A battery pack adjustment method

Abstract

The present invention discloses a method for adjusting a battery pack, comprising: step S1, a BMS battery management system obtains the theoretical internal resistance of the battery pack of each battery pack branch of the battery pack; step S2, the BMS battery management system roughly adjusts the resistance of the internal resistance adjustment device of each battery pack branch, so that the ratio of the total resistance of any two battery pack branches is inversely proportional to the ratio of the SOH values ​​of the battery packs of the two battery pack branches, and then the BMS battery management system calculates the theoretical full time and theoretical empty time of the battery pack branch according to the theoretical total resistance of each battery pack branch; step S3: the BMS battery management system finely adjusts the internal resistance adjustment device of each battery pack branch according to the theoretical full time and theoretical empty time of each battery pack branch and the actual full time and actual empty time. The present invention can effectively improve the service life of the battery pack by adjusting the internal resistance adjustment device of each battery pack branch.

Description

Technical Field

[0001] The present invention relates to the field of battery packs, and in particular to a method for regulating a battery pack. Background Art

[0002] Many existing battery packs use a method of connecting multiple battery pack branches in parallel, and each battery pack branch includes a battery pack. As the battery pack is in use, the internal resistance of each battery pack will gradually increase, and due to the differences between the battery packs, the internal resistance of each battery pack branch (the internal resistance of a battery pack branch refers to the sum of the internal resistances of each battery pack in the battery pack branch) will be inconsistent; in particular, battery packs that use new and old battery packs in parallel will have inconsistent internal resistances of each battery pack branch. The inconsistent internal resistance of each battery pack branch of the battery pack often causes a series of problems. The biggest problem is that some battery pack branches may be filled or discharged first, while other battery pack branches are still in the charging or discharging state. This unbalanced state not only causes the battery pack capacity to be unable to be fully discharged, but may also cause the risk of overloading or over-discharging of some battery packs, thereby accelerating the aging process of the battery pack and shortening the service life of the entire battery pack. .

[0003] In view of the existence of the above problems, it is necessary to study a battery pack adjustment method, which can effectively improve the service life of the battery pack. Summary of the invention

[0004] The object of the present invention is to provide a battery pack adjustment method, which can effectively increase the service life of the battery pack.

[0005] In order to achieve the above object, the solution of the present invention is:

[0006] A method for regulating a battery pack, the battery pack having a plurality of parallel battery pack branches, each battery pack branch comprising a battery pack and an internal resistance regulating device connected in series, the resistance value of the internal resistance regulating device being adjustable;

[0007] The battery pack adjustment method comprises the following steps:

[0008] Step S1: The BMS battery management system obtains the theoretical internal resistance of the battery pack of each battery pack branch of the battery pack, and then proceeds to step S2;

[0009] Step S2: The BMS battery management system roughly adjusts the resistance of the internal resistance regulating device of each battery pack branch so that the ratio of the total resistance of any two battery pack branches is inversely proportional to the ratio of the SOH values ​​of the battery packs of the two battery pack branches. Then, the BMS battery management system calculates the theoretical full charge time and theoretical empty charge time of each battery pack branch according to the theoretical total resistance of each battery pack branch, and then enters step S3;

[0010] The theoretical total resistance of the battery pack branch is the sum of the theoretical internal resistance of the battery pack of the battery pack branch and the resistance of the internal resistance adjustment device of the battery pack branch;

[0011] Step S3: The BMS battery management system fine-tunes the internal resistance regulating device of each battery pack branch, including the following steps:

[0012] Step S31: The BMS battery management system monitors whether the battery pack branch undergoing fine-tuning has completed a continuous and complete charge or discharge; if the battery pack branch has completed a continuous and complete charge, the process proceeds to step S32; if the battery pack branch has completed a continuous and complete discharge, the process proceeds to step S32';

[0013] Step S32: The BMS battery management system compares the actual full charge time of the battery pack branch with the theoretical full charge time of the battery pack branch;

[0014] If the absolute value of the difference between the actual full charge time of the battery pack branch and the theoretical full charge time of the battery pack branch is greater than the set charging time difference threshold and the actual full charge time of the battery pack branch is greater than the theoretical full charge time of the battery pack branch, the BMS battery management system controls the resistance value of the internal resistance adjustment device of the battery pack branch to decrease by the set reduction ratio, and then repeats step S31;

[0015] If the absolute value of the difference between the actual full charge time of the battery pack branch and the theoretical full charge time of the battery pack branch is greater than the set charging time difference threshold and the actual full charge time of the battery pack branch is less than the theoretical full charge time of the battery pack branch, the BMS battery management system controls the resistance value of the internal resistance adjustment device of the battery pack branch to increase by the set increase ratio, and then repeats step S31;

[0016] If the absolute value of the difference between the actual full charge time of the battery pack branch and the theoretical full charge time of the battery pack branch is less than the set charging time difference threshold, the fine adjustment of the battery pack branch is terminated;

[0017] Step S32': the BMS battery management system compares the actual emptying time of the battery pack branch with the theoretical emptying time of the battery pack branch;

[0018] If the absolute value of the difference between the actual discharge time of the battery pack branch and the theoretical discharge time of the battery pack branch is greater than the set discharge time difference threshold and the actual discharge time of the battery pack branch is greater than the theoretical discharge time of the battery pack branch, the BMS battery management system controls the resistance value of the internal resistance regulating device of the battery pack branch to decrease by the set reduction ratio, and then repeats step S31;

[0019] If the absolute value of the difference between the actual discharge time of the battery pack branch and the theoretical discharge time of the battery pack branch is greater than the set discharge time difference threshold and the actual discharge time of the battery pack branch is less than the theoretical discharge time of the battery pack branch, the BMS battery management system controls the resistance value of the internal resistance regulating device of the battery pack branch to increase by the set increase ratio, and then repeats step S31;

[0020] If the absolute value of the difference between the actual discharge time of the battery pack branch and the theoretical discharge time of the battery pack branch is less than the set discharge time difference threshold, the fine adjustment of the battery pack branch is terminated.

[0021] The charging time difference threshold and the discharging time difference threshold are both 2 minutes.

[0022] The setting increase ratio and the setting decrease ratio are 10% to 50%.

[0023] The internal resistance adjusting device adopts an adjustable resistor.

[0024] The BMS battery management system has a table data on the relationship between the SOH value of the battery pack and the internal resistance of the battery pack; the way in which the BMS battery management system obtains the theoretical internal resistance of the battery pack of each battery pack branch of the battery pack is as follows: the BMS battery management system obtains the SOH value of the battery pack of the battery pack branch and performs a table lookup, thereby obtaining the theoretical internal resistance of the battery pack of each battery pack branch.

[0025] After adopting the above scheme, the present invention sets an internal resistance regulating device with adjustable resistance value in each battery pack branch of the battery pack, so that the present invention can adjust the internal resistance regulating device through the BMS battery management system, so that each battery pack branch can achieve full charge and full discharge, so that the capacity of the battery pack of each battery pack branch can be released, thereby improving the service life of the battery pack. Among them, since the theoretical internal resistance of the battery pack obtained by the BMS battery management system may be different from the actual internal resistance of the battery pack, the present invention fine-tunes the battery pack branch according to the theoretical full time, theoretical empty time, actual full time and actual empty time of each battery pack branch, so that the actual full time and actual empty time of each battery pack branch can be close to the theoretical full time and theoretical empty time, respectively, thereby ensuring that each battery pack branch can achieve full charge and full discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the overall flow chart of the present invention.

[0027] Figure 2 The process of step S3 of the present invention is Figure 1 .

[0028] Figure 3 The process of step S3 of the present invention is Figure 2 . DETAILED DESCRIPTION

[0029] In order to further explain the technical solution of the present invention, the present invention is described in detail below through specific embodiments.

[0030] like Figures 1 to 3 As shown, the present invention discloses a method for regulating a battery pack, wherein the battery pack has a plurality of parallel battery pack branches, each battery pack branch includes a battery pack connected in series and an internal resistance regulating device, and the resistance value of the internal resistance regulating device is adjustable; specifically, a method for regulating a battery pack of the present invention includes the following steps:

[0031] Step S1: The BMS battery management system obtains the theoretical internal resistance of the battery pack of each battery pack branch of the battery pack, and then proceeds to step S2;

[0032] Step S2: The BMS battery management system roughly adjusts the resistance of the internal resistance regulating device of each battery pack branch so that the ratio of the total resistance of any two battery pack branches is inversely proportional to the ratio of the SOH values ​​of the battery packs of the two battery pack branches. Then, the BMS battery management system calculates the theoretical full charge time and theoretical empty charge time of each battery pack branch according to the theoretical total resistance of each battery pack branch, and then enters step S3;

[0033] The theoretical total resistance of the battery pack branch is the sum of the theoretical internal resistance of the battery pack of the battery pack branch and the resistance of the internal resistance adjustment device of the battery pack branch;

[0034] Step S3: The BMS battery management system fine-tunes the internal resistance regulating device of each battery pack branch, including the following steps:

[0035] Step S31: The BMS battery management system monitors whether the battery pack branch undergoing fine-tuning has completed a continuous and complete charge or discharge; if the battery pack branch has completed a continuous and complete charge, the process proceeds to step S32; if the battery pack branch has completed a continuous and complete discharge, the process proceeds to step S32';

[0036] Step S32: The BMS battery management system compares the actual full charge time of the battery pack branch with the theoretical full charge time of the battery pack branch;

[0037] If the absolute value of the difference between the actual full charge time of the battery pack branch and the theoretical full charge time of the battery pack branch is greater than the set charging time difference threshold and the actual full charge time of the battery pack branch is greater than the theoretical full charge time of the battery pack branch, the BMS battery management system controls the resistance value of the internal resistance adjustment device of the battery pack branch to decrease by the set reduction ratio, and then repeats step S31;

[0038] If the absolute value of the difference between the actual full charge time of the battery pack branch and the theoretical full charge time of the battery pack branch is greater than the set charging time difference threshold and the actual full charge time of the battery pack branch is less than the theoretical full charge time of the battery pack branch, the BMS battery management system controls the resistance value of the internal resistance adjustment device of the battery pack branch to increase by the set increase ratio, and then repeats step S31;

[0039] If the absolute value of the difference between the actual full charge time of the battery pack branch and the theoretical full charge time of the battery pack branch is less than the set charging time difference threshold, the fine adjustment of the battery pack branch is terminated;

[0040] Step S32': the BMS battery management system compares the actual emptying time of the battery pack branch with the theoretical emptying time of the battery pack branch;

[0041] If the absolute value of the difference between the actual discharge time of the battery pack branch and the theoretical discharge time of the battery pack branch is greater than the set discharge time difference threshold and the actual discharge time of the battery pack branch is greater than the theoretical discharge time of the battery pack branch, the BMS battery management system controls the resistance value of the internal resistance regulating device of the battery pack branch to decrease by the set reduction ratio, and then repeats step S31;

[0042] If the absolute value of the difference between the actual discharge time of the battery pack branch and the theoretical discharge time of the battery pack branch is greater than the set discharge time difference threshold and the actual discharge time of the battery pack branch is less than the theoretical discharge time of the battery pack branch, the BMS battery management system controls the resistance value of the internal resistance regulating device of the battery pack branch to increase by the set increase ratio, and then repeats step S31;

[0043] If the absolute value of the difference between the actual discharge time of the battery pack branch and the theoretical discharge time of the battery pack branch is less than the set discharge time difference threshold, the fine adjustment of the battery pack branch is terminated.

[0044] The present invention sets an internal resistance regulating device with adjustable resistance value in each battery pack branch of the battery pack, so that the present invention can adjust the internal resistance regulating device through the BMS battery management system, so that each battery pack branch can achieve full charge and full discharge, so that the capacity of the battery pack of each battery pack branch can be released, thereby improving the service life of the battery pack. Among them, since there may be a certain difference between the theoretical internal resistance of the battery pack obtained by the BMS battery management system and the actual internal resistance of the battery pack, the present invention fine-tunes the battery pack branch according to the theoretical full time, theoretical empty time, actual full time and actual empty time of each battery pack branch, so that the actual full time and actual empty time of each battery pack branch can be close to the theoretical full time and theoretical empty time, respectively, thereby ensuring that each battery pack branch can achieve full charge and full discharge.

[0045] In an embodiment of the present invention, the charging time difference threshold and the discharging time difference threshold are both 2 minutes.

[0046] In an embodiment of the present invention, the set increase ratio and the set decrease ratio may be 10% to 50%; wherein, the set increase ratio and the set decrease ratio are 50%, which can effectively shorten the adjustment time.

[0047] In an embodiment of the present invention, the internal resistance adjustment device adopts an adjustable resistor.

[0048] In an embodiment of the present invention, the BMS battery management system has a table data of the relationship between the SOH value of the battery pack and the internal resistance of the battery pack; and the BMS battery management system obtains the theoretical internal resistance of the battery pack of each battery pack branch of the battery group in the following manner: the BMS battery management system obtains the SOH value of the battery pack of the battery pack branch and performs a table lookup to obtain the theoretical internal resistance of the battery pack of each battery pack branch. The present invention obtains the theoretical internal resistance of the battery pack of the battery pack branch by table lookup, so the present invention does not need to set up an additional detection circuit for detecting the internal resistance of the battery pack, which helps to reduce costs and simplify the structure.

[0049] In step S2, the principle of "the BMS battery management system roughly adjusts the resistance of the internal resistance regulating device of each battery pack branch so that the ratio of the total resistance of any two battery pack branches is inversely proportional to the ratio of the SOH values ​​of the battery packs of the two battery pack branches" is:

[0050] Taking two battery pack branches as an example, the SOH value, current value and total resistance of the first battery pack branch are Sa, Ia and Ra respectively; the SOH value, current value and total resistance of the second battery pack branch are Sb, Ib and Rb respectively; according to the parallel circuit relationship, we can get: Formula 1: Ia=U / Ra; Formula 2: Ib=U / Rb;

[0051] In order to make the two battery pack branches fully charged or discharged at the same time, the currents of the two battery pack branches should satisfy: Formula 3: Ia=Sa / (Sa+Sb); Formula 4: Ib=Sb / (Sa+Sb);

[0052] Combining the above formulas 1, 2, 3 and 4, we can get: Formula 5: Ra / Rb=Sb / Sa;

[0053] Therefore, when the BMS battery management system makes a coarse adjustment to the resistance value of the internal resistance regulating device of each battery pack branch, the ratio of the total resistance values ​​of any two battery pack branches should be inversely proportional to the ratio of the SOH values ​​of the battery packs of the two battery pack branches, so that the theoretical full charge time and the theoretical empty charge time of each battery pack branch are the same, so as to shorten the time for subsequent fine-tuning.

[0054] The above embodiments and drawings do not limit the product form and style of the present invention. Any appropriate changes or modifications made by ordinary technicians in the relevant technical field should be deemed to be within the patent scope of the present invention.

Claims

1. A method for adjusting a battery pack, characterized in that: The battery pack has a plurality of parallel battery pack branches, each of which includes a battery pack and an internal resistance regulating device connected in series, and the resistance value of the internal resistance regulating device is adjustable; The battery pack adjustment method comprises the following steps: Step S1: The BMS battery management system obtains the theoretical internal resistance of the battery pack of each battery pack branch of the battery pack, and then proceeds to step S2; Step S2: The BMS battery management system roughly adjusts the resistance of the internal resistance regulating device of each battery pack branch so that the ratio of the total resistance of any two battery pack branches is the inverse of the ratio of the SOH values ​​of the battery packs of the two battery pack branches. Then, the BMS battery management system calculates the theoretical full charge time and theoretical empty charge time of each battery pack branch according to the theoretical total resistance of each battery pack branch, and then enters step S3; The theoretical total resistance of the battery pack branch is the sum of the theoretical internal resistance of the battery pack of the battery pack branch and the resistance of the internal resistance adjustment device of the battery pack branch; Step S3: The BMS battery management system fine-tunes the internal resistance regulating device of each battery pack branch, including the following steps: Step S31: The BMS battery management system monitors whether the battery pack branch undergoing fine-tuning has completed a continuous and complete charge or discharge; if the battery pack branch has completed a continuous and complete charge, the process proceeds to step S32; if the battery pack branch has completed a continuous and complete discharge, the process proceeds to step S32'; Step S32: The BMS battery management system compares the actual full charge time of the battery pack branch with the theoretical full charge time of the battery pack branch; If the absolute value of the difference between the actual full charge time of the battery pack branch and the theoretical full charge time of the battery pack branch is greater than the set charging time difference threshold and the actual full charge time of the battery pack branch is greater than the theoretical full charge time of the battery pack branch, the BMS battery management system controls the resistance value of the internal resistance adjustment device of the battery pack branch to decrease by the set reduction ratio, and then repeats step S31; If the absolute value of the difference between the actual full charge time of the battery pack branch and the theoretical full charge time of the battery pack branch is greater than the set charging time difference threshold and the actual full charge time of the battery pack branch is less than the theoretical full charge time of the battery pack branch, the BMS battery management system controls the resistance value of the internal resistance adjustment device of the battery pack branch to increase by the set increase ratio, and then repeats step S31; If the absolute value of the difference between the actual full charge time of the battery pack branch and the theoretical full charge time of the battery pack branch is less than the set charging time difference threshold, the fine adjustment of the battery pack branch is terminated; Step S32': the BMS battery management system compares the actual emptying time of the battery pack branch with the theoretical emptying time of the battery pack branch; If the absolute value of the difference between the actual discharge time of the battery pack branch and the theoretical discharge time of the battery pack branch is greater than the set discharge time difference threshold and the actual discharge time of the battery pack branch is greater than the theoretical discharge time of the battery pack branch, the BMS battery management system controls the resistance value of the internal resistance regulating device of the battery pack branch to decrease by the set reduction ratio, and then repeats step S31; If the absolute value of the difference between the actual discharge time of the battery pack branch and the theoretical discharge time of the battery pack branch is greater than the set discharge time difference threshold and the actual discharge time of the battery pack branch is less than the theoretical discharge time of the battery pack branch, the BMS battery management system controls the resistance value of the internal resistance regulating device of the battery pack branch to increase by the set increase ratio, and then repeats step S31; If the absolute value of the difference between the actual discharge time of the battery pack branch and the theoretical discharge time of the battery pack branch is less than the set discharge time difference threshold, the fine adjustment of the battery pack branch is terminated.

2. A battery pack adjustment method as claimed in claim 1, characterized in that: The charging time difference threshold and the discharging time difference threshold are both 2 minutes.

3. A battery pack adjustment method as claimed in claim 1, characterized in that: The setting increase ratio and the setting decrease ratio are 10% to 50%.

4. A battery pack adjustment method as claimed in claim 1, characterized in that: The internal resistance adjusting device adopts an adjustable resistor.

5. A battery pack adjustment method as claimed in claim 1, characterized in that: The BMS battery management system has a table of data on the relationship between the SOH value of the battery pack and the internal resistance of the battery pack; The BMS battery management system obtains the theoretical internal resistance of the battery pack of each battery pack branch of the battery pack as follows: the BMS battery management system obtains the SOH value of the battery pack of the battery pack branch and performs a table lookup to obtain the theoretical internal resistance of the battery pack of each battery pack branch.

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