mainly as follows: the mixed pulse capability characteristic test is performed on the third battery, and after parameter identification, the ohmic internal resistance r _3x and the open circuit voltage U _3x of the third battery are obtained.

Correspondingly, calculating the aging degree of the third battery by using the first battery parameter, the second battery parameter and the third battery parameter includes the following steps 3-1 to 3-4:

Step 3-1, calculate _the battery state of charge SOC _3x =f _{1 -1} ⁽ U _3x ) of the third battery corresponding to the open circuit voltage U _3x according to the functional relationship U 1 =f ₁ (SOC ₁ ).

Step 3-2, according to the functional relationship r ₁ =f ₂ (SOC ₁ ), calculate the ohmic resistance r _1x =f ₂ (SOC _3x ) of the first battery at the battery state of charge SOC _3x and the ohmic resistance at the preset battery state of charge SOC The ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) at ₀ , in the embodiment of the present invention, the preset battery state of charge SOC ₀ can be set to the battery state of charge of SOC ₀ =0.5, which is equivalent to setting a brand new The ohmic internal resistance of the first battery at SOC ₀ =0.5 is used as the ohmic internal resistance of the new battery. Of course, the preset battery state of charge SOC ₀ can also be set as the battery state of charge with SOC ₀ being other values.

Step 3-3, according to the functional relationship r ₂ =f ₂ (SOC ₂ ), calculate the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) of the second battery at the preset battery state of charge SOC ₀ , for SOC ₀ =0.5 In the case of , it is equivalent to taking the ohmic internal resistance of the fully aged second battery at SOC ₀ =0.5 as the ohmic internal resistance of the fully aged battery.

Step 3-4, calculate according to ohmic internal resistance r _3x , ohmic internal resistance r _1x =f ₂ (SOC _3x ), ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) and ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) Specifically, the aging degree of the third battery can be calculated according to the ohmic internal resistance r _3x , the ohmic resistance r _1x =f ₂ (SOC _3x ) and the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ). The ohmic internal resistance r ₃₀ of the battery state of charge SOC ₀ , that is, the ohmic internal resistance of the battery to be tested is converted to the same state of charge of the battery as the first battery and the second battery. Then, the aging degree of the third battery is calculated according to the ohmic internal resistance r ₃₀ , the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ), and the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ).

To measure the battery aging degree, it is necessary to minimize the interference of the battery state of charge. By converting the battery state of charge of the battery to be tested to the same SOC value, the influence of the battery state of charge on the battery parameters can be eliminated, so that the battery aging degree The detection result is more accurate.

For similar batteries (for example: lithium iron phosphate batteries), the relationship between the state of charge and the internal resistance of these batteries is similar, and there is only a proportional coefficient difference. Therefore, for the brand-new first battery and the battery to be tested As far as the third battery is concerned, has the following relationship:

which is,

Therefore, according to the formula Calculate the ohmic internal resistance r ₃₀ and follow the formula The aging degree D of the third battery is calculated.

The battery aging degree detection method provided by the embodiment of the present invention detects the battery aging degree through rapid battery charging and discharging test combined with parameter identification. This method can realize rapid detection of battery aging degree and greatly reduces the time required for detection. Parameter identification distinguishes between ohmic internal resistance and polarization internal resistance, and eliminates the influence of battery state of charge on battery parameters, making the results of battery aging detection more accurate. Before the rapid detection, the parameter test of the new battery and the completely aged battery was carried out first. This test can perform parameter calibration to make the detection result more accurate. The detection method was tested on a number of lithium iron phosphate batteries with different capacities. The test results show that the method can realize the rapid detection of the battery aging degree, the detection time is short, and the accuracy is high, which can well meet the needs of electric vehicle power batteries. testing requirements.

It should be noted that for the foregoing method embodiments, for the sake of simple description, they are expressed as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described action sequence. Because of the present invention, certain steps may be performed in other orders or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification belong to preferred embodiments, and the actions and modules involved are not necessarily required by the present invention.

Through the description of the above embodiments, those skilled in the art can clearly understand that the method according to the above embodiments can be implemented by means of software plus a necessary general-purpose hardware platform, and of course also by hardware, but in many cases the former is better implementation. Based on such an understanding, the essence of the technical solution of the present invention or the part that contributes to the prior art can be embodied in the form of software products, and the computer software products are stored in a storage medium (such as ROM/RAM, disk, CD) contains several instructions to enable a terminal device (which may be a mobile phone, a computer, a server, or a network device, etc.) to execute the methods described in various embodiments of the present invention.

Example 2

According to an embodiment of the present invention, there is also provided a battery aging detection device for implementing the above battery aging detection method, the battery aging detection device is mainly used to implement the battery provided by the above content of the embodiment of the present invention For the detection method of the aging degree, the following is a specific introduction to the detection device for the battery aging degree provided by the embodiment of the present invention:

Fig. 2 is a schematic diagram of a detection device for a battery aging degree according to an embodiment of the present invention. As shown in Fig. 2 , the detection device for a battery aging degree mainly includes a first test unit 10, a second test unit 20, and a third test unit 30 and computing unit 40, wherein:

The first test unit 10 is used to test the first battery to obtain the first battery parameters, wherein the first battery is a brand-new battery, that is, to test a brand-new battery to obtain the battery parameters of the brand-new battery, which is called the first battery parameter.

The second test unit 20 is used to test the second battery to obtain the second battery parameters, wherein the second battery is a fully aged battery, that is, to test the fully aged battery to obtain the battery parameters of the fully aged battery, which is called as the second battery parameter.

The third test unit 30 is used to test the third battery to obtain the third battery parameters, wherein the third battery is the battery to be tested, the first battery, the second battery and the third battery are the same battery, and the third battery The aging degree is different from the aging degree of the second battery, that is, the battery parameter of the battery to be tested is obtained by testing the battery to be tested which is the same type as the first battery and the second battery, which is called the third battery parameter.

The calculation unit 40 is used to calculate the degree of aging of the third battery by using the first battery parameter, the second battery parameter and the third battery parameter, that is, based on the battery parameters of a new battery and the battery parameters of a completely aged battery, combined with the test The relevant parameters of the battery to be tested are obtained, and the aging degree of the battery to be tested is calculated.

The detection device for the battery aging degree provided by the embodiment of the present invention, by testing the brand-new battery and the completely aged battery, and then calculating the aging degree of the battery to be tested based on the battery parameters of the brand-new battery and the battery parameters of the completely aged battery, realizes In order to avoid the need to charge and discharge the battery to be tested, it avoids the inaccurate response to the aging degree caused by the discharge being affected by the state of charge of the battery, and the parameter test of the brand new battery and the completely aged battery can be used to test the parameters of the battery Calibration makes the detection result more accurate, solves the problem of inaccurate detection of battery aging degree in the prior art, and then achieves the effect of accurately detecting the battery aging degree.

Among them, in the embodiment of the present invention, the battery is mainly tested by using the hybrid pulse power characteristic (Hybrid Pulse PowerCharacteristic, hereinafter referred to as HPPC), as follows:

The first test unit 10 mainly includes a first test subunit, which is used to test the mixed pulse capability characteristics of the first battery, and obtain the functional relationship U ₁ =f ₁ (SOC ₁ ) and the functional relationship r ₁ = f ₂ (SOC ₁ ), where U ₁ is the open circuit voltage of the first battery, SOC ₁ is the battery state of charge of the first battery, r ₁ is the ohmic internal resistance of the first battery, and the first battery parameters include the functional relationship U ₁ =f ₁ (SOC ₁ ) and the functional relationship r ₁ =f ₂ (SOC ₁ ), specifically, the first test subunit can use the following steps 1-1 to 1-5 to test the first battery:

Step 1-1, discharge the first battery with a constant current of 1C until the discharge voltage limit of the first battery.

Step 1-2, let the battery stand for 1 hour.

Step 1-3, charging the first battery with a constant current of 1C until the charging voltage limit of the first battery. Record the charging time t (hours) of the battery, then the initial capacity of the battery is:

_Cnew ＝1C×t

Steps 1-4, let the battery stand for an hour.

In steps 1-5, the first battery is discharged at a constant current of 1C until SOC ₁ =0.9, and a Hybrid Pulse Power Characteristic (Hybrid Pulse Power Characteristic, hereinafter referred to as HPPC) test is performed on the first battery. After standing still for 5 minutes, the battery was discharged at a constant current of 1C until SOC ₁ =0.8, and HPPC test was performed on the battery. The subsequent test process can be analogized, that is, the HPPC test is performed on the battery every 0.1SOC ₁ until the first battery reaches the discharge limit.

Then, the parameter identification is carried out on the HPPC test data of the first battery, and the values of the battery open circuit voltage U ₁ and the ohmic internal resistance r ₁ at different SOC ₁ can be obtained, and the values of the battery open circuit voltage U ₁ and The functional relationship between resistance r ₁ and different SOC ₁ is U ₁ =f ₁ (SOC ₁ ), and the functional relationship r ₁ =f ₂ (SOC ₁ ).

The second test unit 20 mainly includes a second test subunit, which is used to test the mixed pulse capability characteristics of the second battery, and obtain the functional relationship r ₂ =f ₂ (SOC ₂ ), wherein, SOC ₂ is The battery state of charge of the second battery, r ₂ is the ohmic internal resistance of the second battery, and the second battery parameters include a functional relationship r ₂ =f ₂ (SOC ₂ ), specifically, the second test subunit can use the following steps 2 -1 to step 2-4 to test the first battery:

Step 2-1, cyclically charge and discharge the fully aged second battery (the second battery may be a battery that has completed the above steps 1-1 to 1-5). The specific process is as follows: first, charge the second battery with a constant current of 0.5C until it reaches the charging voltage limit; then stand still for 0.5 hours; then discharge the second battery with a constant current of 1C until it reaches the discharge voltage limit; then stand still for 0.5 hours. Record the battery capacity Q during charging and discharging. This process is repeated several times until Q=0.8Q ₀ , where Q ₀ is the nominal capacity of the second battery.

Step 2-2, fully charge the second battery with a constant current of 1C until the second battery reaches the charging voltage limit.

Step 2-3, let the second battery stand for 1 hour.

Step 2-4, discharge the second battery with a constant current of 1C until the SOC ₂ of the second battery = 0.5, and let it stand for 1 hour. The cells were then subjected to HPPC testing.

Then, the parameter identification is performed on the HPPC test data of the second battery, and the values of battery open circuit voltage U ₂ and ohmic internal resistance r ₂ at different SOC ₂ can be obtained, and the values of battery open circuit voltage U ₂ and ohmic internal resistance r 2 can be obtained by interpolation The functional relationship between resistance r ₂ and different SOC ₂ is U ₂ =f ₁ (SOC ₂ ), and the functional relationship is r ₂ =f ₂ (SOC ₂ ), where U ₂ is the open circuit voltage of the second battery.

The third test unit 30 mainly includes a third test subunit, which is used for performing a mixed pulse capability characteristic test on the third battery to obtain the ohmic internal resistance r _3x and the open circuit voltage U _3x of the third battery.

The calculation unit 40 mainly includes first to fourth calculation subunits, wherein:

The first calculation subunit is used to calculate the battery state of charge SOC _3x =f _{1 -1} ⁽ U _3x ) of the third battery corresponding to _the open circuit voltage U _3x according to the functional relationship U 1 =f ₁ (SOC ₁ ).

The second calculation subunit is used to calculate the ohmic resistance r _1x =f ₂ (SOC _3x ) of the first battery in the battery state of charge SOC _3x and the preset battery charge in accordance with the functional relationship r ₁ =f ₂ (SOC ₁ ). The ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) in the state SOC ₀ , in the embodiment of the present invention, the preset battery state of charge SOC ₀ can be set to the battery state of charge of SOC ₀ =0.5, which is equivalent to setting The ohmic internal resistance of the brand new first battery at SOC ₀ =0.5 is used as the ohmic internal resistance of the brand new battery. Of course, the preset battery state of charge SOC ₀ can also be set as the battery state of charge with SOC ₀ being other values.

The third calculation subunit is used to calculate the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) of the second battery at the preset battery state of charge SOC ₀ according to the functional relationship r ₂ =f ₂ (SOC ₀ ), for SOC ₀ =0.5, it is equivalent to taking the ohmic internal resistance of the fully aged second battery at SOC ₀ =0.5 as the ohmic internal resistance of the fully aged battery.

The fourth calculation subunit is used for ohmic internal resistance r _3x , ohmic resistance r _1x =f ₂ (SOC _3x ), ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) and ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) to calculate the aging degree of the third battery, specifically, the fourth calculation subunit mainly includes a first calculation module and a second calculation module, wherein the first calculation module is used to calculate the aging degree of the third battery according to the ohmic internal resistance r _3x , the ohmic resistance r _1x =f ₂ (SOC _3x ) and ohmic internal resistance r ₁₀ = f ₂ (SOC ₀ ) to calculate the ohmic internal resistance r ₃₀ of the third battery at the preset battery state of charge SOC ₀ , that is, convert the ohmic internal resistance of the battery to be tested to the same battery state of charge as the first and second batteries. The second calculation module is used to calculate the aging degree of the third battery according to the ohmic internal resistance r ₃₀ , the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) and the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ).

To measure the battery aging degree, it is necessary to minimize the interference of the battery state of charge. By converting the battery state of charge of the battery to be tested to the same SOC value, the influence of the battery state of charge on the battery parameters can be eliminated, so that the battery aging degree The detection result is more accurate.

For similar batteries (for example: lithium iron phosphate batteries), the relationship between the state of charge and the internal resistance of these batteries is similar, and there is only a proportional coefficient difference. Therefore, for the brand-new first battery and the battery to be tested As far as the third battery is concerned, has the following relationship:

which is,

Therefore, the first calculation module can follow the formula To calculate the ohmic internal resistance r ₃₀ , the second calculation module can follow the formula The aging degree D of the third battery is calculated.

From the above description, it can be seen that the present invention realizes the rapid detection of the aging degree of the battery, and greatly reduces the time required for detection. Parameter identification distinguishes between ohmic internal resistance and polarization internal resistance, and eliminates the influence of battery state of charge on battery parameters, making the results of battery aging detection more accurate. Before the rapid detection, the parameter test of the new battery and the completely aged battery was carried out first. This test can perform parameter calibration to make the detection result more accurate.

Obviously, those skilled in the art should understand that each module or each step of the above-mentioned present invention can be realized by a general-purpose computing device, and they can be concentrated on a single computing device, or distributed in a network formed by multiple computing devices Optionally, they can be implemented with program codes executable by a computing device, so that they can be stored in a storage device and executed by a computing device, or they can be made into individual integrated circuit modules, or they can be integrated into Multiple modules or steps are fabricated into a single integrated circuit module to realize. As such, the present invention is not limited to any specific combination of hardware and software.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims (6)

1. A detection method of battery aging degree, is characterized in that, comprises: Testing the first battery to obtain first battery parameters, wherein the first battery is a brand new battery; Testing the second battery to obtain second battery parameters, wherein the second battery is a fully aged battery; The third battery is tested to obtain third battery parameters, wherein the third battery is the battery to be tested, the first battery, the second battery and the third battery are the same battery, and the first battery the aging degree of the third battery is different from the aging degree of the second battery; and calculating the aging degree of the third battery by using the first battery parameter, the second battery parameter and the third battery parameter; Wherein, testing the first battery to obtain the first battery parameters includes: performing a mixed pulse capability characteristic test on the first battery to obtain the functional relationship U ₁ =f ₁ (SOC ₁ ) and the functional relationship r ₁ =f ₂ ( SOC ₁ ), wherein, U ₁ is the open circuit voltage of the first battery, SOC ₁ is the battery state of charge of the first battery, r ₁ is the ohmic internal resistance of the first battery, and the first battery The parameters include said functional relationship U ₁ =f ₁ (SOC ₁ ) and said functional relationship r ₁ =f ₂ (SOC ₁ ), Testing the second battery to obtain the second battery parameters includes: performing the mixed pulse capability characteristic test on the second battery to obtain a functional relationship r ₂ =f ₂ (SOC ₂ ), wherein SOC ₂ is the first The battery state of charge of the second battery, r ₂ is the ohmic internal resistance of the second battery, and the second battery parameters include the functional relationship r ₂ =f ₂ (SOC ₂ ), Testing the third battery to obtain the parameters of the third battery includes: performing the mixed pulse capability characteristic test on the third battery to obtain the ohmic internal resistance r _3x and the open circuit voltage U _3x of the third battery, Calculating the aging degree of the third battery by using the first battery parameter, the second battery parameter and the third battery parameter includes: calculating the first battery according to the functional relationship U ₁ =f ₁ (SOC ₁ ). The battery state of charge SOC _3x =f ₁ -1(U _3x ) of the three batteries corresponding to the open circuit voltage U _3x ; according to the functional relationship r ₁ =f ₂ (SOC ₁ ), calculate the The ohmic resistance r _1x =f ₂ (SOC _3x ) under the state of charge SOC _3x and the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) under the preset battery state of charge SOC ₀ ; according to the functional relationship r ₂ =f ₂ (SOC ₂ ) Calculate the ohmic internal resistance r ₂₀ of the second battery at the preset battery state of charge SOC ₀ =f ₂ (SOC ₀ ); and according to the ohmic internal resistance r _3x , the The ohmic resistance r _1x =f ₂ (SOC _3x ), the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ), and the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) calculate the aging of the third battery degree. 2. The detection method according to claim 1, characterized in that, according to the ohmic internal resistance r _3x , the ohmic resistance r _1x =f ₂ (SOC _3x ), the ohmic internal resistance r ₁₀ =f ₂ ( SOC ₀ ) and the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) to calculate the aging degree of the third battery includes: According to the ohmic internal resistance r _3x , the ohmic resistance r _1x =f ₂ (SOC _3x ) and the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ), the preset battery charge of the third battery is calculated. Ohmic internal resistance r ₃₀ at electrical state SOC ₀ ; and The aging degree of the third battery is calculated according to the ohmic internal resistance r ₃₀ , the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) and the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ). 3. detection method according to claim 2, is characterized in that, according to the formula calculating said ohmic internal resistance r ₃₀ ; and according to the formula Calculate the aging degree D of the third battery. 4. A detection device for battery aging degree, characterized in that it comprises: The first test unit is configured to test the first battery to obtain first battery parameters, wherein the first battery is a brand new battery; The second testing unit is used to test the second battery to obtain the second battery parameters, wherein the second battery is a fully aged battery; The third testing unit is configured to test a third battery to obtain a third battery parameter, wherein the third battery is a battery to be tested, and the first battery, the second battery and the third battery are the same battery, and the degree of aging of the third battery is different from the degree of aging of the second battery; and a calculation unit, configured to calculate the aging degree of the third battery by using the first battery parameter, the second battery parameter and the third battery parameter; Wherein, the first test unit includes: a first test subunit, which is used to test the mixed pulse capability characteristics of the first battery to obtain the functional relationship U ₁ =f ₁ (SOC ₁ ) and the functional relationship r ₁ =f ₂ (SOC ₁ ), wherein, U ₁ is the open circuit voltage of the first battery, SOC ₁ is the state of charge of the first battery, r ₁ is the ohmic internal resistance of the first battery, and the second A battery parameter includes the functional relationship U ₁ =f ₁ (SOC ₁ ) and the functional relationship r ₁ =f ₂ (SOC ₁ ), and the second test unit includes: a second test subunit for testing the The second battery performs the mixed pulse capability characteristic test, and obtains the functional relationship r ₂ =f ₂ (SOC ₂ ), wherein, SOC ₂ is the battery state of charge of the second battery, and r ₂ is the second battery ohmic internal resistance, the second battery parameters include the functional relationship r ₂ =f ₂ (SOC ₂ ), The third test unit includes: a third test subunit, configured to perform the mixed pulse capability characteristic test on the third battery to obtain the ohmic internal resistance r _3x and the open circuit voltage U _3x of the third battery, The calculation unit includes: a first calculation subunit, configured to calculate the battery state of charge SOC _3x =f of the third battery corresponding to the open circuit voltage U _3x according to the functional relationship U ₁ =f ₁ (SOC ₁ ) ₁ ^-1 (U _3x ); the second calculation subunit is used to calculate the ohmic resistance r of the first battery under the battery state of charge SOC _3x according to the functional relationship r ₁ =f ₂ (SOC ₁ ). _1x =f ₂ (SOC _3x ) and the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) under the preset state of charge of the battery SOC ₀ ; the third calculation subunit is used for according to the functional relationship r ₂ =f ₂ (SOC ₂ ) to calculate the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) of the second battery at the preset battery state of charge SOC ₀ ; The internal resistance r _3x , the ohmic resistance r _1x =f ₂ (SOC _3x ), the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) and the ohmic internal resistance r ₂₀ =f ₂ (SOC ₀ ) are calculated The aging degree of the third battery. 5. The detection device according to claim 4, wherein the fourth calculation subunit comprises: A first calculation module, configured to calculate the third battery according to the ohmic internal resistance r _3x , the ohmic resistance r _1x =f ₂ (SOC _3x ) and the ohmic internal resistance r ₁₀ =f ₂ (SOC ₀ ) ohmic internal resistance r ₃₀ at said preset battery state of charge SOC ₀ ; and _{The second} calculation module _{is used} to _{calculate the third} The aging degree of the battery. 6. The detection device according to claim 5, characterized in that, The first calculation module is used for according to the formula calculating said ohmic internal resistance r ₃₀ ; and The second calculation module is used for according to the formula Calculate the aging degree D of the third battery.