Battery module and battery life prolonging method thereof

Abstract

The invention provides a battery module and a battery life prolonging method thereof, the battery life prolonging method is applied to a battery management system, and a charger is controlled by the battery management system to charge a battery cell group. Before the battery cell group is charged, after a target charging electric quantity value of the battery cell group is set according to the battery health state of the battery cell group, a constant-current charging mode is entered, and a charger starts to charge the battery cell group. And then, calculating a charged electric quantity value of the battery cell group, and when the charged electric quantity value is greater than the target charging electric quantity value, ending the constant-current charging mode. Therefore, the aging condition of the battery is estimated before charging, different life prolonging strategies are adopted, and then the target charging electric quantity value of the battery is dynamically changed, so that the full capacitance can be gradually improved according to the aging degree, and the purpose of prolonging the service life of the battery is achieved.

Description

Technical Field

[0001] The present invention relates to the field of batteries, and in particular to a battery module and a battery life extension method thereof. Background Art

[0002] Most of the existing battery life extension methods use a configurable charger, where the battery pack actively notifies the charger through communication handshake to dynamically change the charging voltage. However, the following problems may be encountered during the charging process:

[0003] (1) Increased complexity of the charging process: Communication with the battery is required before charging, which increases the design complexity of the charger and battery pack and the production cost of the charger.

[0004] (2) Unable to fine-tune: The charging voltage of the charger has accuracy issues, so the dynamic charging voltage also has voltage accuracy defects and cannot accurately fine-tune the full charge voltage.

[0005] Therefore, in view of the above-mentioned difficulties, the present invention proposes a battery module and a battery life extension method thereof to solve the problems generated by the prior art. Summary of the invention

[0006] An object of the present invention is to provide a battery module and a battery life extension method thereof, which can effectively extend the battery life, slow down battery aging, and reduce production costs and design complexity.

[0007] To achieve the above-mentioned purpose, the present invention provides a battery life extension method, which is applied to a battery management system (BMS) to control the charging of a battery pack by a charger through the battery management system. The battery life extension method comprises the following steps: starting the charging operation, before charging the battery pack, setting the target charging power value of the battery pack according to the battery health status of the battery pack, entering the constant current charging mode, and allowing the charger to start charging the battery pack; calculating the charged power value of the battery pack; and when the charged power value is greater than the target charging power value, ending the constant current charging mode.

[0008] In one embodiment of the present invention, the target charging power value is one or a combination of a safe standby capacity and a safe full-charge power.

[0009] In one embodiment of the present invention, the step of terminating the constant current charging mode includes: when the charged capacity value is greater than the target charging capacity value, setting a safe full charge voltage range according to the target charging capacity value, wherein the target charging capacity value is a safe full charge capacity; sensing the battery cell group to obtain a voltage value; and when the voltage value is between the safe full charge voltage range, terminating the constant current charging mode.

[0010] In one embodiment of the present invention, the step of terminating the constant current charging mode includes: when the charged capacity value is greater than the target charging capacity value, setting a safe full charge voltage according to the target charging capacity value, wherein the target charging capacity value is the safe full charge capacity, sensing the battery cell group to obtain a voltage value, and terminating the constant current charging mode when the voltage value is equal to the safe full charge voltage.

[0011] In an embodiment of the present invention, the step of ending the constant current charging mode further includes: notifying the charger to stop charging the battery pack through a communication handshake.

[0012] In one embodiment of the present invention, the step of ending the constant current charging mode further includes: controlling the battery cell group to cut off the charging circuit between the charger and the battery cell group to stop the charging operation.

[0013] In one embodiment of the present invention, the battery life extension method further includes starting a charging operation when the remaining power of the battery cell group is equal to or less than a lower limit backup capacity or a lower limit storage voltage.

[0014] In one embodiment of the present invention, the step of calculating the charged capacity of the battery pack includes: sensing the current values ​​of the discharge circuit and the charge circuit of the battery pack, respectively calculating the discharge capacity and the charge capacity, wherein in the charging operation, the discharge capacity is less than the charge capacity; and calculating the charged capacity value according to the discharge capacity and the charge capacity, and the relationship between the charged capacity values ​​is:

[0015] Charged capacity value = initial remaining capacity + (charged capacity - discharged capacity)

[0016] In one embodiment of the present invention, the target charging capacity value is inversely proportional to the battery health state.

[0017] The present invention also proposes a battery module, the battery module is connected to a load and a charger respectively, and the battery module includes a battery cell group and a battery management system. The battery cell group has a battery health state. The battery management system is connected to the battery cell group, sets a target charging power value according to the battery health state, and stops charging the battery cell group in a constant current charging mode when the charged amount of the battery cell group is greater than the target charging power value, wherein the target charging power value is inversely proportional to the battery health state.

[0018] In one embodiment of the present invention, the battery module further includes a switch and a power calculation unit. The switch connects the battery cell group and the battery management system, and respectively establishes a charging circuit with the charger and a discharging circuit with the load. The power calculation unit is connected to the battery management system, and is used to sense the current value on the charging circuit and the discharging circuit, and is used to calculate the discharge power and the charging power respectively, and obtain the charged value of the battery cell group.

[0019] In one embodiment of the present invention, the battery management system controls the switch to cut off the charging circuit between the charger and the battery pack to stop charging.

[0020] In an embodiment of the present invention, the battery management system may further include a communication module, and the communication module may notify the charger to start or stop charging the battery pack through a communication handshake.

[0021] The following examples are used to illustrate the preferred embodiments of the present invention, and are described in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 FIG. 1 is a flow chart of a first embodiment of a battery life extension method according to the present invention.

[0023] Figure 2 FIG. 4 is a flow chart of a second embodiment of the battery life extension method of the present invention.

[0024] Figure 3 FIG. 4 is a flow chart of a third embodiment of the battery life extension method of the present invention.

[0025] Figure 4 FIG. 4 is a flow chart of a fourth embodiment of a battery life extension method according to the present invention.

[0026] Figure 5 FIG. 4 is a block diagram of a battery module according to an embodiment of the present invention.

[0027] Description of the accompanying drawings: S100-S700, S510-S530, S511, S520', S531-steps; 10-battery module; 11-battery cell group; 12-battery management system; 121-communication module; 13-switch; 14-power calculation unit; 20-load; 30-charger. DETAILED DESCRIPTION

[0028] The battery life extension method of the present invention is applied to a battery management system, and the battery management system controls the charger to charge the battery cell group.

[0029] See also Figure 1 , the battery life extension method includes the following steps:

[0030] Step S100: Start the charging operation. Step S200: Before charging the battery pack, set the target charging power value of the battery pack according to the battery health status of the battery pack.

[0031] Step S300: Entering a constant current charging mode (CC mode) to charge the battery with a fixed current, allowing the charger to start charging the battery pack.

[0032] Step S400: Calculate the charged capacity of the battery pack.

[0033] Step S500: Determine whether the charged power value is greater than the target charged power value, if yes, proceed to step S600, otherwise proceed to step S300.

[0034] Step S600: End the constant current charging mode.

[0035] Generally speaking, new batteries are in a healthy state when they leave the factory. The battery health state (SOH) can be defined as 100%, and the battery health state value is the amount of power that can be released after charging is completed divided by the factory rated capacity. However, as the battery ages and wears out, the battery capacity and performance will gradually decrease, and the battery health state (SOH value) will also gradually decrease.

[0036] Based on the above phenomenon, in order to extend the service life of the battery, in step S200 and step S500 of the first embodiment of the present invention, the target charging power value is the safe standby capacity, and the target charging power value is inversely proportional to the battery health state. Furthermore, when the battery health state value is lower, the target charging power (safe standby capacity) is higher; when the battery health state value is higher, the target charging power (safe standby capacity) is lower. Before charging the battery pack, the battery management system can set the expected charging power value according to the SOH value. For example, when the SOH value is 100%, the target charging power (safe standby capacity) can be set to 80%; when the SOH value is 80%, the target charging power (safe standby capacity) is set to 95%. The aforementioned values ​​are for example only and are not limited thereto.

[0037] In step S400 of the first embodiment, the charged value of the battery pack is calculated by respectively calculating the discharge power and the charge power by sensing the current values ​​of the discharge circuit and the charge circuit of the battery pack. Generally speaking, during the charging operation, the discharge power of the battery pack is less than the charge power. The charged value is further calculated based on the discharge power and the charge power, and the relationship between the charged value is as follows:

[0038] Charged capacity value = initial remaining capacity + (charged capacity - discharged capacity).

[0039] Therefore, when the battery aging condition is not high, the above method can further monitor the battery during the charging process by setting a relatively sufficient reserve capacity to avoid leaving the battery pack in a fully charged and over-voltage state for a long time.

[0040] See also Figure 2 The difference between the second embodiment and the first embodiment is that after step S600 is executed, after the constant current charging mode is ended in step S600, step S700 is executed: determining whether the remaining power of the battery pack is equal to or less than the lower limit standby capacity or the lower limit storage voltage.

[0041] After the battery pack stops the constant current charging mode, the battery pack is in a relatively low voltage range due to self-consumption or peak load consumption. At this time, in step S700, when the remaining power of the battery pack is reduced to the lower limit of the standby capacity or the lower limit of the storage voltage, it will return to step S100 to restart the life extension charging operation.

[0042] Therefore, the battery life extension method of the present invention can prevent the battery life from being shortened due to over-discharge of the battery pack, thereby achieving the effect of extending the battery life.

[0043] See also Figure 3 The difference between the third embodiment and the first embodiment is that the third embodiment further includes steps S510 to S530 between step S500 and step S600. When it is determined in step S500 that the charged power value is greater than the target charged power value, the following steps are performed first:

[0044] Step S510: setting a safe full-charge voltage range according to a target charging power value.

[0045] Step S520: Sense the battery cell group to obtain a voltage value.

[0046] Step S530: Determine whether the voltage value is within the safe full-charge voltage range. If so, proceed to step S600; otherwise, proceed to step S520 to continue to maintain the constant current charging mode and sense the voltage value of the battery pack.

[0047] Generally speaking, a battery cell group includes multiple battery cells. Due to electrochemical principles, the charge of each battery cell in the same battery cell group is different. Therefore, continuous charging of the battery cell with a high charge will cause the battery cell to be overcharged. However, if the charging is suspended when the battery cell with a high charge is fully charged, the battery cell with a low charge will not be fully charged. When the charge of each battery cell is different, continuous charging and discharging may cause aging of a single battery cell, thereby affecting the performance of the entire battery cell group. Therefore, in the third embodiment, in step S510, the target charging power value further includes a safe full charge power. Therefore, setting the safe full charge voltage range according to the safe full charge power can further improve this problem.

[0048] See also Figure 4 The difference between the fourth embodiment and the third embodiment is that step S511, step S520', and step S531 are further included between step S500 and step S600.

[0049] In step S511, a safe full-charge voltage is set according to the target charging power value. Then, step S520' is executed to sense the battery cell group to obtain the voltage value. Step S531 is further executed to determine whether the voltage value is equal to the safe full-charge voltage. When the voltage value is not equal to the safe full-charge voltage, the process returns to step S520 to continue to maintain the constant current charging mode and sense the voltage value of the battery cell group. When the voltage value of the battery cell group is equal to the safe full-charge voltage, step 600 is executed to end the constant current charging mode.

[0050] In step S511, the target charging power value is the safe full-charge power. For example, assuming that the factory rated voltage of a new battery pack is 4V, the general full-charge voltage will be set at 3.8V. In this embodiment, the safe full-charge voltage can be set to 3.6V through step S511. The goal is to stop charging when the voltage value of the battery pack reaches 3.6V. However, if only the voltage is judged alone, there is no way to determine whether the charged power is sufficient. Therefore, first through steps S200 to S500, it is first determined that the charged value of the battery pack is greater than the safe standby capacity, and then it is further determined that the voltage value of the battery pack is equal to the safe full-charge voltage. Under the condition of better battery health, the safe standby capacity and safe full-charge power of the battery pack can be set so that the battery pack will not be in an over-high voltage state for a long time when fully charged, so as to have the effect of extending the battery life.

[0051] See also Figure 5 In one embodiment, the battery module 10 of the present invention is connected to the load 20 and the charger 30 respectively, and the battery module 10 includes a battery cell group 11 and a battery management system 12 .

[0052] The battery pack 11 has a battery health state. The battery management system 12 is connected to the battery pack 11, sets a target charging power value according to the battery health state, and stops charging the battery pack 11 in a constant current charging mode when the charged power of the battery pack 11 is greater than the target charging power value.

[0053] Among them, the target charging power value is inversely proportional to the battery health state.

[0054] In one embodiment, the battery module 10 includes a switch 13 and a power calculation unit 14 .

[0055] The switch 13 connects the battery pack 11 and the battery management system 12, and respectively establishes a charging circuit with the charger 30 and a discharging circuit with the load 20. The power calculation unit 14 is connected to the battery management system 12, and is used to sense the current values ​​on the charging circuit and the discharging circuit, and respectively calculate the discharge power and the charging power to obtain the charged value of the battery pack 11. The power calculation unit 14 can be a coulomb counter.

[0056] In one embodiment, the battery management system 12 can control the switch 13 to cut off the charging circuit between the charger 30 and the battery cell group 11 to stop charging.

[0057] In one embodiment, the battery management system 12 may further include a communication module 121 . The communication module 121 may notify the charger 30 to start or stop charging the battery cell group 11 through communication handshake.

[0058] In summary, the battery module and battery life extension method described in the present invention can monitor the voltage and charging and discharging behavior of the battery pack before charging, estimate the battery aging status, adopt different life extension strategies, and dynamically change the full charge capacity or full charge voltage of the battery after full charge. During the charging process of the battery pack, when it is found that the charging capacity has met the minimum system capacity requirement, charging can be stopped. By gradually increasing the full charge capacity according to the degree of aging, the purpose of extending the battery life is achieved.

[0059] The above description is only used to illustrate the preferred implementation mode of the present invention, and is not intended to limit the scope of implementation. All simple replacements and equivalent changes made according to the claims and the patent specification of the present invention are within the protection scope of the present invention.

Claims

1. A battery life extension method, applied to a battery management system, through which a charger is controlled to charge a battery pack, characterized in that: The battery life extension method comprises the following steps: Initiating a charging operation; Before charging the battery pack, a target charging power value of the battery pack is set according to a battery health status of the battery pack, and then a constant current charging mode is entered to allow the charger to start charging the battery pack; Calculating a charged value of the battery pack; as well as When the charged power value is greater than the target charging power value, the constant current charging mode is terminated.

2. The battery life extension method according to claim 1, characterized in that: The target charging power value is a safe reserve capacity.

3. The battery life extension method according to claim 1, characterized in that: The target charging power value is one or a combination of a safe standby capacity and a safe full-charge power.

4. The battery life extension method according to claim 3, characterized in that: The steps of ending the constant current charging mode include: When the charged capacity value is greater than the target charged capacity value, a safe full-charge voltage range is set according to the target charged capacity value, wherein the target charged capacity value is the safe full-charge capacity; sensing the battery cell group to obtain a voltage value; and When the voltage value is within the safe full-charge voltage range, the constant current charging mode is terminated.

5. The battery life extension method according to claim 3, characterized in that: The steps of ending the constant current charging mode include: When the charged capacity value is greater than the target charging capacity value, a safe full-charge voltage is set according to the target charging capacity value, wherein the target charging capacity value is the safe full-charge capacity; sensing the battery cell group to obtain a voltage value; and When the voltage value is equal to the safe full-charge voltage, the constant-current charging mode is terminated.

6. The battery life extension method according to claim 1, characterized in that: The step of ending the constant current charging mode also includes: The charger is notified to stop the charging operation on the battery pack through communication handshake.

7. The battery life extension method according to claim 1, characterized in that: The step of ending the constant current charging mode also includes: The battery cell group is controlled to cut off a charging circuit between the charger and the battery cell group to stop the charging operation.

8. The battery life extension method according to claim 1, characterized in that: It also includes the following steps: When the remaining power of the battery pack is equal to or less than a lower limit standby capacity or a lower limit storage voltage, the charging operation is started.

9. The battery life extension method according to claim 1, characterized in that: The step of calculating the charged value of the battery pack includes: Sensing current values ​​of a discharge circuit and a charge circuit of the battery pack to calculate a discharge quantity and a charge quantity respectively, wherein, during the charging operation, the discharge quantity is less than the charge quantity; and The charged capacity value is calculated based on the discharged capacity and the charged capacity. The relationship between the charged capacity values ​​is: Charged capacity value = initial remaining capacity + (charged capacity - discharged capacity).

10. The battery life extension method according to claim 1, characterized in that: The target charging capacity value is inversely proportional to the battery health state.

11. A battery module, connected to a load and a charger respectively, characterized in that: The battery module contains: a battery pack having a battery health status; and A battery management system is linked to the battery pack, sets a target charging power value according to the battery health state, and stops charging the battery pack when a charged amount of the battery pack under constant current charging mode is greater than the target charging power value, wherein the target charging power value is inversely proportional to the battery health state.

12. The battery module according to claim 11, characterized in that: The battery module further comprises: a switch, connecting the battery pack and the battery management system, and establishing a charging circuit with the charger and a discharging circuit with the load respectively; and A power calculation unit is linked to the battery management system and is used to sense the current values ​​on the charging circuit and the discharging circuit to respectively calculate a discharge power and a charge power, thereby obtaining the charged value of the battery pack.

13. The battery module according to claim 12, characterized in that: The battery management system controls the switch to cut off the charging circuit between the charger and the battery cell group to stop charging.

14. The battery module according to claim 11, characterized in that: The battery management system further includes: A communication module notifies the charger to start or stop charging the battery pack through communication handshake.

Images