阅读说明：本技术 一种电池组中单体电池的均衡控制系统、方法和汽车 (Balanced control system and method for single batteries in battery pack and automobile ) 是由 郭伟林 牛高产 滕云龙 刘敏通 胡友涛 于 2021-07-29 设计创作，主要内容包括：本发明公开了一种电池组中单体电池的均衡控制系统、方法和汽车,该装置包括：每个主动均衡单元,对一组单体电池串中的每个单体电池的电池参数进行采样；通讯单元,实现相邻两个主动均衡单元之间的通讯；控制单元,在所有主动均衡单元之间通讯的情况下,根据每个单体电池的电池参数,在需要对一组单体电池串中的相应单体电池进行主动均衡控制的情况下,发送主动均衡指令；每个主动均衡单元,在接收到主动均衡指令的情况下,对一组单体电池串中的相应单体电池的电池参数进行主动均衡处理。该方案,通过对电池组中单体电池在充放电过程中进行均衡控制,防止电池组在充放电过程中出现过充与过放现象,有利于延长电池组的使用寿命。(The invention discloses a system and a method for balancing and controlling single batteries in a battery pack and an automobile, wherein the device comprises the following components: each active equalization unit is used for sampling the battery parameters of each single battery in a group of single battery strings; the communication unit is used for realizing communication between two adjacent active equalization units; the control unit is used for sending an active equalization instruction under the condition that the active equalization unit communicates with each other and the corresponding single batteries in a group of single battery strings need to be actively equalized and controlled according to the battery parameters of each single battery; and each active equalization unit is used for actively equalizing the battery parameters of the corresponding single batteries in the group of single battery strings under the condition of receiving the active equalization instruction. This scheme, through carrying out equalizing control to monomer battery in the group battery at the charge-discharge in-process, prevent that the group battery from appearing overcharging and overdischarging phenomenon at the charge-discharge in-process, be favorable to prolonging the life of group battery.)

1. A system for controlling the balance of single batteries in a battery pack, wherein the battery pack comprises: a set number of cells; the set number of single batteries form more than two groups of single battery strings;

the balancing control system of the single batteries in the battery pack comprises: the device comprises an active equalization unit, a communication unit and a control unit; the number of the active equalization units is the same as the number of the single battery strings; each active equalization unit corresponds to a group of single battery strings; the communication unit is arranged between two adjacent active equalization units; wherein the content of the first and second substances,

each active equalization unit is configured to sample the battery parameters of each single battery in a group of single battery strings in more than two groups of single battery strings;

the communication unit is configured to realize communication between two adjacent active equalization units;

the control unit is configured to determine whether active equalization control needs to be performed on corresponding single batteries in a group of single battery strings according to battery parameters of each single battery in the group of single battery strings obtained through sampling under the condition that all the active equalization units communicate with each other, and send an active equalization instruction under the condition that the active equalization control needs to be performed on the corresponding single batteries in the group of single battery strings;

each active equalization unit is further configured to perform active equalization processing on battery parameters of corresponding single batteries in a group of single battery strings under the condition that the active equalization instruction is received.

2. The system for controlling the balance of the single batteries in the battery pack according to claim 1, wherein each active balancing unit is further connected to a set direct current power supply; the battery parameters include: a voltage parameter;

each active equalization unit performs active equalization processing on battery parameters of corresponding single batteries in a group of single battery strings, and the active equalization processing comprises the following steps:

and actively equalizing the battery parameters of the corresponding single batteries in the group of single battery strings through the set direct-current power supply so as to realize the active equalization of the voltage parameters of the corresponding single batteries in the group of single battery strings.

3. The system for controlling the balancing of the unit cells in the battery pack according to claim 2, wherein each of the active balancing units comprises: the device comprises a sampling unit, a battery gating unit, a phase change unit and a balancing unit; wherein the content of the first and second substances,

each active equalization unit samples battery parameters of each single battery in a group of single battery strings, and the active equalization unit comprises:

the sampling unit is configured to sample a voltage parameter of each single battery in a group of single battery strings;

each active equalization unit performs active equalization processing on battery parameters of corresponding single batteries in a group of single battery strings through the set direct-current power supply, and the active equalization processing comprises the following steps:

the battery gating unit is configured to gate corresponding single batteries in a group of single battery strings according to the active balancing instruction under the condition that the active balancing instruction is received;

the phase commutation unit is configured to perform phase commutation processing on the positive and negative conditions of the corresponding single batteries in the gated single battery strings so that the corresponding single batteries in the gated single battery strings can be connected to the equalization unit in a set output mode;

the balancing unit is configured to control voltage parameter balancing processing between the single battery and the set direct-current power supply for the corresponding single battery in a group of single battery strings connected to the balancing unit.

4. The system for controlling the balance of the single batteries in the battery pack according to claim 3, wherein the sampling unit comprises: a chip of type LTC 6811;

the battery gating unit includes: a first switching tube unit;

the commutation cell includes: a second switching tube unit;

the equalization unit includes: and a transformer balancing unit.

5. The system for controlling the balancing of the unit batteries in the battery pack according to any one of claims 1 to 4, wherein each of the active balancing units further comprises: a battery temperature sampling unit; the battery parameters further include: a temperature parameter;

each active equalization unit samples battery parameters of each battery cell in a group of battery cell strings, and the active equalization unit further comprises:

the battery temperature sampling unit is configured to sample the temperature parameter of each single battery in a group of single battery strings;

each active equalization unit performs active equalization processing on battery parameters of corresponding single batteries in a group of single battery strings, and the active equalization unit further comprises:

and actively equalizing the battery parameters of the corresponding single batteries in the group of single battery strings through the set temperature control equipment so as to realize the active equalization of the temperature parameters of the corresponding single batteries in the group of single battery strings.

6. The system for controlling the balance of the unit batteries in the battery pack according to any one of claims 1 to 4, wherein the communication unit comprises: a capacitive isolation communication unit;

and under the condition that the number of the active equalization units is three, the number of the capacitive isolation communication units is two.

7. The system for controlling the balance among the single batteries in the battery pack according to claim 6, wherein the capacitive isolation communication unit comprises: the resistor module comprises a capacitor module and a pair of resistor modules which are symmetrically arranged at two ends of the capacitor module; and the pair of resistance modules are respectively connected with the two adjacent active equalization units.

8. The system for controlling the balance of the unit cells in the battery pack according to any one of claims 1 to 4, further comprising: an isolation unit; the isolation unit includes: at least one of a communication isolation unit and a drive isolation unit; wherein the content of the first and second substances,

under the condition that the isolation unit comprises a communication isolation unit, the communication isolation unit is arranged in more than two active equalization units, and the communication signals between the more than two active equalization units and the control unit are isolated by the communication isolation unit between the last active equalization unit and the control unit;

in the case that the isolation unit includes a drive isolation unit, the drive isolation unit is disposed between the control unit and each of the active equalization units, and configured to perform isolation processing on a drive signal of each of the active equalization units.

9. The system of claim 8, wherein in the case where the isolation unit includes a communication isolation unit, the communication isolation unit includes: a chip of type SI8641 ED;

in a case where the isolation unit includes a drive isolation unit, the drive isolation unit includes: an opto-isolator.

10. An automobile, comprising: the system for controlling the balance of the unit cells in the battery pack according to any one of claims 1 to 9.

11. A method for controlling the balance of individual cells in a battery pack, the battery pack comprising: a set number of cells; the set number of single batteries form more than two groups of single battery strings;

the method for controlling the balance of the single batteries in the battery pack comprises the following steps:

through each active equalization unit, aiming at each single battery in one group of single battery strings in more than two groups of single battery strings, sampling battery parameters of each single battery in the group of single battery strings; the number of the active equalization units is the same as the number of the single battery strings; each active equalization unit corresponds to a group of single battery strings;

the communication between two adjacent active equalization units is realized through a communication unit; the communication unit is arranged between the two adjacent active equalization units;

through the control unit, under the condition of communication among all the active equalization units, determining whether active equalization control needs to be carried out on corresponding single batteries in a group of single battery strings according to the battery parameters of each single battery in the group of single battery strings obtained through sampling, and sending an active equalization instruction under the condition that the active equalization control needs to be carried out on the corresponding single batteries in the group of single battery strings;

and through each active equalization unit, under the condition of receiving the active equalization instruction, performing active equalization processing on the battery parameters of the corresponding single batteries in a group of single battery strings.

Technical Field

The invention belongs to the technical field of battery management, particularly relates to a system and a method for balancing and controlling single batteries in a battery pack and an automobile, and particularly relates to a system and a method for actively balancing and controlling the single batteries of a new energy electric automobile and an automobile.

Background

In a new energy automobile (i.e., a new energy electric automobile) system, no matter a Hybrid Electric Vehicle (HEV) or an Electric Vehicle (EV), an automobile power battery as an energy storage medium cannot be used. Lithium ion batteries (i.e., lithium batteries) have already occupied the dominant position of automobile power batteries, and in order to achieve longer driving range, a plurality of batteries are generally required to be connected in series and/or in parallel to form a battery pack for use. Considering the energy, power and environmental requirements of automobiles, it is absolutely not a simple task to safely and reliably use large lithium ion battery packs. Therefore, a proper battery management system is needed to perform balance control on the single batteries in the battery pack in the charging and discharging process, so that the advantages of the novel lithium battery can be fully utilized.

The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.

Disclosure of Invention

The invention aims to provide a system and a method for controlling the balance of single batteries in a battery pack and an automobile, which aim to solve the problem that the service life of the battery pack is influenced by the phenomena of overcharge and overdischarge in the charging and discharging processes of the battery pack, achieve the effect of preventing the phenomena of overcharge and overdischarge in the charging and discharging processes of the battery pack by performing the balance control on the single batteries in the battery pack, and be beneficial to prolonging the service life of the battery pack.

The invention provides a battery pack in a balancing control system of single batteries, which comprises: a set number of cells; the set number of single batteries form more than two groups of single battery strings; the balancing control system of the single batteries in the battery pack comprises: the device comprises an active equalization unit, a communication unit and a control unit; the number of the active equalization units is the same as the number of the single battery strings; each active equalization unit corresponds to a group of single battery strings; the communication unit is arranged between two adjacent active equalization units; each active equalization unit is configured to sample a battery parameter of each single battery in a group of single battery strings in more than two groups of single battery strings; the communication unit is configured to realize communication between two adjacent active equalization units; the control unit is configured to determine whether active equalization control needs to be performed on corresponding single batteries in a group of single battery strings according to battery parameters of each single battery in the group of single battery strings obtained through sampling under the condition that all the active equalization units communicate with each other, and send an active equalization instruction under the condition that the active equalization control needs to be performed on the corresponding single batteries in the group of single battery strings; each active equalization unit is further configured to perform active equalization processing on battery parameters of corresponding single batteries in a group of single battery strings under the condition that the active equalization instruction is received.

In some embodiments, each active equalization unit is further connected to a set dc power supply; the battery parameters include: a voltage parameter; each active equalization unit performs active equalization processing on battery parameters of corresponding single batteries in a group of single battery strings, and the active equalization processing comprises the following steps: and actively equalizing the battery parameters of the corresponding single batteries in the group of single battery strings through the set direct-current power supply so as to realize the active equalization of the voltage parameters of the corresponding single batteries in the group of single battery strings.

In some embodiments, each of the active equalization units comprises: the device comprises a sampling unit, a battery gating unit, a phase change unit and a balancing unit; wherein, every initiative equalizing unit samples the battery parameter of every battery cell in a set of battery cell string, includes: the sampling unit is configured to sample a voltage parameter of each single battery in a group of single battery strings; each active equalization unit performs active equalization processing on battery parameters of corresponding single batteries in a group of single battery strings through the set direct-current power supply, and the active equalization processing comprises the following steps: the battery gating unit is configured to gate corresponding single batteries in a group of single battery strings according to the active balancing instruction under the condition that the active balancing instruction is received; the phase commutation unit is configured to perform phase commutation processing on the positive and negative conditions of the corresponding single batteries in the gated single battery strings so that the corresponding single batteries in the gated single battery strings can be connected to the equalization unit in a set output mode; the balancing unit is configured to control voltage parameter balancing processing between the single battery and the set direct-current power supply for the corresponding single battery in a group of single battery strings connected to the balancing unit.

In some embodiments, the sampling unit includes: a chip of type LTC 6811; the battery gating unit includes: a first switching tube unit; the commutation cell includes: a second switching tube unit; the equalization unit includes: and a transformer balancing unit.

In some embodiments, each of the active equalization units further comprises: a battery temperature sampling unit; the battery parameters further include: a temperature parameter; each active equalization unit samples battery parameters of each battery cell in a group of battery cell strings, and the active equalization unit further comprises: the battery temperature sampling unit is configured to sample the temperature parameter of each single battery in a group of single battery strings; each active equalization unit performs active equalization processing on battery parameters of corresponding single batteries in a group of single battery strings, and the active equalization unit further comprises: and actively equalizing the battery parameters of the corresponding single batteries in the group of single battery strings through the set temperature control equipment so as to realize the active equalization of the temperature parameters of the corresponding single batteries in the group of single battery strings.

In some embodiments, the communication unit comprises: a capacitive isolation communication unit; and under the condition that the number of the active equalization units is three, the number of the capacitive isolation communication units is two.

In some embodiments, the capacitively isolated communication unit comprises: the resistor module comprises a capacitor module and a pair of resistor modules which are symmetrically arranged at two ends of the capacitor module; and the pair of resistance modules are respectively connected with the two adjacent active equalization units.

In some embodiments, further comprising: an isolation unit; the isolation unit includes: at least one of a communication isolation unit and a drive isolation unit; under the condition that the isolation unit comprises a communication isolation unit, the communication isolation unit is arranged in more than two active equalization units, and the communication isolation unit is arranged between the last active equalization unit and the control unit and is configured to isolate communication signals between the more than two active equalization units and the control unit; in the case that the isolation unit includes a drive isolation unit, the drive isolation unit is disposed between the control unit and each of the active equalization units, and configured to perform isolation processing on a drive signal of each of the active equalization units.

In some embodiments, where the isolation unit comprises a communication isolation unit, the communication isolation unit comprises: a chip of type SI8641 ED; in a case where the isolation unit includes a drive isolation unit, the drive isolation unit includes: an opto-isolator.

In accordance with the above system, a further aspect of the present invention provides an automobile comprising: the balancing control system for the single batteries in the battery pack is described above.

In a further aspect, the present invention provides a method for controlling balancing of unit cells in a battery pack, where the battery pack includes: a set number of cells; the set number of single batteries form more than two groups of single battery strings; the method for controlling the balance of the single batteries in the battery pack comprises the following steps: through each active equalization unit, aiming at each single battery in one group of single battery strings in more than two groups of single battery strings, sampling battery parameters of each single battery in the group of single battery strings; the number of the active equalization units is the same as the number of the single battery strings; each active equalization unit corresponds to a group of single battery strings; the communication between two adjacent active equalization units is realized through a communication unit; the communication unit is arranged between the two adjacent active equalization units; through the control unit, under the condition of communication among all the active equalization units, determining whether active equalization control needs to be carried out on corresponding single batteries in a group of single battery strings according to the battery parameters of each single battery in the group of single battery strings obtained through sampling, and sending an active equalization instruction under the condition that the active equalization control needs to be carried out on the corresponding single batteries in the group of single battery strings; and through each active equalization unit, under the condition of receiving the active equalization instruction, performing active equalization processing on the battery parameters of the corresponding single batteries in a group of single battery strings.

Therefore, according to the scheme of the invention, more than two paths of bidirectional active equalization are carried out aiming at the single batteries in the battery pack, wherein each group of single battery strings adopts one path of active equalization circuit to carry out active equalization; therefore, the single batteries in the battery pack are subjected to balance control in the charging and discharging process, the overcharge and overdischarge phenomena of the battery pack in the charging and discharging process are prevented, and the service life of the battery pack is prolonged.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.

Drawings

Fig. 1 is a schematic structural diagram of an embodiment of a balancing control system for single batteries in a battery pack according to the present invention;

FIG. 2 is a schematic diagram of an embodiment of an active equalization control system;

FIG. 3 is a schematic diagram of an embodiment of a capacitively isolated communication unit;

FIG. 4 is a schematic structural diagram of an embodiment of a battery temperature sampling unit;

FIG. 5 is a schematic diagram of an embodiment of a battery gating cell;

FIG. 6 is a schematic structural diagram of an embodiment of a commutation cell;

FIG. 7 is a schematic structural diagram of an embodiment of a transformer equalizing unit;

FIG. 8 is a schematic structural diagram of an embodiment of an isolated drive unit;

fig. 9 is a flowchart illustrating a method for controlling the balancing of the unit cells in the battery pack according to an embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the production process of the battery, the factors such as the process cause that each single battery has slight difference in the aspects of capacity and internal resistance; in the series use process, the use method is not proper, so that the slight difference is gradually increased. Such differences occur in the voltage of the same or similar type of battery. When the battery pack is charged in series, the battery with small capacity can be fully charged in the same time, and the battery with large capacity is not fully charged; when a large-capacity battery is fully charged, a small-capacity unit battery may be in an overcharged state. When discharging, the battery with small capacity is discharged first, and the battery with large capacity is not discharged yet, at this time, the battery with small capacity may be in an over-discharge state. Such overcharging and overdischarging can form a vicious cycle, resulting in a cell that varies significantly after many cycles of charging and discharging even if the initial variation is small, which, without some measure to give effective control, can result in a cell of small capacity in the battery pack prematurely ending its useful life. According to the principle of the 'wooden barrel short plate', the single battery with small capacity can influence the use effect of the whole battery pack, so that the whole battery pack cannot provide rated voltage and capacity for the outside, and the single battery with the depleted capacity is a large resistor and can continuously consume the energy of the battery pack. Moreover, the small-capacity single battery also aggravates the service life attenuation of the whole battery pack, and in severe cases, potential safety hazards and accidents are also generated. Therefore, effective control of this large difference in hazards is necessary. The voltage equalization is to control the voltage difference of the single batteries in the battery pack within a reasonable range through the balance of energy.

In the production process of the lithium power battery core, each lithium power battery monomer has slight difference, namely the problem of consistency, and the inconsistency is mainly expressed in the aspects of the capacity, the internal resistance, the self-discharge efficiency, the charge and discharge efficiency and the like of the lithium power battery monomer. The inconsistency of the lithium power battery monomer is conducted to the lithium power battery pack, which inevitably brings about the capacity loss of the lithium power battery pack, and further causes the reduction of the service life. In the using process of the assembled vehicle of the lithium power battery, the phenomenon of single body inconsistency can also occur due to the self-discharge degree, the part temperature and the like, and the single body inconsistency of the lithium power battery further influences the charging and discharging characteristics of the lithium power battery pack. And the capacity difference of 20% of the lithium power battery monomer brings about 40% capacity loss of the lithium power battery pack.

According to an embodiment of the present invention, there is provided a balancing control system of unit batteries in a battery pack. Referring to fig. 1, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The battery pack includes: a set number of cells. The set number of single batteries form more than two groups of single battery strings.

The balancing control system of the single batteries in the battery pack comprises: the device comprises an active equalization unit, a communication unit and a control unit. The number of the active equalization units is the same as the number of the single battery strings. Each active equalization unit corresponds to one group of single battery strings. And the communication unit is arranged between two adjacent active equalization units. Each active equalization unit is connected to the control unit.

Each active equalization unit is configured to sample a battery parameter of each single battery in a group of single battery strings in more than two groups of single battery strings.

The communication unit is configured to realize communication between two adjacent active equalization units.

The control unit is configured to determine whether active equalization control needs to be performed on corresponding single batteries in a group of single battery strings according to battery parameters of each single battery in the group of single battery strings obtained through sampling under the condition that communication is performed between all the active equalization units, for example, under the condition that communication is performed between two LTCs 6811, and send an active equalization instruction under the condition that active equalization control needs to be performed on corresponding single batteries in the group of single battery strings.

Each active equalization unit is further configured to perform active equalization processing on battery parameters of corresponding single batteries in a group of single battery strings under the condition that the active equalization instruction is received.

According to the scheme provided by the invention, the single battery active equalization control system of the new energy electric vehicle is provided, more than two paths of active equalization are simultaneously carried out, the equalization efficiency can be improved, the phenomena of overcharge and overdischarge of the battery in the charging and discharging processes are prevented, the service life of the battery is prolonged, the equalization efficiency is high, and the service life of the battery is prolonged. Therefore, the service life of the battery pack can be prolonged by effectively solving the battery difference phenomenon, the size and the cost of the controller can be reduced, and the low-cost integration at the current stage has great competitive advantage.

In some embodiments, each of the active equalization units is further connected to a set dc power supply (e.g., a 24V dc power supply). The battery parameters include: a voltage parameter.

Each active equalization unit performs active equalization processing on battery parameters of corresponding single batteries in a group of single battery strings, and the active equalization processing comprises the following steps: and actively equalizing the battery parameters of the corresponding single batteries in the group of single battery strings through the set direct-current power supply so as to realize the active equalization of the voltage parameters of the corresponding single batteries in the group of single battery strings.

Fig. 2 is a schematic structural diagram of an embodiment of an active equalization control system. In the example shown in fig. 2, the first active equalization circuit, the second active equalization circuit, and the third active equalization circuit have the same structure. In a first active equalization circuit, comprising: the device comprises an LTC6811 battery voltage and temperature acquisition unit (such as a sampling chip LTC6811 and a battery temperature sampling unit), a battery gating unit, a phase change unit and a transformer equalization unit. For example: and each 12 strings of the 36 strings of single batteries are sampled by adopting a sampling chip LTC6811, and 3-path bidirectional equalization can be performed, so that the equalization efficiency during equalization is greatly improved. The balance can prevent the overcharge and overdischarge phenomena of the battery in the charge and discharge process, so that the voltage of the battery is kept in a reasonable range, the battery is not damaged, and the service life of the battery is prolonged. Therefore, more than two paths of bidirectional active equalization, preferably more than 3 paths of bidirectional active equalization, can improve the equalization efficiency, prevent the overcharge and overdischarge phenomena of the battery in the charge and discharge process, prolong the service life of the battery, have high equalization efficiency and prolong the service life of the battery.

In some embodiments, each of the active equalization units comprises: the device comprises a sampling unit, a battery gating unit, a phase change unit and an equalizing unit.

Wherein, every initiative equalizing unit samples the battery parameter of every battery cell in a set of battery cell string, includes: the sampling unit is configured to sample a voltage parameter of each single battery in a group of single battery strings.

Each active equalization unit performs active equalization processing on battery parameters of corresponding single batteries in a group of single battery strings through the set direct-current power supply, and the active equalization processing comprises the following steps:

the battery gating unit is configured to gate corresponding single batteries in a group of single battery strings according to the active balancing instruction under the condition that the active balancing instruction is received.

The phase changing unit is configured to perform phase changing processing according to the positive and negative conditions of the corresponding single batteries in the gated single battery string group, so that the corresponding single batteries in the gated single battery string group can be connected to the balancing unit in a set output mode.

The balancing unit is configured to control voltage parameter balancing processing between the single battery and the set direct-current power supply for the corresponding single battery in a group of single battery strings connected to the balancing unit.

In some embodiments, the sampling unit includes: chip type LTC 6811.

In the LTC6811 battery voltage and temperature acquisition unit, the sampling chip LTC6811 is a battery pack monitor with a plurality of batteries, and mainly comprises a battery voltage acquisition function (pin C)₀-C₁₂) Balanced driving function (pin S)₁-S₁₂) A battery temperature sampling function (GPIO0-GPIO4) and a communication function (IP, IM). The isolation chip SI8641ED (i.e. the isolation chip with model number SI8641 ED) is a communication isolation interface, and its main function is to isolate the strong current cell side from the weak current 24V side to ensure that the information transmission is normal and not interfered, wherein, pin a of the isolation chip SI8641ED₁-A₄And pin B₁-B₄And is a four-wire interface for communication. The MCU is a main control unit, and the main work function of the MCU comprises communication work function and driving function.

The battery gating unit includes: and the first switching tube unit comprises a triode and two MOS tubes.

Fig. 5 is a schematic structural diagram of an embodiment of a battery gating unit. The battery gating unit as shown in fig. 5 includes: two resistors (e.g., a first resistor and a second resistor),The transistor and two MOS tubes (such as a first MOS tube and a second MOS tube). One end of the first resistor is connected to the equalizing drive function pin S of the sampling chip LTC6811_N(N is a natural number), and the other end of the first resistor is connected to the base of the triode. The emitter of the triode is connected to a battery voltage acquisition function pin C of a sampling chip LTC6811_N(N is a natural number). And the collector electrode of the triode is connected to the grid electrode of the first MOS tube, connected to the grid electrode of the second MOS tube, and connected to the drain electrode of the first MOS tube and the drain electrode of the second MOS tube after passing through the second resistor. The source electrode of the first MOS tube is connected to a battery voltage acquisition functional pin C of a sampling chip LTC6811_N+3(N is a natural number). The source electrode of the second MOS tube is also connected to a battery voltage acquisition function pin C of the sampling chip LTC6811_N+3(N is a natural number). The battery gating unit can monitor the voltage of 12 strings of single batteries by the sampling chip LTC6811, and only one path of equalization is performed each time, and the specific equalization of which path needs the gating unit shown in fig. 5 to complete. The gating path is related to sampling, is determined by feedback after sampling, and is controlled by a program.

In the related scheme, the main chip is adopted to send out the driving signal for gate driving, and the scheme of the invention directly sends out the driving signal for gate driving through the sampling chip LTC6811, thereby not only reducing the design of peripheral circuits, but also improving the utilization rate of the sampling chip.

The commutation cell includes: and the second switching tube unit is provided with four MOS tubes.

FIG. 6 is a schematic structural diagram of an embodiment of a commutation cell. As shown in fig. 6, the commutation cell includes: and four MOS tubes, such as a first MOS tube, a second MOS tube, a third MOS tube and a fourth MOS tube. The grid electrode of the first MOS tube is used for receiving a driving signal PWM1, the drain electrode of the first MOS tube is connected to the drain electrode of the second MOS tube, and the source electrode of the first MOS tube is connected to the drain electrode of the third MOS tube. The grid electrode of the second MOS tube is used for receiving the driving signal PWM2, and the source electrode of the second MOS tube is connected with the drain electrode of the fourth MOS tube. And the source electrode of the third MOS tube is connected with the source electrode of the fourth MOS tube. The gate of the third MOS transistor is used for receiving the driving signal PWM2, and the gate of the fourth MOS transistor is used for receiving the driving signal PWM 1. Since the phase shifting unit may be positive, negative, or positive, the phase shifting unit shown in fig. 5 needs to perform phase shifting to make the output terminals thereof be positive, negative, or negative, in order to ensure that the terminals connected to the transformer are balanced, positive, negative, or negative. The PWM1 is turned on as above positive bottom negative and PWM2 is turned on as below positive top negative.

The four MOS tubes are used for carrying out phase change operation on the high-voltage side, so that the balance normal operation of different single batteries is ensured.

The equalization unit includes: and a transformer balancing unit.

Fig. 7 is a schematic structural diagram of an embodiment of a transformer equalizing unit. As shown in fig. 7, the transformer equalizing unit includes: the circuit comprises a transformer, a first capacitor, a second capacitor, a third capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a diode, a first MOS tube, a second MOS tube, a third MOS tube and a fourth MOS tube. The first capacitor can be an electrolytic capacitor, the anode of the first capacitor is connected to one end of the primary winding of the transformer, and the other end of the primary winding of the transformer is connected to the source electrode of the second MOS tube. The cathode of the first capacitor is connected to the source electrode of the first MOS tube through the first resistor. The drain electrode of the first MOS tube is connected with the drain electrode of the second MOS tube, and the drain electrode of the first MOS tube is also connected to the grid electrode of the first MOS tube and the grid electrode of the second MOS tube after passing through the second resistor. The gate of the first MOS transistor is used for receiving the driving signal PWM 3.

The second capacitor can be an electrolytic capacitor. The anode of the second capacitor is connected to the cathode of the diode after passing through the third capacitor, and is also connected to one end of the primary winding of the transformer. And the fifth resistor is connected with the third capacitor in parallel. And the cathode of the second capacitor is connected to the anode of the diode and is also connected to the source electrode of the fourth MOS tube through the fourth resistor. And the other end of the primary winding of the transformer is connected to the source electrode of the third MOS tube.

The drain electrode of the third MOS tube is connected with the drain electrode of the fourth MOS tube, and the drain electrode of the third MOS tube is also connected to the grid electrode of the third MOS tube and the grid electrode of the fourth MOS tube after passing through the second resistor. The gate of the third MOS transistor is used for receiving the driving signal PWM 4. The equalizing transformer in the transformer equalizing unit is the center of energy conversion of the whole equalizing circuit, and energy of the equalizing transformer is transmitted by controlling the on and off of switching tubes (such as four MOS tubes) so as to achieve the aim of equalization. The energy is transmitted in two directions in the equalizing process through the transformer by the interactive opening of the driving signal PWM3 and the driving signal PWM 4.

In some embodiments, each of the active equalization units further comprises: and a battery temperature sampling unit. The battery parameters further include: a temperature parameter.

Each active equalization unit samples battery parameters of each battery cell in a group of battery cell strings, and the active equalization unit further comprises: the battery temperature sampling unit is configured to sample the temperature parameter of each single battery in a group of single battery strings.

Each active equalization unit performs active equalization processing on battery parameters of corresponding single batteries in a group of single battery strings, and the active equalization unit further comprises: and actively equalizing the battery parameters of the corresponding single batteries in the group of single battery strings through the set temperature control equipment so as to realize the active equalization of the temperature parameters of the corresponding single batteries in the group of single battery strings.

Fig. 4 is a schematic structural diagram of an embodiment of a battery temperature sampling unit. As shown in fig. 4, the battery temperature sampling unit includes: capacitance, resistance and NTC resistance (negative temperature coefficient thermistor). One end of the resistor is connected to a GPIO terminal (general purpose input/output) of the sampling chip LTC6811, and is connected to a CO terminal of the sampling chip LTC6811 through a capacitor. The CO terminal, corresponding to the total negative of the 12 cells, corresponds to the ground of this LTC 6811.

The other end of the resistor is also connected to the CO terminal of the sampling chip LTC6811 via another capacitor, and is also connected to a dc power supply such as a 3V power supply via an NTC resistor. The battery temperature sampling unit displays the change of the battery temperature by measuring the change of the NTC resistance voltage, monitors the battery temperature and prevents the battery from working in a low-temperature environment and causing explosion danger when the battery is too high in temperature.

In some embodiments, the communication unit comprises: the capacitor isolates the communication unit.

And under the condition that the number of the active equalization units is three, the number of the capacitive isolation communication units is two.

In the example shown in fig. 2, the first capacitance communication circuit and the second capacitance communication circuit have the same configuration. A first capacitive communication circuit, comprising: the capacitor isolates the communication unit. And a capacitor is adopted to replace a transformer for communication. And the volume of the controller can be reduced by adopting capacitance communication. For example: the communication between the sampling chips LTC6811 (the sampling chip of the model LTC 6811) replaces the transformer communication by the characteristic that the capacitor separates direct connection and intersection, has outstanding advantages on the requirement of integration, and can effectively reduce the volume of a circuit board.

In some embodiments, the capacitively isolated communication unit comprises: the circuit comprises a capacitor module and a pair of resistor modules symmetrically arranged at two ends of the capacitor module. And the pair of resistance modules are respectively connected with the two adjacent active equalization units.

Fig. 3 is a schematic structural diagram of an embodiment of a capacitive isolation communication unit. Capacitive modules, such as the first capacitor and the second capacitor in fig. 3. Resistor modules, such as the five resistors in fig. 3. As shown in fig. 3, the capacitive isolation communication unit includes: the circuit comprises a first resistance module, a first capacitor, a second capacitor and a second resistance module. The first resistance module and the second resistance module have the same structure and are symmetrically arranged at two ends of the first capacitor and the second capacitor. A first resistance module comprising: and the five resistors are connected in series and parallel, wherein the first four resistors are connected in series two by two and then are respectively connected to two ends of the fifth resistor. And two ends of the fifth resistor are also respectively connected to one end of the first capacitor and one end of the second capacitor. The main function of the capacitance isolation communication unit is to perform communication between adjacent sampling chips LTC6811, so as to ensure the reception and transmission of information, and the volume of the controller can be effectively reduced by adopting capacitance communication. In the related scheme, a transformer is mostly adopted for isolation, and the occupied space is large. The scheme of the invention adopts the capacitance isolation communication, thereby not only reducing the volume, but also reducing the cost.

In some embodiments, further comprising: and an isolation unit. The isolation unit includes: at least one of a communication isolation unit and a drive isolation unit. Wherein the content of the first and second substances,

under the condition that the isolation unit comprises a communication isolation unit, the communication isolation unit is arranged in more than two active equalization units, and the communication signals between the more than two active equalization units and the control unit are isolated by the communication isolation unit between the last active equalization unit and the control unit.

In the case that the isolation unit includes a drive isolation unit, the drive isolation unit is disposed between the control unit and each of the active equalization units, and configured to perform isolation processing on a drive signal of each of the active equalization units.

In some embodiments, where the isolation unit comprises a communication isolation unit, the communication isolation unit comprises: chip model SI8641 ED.

In the example shown in fig. 2, the communication isolation circuit includes: the SI8641ED communication interface isolates the units. An isolated drive circuit comprising: the drive unit is isolated. And the interface isolator is adopted for communication isolation, so that the cost can be reduced. For example: the interface isolator is used for communication isolation between strong current and weak current, and compared with a transformer and an isolation chip with the type of LTC6820, the cost can be effectively reduced.

In a case where the isolation unit includes a drive isolation unit, the drive isolation unit includes: an opto-isolator.

As shown in fig. 2, the active equalization control system includes: the circuit comprises three active equalization circuits (namely a first active equalization circuit, a second active equalization circuit and a third active equalization circuit), a first capacitor communication circuit, a second capacitor communication circuit, a communication isolation circuit and an isolation driving circuit. And the three active equalizing circuits are all connected to a 24V direct-current power supply. The first capacitance communication circuit is arranged between the first active equalization circuit and the second active equalization circuit. And the second capacitance communication circuit is arranged between the second active equalization circuit and the third active equalization circuit. And the communication isolation circuit is arranged between the third active equalization circuit and the main control unit (such as the MCU). And the isolation driving circuit is connected to the main control unit.

Fig. 8 is a schematic structural diagram of an embodiment of an isolation driving unit. As shown in fig. 8, the isolation driving unit includes: an opto-isolator. The input end of the isolation driving unit is connected to the MCU, and the output end of the isolation driving unit is connected to the output end of a driving signal, such as the output end of a corresponding PWM signal, so that the isolation and amplification of the control signal are carried out, and the normal conduction and the normal disconnection of the switching tube can be ensured.

In the scheme of the invention, 3 sampling chips LTC6811 simultaneously acquire voltages of 36 single batteries, five battery voltages are detected every 12, detection information of the five battery voltages is transmitted through a capacitance isolation communication unit shown in fig. 2, and finally the detection information is connected to an MCU through an isolation chip SI8641ED as a communication isolation interface, the MCU determines balanced single batteries by judging and feeding back to the sampling chips LTC6811, the sampling chips LTC6811 themselves transmit driving signals to complete gating of the required balanced batteries, and simultaneously transmit PWM control signals to drive a switching tube in fig. 6 and fig. 7 to perform phase change and energy transmission through an isolation driving unit shown in fig. 8, so as to finally complete balancing operation.

By adopting the technical scheme of the invention, more than two paths of bidirectional active equalization are carried out aiming at the single batteries in the battery pack, wherein each group of single battery strings adopts one path of active equalization circuit to carry out active equalization. Therefore, the single batteries in the battery pack are subjected to balance control in the charging and discharging process, the overcharge and overdischarge phenomena of the battery pack in the charging and discharging process are prevented, and the service life of the battery pack is prolonged.

According to the embodiment of the invention, the automobile corresponding to the balance control system of the single batteries in the battery pack is also provided. The automobile may include: the balancing control system for the single batteries in the battery pack is described above.

Since the processing and functions of the automobile of this embodiment are basically corresponding to the embodiments, principles and examples of the foregoing devices, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.

By adopting the technical scheme of the invention, more than two paths of bidirectional active equalization are carried out aiming at the monocells in the battery pack, wherein each group of single battery strings adopts one path of active equalization circuit for active equalization, so that the battery difference phenomenon can be effectively solved, and the service life of the battery pack is prolonged.

According to the embodiment of the invention, a method for controlling the balance of the single batteries in the battery pack corresponding to the automobile is also provided, as shown in fig. 9, which is a schematic flow chart of an embodiment of the method of the invention. The battery pack includes: a set number of cells. The set number of single batteries form more than two groups of single battery strings.

The method for controlling the balance of the single batteries in the battery pack comprises the following steps: step S110 to step S140.

At step S110, by each active balancing unit, for each cell in a group of cell strings in two or more groups of cell strings, a battery parameter of each cell in the group of cell strings is sampled. The number of the active equalization units is the same as the number of the groups of the single battery strings. Each active equalization unit corresponds to one group of single battery strings.

At step S120, communication between two adjacent active equalization units is implemented through the communication unit. And the communication unit is arranged between the two adjacent active equalization units.

In step S130, under the condition that all the active balancing units communicate with each other, the control unit determines whether active balancing control needs to be performed on corresponding single batteries in a group of single battery strings according to the battery parameters of each single battery in the group of single battery strings obtained by sampling, and sends an active balancing instruction under the condition that active balancing control needs to be performed on corresponding single batteries in the group of single battery strings. And each active equalization unit is connected to the control unit.

In step S140, by each active equalization unit, performing active equalization processing on battery parameters of a corresponding battery cell in a group of battery cell strings when the active equalization instruction is received.

According to the scheme provided by the invention, the single battery active equalization control system of the new energy electric vehicle is provided, more than two paths of active equalization are simultaneously carried out, the equalization efficiency can be improved, the phenomena of overcharge and overdischarge of the battery in the charging and discharging processes are prevented, the service life of the battery is prolonged, the equalization efficiency is high, and the service life of the battery is prolonged. Therefore, the service life of the battery pack can be prolonged by effectively solving the battery difference phenomenon, the size and the cost of the controller can be reduced, and the low-cost integration at the current stage has great competitive advantage.

Since the processing and functions implemented by the method of this embodiment substantially correspond to the embodiments, principles and examples of the automobile, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment, which is not described herein.

By adopting the technical scheme of the embodiment, more than two paths of bidirectional active equalization are performed on the monocells in the battery pack, wherein each group of single battery strings adopt one path of active equalization circuit for active equalization, so that the voltage of the battery is kept in a reasonable range, the battery is not damaged, and the service life of the battery is prolonged.

In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.

The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.