Modular battery, uninterruptible power supply, direct current screen and two-wheeled / three-wheeled electric vehicle battery system
By incorporating a battery management control module and a discharge freewheeling diode in the modular battery system, the problems of complex structure and high cost of large battery systems are solved, achieving low-cost, highly compatible, and safe redundant battery management, suitable for uninterruptible power supplies, DC power supplies, and two-wheeled/three-wheeled electric vehicles.
Patent Information
- Application Number
- CN202422435041.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-09
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2034-10-09
AI Technical Summary
Existing large-scale battery systems are complex in structure and expensive, and the cost of battery management systems accounts for a high proportion in high-voltage, small-capacity energy storage scenarios, which hinders the industrialization and promotion of lithium batteries to replace lead-acid batteries.
The modular battery system is adopted, with each battery module including a battery management control module. It uses a charge/discharge control switch and a discharge freewheeling diode to achieve overcharge and over-discharge protection. No signal lines are required between modules. It utilizes existing power switches and voltage detection integrated circuits and is compatible with traditional chargers.
It reduces the cost of the battery system's BMS, improves scalability and compatibility, and is suitable for uninterruptible power supplies, DC power supplies, and two-wheeled/three-wheeled electric vehicles, achieving safety redundancy protection and high cost-effectiveness.
Smart Images
Figure CN223729462U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a modular battery system, in particular, to the bypass function of the battery module by using a freewheeling diode, reducing the voltage stress of the discharge control switch, effectively reducing the cost and complexity, especially suitable for uninterruptible power supply, DC screen and two-wheel / three-wheel electric light vehicle fields. BACKGROUND
[0002] Most large battery systems currently use a hierarchical centralized battery management (BMS) scheme. Signal lines for isolated communication must be configured between modules, and external high-voltage boxes and other system master controls must be used. The overall structure is complex, the cost is high, and it is not conducive to production, transportation, and after-sales maintenance. In addition, for some uninterruptible power supply (UPS) and DC screen and household energy storage applications, high voltages in the range of 100-500V are required, while the capacity of the energy storage battery is relatively small. The cost of the battery management system is high, which seriously hinders the industrialization and promotion of lithium battery replacement for lead-acid batteries.
[0003] In order to solve the standard modularization problem of large battery systems, patent CN2022103641990 provides a distributed battery management system scheme based on a switch array. In theory, this scheme has strong battery equalization performance and software configurable ability. However, its main defect is that two power electronic switches need to be configured for each string of battery cells, which is difficult to implement and has a high cost. In order to further simplify the design, patent CN2022104955321 treats the entire battery module as a management object and uses two electronic switches for software control to achieve a compromise between the complexity of the switch array and the technical performance of the battery. This scheme is convenient for implementing overcharge and overdischarge protection functions of the battery, but for battery overcurrent and short circuit protection functions, a large number of discrete devices must be used to build peripheral circuits to achieve the functions, and a large number of existing mature ICs are useless. Moreover, unlike conventional battery systems, the total voltage of the battery system may gradually decrease during the charging process. Therefore, the charger is not compatible and must be specially customized, which increases the cost.
[0004] Compared with the prior art, the application has the following three advantages. First, the standard modular characteristics are retained. Only the positive and negative power lines of the battery modules are connected in sequence, without any signal line for isolating communication, and the application is fully compatible with the conventional lead-acid battery application mode. Second, the discharge control switch of the battery module only needs to meet the voltage specification of the battery module itself, and is irrelevant to the total voltage of the battery system accumulated by the series connection of multiple battery modules. Finally, the application is convenient for integrated design. The existing various power switches and voltage detection and protection integrated circuits can be fully utilized to realize various functions such as battery overcharge, overdischarge and short-circuit protection, and a custom charger is not needed, and a conventional lead-acid battery charger can be normally used. Therefore, the application can greatly reduce the BMS cost of the battery system, has excellent scalability and compatibility, and is expected to become an important application technology in the field of "lead to lithium". SUMMARY
[0005] The application aims to provide a modular battery system composed of one battery module or multiple battery modules connected in series. Each battery module includes a battery pack and a battery management control module, and the battery management control module includes a battery state parameter detection and charge-discharge control protection module. The charge-discharge control protection module includes a charge control switch and a discharge control switch as well as a discharge freewheeling diode. The charge control switch realizes the overcharge protection function of the battery, and the discharge control switch realizes the overdischarge protection function of the battery. The discharge freewheeling diode enables other battery modules to continue discharging when the battery module itself stops discharging and the discharge control switch of the battery module is disconnected.
[0006] The battery can be a lithium ion battery, a sodium ion battery, a solid-state battery, a nickel-hydrogen battery, a nickel-cadmium battery and other types of rechargeable batteries.
[0007] The charge-discharge control switch can use a relay, a triode, a MOSFET, an IGBT and other switching devices, and multiple switching devices can be further connected in series or parallel to meet the current, voltage parameter or reliability requirements.
[0008] The discharge freewheeling diode can use a single or multiple discrete devices connected in parallel or a high-power diode module.
[0009] In a preferred embodiment, the cathode of the discharge freewheeling diode is connected to the positive electrode of the battery module, and the anode of the discharge freewheeling diode is connected to the negative electrode of the battery module.
[0010] In a preferred embodiment, the charge-discharge control switch uses an N-type power MOSFET device and is placed on the negative side of the battery pack. The cathode of the discharge freewheeling diode is connected to the positive pole of the battery pack, and the anode of the discharge freewheeling diode is connected to the drain of the discharge control MOSFET or the source of the charge control MOSFET.
[0011] In a preferred embodiment, the battery state parameter detection module measures signals such as voltage, current, or temperature of a single string of batteries using an analog front-end chip (AFE), and calculates and identifies abnormal risks such as overcharging, over-discharging, or overheating of the batteries, and then sends the risks to the charge-discharge control module to trigger protection actions.
[0012] In a preferred embodiment, the battery module also has a wireless communication function, which can send wireless signals to other battery modules or external charge-discharge equipment to achieve safe and redundant protection of the batteries when the function of the self charge-discharge control protection module unexpectedly fails.
[0013] Another object of the present application is to provide an uninterruptible power supply system comprising the modular battery system in any of the above embodiments and a UPS host that can be used with long-term existing lead-acid battery products on the market.
[0014] Another object of the present application is to provide a DC screen comprising the modular battery system in any of the above embodiments and a DC screen power electronic module that can be used with long-term existing lead-acid battery products on the market.
[0015] Another object of the present application is to provide a two-wheel / three-wheel electric vehicle battery system comprising the modular battery system in any of the above embodiments and a matching charge-discharge device that can be used with long-term existing lead-acid battery products on the market. BRIEF DESCRIPTION OF DRAWINGS
[0016] Figure 1 A functional structure block diagram of the modular battery system provided by the present application is shown.
[0017] Figure 2 An implementation scheme of a battery module is shown.
[0018] Figure 3 Another implementation scheme of a battery module is shown. DETAILED DESCRIPTION
[0019] In order to make the purposes, technical solutions and beneficial technical effects of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.
[0020] As Figure 1 shown, the present application provides a modular battery system, each battery module 101 comprising a battery pack 102 and a battery management and control module 106. The battery management and control module 106 comprises a battery state parameter detection module 103, a charge and discharge control switch 105 and a discharge freewheeling diode 104. The battery state parameter detection module 103 detects the state information such as voltage, current or temperature of each battery in real time, and outputs a battery protection signal to the charge and discharge control switch module 105 when overcharging, overdischarging, overcurrent or overheating of the battery is found, so as to shut off the battery pack charging and discharging in time. The positive and negative power lines of the battery modules are connected in sequence, without any additional communication cable, which is the same as the conventional lead-acid battery application mode. On the one hand, the battery module of the present application only needs to use the battery state information inside the module to make a decision to realize complete battery protection, avoiding the complex communication problem of the BMS scheme in the traditional large battery system. On the other hand, the present application introduces a discharge freewheeling diode, which greatly reduces the voltage stress of the discharge control switch and reduces the core material cost of the BMS.
[0021] For example, a 192V battery system is designed to be composed of 4 48V battery modules in series. When the battery power of a certain string of the No. 1 battery module is discharged during the discharging process, the discharge protection switch of the module needs to be disconnected, so that the battery pack of the No. 1 battery module stops discharging, but due to the existence of the freewheeling diode, the other three battery modules can still continue to discharge normally, at this time the total voltage of the whole battery system is reduced to 48*3=144V. The voltage across the discharge protection switch of the No. 1 battery module is only the sum of the voltage of the battery pack of the No. 1 battery module itself and the voltage drop of the discharge freewheeling diode, which is only 1 / 4 of the highest voltage of the whole battery system. The nominal 48V battery module has a maximum voltage of about 60V. There are a large number of material models in the consumer electronics and two-wheeled electric vehicle fields that meet this requirement, with low cost. Therefore, compared with high-voltage devices of 192V specification, it has extremely high cost performance.
[0022] As Figure 2As shown, this invention provides a battery module implementation scheme for a modular battery system. Each battery module includes a battery state parameter detection module 201, a passive battery balancing module 203, a charge / discharge control switch SW1 and a drive circuit 202, a discharge freewheeling diode 204, a current detection resistor RC, and battery module positive terminal Pack+ and battery module negative terminal Pack-. The battery state parameter detection module 201 is connected to the positive and negative terminals of each individual cell in the battery pack via a voltage sampling line. The passive battery balancing module 203 is also connected to the positive and negative terminals of each individual cell in the battery pack via a battery balancing line interface. Therefore, when the passive balancing current is small, the battery balancing line and the voltage sampling line can be reused. Furthermore, the battery state parameter detection module 201 can be implemented using pure hardware circuitry, such as a single-cell battery protection IC or a multi-cell integrated protection IC, or it can be implemented using embedded software or a high-performance computing system after ADC sampling and conversion. The anode of the discharge freewheeling diode 204 is connected to the negative terminal Pack- of the battery module, and the cathode of the discharge freewheeling diode 204 is connected to the positive terminal Pack+ of the battery module. The discharge freewheeling diode 204 is in reverse connection with the battery pack. When the battery module's charge / discharge control switch is on, there is usually no current flowing through it (only a very small reverse leakage current from the diode). Once the discharge control switch of a certain battery module is off, the other remaining battery modules in the battery system and the external load form a closed loop, causing the discharge freewheeling diode 204 of that battery module to be forward biased and in a conducting state, thus achieving the effect of bypassing the battery module's discharge.
[0023] like Figure 3 As shown, this invention provides another battery module implementation scheme for a modular battery system. An N-type MOSFET is used as the charge / discharge control switch and placed on the negative side of the battery pack. The drain of the charge control switch SWC is connected to the drain of the discharge control switch SWD, the source of the charge control switch SWC is connected to the negative terminal of the battery module, and the source of the discharge control switch SWD is connected to the current sensing resistor RC. A multi-string integrated analog front-end chip (AFC) is used to detect battery state parameters, including the voltage of each individual cell in each string, battery pack temperature, and current. Battery balancing is achieved through a passive balancing circuit using resistor discharge, and can be further improved by combining the trickle balancing scheme of patent CN2022229672825. This invention can fully utilize electronic components and other materials from consumer electronics and two-wheeled / three-wheeled electric vehicles to realize a high-voltage battery system, with significant advantages such as high integration and low cost.
[0024] The modular battery system provided by the application can independently operate each battery module, and realize various protection functions of all batteries in the battery module, so that communication between the battery modules and between the battery modules and the system is not required. However, for some application fields, users want to remotely view the state information of all battery monomers in real time, at which time a wireless communication module can be added to each battery module. A feasible method is that a gateway node with public network linking capability is added at the battery system level, and each battery module communicates with the gateway node to transmit the battery state information of the battery module. The configuration of the wireless communication function can also bring an additional benefit: when a battery module loses the charge and discharge control due to some reason, the emergency help information can be sent to other battery modules or the system in a wireless communication mode, and the safe redundancy function is realized by disconnecting the charge and discharge of other battery modules or system devices.
[0025] The modular battery system provided by the application has the advantages of high cost performance and strong compatibility, has a wide application prospect, and is especially suitable for lead-acid replacement fields. For example, the UPS industry often uses 96V, 192V and 384V battery voltage specifications, corresponding to 8, 16 and 32 12V lead-acid batteries respectively. The modular battery system scheme of the application can use lithium iron phosphate batteries to design 48V battery modules, and only 2, 4 and 8 battery modules need to be connected in series. Since the battery module scheme of the application does not need to communicate with external charge and discharge equipment, it is extremely similar to the traditional lead-acid battery. Therefore, when the battery module of the application is used to replace the lead-acid battery, the UPS host can use the lead-acid battery supporting products that have been used on the market for a long time. This brings great convenience to the market promotion of "lead to lithium" in the UPS field. On the one hand, it does not need to develop a new UPS host supporting lithium battery, which reduces the technical research and development investment, and on the other hand, for many inventory UPSs, only the old lead-acid battery needs to be replaced with the modular lithium battery of the application, and the original UPS host can continue to be used, effectively saving costs.
[0026] For example, the direct current screen commonly used in the power industry generally uses 110V and 220V battery voltage specifications, corresponding to 9 and 18 12V lead-acid batteries respectively. The modular battery system scheme of the application can use lithium iron phosphate batteries to design 36V battery modules, and only 3 and 6 battery modules need to be connected in series. Similar to the UPS industry, the power electronic module of the direct current screen using the battery module of the application can also directly use the lead-acid battery supporting products that have been used on the market for a long time.
[0027] The modular battery system provided by the application also has advantages of high reliability and safety redundancy, and is very suitable for the two-wheel / three-wheel electric vehicle field related to personal safety. For example, 4 strings of lithium iron phosphate batteries are designed as 12V battery modules, and lead-acid batteries can be replaced one by one. For example, 48V electric bicycles only need to use 4 battery modules in series. When a battery module needs battery protection during the charging and discharging process, and the charging and discharging control switch fails, if the battery consistency is good, the other three battery modules will also quickly enter the battery protection state, thereby stopping the charging and discharging process of the whole battery system, and realizing the safety protection of the faulty battery module. Unlike the conventional centralized lithium battery scheme with only one charging and discharging control switch, each battery module provided by the application is equipped with an independent charging and discharging control switch, which plays a redundant backup role, can effectively solve the BMS single point failure problem, and improve the safety performance of the electric light vehicle lithium battery.
[0028] In summary, the modular battery system provided by the application has excellent compatibility, safety and cost performance, and can be widely used in small and medium-sized energy storage systems such as uninterruptible power supply, direct current screen and household energy storage, and two-wheel / three-wheel electric vehicle field.
Claims
1. A modular battery, uninterruptible power supply, DC power panel and two / three wheeler electric vehicle battery system characterized by, The battery system is composed of one battery module or multiple battery modules connected in series; each battery module includes a battery pack and a battery management control module, the battery management control module includes a battery state parameter detection and charge-discharge control protection module; the charge-discharge control protection module includes a charge control switch and a discharge control switch and a discharge freewheeling diode; the charge control switch realizes overcharge protection function of the battery, the discharge control switch realizes over-discharge protection function of the battery, and the discharge freewheeling diode enables other battery modules to continue discharging when the battery module itself does not discharge and the discharge control switch of the battery module is disconnected.
2. A modular battery, UPS, DC power panel and two / three wheeler electric vehicle battery system as claimed in claim 1 wherein, The cathode of the discharge freewheeling diode is connected to the anode of the battery module, and the anode of the discharge freewheeling diode is connected to the cathode of the battery module.
3. A modular battery, UPS, DC power panel and two / three wheeler electric vehicle battery system as claimed in claim 1 wherein, The charge control switch and the discharge control switch use N-type power MOSFET and are placed on the negative side of the battery; the cathode of the discharge freewheeling diode is connected to the anode of the battery module, and the anode of the discharge freewheeling diode is connected to the drain of the discharge control MOSFET or the source of the charge control MOSFET.
4. A modular battery, UPS, DC power pack and two / three wheeler electric vehicle battery system as claimed in claim 1 wherein, The battery state parameter detection module uses an AFE chip to measure the voltage, current or temperature signals of a single string battery, and calculates and identifies abnormal risks such as overcharge, over-discharge or overheat of the battery, and then sends the signals to the charge-discharge control module to trigger protection actions.
5. A modular battery, UPS, DC power panel and two / three wheeler electric vehicle battery system as claimed in claim 4 wherein, The battery module also has wireless communication function, when the function of the charge-discharge control protection module itself fails unexpectedly, it can send wireless signals to other battery modules or external charge-discharge equipment to realize safety redundancy protection of the battery system.
6. An uninterruptible power supply, characterized by The uninterruptible power supply includes the modular battery system of any one of claims 1-5 and a UPS host.
7. A DC screen, characterized in that The DC screen includes the modular battery system of any one of claims 1-5 and a DC screen power electronic module.
8. A two-wheel / three-wheel electric vehicle battery system, characterized by, The battery system includes the modular battery system of any one of claims 1-5 and a matching charge-discharge device.