Lithium battery system charging and discharging method, system and equipment

Abstract

The present application discloses a charging and discharging method, system and device for a lithium battery system, the charging and discharging method comprising: obtaining a first initial power of a first lithium battery group and a second initial power of a second lithium battery group; comparing the first initial power and the second initial power with a first preset power or a third preset power, respectively; in a charging stage, if at least one of the first initial power and the second initial power is less than the first preset power, charging the lithium battery group with less than the first preset power for the first time so that the power of the lithium battery group reaches the first preset power; then charging the two lithium battery groups for the second time in sequence so that the power of the two lithium battery groups is greater than or equal to the second preset power; in a discharging stage, if at least one of the first initial power and the second initial power is greater than the third preset power, discharging the lithium battery group with greater than the third preset power so that the power of the corresponding lithium battery group is equal to the third preset power.

Description

Technical Field

[0001] The present application relates to the field of lithium battery technology, and in particular to a charging and discharging method, system, and device for a lithium battery system. Background Art

[0002] With the rapid development of the new energy vehicle and battery energy storage industries, lithium-ion batteries, with their advantages such as high integration rate and large capacity, are widely used. However, in a lithium-ion battery system, once a cell triggers thermal runaway due to electrical, mechanical, or thermal abuse, it rapidly releases a large amount of heat due to a violent chain redox reaction. This energy can trigger thermal runaway in surrounding cells, triggering heat propagation and seriously threatening the safety of the battery system and users.

[0003] In the existing technology, thermal runaway is prevented by using advanced thermal management systems and multi-level battery management technologies, but the effect is poor and the design difficulty and cost of the battery system are greatly increased.

[0004] Therefore, how to prevent heat spread in lithium batteries is an urgent problem that needs to be solved. Summary of the Invention

[0005] The present application provides a charging and discharging method, system and device for a lithium battery system, aiming to prevent heat spread in the lithium battery.

[0006] On the one hand, an embodiment of the present application provides a charging and discharging method for a lithium battery system, wherein the lithium battery system includes a first lithium battery group, a second lithium battery group, and a battery management module, wherein the first lithium battery group and the second lithium battery group are insulated and arranged adjacent to each other, and the battery management module is electrically connected to the first lithium battery group and the second lithium battery group, respectively, and the battery management module is used to obtain the battery power of the first lithium battery group and the second lithium battery group. The charging and discharging method includes: in a charging stage or a discharging stage, obtaining a first initial power of the first lithium battery group and a second initial power of the second lithium battery group; comparing the first initial power and the second initial power with a first preset power or a third preset power, respectively; in the charging stage, if at least one of the first initial power and the second initial power is less than the first preset power, charging the first lithium battery group with a power less than the first preset power. At least one of the first lithium battery group and the second lithium battery group is charged for the first time, so that at least one of the first initial power and the second initial power is equal to the first preset power, wherein the first lithium battery group and the second lithium battery group are respectively charged for the first time in two adjacent and continuous time periods; after the first charging is completed, the first lithium battery group and the second lithium battery group are charged for the second time in sequence, so that the first target power of the first lithium battery group and the second target power of the second lithium battery group are both greater than or equal to the second preset power; in the discharging stage, if at least one of the first initial power and the second initial power is greater than the third preset power, at least one of the first lithium battery group and the second lithium battery group that is greater than the third preset power is discharged, so that at least one of the first initial power and the second initial power is equal to the third preset power.

[0007] Optionally, in some embodiments of the present application, the first lithium battery pack and the second lithium battery pack each include a plurality of sub-batteries, and the first preset power level is less than a thermal runaway triggering threshold power level.

[0008] Optionally, in some embodiments of the present application, if at least one of the first initial power and the second initial power is less than the first preset power, the step of charging at least one of the first lithium battery group and the second lithium battery group with a power less than the first preset power for the first time so that at least one of the first initial power and the second initial power is equal to the first preset power specifically includes: if the first initial power is less than the first preset power and the second initial power is greater than or equal to the first preset power, charging the first lithium battery group for the first time so that the first initial power is equal to the first preset power; or, if the second initial power is less than the first preset power and the first initial power is greater than or equal to the first preset power, charging the second lithium battery group for the first time so that the second initial power is equal to the first preset power; or, if the first initial power and the second initial power are both less than the first preset power, charging the first lithium battery group and the second lithium battery group for the first time in sequence so that the first initial power and the second initial power are both equal to the first preset power.

[0009] Optionally, in some embodiments of the present application, if the first initial power and the second initial power are both less than the first preset power, the first lithium battery group and the second lithium battery group are charged for the first time in sequence so that the first initial power and the second initial power are both equal to the first preset power. The steps specifically include: if the first initial power and the second initial power are equal to and both are less than the first preset power, the first lithium battery group and the second initial power are charged for the first time in sequence so that the first initial power and the second initial power are both equal to the first preset power; if the first initial power and the second initial power are not equal and both are less than the first preset power, the first initial power and the second initial power are compared, and the first lithium battery group and the second lithium battery group are charged for the first time in the order of large to small so that the first initial power and the second initial power are both equal to the first preset power.

[0010] Optionally, in some embodiments of the present application, the second preset power level is less than the battery power level corresponding to triggering thermal runaway after the sub-battery is laterally heated for a preset period of time by a heating block with a preset heating power.

[0011] Optionally, in some embodiments of the present application, the preset heating power is calculated according to the following formula: :

[0012]

[0013] in, 、 is the characteristic temperature of thermal runaway of lithium battery, The thermal runaway instability temperature of the battery in the Heat-Wait-Seek test of the Accelerating Rate Calorimeter (ARC) is The maximum temperature of thermal runaway of the battery in the Heat-Wait-Seek test of the Accelerating Rate Calorimeter (ARC). is the energy transfer correction factor, The preset duration for heating the side of the sub-battery. For the quality of the battery, is the specific heat capacity of the battery.

[0014] Optionally, in some embodiments of the present application, after the first charging is completed, the step of charging the first lithium battery group and the second lithium battery group for a second time in sequence so that the first target power of the first lithium battery group and the second target power of the second lithium battery group are both greater than or equal to the second preset power specifically includes: after the first charging is completed, if the first initial power and the second initial power are equal to and equal to the first preset power, charging the first lithium battery group and the second lithium battery group for a second time in sequence so that the first target power of the first lithium battery group and the second target power of the second lithium battery group are both equal to the second preset power; or, after the first charging is completed, if the first initial power and the second initial power are both less than the second preset power and are not equal, comparing the first initial power and the second initial power, and charging the first lithium battery group and the second lithium battery group for a second time in the order of larger first and smaller later, so that the first target power of the first lithium battery group and the second target power of the second lithium battery group are both equal to the second preset power.

[0015] Optionally, in some embodiments of the present application, the third preset power is equal to the first preset power.

[0016] Optionally, in some embodiments of the present application, in the discharging stage, if at least one of the first initial power and the second initial power is greater than the third preset power, the step of discharging at least one of the first lithium battery group and the second lithium battery group whose power is greater than the third preset power so that at least one of the first initial power and the second initial power is equal to the third preset power specifically includes: if the first initial power is greater than the third preset power and the second initial power is less than or equal to the third preset power, discharging the first lithium battery group so that the first initial power is equal to the third preset power; or, if the second initial power is greater than the third preset power and the first initial power is less than or equal to the third preset power, discharging the second lithium battery group so that the second initial power is equal to the third preset power; or, if both the first initial power and the second initial power are greater than the third preset power, discharging the first lithium battery group and the second lithium battery group in sequence so that both the first initial power and the second initial power are equal to the third preset power.

[0017] Optionally, in some embodiments of the present application, the charging and discharging method further includes: comparing the first initial power and the second initial power with a fourth preset power respectively; in the discharging stage, if at least one of the first initial power and the second initial power is greater than the fourth preset power, discharging at least one of the first lithium battery group and the second lithium battery group with a power greater than the fourth preset power for the first time, so that at least one of the first initial power and the second initial power is equal to the fourth preset power, wherein the first lithium battery group and the second lithium battery group are discharged for the first time in two adjacent and continuous time periods respectively; after the first discharge is completed, if at least one of the first initial power and the second initial power is greater than the third preset power, discharging at least one of the first lithium battery group and the second lithium battery group with a power greater than the third preset power for the second time, so that at least one of the first initial power and the second initial power is equal to the third preset power.

[0018] Optionally, in some embodiments of the present application, the fourth preset power is equal to the second preset power.

[0019] Optionally, in some embodiments of the present application, the fourth preset power level and the second preset power level both have a value range between 75% and 85% of the maximum power level of the sub-battery.

[0020] On the other hand, the present application provides a lithium battery system, including a first lithium battery group, a second lithium battery group and a battery management module, wherein the first lithium battery group and the second lithium battery group are insulated and arranged adjacent to each other; the battery management module is electrically connected to the first lithium battery group and the second lithium battery group, respectively, and the battery management module includes an acquisition unit and a control unit, wherein the acquisition unit is used to acquire a first initial power of the first lithium battery group and a second initial power of the second lithium battery group during a charging stage or a discharging stage, and compare the first initial power and the second initial power with a first preset power or a third preset power, respectively; the control unit is used to, during the charging stage, if at least one of the first initial power and the second initial power is less than the first preset power, perform a first charging operation on at least one of the first lithium battery group and the second lithium battery group having a power less than the first preset power The control unit is further configured to charge the first lithium battery group and the second lithium battery group for a second time in sequence after the first charging is completed, so that the first target power of the first lithium battery group and the second target power of the second lithium battery group are both greater than or equal to the second preset power; the control unit is further configured to discharge the first lithium battery group and the second lithium battery group that are greater than the third preset power if at least one of the first initial power and the second initial power is greater than the third preset power during the discharge phase, so that at least one of the first initial power and the second initial power is equal to the third preset power.

[0021] On the other hand, the present application also provides an electronic device, which is used to run a program, wherein the lithium battery charging and discharging method described above is executed when the program is running.

[0022] On the other hand, the present application also provides a computer storage medium, which includes a storage program, wherein when the storage program is running, the device where the storage medium is located is controlled to execute the lithium battery charging and discharging method as described above.

[0023] In the charging and discharging method, system and device of the lithium battery system provided in the present application, a first initial power of the first lithium battery group and a second initial power of the second lithium battery group are obtained in a charging stage or a discharging stage; the first initial power and the second initial power are compared with a first preset power or a third preset power respectively; in the charging stage, if at least one of the first initial power and the second initial power is less than the first preset power, at least one of the first lithium battery group and the second lithium battery group with a power less than the first preset power is charged for the first time, so that at least one of the first initial power and the second initial power is equal to the first preset power, wherein, in the two phases The first lithium battery group and the second lithium battery group are respectively charged for the first time in adjacent and continuous time periods; after the first charging is completed, the first lithium battery group and the second lithium battery group are sequentially charged for the second time, so that the first target power of the first lithium battery group and the second target power of the second lithium battery group are both greater than or equal to the second preset power; in the discharging stage, if at least one of the first initial power and the second initial power is greater than the third preset power, at least one of the first lithium battery group and the second lithium battery group that is greater than the third preset power is discharged, so that at least one of the first initial power and the second initial power is equal to the third preset power. That is, by connecting adjacent batteries in physical space to different circuits, a first lithium battery group and a second lithium battery group with different and independent states of charge are formed. This lithium battery system and the corresponding charging and discharging method can not only reduce the energy transferred to adjacent batteries through the tabs during battery thermal runaway, but also make the battery group with lower battery power adjacent to the battery group with higher battery power for most of the operating time. Based on the differences in thermal runaway behaviors of lithium batteries under different states of charge, the propagation of thermal runaway between battery groups is suppressed to a greater extent, thereby preventing heat spread in lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of the lithium battery system provided by this application;

[0025] Figure 2 This is a flow chart of the lithium battery system charging and discharging method provided by this application;

[0026] Figure 3 This is the first flow chart of the discharge phase in the lithium battery system charge and discharge method provided by this application;

[0027] Figure 4 This is the second flow chart of the discharge phase in the lithium battery system charge and discharge method provided by this application;

[0028] Figure 5This is the third flow chart of the discharge stage in the lithium battery system charging and discharging method provided in this application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. The described technical solutions are only used to explain and illustrate the ideas of the present application and should not be regarded as limiting the scope of protection of the present application.

[0030] The various embodiments provided in this application are similar, and features in different embodiments may be combined with each other.

[0031] like Figure 1 As shown, an embodiment of the present application provides a lithium battery system 100 , including a first lithium battery pack 10 , a second lithium battery pack 20 , and a battery management module 30 .

[0032] Specifically, the first lithium battery pack 10 and the second lithium battery pack 20 are insulated and arranged adjacent to each other. The first lithium battery pack 10 includes a plurality of first sub-batteries 11, and the second lithium battery pack 20 includes a plurality of second sub-batteries 21. Each first sub-battery 11 is arranged adjacent to at least one second sub-battery 21, so that during the majority of the operating time, battery packs with lower battery charges are adjacent to battery packs with higher battery charges. Based on the differences in thermal runaway behavior of lithium batteries at different states of charge (higher battery charges have higher chemical potential energy, resulting in more intense exothermic reactions during thermal runaway, and higher energy release rates and total energy released during thermal runaway, while lower battery charges have lower chemical potentials), the propagation of thermal runaway between battery packs is suppressed to a greater extent, thereby preventing heat spread in the lithium batteries.

[0033] It should be noted that Figure 1 The arrangement of the first lithium battery pack and the second lithium battery pack is only an example. The present application does not limit the specific arrangement of the first lithium battery pack and the second lithium battery pack, and those skilled in the art can adjust it according to actual needs.

[0034] Specifically, the battery management module 30 is electrically connected to the first lithium battery pack 10 and the second lithium battery pack 20 , respectively. The battery management module 30 includes an acquisition unit 31 and a control unit 32 .

[0035] Specifically, the acquisition unit 31 is configured to acquire a first initial charge of the first lithium battery pack 10 and a second initial charge of the second lithium battery pack 20 during a charging phase or a discharging phase, and compare the first initial charge and the second initial charge with a first preset charge or a third preset charge, respectively. The control unit 32 is configured to, during a charging phase, if at least one of the first initial charge and the second initial charge is less than the first preset charge, perform a first charge on at least one of the first lithium battery pack 10 and the second lithium battery pack 20 having a charge less than the first preset charge, so that at least one of the first initial charge and the second initial charge is equal to the first preset charge, wherein the first charge is performed on the first lithium battery pack 10 and the second lithium battery pack 20, respectively, within two adjacent and consecutive time periods.

[0036] Specifically, the control unit 32 is further configured to, after the first charge is completed, sequentially charge the first lithium battery pack 10 and the second lithium battery pack 20 for a second time, such that the first target charge of the first lithium battery pack 10 and the second target charge of the second lithium battery pack 20 are both greater than or equal to the second preset charge. The control unit 32 is further configured to, during the discharge phase, if at least one of the first initial charge and the second initial charge is greater than a third preset charge, discharge at least one of the first lithium battery pack 10 and the second lithium battery pack 20, which has a charge greater than the third preset charge, such that at least one of the first initial charge and the second initial charge is equal to the third preset charge.

[0037] The lithium battery system provided in the present application forms a first lithium battery group 10 and a second lithium battery group 20 with different and independent charge states by connecting adjacent batteries in physical space to different circuits. This lithium battery system and the corresponding charging and discharging method can not only reduce the energy transferred to adjacent batteries through the tabs during battery thermal runaway, but also enable battery groups with lower battery power to be adjacent to battery groups with higher battery power for most of the operating time. Based on the differences in thermal runaway behaviors of lithium batteries under different charge states, the propagation of thermal runaway between battery groups is suppressed to a greater extent, thereby preventing heat spread in lithium batteries.

[0038] like Figure 2 and Figure 3 As shown, an embodiment of the present application provides a charging and discharging method for a lithium battery system, the lithium battery system including a first lithium battery pack, a second lithium battery pack, and a battery management module. The first lithium battery pack and the second lithium battery pack are insulated and arranged adjacent to each other. The battery management module is electrically connected to the first lithium battery pack and the second lithium battery pack, respectively, and is used to obtain the battery power of the first lithium battery pack and the second lithium battery pack. The charging and discharging method includes:

[0039] S10. In a charging phase or a discharging phase, obtaining a first initial power of the first lithium battery pack and a second initial power of the second lithium battery pack.

[0040] By obtaining a first initial charge of the first lithium battery pack and a second initial charge of the second lithium battery pack, it is determined whether the charge and discharge conditions are met.

[0041] S20: Compare the first initial power level and the second initial power level with the first preset power level or the third preset power level respectively.

[0042] In an embodiment of the present application, each of the first and second lithium battery packs includes multiple sub-batteries (including a first and a second sub-battery), and the first predetermined charge level is less than a thermal runaway triggering threshold charge level. Specifically, the thermal runaway triggering threshold charge level can be the battery charge level set by the battery manufacturer for triggering thermal runaway, or the maximum battery charge level that will not trigger thermal runaway under heating conditions specified in the GB-38031-2020 standard, or later versions, Safety Requirements for Power Batteries for Electric Vehicles.

[0043] S30. During the charging stage, if at least one of the first initial power and the second initial power is less than the first preset power, the first lithium battery group and the second lithium battery group having a power less than the first preset power are charged for the first time, so that at least one of the first initial power and the second initial power is equal to the first preset power, wherein the first charging is performed on the first lithium battery group and the second lithium battery group respectively in two adjacent and continuous time periods.

[0044] In an embodiment of the present application, step S30 specifically includes:

[0045] As an embodiment of the present application: if the first initial power is less than the first preset power and the second initial power is greater than or equal to the first preset power, the first lithium battery pack is charged for the first time so that the first initial power is equal to the first preset power.

[0046] As another embodiment of the present application: if the second initial power is less than the first preset power and the first initial power is greater than or equal to the first preset power, the second lithium battery pack is charged for the first time so that the second initial power is equal to the first preset power.

[0047] As another embodiment of the present application: if the first initial power and the second initial power are both less than the first preset power, the first lithium battery pack and the second lithium battery pack are charged for the first time in sequence so that the first initial power and the second initial power are both equal to the first preset power.

[0048] Specifically, if the first initial power and the second initial power are equal and both are less than the first preset power, the first lithium battery pack and the second lithium battery pack are charged for the first time in sequence so that the first initial power and the second initial power are both equal to the first preset power.

[0049] Specifically, if the first initial power and the second initial power are not equal and are both less than the first preset power, the first initial power and the second initial power are compared, and the first lithium battery pack and the second lithium battery pack are charged for the first time in the order of large first and small later, so that the first initial power and the second initial power are both equal to the first preset power.

[0050] For example, the first initial power and the second initial power are not equal and are both less than the first preset power. After comparison, the first initial power is greater than the second initial power, then the first lithium battery pack is charged for the first time so that the first initial power is equal to the first preset power, and then the second lithium battery pack is charged for the first time so that the second initial power is equal to the first preset power.

[0051] On the contrary, the first initial power and the second initial power are not equal and are both less than the first preset power. After comparison, the second initial power is greater than the first initial power, then the second lithium battery pack is charged for the first time so that the second initial power is equal to the first preset power, and then the first lithium battery pack is charged for the first time so that the first initial power is equal to the first preset power.

[0052] S40: After the first charge is completed, charge the first lithium battery pack and the second lithium battery pack in sequence for a second time, so that the first target power of the first lithium battery pack and the second target power of the second lithium battery pack are both greater than or equal to the second preset power.

[0053] In an embodiment of the present application, the second preset power level is less than the battery power level at which thermal runaway is triggered after a heating block with a preset heating power is used to heat the side of a sub-battery for a preset period of time. Preferably, the second preset power level is the maximum battery power level at which thermal runaway is not triggered after a heating block with a preset heating power is used to heat the side (a relatively large side) of a sub-battery for a preset period of time.

[0054] In the embodiment of the present application, the preset heating power is calculated according to the following formula: :

[0055]

[0056] in, 、 is the characteristic temperature of thermal runaway of lithium battery, The thermal runaway instability temperature of the battery in the Heat-Wait-Seek test of the Accelerating Rate Calorimeter (ARC) is The maximum temperature of thermal runaway of the battery in the Heat-Wait-Seek test of the Accelerating Rate Calorimeter (ARC). is the energy transfer correction factor, The preset duration for heating the side of the sub-battery. For the quality of the battery, is the specific heat capacity of the battery.

[0057] In the embodiments of the present application, Refer to GB-38031-2020 which requires a time of not less than 5 minutes. Greater than or equal to 5 minutes.

[0058] In the embodiment of the present application, step S40 specifically includes:

[0059] As an embodiment of the present application: after the first charging is completed, if the first initial power and the second initial power are equal and both equal to the first preset power, the first lithium battery group and the second lithium battery group are charged for the second time in sequence, so that the first target power of the first lithium battery group and the second target power of the second lithium battery group are both equal to the second preset power.

[0060] As another embodiment of the present application: after the first charging is completed, if the first initial power and the second initial power are both less than the second preset power and are not equal, the first initial power and the second initial power are compared, and the first lithium battery group and the second lithium battery group are charged for the second time in the order of large first and small later, so that the first target power of the first lithium battery group and the second target power of the second lithium battery group are both equal to the second preset power.

[0061] In an embodiment of the present application, after step S40, the following steps are further included:

[0062] S41. Charge the first and second lithium battery packs for a third time, so that the power levels of the sub-batteries in the first and second lithium battery packs are both between 95% and 100%. Specifically, the power levels of the sub-batteries in the first and second lithium battery packs can be any one of 95%, 96%, 97%, 98%, 99%, and 100%. Preferably, after the third charge is completed, the power levels of the sub-batteries in the first and second lithium battery packs are both 100%.

[0063] As an embodiment of the present application, the first lithium battery pack and the second lithium battery pack are sequentially charged for a third time, so that the power levels of the sub-batteries in the first lithium battery pack and the second lithium battery pack are both between 95% and 100%. For example, the first lithium battery pack is first charged for a third time, so that the power levels of the sub-batteries in the first lithium battery pack reach 100%, and then the second lithium battery pack is charged for a third time, so that the power levels of the sub-batteries in the second lithium battery pack reach 100%.

[0064] As another embodiment of the present application: the first lithium battery pack and the second lithium battery pack are charged for a third time simultaneously, so that the power levels of the sub-batteries in the first lithium battery pack and the second lithium battery pack both reach 100%.

[0065] S50. In the discharge stage, if at least one of the first initial power and the second initial power is greater than the third preset power, at least one of the first lithium battery pack and the second lithium battery pack with a power greater than the third preset power is discharged so that at least one of the first initial power and the second initial power is equal to the third preset power.

[0066] It should be noted that Figure 1 As only one embodiment of the present application, the charging and discharging stages of the lithium battery pack are two independent stages, that is, the lithium battery pack only completes charging or completes discharging within a continuous period of time. In this case, step S50 is located after step S20. As another embodiment of the present application, the charging and discharging stages of the lithium battery pack can be two continuous stages, that is, the lithium battery pack is charged during the charging stage and is discharged within a set period of time after charging is completed to complete discharging. In this case, step S50 is located after step S40.

[0067] In the embodiment of the present application, the third preset power level is equal to the first preset power level. Preferably, the third preset power level and the first preset power level are both the maximum battery power levels corresponding to the sub-battery not triggering thermal runaway when heated in a manner described in GB-38031-2020 or later versions of Safety Requirements for Power Batteries for Electric Vehicles.

[0068] In the embodiment of the present application, step S50 specifically includes:

[0069] As an embodiment of the present application: if the first initial power level is greater than a third preset power level and the second initial power level is less than or equal to the third preset power level, the first lithium battery pack is discharged so that the first initial power level is equal to the third preset power level. Alternatively, if the second initial power level is greater than the third preset power level and the first initial power level is less than or equal to the third preset power level, the second lithium battery pack is discharged so that the second initial power level is equal to the third preset power level.

[0070] As an implementation mode of the present application: if the first initial power and the second initial power are both greater than the third preset power, the first lithium battery pack and the second lithium battery pack are discharged in sequence so that the first initial power and the second initial power are both equal to the third preset power.

[0071] like Figure 4 As shown, the charging and discharging method further includes:

[0072] S11 , comparing the first initial power level and the second initial power level with a fourth preset power level respectively.

[0073] S12. In the discharge stage, if at least one of the first initial power and the second initial power is greater than the fourth preset power, at least one of the first lithium battery group and the second lithium battery group whose power is greater than the fourth preset power is discharged for the first time, so that at least one of the first initial power and the second initial power is equal to the fourth preset power, wherein the first discharge of the first lithium battery group and the second lithium battery group is performed respectively in two adjacent and continuous time periods.

[0074] S13. After the first discharge is completed, if at least one of the first initial power level and the second initial power level is greater than a third preset power level, discharge at least one of the first lithium battery pack and the second lithium battery pack whose power level is greater than the third preset power level for a second time, so that at least one of the first initial power level and the second initial power level is equal to the third preset power level.

[0075] In the embodiment of the present application, the fourth preset power level is equal to the second preset power level. Preferably, the fourth preset power level and the second preset power level are the maximum battery power levels corresponding to the maximum battery power level at which thermal runaway will not be triggered after a heating block with a preset heating power is used to heat the side surface (the side with a relatively large area) of the sub-battery for a preset period of time.

[0076] In an embodiment of the present application, the fourth preset power level and the second preset power level both have a value range of 75% to 85% of the maximum power of the sub-battery. Specifically, the fourth preset power level and the second preset power level both have a value range of 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, and 85% of the maximum power of the sub-battery. Preferably, the fourth preset power level and the second preset power level both have a value range of 80% of the maximum power of the sub-battery.

[0077] like Figure 5 As shown, after step S13, the following steps are further included:

[0078] S14. After the second discharge is completed, the first lithium battery pack and the second lithium battery pack are discharged for a third time, so that the power levels of the sub-batteries in the first lithium battery pack and the second lithium battery pack are between 5% and 0%. Specifically, the power levels of the sub-batteries in the first lithium battery pack and the second lithium battery pack can be any one of 5%, 4%, 3%, 2%, 1%, and 0%. Preferably, after the third discharge is completed, the power levels of the sub-batteries in the first lithium battery pack and the second lithium battery pack are 0%.

[0079] As an embodiment of the present application, the first lithium battery pack and the second lithium battery pack are sequentially discharged for a third time, so that the power levels of the sub-batteries in the first lithium battery pack and the second lithium battery pack are both between 5% and 0%. For example, the first lithium battery pack is first charged for a third time, so that the power levels of the sub-batteries in the first lithium battery pack are 0%, and then the second lithium battery pack is discharged for a third time, so that the power levels of the sub-batteries in the second lithium battery pack are 0%.

[0080] As another embodiment of the present application: the first lithium battery pack and the second lithium battery pack are discharged for a third time simultaneously, so that the power levels of the sub-batteries in the first lithium battery pack and the second lithium battery pack are both 0%.

[0081] On the other hand, the present application also provides an electronic device, which is used to run a program, wherein the above-mentioned lithium battery charging and discharging method is executed when the program is running.

[0082] On the other hand, the present application also provides a computer storage medium, which includes a storage program, wherein when the storage program is running, the device where the storage medium is located is controlled to execute the above lithium battery charging and discharging method.

[0083] In the electronic device and computer storage medium of the lithium battery system provided herein, a first initial charge of a first lithium battery pack and a second initial charge of a second lithium battery pack are obtained during a charging phase or a discharging phase. The first initial charge and the second initial charge are compared with a first preset charge or a third preset charge, respectively. During the charging phase, if at least one of the first initial charge and the second initial charge is less than the first preset charge, a first charge is performed on at least one of the first lithium battery pack and the second lithium battery pack, which has a charge less than the first preset charge, so that at least one of the first initial charge and the second initial charge equals the first preset charge. The first charge is performed on the first lithium battery pack and the second lithium battery pack, respectively, during two adjacent and consecutive time periods. After the first charge is completed, a second charge is performed on the first lithium battery pack and the second lithium battery pack, respectively, so that the first target charge of the first lithium battery pack and the second target charge of the second lithium battery pack are both greater than or equal to the second preset charge. During the discharging phase, if at least one of the first initial charge and the second initial charge is greater than the third preset charge, the at least one of the first lithium battery pack and the second lithium battery pack, which has a charge greater than the third preset charge, is discharged so that at least one of the first initial charge and the second initial charge equals the third preset charge. That is, by connecting adjacent batteries in physical space to different circuits, a first lithium battery group and a second lithium battery group with different and independent states of charge are formed. This lithium battery system and the corresponding charging and discharging method can not only reduce the energy transferred to adjacent batteries through the tabs during battery thermal runaway, but also make the battery group with lower battery power adjacent to the battery group with higher battery power for most of the operating time. Based on the differences in thermal runaway behaviors of lithium batteries under different states of charge, the propagation of thermal runaway between battery groups is suppressed to a greater extent, thereby preventing heat spread in lithium batteries.

[0084] The above is a detailed introduction to the charging and discharging method, system and equipment of a lithium battery system input in the embodiments of the present application. The description of the above embodiments is only used to help understand the core idea of the present application, and the above description should not be understood as limiting the scope of protection of the present application.

Claims

1. A charging and discharging method for a lithium battery system, characterized in that: The lithium battery system includes a first lithium battery group, a second lithium battery group, and a battery management module. The first lithium battery group and the second lithium battery group are insulated and arranged adjacent to each other. The battery management module is electrically connected to the first lithium battery group and the second lithium battery group, respectively. The battery management module is used to obtain the battery power of the first lithium battery group and the second lithium battery group. The charging and discharging method includes: In a charging phase or a discharging phase, obtaining a first initial power of the first lithium battery pack and a second initial power of the second lithium battery pack; Comparing the first initial power level and the second initial power level with a first preset power level or a third preset power level, respectively; The first lithium battery pack and the second lithium battery pack each include a plurality of sub-batteries, and the first preset power is less than a thermal runaway triggering threshold power; In the charging stage, if at least one of the first initial power and the second initial power is less than the first preset power, at least one of the first lithium battery group and the second lithium battery group whose power is less than the first preset power is charged for the first time, so that at least one of the first initial power and the second initial power is equal to the first preset power. The first charging of the first lithium battery group and the second lithium battery group is performed in two adjacent and continuous time periods, respectively, specifically including: If the first initial power is less than the first preset power and the second initial power is greater than or equal to the first preset power, charging the first lithium battery pack for the first time so that the first initial power is equal to the first preset power; Alternatively, if the second initial power is less than the first preset power and the first initial power is greater than or equal to the first preset power, charging the second lithium battery pack for the first time so that the second initial power is equal to the first preset power; After the first charge is completed, charging the first lithium battery pack and the second lithium battery pack for a second time in sequence, so that the first target power of the first lithium battery pack and the second target power of the second lithium battery pack are both greater than or equal to a second preset power, wherein the second preset power ranges from 75% to 85% of the maximum power of the sub-battery; During the discharge stage, if at least one of the first initial power and the second initial power is greater than the third preset power, at least one of the first lithium battery pack and the second lithium battery pack with a power greater than the third preset power is discharged so that at least one of the first initial power and the second initial power is equal to the third preset power.

2. The charging and discharging method of the lithium battery system according to claim 1, characterized in that: If at least one of the first initial power and the second initial power is less than the first preset power, the step of charging at least one of the first lithium battery pack and the second lithium battery pack whose power is less than the first preset power for the first time so that at least one of the first initial power and the second initial power is equal to the first preset power specifically includes: If the first initial power and the second initial power are both less than the first preset power, the first lithium battery pack and the second lithium battery pack are charged for the first time in sequence so that the first initial power and the second initial power are both equal to the first preset power.

3. The charging and discharging method of the lithium battery system according to claim 2, characterized in that: If both the first initial power and the second initial power are less than the first preset power, the step of sequentially charging the first lithium battery pack and the second lithium battery pack for the first time so that both the first initial power and the second initial power are equal to the first preset power specifically includes: If the first initial power level and the second initial power level are equal and both are less than the first preset power level, charging the first lithium battery pack and the second lithium battery pack for the first time in sequence so that the first initial power level and the second initial power level are both equal to the first preset power level; If the first initial power level and the second initial power level are not equal and are both less than the first preset power level, the first initial power level and the second initial power level are compared, and the first lithium battery pack and the second lithium battery pack are charged for the first time in the order of large to small, so that the first initial power level and the second initial power level are both equal to the first preset power level.

4. The charging and discharging method of the lithium battery system according to claim 1, wherein: The second preset power level is less than the battery power level corresponding to triggering thermal runaway after the sub-battery is heated laterally by a heating block with a preset heating power for a preset time period.

5. The charging and discharging method of the lithium battery system according to claim 4, characterized in that: The preset heating power is calculated according to the following formula: : in, 、 is the characteristic temperature of thermal runaway of lithium battery, The thermal runaway instability temperature of the battery in the heat-wait-search test of the accelerated calorimeter, The maximum temperature of thermal runaway of the battery in the heat-wait-search test of the accelerated calorimeter, is the energy transfer correction factor, The preset duration for heating the side of the sub-battery. For the quality of the battery, is the specific heat capacity of the battery.

6. The charging and discharging method of the lithium battery system according to claim 4, characterized in that: The step of sequentially charging the first lithium battery pack and the second lithium battery pack for a second time after the first charging is completed so that the first target power of the first lithium battery pack and the second target power of the second lithium battery pack are both greater than or equal to the second preset power specifically includes: After the first charging is completed, if the first initial power level and the second initial power level are equal and both equal to the first preset power level, charging the first lithium battery pack and the second lithium battery pack for a second time in sequence so that the first target power level of the first lithium battery pack and the second target power level of the second lithium battery pack are both equal to the second preset power level; Alternatively, after the first charging is completed, if the first initial power and the second initial power are both less than the second preset power and are not equal, the first initial power and the second initial power are compared, and the first lithium battery group and the second lithium battery group are charged for a second time in the order of large to small, so that the first target power of the first lithium battery group and the second target power of the second lithium battery group are both equal to the second preset power.

7. A lithium battery system, characterized in that: The battery pack comprises a first lithium battery pack, a second lithium battery pack and a battery management module, wherein the first lithium battery pack and the second lithium battery pack are insulated and arranged adjacent to each other; The battery management module is electrically connected to the first lithium battery pack and the second lithium battery pack, respectively, and includes an acquisition unit and a control unit. The acquisition unit is used to obtain a first initial power of the first lithium battery pack and a second initial power of the second lithium battery pack during a charging stage or a discharging stage, and compare the first initial power and the second initial power with a first preset power or a third preset power, respectively. The first lithium battery pack and the second lithium battery pack each include a plurality of sub-batteries, and the first preset power is less than a thermal runaway trigger threshold power. The control unit is configured to, during the charging stage, if at least one of the first initial power and the second initial power is less than the first preset power, charge the first lithium battery pack and the second lithium battery pack, which have a power less than the first preset power, for the first time, so that at least one of the first initial power and the second initial power is equal to the first preset power. The first charging of the first lithium battery pack and the second lithium battery pack in two adjacent and continuous time periods specifically includes: if the first initial power is less than the first preset power and the second initial power is greater than or equal to the first preset power, charging the first lithium battery pack for the first time so that the first initial power is equal to the first preset power; Alternatively, if the second initial power is less than the first preset power and the first initial power is greater than or equal to the first preset power, charging the second lithium battery pack for the first time so that the second initial power is equal to the first preset power; The control unit is further configured to, after the first charging is completed, sequentially charge the first lithium battery pack and the second lithium battery pack for a second time, so that a first target power of the first lithium battery pack and a second target power of the second lithium battery pack are both greater than or equal to a second preset power, wherein the second preset power ranges from 75% to 85% of the maximum power of the sub-battery; The control unit is also used to, during the discharge stage, if at least one of the first initial power and the second initial power is greater than the third preset power, discharge at least one of the first lithium battery pack and the second lithium battery pack with a power greater than the third preset power, so that at least one of the first initial power and the second initial power is equal to the third preset power.

8. An electronic device, characterized in that: The electronic device is used to run a program, wherein the charging and discharging method for the lithium battery system according to any one of claims 1 to 6 is executed when the program is run.

9. A computer storage medium, characterized in that The storage medium includes a storage program, wherein when the storage program is running, the device where the storage medium is located is controlled to execute the charging and discharging method for the lithium battery system according to any one of claims 1 to 6.

Images