Charging and discharging method, system and equipment of lithium battery system

Abstract

The invention discloses a charging and discharging method, system and equipment of a lithium battery system. The charging and discharging method comprises the following steps: acquiring a first initial electric quantity of a first lithium battery pack and a second initial electric quantity of a second lithium battery pack; comparing the first initial electric quantity and the second initial electric quantity with a first preset electric quantity or a third preset electric quantity respectively; in the charging stage, if at least one of the first initial electric quantity and the second initial electric quantity is smaller than the first preset electric quantity, the lithium battery pack smaller than the first preset electric quantity is charged for the first time, so that the electric quantity of the lithium battery pack reaches the first preset electric quantity; then the two lithium battery packs are charged for the second time in sequence, so that the electric quantities of the two lithium battery packs are both larger than or equal to the second preset electric quantity; and in a discharging stage, if at least one of the first initial electric quantity and the second initial electric quantity is greater than a third preset electric quantity, discharging the lithium battery pack greater than the third preset electric quantity, so that the electric quantity of the corresponding lithium battery pack is equal to the third preset electric quantity.

Description

Technical Field

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

[0002] With the rapid development of new energy vehicles and battery energy storage industries, lithium-ion batteries with advantages such as high integration rate and large capacity are widely used. However, in a lithium-ion battery system, once a battery triggers thermal runaway due to electrical, mechanical, thermal abuse, etc., it will quickly release a large amount of heat due to the violent chain redox reaction. This part of energy may cause thermal runaway of surrounding batteries, thereby triggering heat spread, seriously threatening the safety of the battery system and users.

[0003] In the prior art, advanced thermal management systems and multi-level battery management technologies are used to prevent thermal runaway, 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 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, the lithium battery system comprising 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 comprises: 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 which is less than the first preset power. The first lithium battery group and at least one of the second lithium battery group 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 lithium battery group and the second lithium battery group are charged for the first time in two adjacent and continuous time periods respectively; 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 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 trigger 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 for the first time at least one of the first lithium battery group and the second lithium battery group whose power is less than the first preset power 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 equal to the first preset power. The step specifically includes: 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 lithium battery group are charged for the first time in sequence so that the first initial power and the second initial power are 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 sequence in the order of large to small, so that the first initial power and the second initial power are equal to the first preset power.

[0010] Optionally, in some embodiments of the present application, the second preset power is less than the battery power corresponding to thermal runaway triggered 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: : 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). 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 sub-battery sideways. For the quality of the battery, is the specific heat capacity of the battery.

[0012] 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 power first and smaller power 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.

[0013] Optionally, in some embodiments of the present application, the third preset power is equal to the first preset power.

[0014] 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 the first initial power and the second initial power are both greater than the third preset power, discharging the first lithium battery group and the second lithium battery group in sequence so that the first initial power and the second initial power are both equal to the third preset power.

[0015] 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, performing a first discharge on at least one of the first lithium battery group and the second lithium battery group that is greater than the fourth preset power, 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 respectively discharged for the first time in two adjacent and continuous time periods; 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, performing a second discharge on at least one of the first lithium battery group and the second lithium battery group that 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.

[0016] Optionally, in some embodiments of the present application, the fourth preset power is equal to the second preset power.

[0017] Optionally, in some embodiments of the present application, the value ranges of the fourth preset power level and the second preset power level are both between 75% and 85% of the maximum power level of the sub-battery.

[0018] 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 at least one of the first lithium battery group and the second lithium battery group that is greater than the third preset power during the discharge phase if at least one of the first initial power and the second initial 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.

[0019] 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 as described above is executed when the running program is running.

[0020] 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.

[0021] 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 respectively compared with a first preset power or a third preset 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, wherein in the two phases The first lithium battery group and the second lithium battery group are charged for the first time in adjacent and continuous time periods respectively; 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. 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 charge states 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 difference in thermal runaway behavior of lithium batteries under different charge states, the propagation of thermal runaway between battery groups can be suppressed to a greater extent, thereby preventing the thermal spread of lithium batteries. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a schematic diagram of a lithium battery system provided by the present application; Figure 2 is a flow chart of the lithium battery system charging and discharging method provided by the present application; Figure 3 This is the first flow chart of the discharge phase in the lithium battery system charge and discharge method provided by the present application; Figure 4 This is the second flow chart of the discharge phase in the lithium battery system charge and discharge method provided by the present application; Figure 5 This is the third flow chart of the discharge stage in the lithium battery system charge and discharge method provided in this application. DETAILED DESCRIPTION

[0023] 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.

[0024] The various embodiments provided in this application are similar, and features in different embodiments may be combined with each other.

[0025] 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 .

[0026] Specifically, the first lithium battery group 10 and the second lithium battery group 20 are insulated and arranged adjacent to each other. The first lithium battery group 10 includes a plurality of first sub-batteries 11, and the second lithium battery group 20 includes a plurality of second sub-batteries 21, and each first sub-battery 11 is arranged adjacent to at least one second sub-battery 21, so that during most of the operating time, the battery group with lower battery power is adjacent to the battery group with higher battery power, based on the difference in thermal runaway behavior under different states of charge of lithium batteries (high-power batteries have higher chemical potential energy, more violent exothermic reactions during thermal runaway, higher energy release rate and total energy released during thermal runaway, and lower vice versa), so as to suppress the propagation of thermal runaway between battery groups to a greater extent, thereby preventing the thermal spread of lithium batteries.

[0027] It should be noted that Figure 1 The arrangement of the first lithium battery group and the second lithium battery group is only an example. The present application does not limit the specific arrangement of the first lithium battery group and the second lithium battery group, and those skilled in the art can adjust it according to actual needs.

[0028] 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 .

[0029] Specifically, the acquisition unit 31 is used to acquire the first initial power of the first lithium battery group 10 and the second initial power of the second lithium battery group 20 during the charging stage or the discharging stage, and compare the first initial power and the second initial power with the first preset power or the third preset power, respectively. The control unit 32 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 the first charge on at least one of the first lithium battery group 10 and the second lithium battery group 20 whose power is less than the first preset power, 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 charge is performed on the first lithium battery group 10 and the second lithium battery group 20 respectively in two adjacent and continuous time periods.

[0030] Specifically, the control unit 32 is further configured to perform a second charge on the first lithium battery pack and the second lithium battery pack in sequence after the first charge is completed, so that the first target power of the first lithium battery pack 10 and the second target power of the second lithium battery pack 20 are both greater than or equal to the second preset power. The control unit 32 is also configured to discharge at least one of the first lithium battery pack 10 and the second lithium battery pack 20 whose power is greater than the third preset power during the discharge phase if at least one of the first initial power and the second initial 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.

[0031] The lithium battery system provided in the present application connects adjacent batteries in physical space to different circuits to form a first lithium battery group 10 and a second lithium battery group 20 with different charge states and independent of each other. This lithium battery system and the corresponding charging and discharging method can not only reduce the energy transferred to adjacent batteries through the pole ears during battery thermal runaway, but also enable battery groups with lower battery power to be adjacent to battery groups with higher battery power during 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.

[0032] 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 comprising 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, 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 comprises: S10. In a charging stage or a discharging stage, obtaining a first initial power of the first lithium battery pack and a second initial power of the second lithium battery pack.

[0033] By acquiring a first initial power of the first lithium battery pack and a second initial power of the second lithium battery pack, it is determined whether the charging and discharging conditions are met.

[0034] S20: Compare the first initial power and the second initial power with the first preset power or the third preset power respectively.

[0035] In an embodiment of the present application, the first lithium battery pack and the second lithium battery pack each include a plurality of sub-batteries (the sub-batteries include the first sub-battery and the second sub-battery), and the first preset power is less than the thermal runaway triggering threshold power. Specifically, the thermal runaway triggering threshold power can be the battery power corresponding to the triggering of thermal runaway set by the battery manufacturer, or the maximum battery power corresponding to the heating method that will not trigger thermal runaway according to the GB-38031-2020 standard or a newer version of the safety requirements for power batteries for electric vehicles.

[0036] 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, at least one of the first lithium battery group and the second lithium battery group having 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 the first charging of the first lithium battery group and the second lithium battery group is performed respectively in two adjacent and continuous time periods.

[0037] In the embodiment of the present application, step S30 specifically includes: As an implementation mode 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.

[0038] As another implementation 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.

[0039] As another implementation 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.

[0040] 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.

[0041] 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 group and the second lithium battery group 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.

[0042] 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, so 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.

[0043] 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.

[0044] S40. After the first charging is completed, the first lithium battery group and the second lithium battery group are charged 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.

[0045] In an embodiment of the present application, the second preset power is less than the battery power corresponding to the thermal runaway triggered after the side heating of the sub-battery is performed for a preset period of time by the heating block with a preset heating power. Preferably, the second preset power is the maximum battery power corresponding to the thermal runaway not triggered after the side heating (the side with a relatively large area) of the sub-battery is performed for a preset period of time by the heating block with a preset heating power.

[0046] In the embodiment of the present application, 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-Seek test of the Accelerating Rate Calorimeter (ARC). 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 sub-battery sideways. For the quality of the battery, is the specific heat capacity of the battery.

[0047] In the embodiments of the present application, Refer to GB-38031-2020 which requires no less than 5 minutes. Greater than or equal to 5 minutes.

[0048] In the embodiment of the present application, step S40 specifically includes: As an implementation mode 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 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.

[0049] As another implementation mode 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 a 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.

[0050] In an embodiment of the present application, after step S40, the following steps are further included: S41, charging the first lithium battery group and the second lithium battery group for the third time, so that the power of the sub-batteries in the first lithium battery group and the second lithium battery group is between 95% and 100%. Specifically, the power of the sub-batteries in the first lithium battery group and the second lithium battery group includes any one of 95%, 96%, 97%, 98%, 99%, and 100%. Preferably, after the third charging is completed, the power of the sub-batteries in the first lithium battery group and the second lithium battery group is 100%.

[0051] As an implementation of the present application: the first lithium battery group and the second lithium battery group are charged for the third time in sequence, so that the power of the sub-batteries in the first lithium battery group and the second lithium battery group is between 95% and 100%. For example, the first lithium battery group is charged for the third time first, so that the power of the sub-batteries in the first lithium battery group reaches 100%, and then the second lithium battery group is charged for the third time, so that the power of the sub-batteries in the second lithium battery group reaches 100%.

[0052] As another implementation of the present application: the first lithium battery pack and the second lithium battery pack are charged for a third time at the same time, so that the power levels of the sub-batteries in the first lithium battery pack and the second lithium battery pack both reach 100%.

[0053] 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 whose power 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.

[0054] It should be noted that Figure 1 As only one embodiment of the present application, the charging stage and the discharging stage of the lithium battery pack are two independent stages, that is, in a continuous period of time, the lithium battery pack only completes charging or completes discharging, in this case, step S50 is located after step S20. As other embodiments of the present application, the charging stage and the discharging stage of the lithium battery pack can be two continuous stages, that is, the lithium battery pack is charged in the charging stage, and is discharged within a set period of time after the charging is completed to complete the discharging, in this case, step S50 is located after step S40.

[0055] In an embodiment of the present application, the third preset power is equal to the first preset power. Preferably, the third preset power and the first preset power are both the maximum battery power corresponding to the sub-battery not triggering thermal runaway under the heating method described in GB-38031-2020 or a newer version of the safety requirements for power batteries for electric vehicles.

[0056] In the embodiment of the present application, step S50 specifically includes: As an implementation mode of the present application: 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, the first lithium battery pack is discharged so that the first initial power is equal to the third preset power. Alternatively, 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, the second lithium battery pack is discharged so that the second initial power is equal to the third preset power.

[0057] 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.

[0058] like Figure 4 As shown, the charging and discharging method further includes: S11, comparing the first initial power and the second initial power with a fourth preset power respectively.

[0059] 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 in two adjacent and continuous time periods respectively.

[0060] S13. 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, a second discharge is performed on at least one of the first lithium battery pack and the second lithium battery pack 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.

[0061] In an embodiment of the present application, the fourth preset power is equal to the second preset power. Preferably, the fourth preset power and the second preset power are the maximum battery power corresponding to the thermal runaway not being triggered after the heating block with a preset heating power is used to heat the side (the side with a relatively large area) of the sub-battery for a preset period of time.

[0062] In an embodiment 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. Specifically, the fourth preset power level and the second preset power level both have values ​​of 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84% and 85% of the maximum power level of the sub-battery. Preferably, the fourth preset power level and the second preset power level are both 80% of the maximum power level of the sub-battery.

[0063] like Figure 5 As shown, after step S13, the following steps are also included: S14. After the second discharge is completed, the first lithium battery group and the second lithium battery group are discharged for the third time, so that the power of the sub-batteries in the first lithium battery group and the second lithium battery group is between 5% and 0%. Specifically, the power of the sub-batteries in the first lithium battery group and the second lithium battery group includes any one of 5%, 4%, 3%, 2%, 1%, and 0%. Preferably, after the third discharge is completed, the power of the sub-batteries in the first lithium battery group and the second lithium battery group is 0%.

[0064] As an implementation mode of the present application: the first lithium battery group and the second lithium battery group are discharged for the third time in sequence, so that the power of the sub-batteries in the first lithium battery group and the second lithium battery group is between 5% and 0%. For example, the first lithium battery group is charged for the third time, so that the power of the sub-batteries in the first lithium battery group is 0%, and then the second lithium battery group is discharged for the third time, so that the power of the sub-batteries in the second lithium battery group is 0%.

[0065] As another implementation manner of the present application: the first lithium battery group and the second lithium battery group are discharged for a third time at the same time, so that the power levels of the sub-batteries in the first lithium battery group and the second lithium battery group are both 0%.

[0066] On the other hand, the present application also provides an electronic device, which is used to run a program, wherein the above lithium battery charging and discharging method is executed when the program is running.

[0067] On the other hand, the present application also provides a computer storage medium, 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 above lithium battery charging and discharging method.

[0068] In the electronic device and computer storage medium of the lithium battery system provided by the present application, the first initial power of the first lithium battery group and the second initial power of the second lithium battery group are obtained in the charging stage or the discharging stage. The first initial power and the second initial power are compared with the first preset power or the 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, the first charging is performed on at least one of the first lithium battery group and the second lithium battery group whose power is less than the first preset power, 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. 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 whose power 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 charge states 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 difference in thermal runaway behavior of lithium batteries under different charge states, the propagation of thermal runaway between battery groups can be suppressed to a greater extent, thereby preventing the thermal spread of lithium batteries.

[0069] 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, and the charging and discharging method includes: In a charging stage or a discharging stage, 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 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, 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, 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; After the first charging is completed, charging the first lithium battery group and the second lithium battery group for a second time in sequence, so that a first target power of the first lithium battery group and a second target power of the second lithium battery group are both greater than or equal to a second preset power; 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 group and the second lithium battery group 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: 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.

3. The charging and discharging method of a lithium battery system according to claim 1 or 2, 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 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; Alternatively, 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.

4. The charging and discharging method of the lithium battery system according to claim 3, characterized in that: If the first initial power and the second initial power are both 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 the first initial power and the second initial power are both equal to the first preset power specifically includes: If the first initial power and the second initial power are equal and both are less than the first preset power, charging the first lithium battery pack and the second lithium battery pack 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 are both less than the first preset power, compare the first initial power and the second initial power, and charge the first lithium battery pack and the second lithium battery pack 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.

5. The charging and discharging method of a lithium battery system according to claim 2, characterized in that: The second preset power level is less than the battery power level corresponding to thermal runaway triggered after the sub-battery is heated laterally for a preset period of time by a heating block with a preset heating power.

6. The charging and discharging method of the lithium battery system according to claim 5, 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 sub-battery sideways. For the quality of the battery, is the specific heat capacity of the battery.

7. The charging and discharging method of a lithium battery system according to claim 5, 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 and the second initial power are equal and equal to the first preset power, the first lithium battery group and the second lithium battery group are charged 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 equal to the second preset power; 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, compare the first initial power and the second initial power, and charge the first lithium battery group and the second lithium battery group 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.

8. The charging and discharging method of a lithium battery system according to claim 1 or 2, characterized in that: The third preset power is equal to the first preset power.

9. The charging and discharging method of the lithium battery system according to claim 8, characterized in that: 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 pack and the second lithium battery pack 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 pack so that the first initial power is equal to the third preset power; Alternatively, 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, the second lithium battery pack is discharged so that the second initial power is equal to the third preset power; Alternatively, 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.

10. The charging and discharging method of a lithium battery system according to claim 2, characterized in that: The charging and discharging method further comprises: 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, 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 is performed on the first lithium battery group and the second lithium battery group respectively in two adjacent and continuous time periods; 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, a second discharge is performed on at least one of the first lithium battery pack and the second lithium battery pack 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.

11. The charging and discharging method of a lithium battery system according to claim 10, characterized in that: The fourth preset power is equal to the second preset power.

12. The charging and discharging method of a lithium battery system according to claim 10, characterized in that: The value ranges of the fourth preset power level and the second preset power level are both between 75% and 85% of the maximum power level of the sub-battery.

13. A lithium battery system, characterized in that: It 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; The battery management module is electrically connected to the first lithium battery pack and the second lithium battery pack, respectively, and comprises an acquisition unit and a control unit, wherein the acquisition unit is used to acquire 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 control unit is used for, 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 for the first time at least one of the first lithium battery group and the second lithium battery group whose power is less than the first preset power, 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; The control unit is further configured to charge the first lithium battery pack and the second lithium battery pack in sequence for a second time after the first charging is completed, 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; The control unit is also used to discharge at least one of the first lithium battery pack and the second lithium battery pack whose power is greater than the third preset power 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, so that at least one of the first initial power and the second initial power is equal to the third preset power.

14. An electronic device, characterized in that: The electronic device is used to run a program, wherein the lithium battery charging and discharging method according to any one of claims 1 to 12 is executed when the program is run.

15. 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 lithium battery charging and discharging method as described in any one of claims 1-12.

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