TW201337297A - Method for estimating state of health (SOH) of battery cell - Google Patents

Abstract

A method for estimating state of health (SOH) of a battery cell which has been discharged twice is provided. First, every time the battery cell is discharged, an average discharge current (I<SB>dis, avg</SB>) is estimated and an updated whole life charge capacity (WLCC<SB>new</SB>) is obtained accordingly. Then, remain life charge capacity (RLCC<SB>new1</SB>) is calculated according to the updated whole life charge capacity (WLCC<SB>new</SB>), the state of health (SOH<SB>orig</SB>) of the battery cell before this discharge, the full charge capacity (FCC), the temperature during discharging, and the depth-of-discharge (DOD). Thereafter, a ratio of an updated remain life charge capacity (RLCC<SB>new1</SB>) and the updated whole life charge capacity (WLCC<SB>new</SB>) is calculated so as to obtain an updated state of health (SOH<SB>new1</SB>).

Description

Battery core health assessment method

The present application relates to a method for evaluating a state of health (SOH) of a battery cell, and particularly relates to an evaluation method for a battery cell health state capable of obtaining a residual power storage capacity (RLCC) in real time. .

With the advancement of technology, electronic products have become one of the indispensable items in human daily life. In order for an electronic product to have portable characteristics, the electronic product itself must have a battery to supply the power required for its own operation. In order to facilitate the user to determine the residual power of the battery in the electronic product, many conventional techniques have been proposed to evaluate the residual power of the battery. However, in addition to the residual power of the battery, the health of the battery (SOH) is also an important indicator for users and developers. Therefore, it has been proposed in the prior art to calculate the time of the constant current mode period during battery charging and use this as a basis for estimating the health of the battery. However, this estimation method must be applied when the battery is in charging mode.

In addition, there are also known techniques for observing the degree of voltage drop per unit time in the case of a large current battery, and as a basis for estimating the health of the battery. However, since the internal resistance of the battery cannot be accurately measured, the accuracy of this estimation method is open to question.

The application provides a method for evaluating the health status of a battery core, which can instantly obtain the health status of the battery core.

The present application provides a method for evaluating the health of a battery cell for evaluating the health of a battery cell that has been discharged at least twice, including the following steps. First, after the end of each discharge of the battery cell, the average discharge current rate (I _{dis, avg} ) of the discharge and the difference between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge are calculated (ΔI _{dis , avg} ). When the battery core is being charged or before charging, it is determined whether the difference between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge (ΔI _{dis, avg} ) is greater than or equal to a first threshold value, when the discharge is performed When the difference between the average discharge current rate and the average discharge current rate of the previous discharge (ΔI _{dis, avg} ) is less than the first threshold, the lifetime of the battery core (WLCC _orig ) is not updated, and the average of the discharge is When the difference between the discharge current rate and the average discharge current rate of the previous discharge (ΔI _{dis, avg} ) is greater than or equal to the first threshold value, an updated lifetime storage capacity is obtained according to the average discharge current rate of the discharge (WLCC _new ). Then, based on the updated lifetime storage capacity (WLCC _new ), the difference between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge (ΔI _{dis, avg} ), and the total discharge capacity (FCC), Corresponding to one of the remaining stored power reserves (RLCC _new1 ). Next, the ratio of the updated remaining storage capacity (RLCC _new1 ) to the updated lifetime storage capacity (WLCC _new ) is calculated to obtain an updated health state coefficient (SOH _new1 ).

In an embodiment of the present application, the foregoing method for evaluating the health status of the battery core may further include: recording a total discharge capacity (FCC), a discharge current (I) of the battery core during each discharge of the battery core, Voltage (V) and temperature (T).

In an embodiment of the present application, the foregoing method for evaluating the health status of the battery core may further include: an average discharge rate according to the updated lifetime storage capacity (WLCC _new ), the average discharge current rate of the discharge, and an average discharge of the previous discharge. After the difference in current rate (ΔI _{dis, avg} ) and the total discharge capacity (FCC) of this time to obtain the corresponding updated remaining storage capacity (RLCC _new1 ), the updated remaining storage capacity is corrected according to the temperature (T) at the time of the discharge. (RLCC _new1 ).

In one embodiment of the present application, the evaluation method of the state of health of the battery cell may further comprise: updating the lifetime in accordance with the storage capacity (WLCC _new), average discharge current rate and the previous discharge in the discharge average discharge The difference in current rate (ΔI _{dis, avg} ) and the total discharge capacity (FCC) to obtain the corresponding updated remaining storage capacity (RLCC _new1 ), based on the temperature (T) and depth of discharge (DOD) at this discharge Correct the updated remaining storage capacity (RLCC _new2 ).

In an embodiment of the present application, the foregoing method for evaluating the health status of the battery core may further include: an average discharge rate according to the updated lifetime storage capacity (WLCC _new ), the average discharge current rate of the discharge, and an average discharge of the previous discharge. After the difference in current rate (ΔI _{dis, avg} ) and the total discharge capacity (FCC) of this time to obtain the corresponding updated remaining storage capacity (RLCC _new1 ), the remaining storage of the update is corrected according to the depth of discharge (DOD) at the time of the discharge. Electricity (RLCC _new1 ).

In an embodiment of the present application, the foregoing method for evaluating a battery cell health state may further include: calculating an average discharge current rate (I _{dis, avg} ) of the discharge and an average discharge current rate of the discharge. Before the difference (ΔI _{dis, avg} ) of the average discharge current rate of the previous discharge, it is judged whether or not the battery cell is still being discharged.

In an embodiment of the present application, the updated remaining storage capacity (RLCC _new1 ) is calculated as follows:

RLCC _new1 = {1/2‧[x*NC+(x*NC+ΔQ _R ±ΔQ _rec )]‧|(ΔQ _R ±ΔQ _rec )/Slope _new |}-FCC;

Where NC is the nominal capacity of the battery core, x*NC is the unsuitable capacitance standard of the battery core, x*NC+ΔQ _R is the total discharge capacity (FCC) of the battery core discharge, ΔQ _rec is The amount of discharge compensated by the difference in average discharge current rate (ΔI _{dis, avg} ), and Slope _{new is} determined by the updated lifetime storage capacity (WLCC _new ).

When the difference between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge is positive (light load to heavy load), the updated remaining storage capacity (RLCC _new1 ) is calculated as follows:

RLCC _new1 ={1/2‧[x*NC+(x*NC+ΔQ _R -ΔQ _rec )]‧|(ΔQ _R -ΔQ _rec )/Slope _new |}-FCC

When the difference between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge is negative (heavy load to light load), the updated remaining storage capacity (RLCC _new1 ) is calculated as follows:

RLCC _new1 ={1/2‧[x*NC+(x*NC+ΔQ _R +ΔQ _rec )]‧|(ΔQ _R +ΔQ _rec )/Slope _new |}-FCC

The present application further provides a method for evaluating the health of a battery cell for evaluating the health of a battery cell that has been discharged at least twice, including the following steps. First, after the end of each discharge of the battery cell, the average discharge current rate (I _{dis, avg} ) of the discharge is calculated, and the average discharge current rate (I _{dis, avg} ) of the discharge is compared with the average of the previous discharge. The discharge current rate is obtained and the updated lifetime storage capacity (WLCC _new ) is obtained. Thereafter, according to the updated lifetime storage capacity (WLCC _new ), the remaining storage capacity of the battery core before the discharge (RLCC _orig ), the average discharge current rate of the discharge, the average discharge current rate of the previous discharge, and the battery The total discharge capacity (FCC) of the core is calculated to calculate a corresponding updated remaining storage capacity (RLCC _new1 ). Next, the ratio of the updated remaining storage capacity (RLCC _new1 ) to the updated lifetime storage capacity (WLCC _new ) is calculated to obtain an updated health state coefficient (SOH _new1 ).

In an embodiment of the present application, the foregoing method for evaluating the health status of the battery core may further include the steps of: recording the total discharge capacity (FCC) and discharge current of the battery core during each discharge of the battery core (I) ), voltage (V), and temperature (T); before calculating the average discharge current rate (I _{dis, avg} ) of the discharge, determining whether the battery cell is still discharging; and according to the temperature (T) at the time of the discharge And the depth of discharge (DOD) corrects the total discharge capacity (FCC) by the temperature coefficient (TC) and the depth of discharge (DDC).

The present application further provides a battery module including a battery core and a control unit, wherein the battery core can be repeatedly charged and discharged, and the control unit is electrically coupled to the battery core to control the battery core to repeatedly charge and discharge. In addition, the control unit evaluates the health status of the battery cell according to the aforementioned battery cell health assessment method.

Since the present application can evaluate the state of health after the end of the battery cell discharge, the present application can immediately and accurately evaluate the health status of the battery cell.

The above-described features and advantages of the present application will become more apparent and understood.

1 is a flow chart of a method for evaluating battery operation and health status of the present application, and FIG. 2 is a schematic diagram of a battery module of the present application. Referring to FIG. 1 and FIG. 2 simultaneously, first, a battery cell B is provided (step S100), and the battery cell B is discharged (step S110). In this embodiment, the battery core B is assembled in an electronic component E, for example, and controls the battery core B to output an appropriate current and voltage to the electronic component E according to the operational requirements of the electronic component E, so that the electronic component E can be normally Operation. For example, the battery core B is, for example, a manganese/zinc battery, a carbon/zinc battery, an alkaline manganese battery, a lithium battery core, a solar battery, a fuel battery, or the like.

The lifetime storage capacity defined by the present invention is the total amount of power that can be discharged when the battery core B starts from the first use until it reaches a non-appropriate standard, for example, if the first discharge of the battery core B is 10 amp hours, The second discharge amount is 8 ampere hours, and then the maximum amount of electricity stored per time is less than 8 ampere hours. In this case, if the proper standard is defined as 80% or more of the ideal storage capacity (10 ampere hours) (ie, For 8 amp hours or more, the lifetime storage capacity (WLCC) is 18 (10+8) ampere hours.

The remaining stored electricity (RLCC) is defined as the amount of electricity that can be discharged before the battery core B ages to the non-appropriate standard. For example, in the above example, the remaining battery power of the battery core B after the first discharge is 8 amp hours. The total discharge capacity (FCC) is defined as the amount of electricity discharged by the battery during a certain period of time or a certain number of times. For example, the total discharge capacity (FCC) of the first discharge of the battery core B is 10 amp hours.

In addition, the non-appropriate standard is usually defined as the battery unit B is reduced in the total storage capacity that can be stored per charge to a predetermined standard ratio due to aging of the material, etc., and the standard ratio is a non-appropriate standard. The non-appropriate standard is that the battery's power-up capability drops to 80% of the ideal value (10 amp hours) (ie, 8 amp hours).

During the discharge of the battery cell B, the present embodiment measures the discharge current (I), the voltage (V), the temperature (T), and the total discharge of the battery B at the current discharge through the aforementioned control unit CU. Discharge capacity (FCC). In detail, in the present embodiment, during the discharge of the battery cell B, the current (I), the voltage (V) output by the battery cell B, and the temperature (T) of the battery cell B itself are continuously measured and recorded (step S120). Then, in the present embodiment, it is judged whether or not the battery cell B is still in the discharged state based on the direction and magnitude of the current (I) (step S130).

If it is judged that the battery cell B is still in the discharge state, continuously measure the discharge current (I), the voltage (V), and the temperature (T) of the battery cell B itself, and measure the current measured during the discharge (I The accumulation (integration) is performed in a Coulomb counter manner to obtain the total discharge capacity (FCC) released at the current stage of the battery cell B (step S140). On the other hand, if it is judged that the battery cell B does not continue to discharge, it means that the battery cell B has been discharged. At this time, the average discharge current rate (I _{dis, avg} ) of the discharge and the average discharge current rate of the discharge are calculated. The difference (ΔI _{dis, avg} ) of the average discharge current rates of the previous discharges (step S150), and the average discharge current rate is the average of the discharge currents.

It is worth noting that when the battery cell B does not continue to discharge (ie, the battery cell B has completed discharging), the accumulated total discharge capacity (FCC) obtained in step S140 can be used to calculate the average discharge current rate (I _{dis , avg} ). In detail, in this embodiment, all the total discharge capacity (FCC) of the battery cell B during the discharge process can be divided by the discharge time to calculate the average discharge current rate of the discharge (I _{dis, avg} ).

After completing the discharge of the battery core B and obtaining the updated lifetime storage capacity (WLCC _new ), the embodiment may further determine whether the battery core B is to be charged (step S160), and if the battery core B is about to be charged, according to the update The lifetime storage capacity (WLCC _new ), the difference between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge (ΔI _{dis, avg} ) and the total discharge capacity (FCC) of this time to calculate the corresponding one The updated remaining storage capacity (RLCC _new1 ) is as shown in step S170, step S180, and step S190.

It should be noted that, before performing the subsequent steps S170, S180 and S190, the embodiment may first determine whether the battery core starts charging.

In step S170, when the battery cell B is being charged or before charging, it is determined whether the difference (ΔI _{dis, avg} ) between the average discharge current rate of the current discharge and the average discharge current rate of the previous discharge is greater than or equal to a first threshold. value. When the difference (ΔI _{dis, avg} ) between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge is less than the first threshold, the lifetime storage (WLCC _orig ) of the battery B is not updated (step S180). Since the difference between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge (ΔI _{dis, avg} ) is less than the first threshold, it is only necessary to directly subtract the remaining remaining power of the battery from the current one. The total remaining capacity (FCC) can obtain an updated remaining amount of stored electricity (RLCC _new3 ) (step S182). In addition, since the updated remaining storage capacity (RLCC _new3 ) is affected by the temperature (T) at the time of discharge and the Depth of dischagre (DOD), the present embodiment can selectively select the temperature at the time of the discharge (T And / or depth of discharge (DOD) to correct the total discharge capacity (FCC) to obtain the corrected remaining storage capacity (RLCC _new4 ) and the corrected health state coefficient (SOH _new3 ) (steps S184 and S186). For example, in this embodiment, a temperature coefficient (TC) can be obtained according to the temperature (T) of the discharge, and the total discharge capacity (TC*FCC) is corrected by the temperature coefficient, and then corrected. the remaining storage capacity _(RLCC new4) and state of health after the correction coefficient _(SOH new3).

In addition, in this embodiment, a Depth-of-discharge coefficient (DDC) can be obtained according to the depth of discharge (DOD) of the discharge, and the total discharge capacity (DDC*FCC) is corrected by the discharge depth coefficient. ), and then the corrected remaining storage capacity (RLCC _new4 ) and the corrected health state coefficient (SOH _new3 ). It should be noted that this embodiment can also obtain a temperature coefficient (TC) and a depth of discharge coefficient (DDC) according to the temperature (T) and depth of discharge (DOD) of the discharge, and correct the temperature coefficient and the depth coefficient of discharge. The total discharge capacity (TC*DDC*FCC), the corrected remaining storage capacity (RLCC _new4 ), and the corrected health state coefficient (SOH _new3 ).

When the difference between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge (ΔI _{dis, avg} ) is greater than or equal to the first threshold value, the average discharge current rate according to the discharge (I _{dis, avg)} to obtain an update of the lifelong storage capacity (WLCC _new). In detail, in this embodiment _, a correspondence table between the average discharge current rate (I _{dis, avg} ) and the updated lifetime storage capacity (WLCC _new ) can be established in advance, and the average discharge current rate according to the discharge (I _{dis, avg} ) Query the corresponding updated lifetime storage capacity (WLCC _new ). After obtaining the updated lifetime storage capacity (WLCC _new ), the present embodiment is based on the updated lifetime storage capacity (WLCC _new ), the average discharge current rate of the discharge, and the average discharge current rate of the previous discharge (ΔI _{dis , avg} ) and this total discharge capacity (FCC), the corresponding updated remaining storage capacity (RLCC _new1 ) is calculated (step S190). The calculation method of the updated remaining storage capacity (RLCC _new1 ) will be described in detail later with reference to FIG. 3.

Referring to FIG. 1 and FIG. 2, after step S190, next, the ratio of the updated remaining storage capacity (RLCC _new1 ) to the updated lifetime storage capacity (WLCC _new ) is calculated to obtain an updated health state coefficient (SOH _new1). ) (step S200).

Since the updated remaining storage capacity (RLCC _new1 ) and the updated health state coefficient (SOH _new1 ) are affected by the temperature (T) at the time of discharge and the depth of discharge (DOD), the present embodiment can selectively depend on the temperature at the time of discharge. (T) and / or the depth of discharge (DOD) corrected total discharge capacity (FCC), to obtain the corrected remaining storage capacity (RLCC _new2) and the modified state of health factor (SOH _new2) (step S210 and step S220) .

Fig. 3A shows the relationship between the number of discharges and the capacity of the battery cell at different temperatures, and Fig. 3B shows the relationship between the number of discharges and the capacity of the battery cell at different discharge depths.

Referring to FIG. 3A, in order to influence the reaction temperature on the updated remaining storage capacity (RLCC _new1 ), the calculation manner is corresponding to step S210, step S220, step S184 and step S186, and the embodiment is corrected by the temperature coefficient TC(T). The total discharge capacity (FCC) is used to obtain the corrected remaining storage capacity (RLCC _new2 ), and the corrected remaining storage capacity (RLCC _new2 ) is calculated as follows:

RLCC _new2 = (RLCC _new1 +FCC)-TC(T)‧FCC

The derivation of the temperature coefficient TC(T) will be described below. Referring to FIG. 3A, where NC is the rated capacity of the battery cell B (ie, a single discharge capacity), a and b are positive numbers less than 1, and Cycle _T2 and Cycle _T1. For the number of discharges, in the case of temperatures T1 and T2, the cumulative total discharges of multiple discharges (ie, Cycle _T2 and Cycle _T1 ) are FCC _T1 and FCC _T2 , respectively, and the numerical system of the vertical axis represents the percentage (residual capacity). / total capacity).

Assume that T1>T2=>FCC _T2 =TC(T)‧FCC _T1 and TC(T)>1=>[(a+b)‧NC‧Cycle _T2 ]/2=TC(T)‧[(a+ b)‧NC‧Cycle _T1 ]/2=>TC(T)=Cycle _T2 /Cycle _T1

Since Slope _T1 = (ab)‧NC/Cycle _T1 and Slope _T2 =(ab)‧NC/Cycle _T2 , TC(T)=Cycle _T2 /Cycle _T1 =Slope _T1 /Slope _T2 .

Referring to FIG. 3B, in order to influence the influence of the discharge depth on the updated remaining storage capacity (RLCC _new1 ), the calculation manner is corresponding to step S210, step S220, step S184 and step S186, and the discharge depth coefficient DDC (DOD) is used in this embodiment. To correct the total discharge capacity (FCC) to obtain the corrected remaining storage capacity (RLCC _new2 ), and the corrected remaining storage capacity (RLCC _new2 ) is calculated as follows:

RLCC _new2 = (RLCC _new1 +FCC)-DDC(DOD)‧FCC

The derivation of the discharge coefficient DDC (DOD), where NC is the rated capacity of the battery cell B, and x*NC is the non-appropriate capacitance standard of the battery cell B, please refer to FIG. 3B, where the NC is the rating of the battery cell B. The capacitance, a and b are positive numbers less than 1, and Cycle _DOD1 and Cycle _DOD2 are the number of discharges, FCC _DOD1 and FCC _DOD2 are the electrical discharge depths DOD1 and DOD2, and Cycle _DOD1 and Cycle _DOD2 are the cumulative discharges respectively. In addition, the number of vertical axes represents the percentage (residual capacity / total capacitance).

Assume that DOD1>DOD2=>FCC _DOD2 =DDC(DOD)‧FCC _DOD1 and DDC(DOD)>1=>[(a+b)‧x*NC‧Cycle _DOD2 ]/2=DDC‧[(a+b )‧x*NC‧Cycle _DOD1 ]/2=>DDC=Cycle _DOD2 /Cycle _DOD1

Since Slope _DOD1 = (ab)‧x*NC/Cycle _DOD1 and Slope _DOD2 = (ab)‧x*NC/Cycle _DOD2 , DDC=Cycle _DOD2 /Cycle _DOD1 =Slope _DOD1 /Slope _DOD2 .

In the above embodiment, the total discharge capacity (FCC) is also corrected by the temperature coefficient TC(T) and the discharge depth coefficient DDC (DOD) to obtain the corrected remaining storage capacity (RLCC _new2 ), and the corrected remaining storage. The amount of electricity (RLCC _new2 ) is calculated as follows:

RLCC _new2 = (RLCC _new1 +FCC)-TC(T)‧DDC(DOD)‧FCC

In this embodiment, the battery core B is electrically coupled to a control unit CU to form a battery module M, wherein the control unit CU is used to control the battery core B to complete the foregoing steps S100 to S220 to achieve evaluation. The purpose of battery B's health status.

FIG. 4 is a calculation manner of the battery health coefficient recovery recovery (SOH recovery) caused by the difference of the average discharge current rate (ΔI _{dis, avg} ) in the embodiment, and the calculation manner is corresponding to step S190 and step S200. Referring to FIG. 4, the updated remaining storage capacity (RLCC _new1 ) of this embodiment is calculated as follows: (a):

RLCC _new1 ={1/2‧[x*NC+(x*NC+ΔQ _R ±ΔQ _rec )]‧|(ΔQ _R ±ΔQ _rec )/Slope _new |}-FCC...(a)

Where NC is the rated capacity of battery core B, x*NC is the unsuitable capacitance standard of battery core B, x*NC+ΔQ _R is the total discharge capacity (FCC) of the previous discharge of battery core B, and ΔQ _rec is the compensation Power, and Slope _{new is} determined by the updated lifetime storage (WLCC _new ).

The derivation of the updated remaining storage capacity (RLCC _new1 ) will be explained below.

RLCC _orig = 1/2‧[x*NC+(x*NC+ΔQ _R )]‧Cycle _R (1)Slope _orig =|ΔQ _R /Cycle _R |...(2 )

From equations (1) and (2), we can derive:

ΔQ _R =-x*NC+[(x*NC) ² +2|Slope _orig |‧RLCC _orig ] ^1/2 ......(3)

Slope _orig = (NC-x*NC)/CycleT _orig is known (according to the battery parameter table).

ΔQ _rec can be obtained by querying the average discharge current rate-discharge capacity table of the battery in advance:

ΔQ _rec =f(I _dis,avg )......(4)

From the formulas (1), (2), (3) and (4), the following formula (a) can be derived:

RLCC _new1 ={1/2‧[x*NC+(x*NC+ΔQ _R ±ΔQ _rec )]‧|(ΔQ _R ±ΔQ _rec )/Slope _new |}-FCC...(a)

Where Slope _new =(NC-x*NC)/CycleT _new is known (according to the battery parameter lookup table), in addition, the updated lifetime power storage (WLCC _new ) obtained in step S190 is based on the average current of the discharge. , to obtain a new CycleT _new value, as shown in Figure 4, the lifetime storage capacity during heavy load is less than the lifetime storage capacity at light load.

For example, the NC is, for example, 12 Ah, and the x*NC is, for example, 9.6 Ah (ie, x is equal to 0.8), where NC and x vary with different battery cells. In the present embodiment, ΔQ _{rec is} determined by the difference between the average discharge current rate of the current discharge and the average discharge current rate of the previous discharge (ΔI _{dis, avg} ), and ΔQ _rec can be obtained by way of inquiry (see FIG. 5). . Taking the LiFePO ₄ cell with a rated capacitance of 12 Ah as an example, the relationship between the discharge capacity and the average discharge current rate (I _{dis, avg} ) is shown in Fig. 5. In addition, Slope _new can be obtained by reversing the updated lifetime storage (WLCC _new ).

When the difference between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge is positive (meaning that the battery core B is changed from light load to heavy load), the updated remaining storage capacity (RLCC _new1 ) The calculation is as follows (a1):

RLCC _new1 ={1/2‧[x*NC+(x*NC+ΔQ _R -ΔQ _rec )]‧|(ΔQ _R -ΔQ _rec )/Slope _new |}-FCC...(a1)

When the difference between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge is negative (meaning that the battery core B is changed from heavy load to light load), the calculation of the updated remaining storage capacity (RLCC _new1 ) The method is as follows (a2):

RLCC _new1 ={1/2‧[x*NC+(x*NC+ΔQ _R +ΔQ _rec )]‧|(ΔQ _R +ΔQ _rec )/Slope _new |}-FCC...(a2)

Bearing the above, the difference in the average discharge current rate and the previous average discharge current rate of discharge of the discharge (ΔI _{dis, avg)} will directly affect the battery cell B updates the remaining storage capacity (RLCC _new1). In addition, the remaining storage capacity (RLCC _new1 , RLCC _new2 , RLCC _new3, or RLCC _new4 ) calculated by the above steps is divided by the corresponding lifetime storage capacity (or WLCC _new or WLCC _orig ) to generate a corresponding health state coefficient (SOH). _new1, SOH _new2 or _SOH new3), to indicate the state of health of the battery cell B and, according to the above-described embodiments, the skilled artisan can choose whether parameters such as temperature (T), depth of discharge (DOD) or the average discharge current rate in accordance with (I _{Dis, avg} ) to correct the health state coefficient.

Since the present application can evaluate the state of health after the end of the discharge of the battery cell B, the present application can immediately and accurately evaluate the health status of the battery cell.

Although the present application has been disclosed in the above embodiments, it is not intended to limit the application, and any person having ordinary skill in the art can make some changes without departing from the spirit and scope of the present application. Retouching, the scope of protection of this application is subject to the definition of the scope of the patent application attached.

S100～S220. . . Battery cell operation and assessment of health status

M. . . Battery module

B. . . Battery core

CU. . . control unit

E. . . Electronic component

1 is a flow chart of a method for evaluating battery operation and health status of the present application.

2 is a schematic view of a battery module of the present application.

Figure 3A shows the relationship between the number of discharges and the capacitance of the battery cell at different temperatures.

Figure 3B shows the relationship between the number of discharges and the capacitance of the battery cell at different discharge depths.

FIG. 4 is a calculation manner of the updated remaining storage capacity (RLCC _new1 ) in the embodiment.

Fig. 5 is a graph showing the relationship between the discharge capacity of the LiFePO ₄ cell and the average discharge current rate (I _{dis, avg} ).

S100～S220. . . Battery cell operation and assessment of health status

Claims (10)

An evaluation method for a battery cell health state for evaluating a health state of a battery cell that has been discharged at least twice, the method comprising: calculating an average discharge current rate of the discharge battery after each discharge of the battery core ( I _{dis, avg} ) and the difference between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge (ΔI _{dis, avg} ); determining the average discharge of the discharge when the battery is charged or before charging Whether the difference between the current rate and the average discharge current rate of the previous discharge (ΔI _{dis, avg} ) is greater than or equal to a first threshold value, when the average discharge current rate of the discharge is different from the average discharge current rate of the previous discharge ( when ΔI _{dis, avg)} is less than the first threshold, does not update the lifetime of the battery storage capacity of the core (WLCC _orig), average discharge current when the difference between the average discharge current rate and the previous rate of discharge of the discharges (ΔI _{dis , AVG)} is greater than or equal to the first threshold value, obtaining a power storage life updates (WLCC _new) according to the average discharge current rate discharge times; and update based on the lifetime of the storage capacity (WLCC _new), the discharge time The difference in the average discharge current and the average discharge rate of the previous discharge current rate (ΔI _{dis, avg)} and the total discharge capacity (FCC), calculates the remaining storage capacity (RLCC _new1) a corresponding updates; and calculating the The ratio of the updated remaining storage capacity (RLCC _new1 ) to the updated lifetime storage capacity (WLCC _new ) to obtain an updated health state coefficient (SOH _new1 ). The method for evaluating the health status of the battery core according to the first aspect of the patent application includes: recording the total discharge capacity (FCC), discharge current (I) of the battery core during each discharge of the battery core, Voltage (V) and temperature (T). The method for evaluating the health status of the battery core as described in claim 2, further comprising: after obtaining the corresponding remaining storage capacity (RLCC _new1 ) according to the updated lifetime storage capacity (WLCC _new ), according to the The temperature (T) at the time of the secondary discharge corrects the remaining stored power of the update (RLCC _new1 ). The method for evaluating the health status of the battery core as described in claim 2, further comprising: after obtaining the corresponding remaining storage capacity (RLCC _new1 ) according to the updated lifetime storage capacity (WLCC _new ), according to the The temperature (T) and the depth of discharge (DOD) at the time of the secondary discharge correct the updated remaining storage capacity (RLCC _new1 ). The method for evaluating the health status of the battery core as described in claim 2, further comprising: after obtaining the corresponding remaining storage capacity (RLCC _new1 ) according to the updated lifetime storage capacity (WLCC _new ), according to the The depth of discharge (DOD) at the time of the secondary discharge corrects the updated remaining storage capacity (RLCC _new1 ). The method for evaluating the health status of the battery core according to the first aspect of the patent application includes: calculating the average discharge current rate (I _{dis, avg} ) of the discharge and the average discharge current rate of the discharge and the previous time. Before the difference in the average discharge current rate of the discharge (ΔI _{dis, avg} ), it is judged whether or not the battery cell is still being discharged. The method for evaluating the health status of the battery core as described in claim 1, wherein the updated remaining storage capacity (RLCC _new1 ) is calculated as follows: RLCC _new1 = {1/2‧[x*NC+(x*NC +ΔQ _R ±ΔQ _rec )]‧|ΔQ _R +ΔQ _rec /Slope _new |}-FCC; where NC is the rated capacity of the cell, x*NC is the unsuitable capacitance standard of the cell, NC+ ΔQ _{R is} the total discharge capacity (FCC) of the previous discharge of the cell, ΔQ _rec is the compensation charge, and Slope _{new is} determined by the updated lifetime charge (WLCC _new ); when the average discharge current rate of the discharge is before When the difference in the average discharge current rate of the secondary discharge is positive, the updated remaining storage capacity (RLCC _new1 ) is calculated as follows: RLCC _new1 = {1/2‧[x*NC+(x*NC+ΔQ _R -ΔQ) _Rec )]‧|ΔQ _R +ΔQ _rec /Slope _new |}-FCC; when the difference between the average discharge current rate of the discharge and the average discharge current rate of the previous discharge is negative, the updated remaining storage capacity ( RLCC _new1 ) is calculated as follows: RLCC _new1 = {1/2‧[x*NC+(x*NC+ΔQ _R +ΔQ _rec )]‧|ΔQ _R +ΔQ _rec /Slope _new |}-FCC. An evaluation method for a battery cell health state for evaluating a health state of a battery cell that has been discharged at least twice, the method comprising: calculating an average discharge current rate of the discharge battery after each discharge of the battery core ( I _{dis, avg} ); according to the average discharge current rate (I _{dis, avg} ) of the discharge and the average discharge current rate of the previous discharge, obtain an updated lifetime storage capacity (WLCC _new ); according to the updated lifetime storage capacity (WLCC _new ), the remaining storage capacity of the battery cell before the discharge (RLCC _orig ), the average discharge current rate of the discharge, the average discharge current rate of the previous discharge, and the total discharge capacity (FCC), calculates the remaining storage capacity (RLCC _new1) updates a corresponding one; and calculating the remaining storage capacity of the update (RLCC _new1) updates the lifetime of storage capacity (WLCC _new) of the ratio to obtain a health status updates coefficients ( SOH _new1 ). The method for evaluating the health status of the battery core according to the scope of claim 8 further includes: recording the total discharge capacity (FCC), discharge current (I) of the battery core during each discharge of the battery core, Voltage (V) and temperature (T); before calculating the average discharge current rate (I _{dis, avg} ) of the discharge, determining whether the battery cell is still discharging; and in the lifetime storage capacity according to the update (WLCC _new ) obtained after the update of the residual amount reservoir (RLCC _new1) corresponding, (T) and the depth of discharge (DOD) correcting the remaining storage capacity of the update (RLCC _new1) the temperature at which the discharges. A battery module comprising: a battery core capable of repeatedly charging and discharging; and a control unit electrically coupled to the battery core to control repeated charging and discharging of the battery cell, wherein the control unit is according to the patent application scope 8 The battery cell health assessment method described in the item evaluates the health status of the battery cell.