Manufacturing method and operating method of recycled battery system

Abstract

A method for manufacturing a reused battery system (1) is provided with: a used battery management unit (10) receiving characteristic map data (1P) corresponding to the state after the start of reuse of the used battery; the management unit (10) verifies the received characteristic mapping data (1P) using the error detection code attached to the characteristic mapping data (1P); and if the received characteristic mapping data (1P) is correct, the management unit (10) stores the characteristic mapping data (1P) in the storage unit (101).

Description

Technical Field

[0001] One aspect of the present invention relates to a method of manufacturing (construction method) for a reuse battery system. Background Technology

[0002] Patent document 1 discloses a method for reusing secondary batteries, which can test (screen) batteries that are not suitable for reuse before they are removed from a vehicle, transported to a factory, disassembled at a factory, or have their capacity measured.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-53167 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] In recent years, attempts have been made to apply batteries (mainly lithium-ion batteries) already used in primary applications to secondary applications such as backup power systems and energy storage systems.

[0008] Various technologies have been developed to improve the reliability of such secondary battery systems (reused battery systems).

[0009] One aspect of the present invention provides a method for manufacturing a reusable battery system to improve the operational reliability of the system.

[0010] Methods for solving problems

[0011] A method for manufacturing a reusable battery system according to one aspect of the present invention includes: a management unit for a used battery receiving characteristic map data corresponding to the state of the used battery after the start of its reuse; the management unit verifying the received characteristic map data using an error detection code appended to the characteristic map data; and verifying that the received characteristic map data is correct (appropriate). In the case of [missing information], the management unit saves the feature mapping data in the storage unit.

[0012] Invention Effects

[0013] By accurately storing characteristic mapping data with a large amount of data in the storage unit of the management unit according to the above method, it is possible to manufacture a reusable battery system with improved operational reliability. Attached Figure Description

[0014] Figure 1This is a block diagram illustrating an example of a battery reuse system.

[0015] Figure 2 This diagram shows an example of the configuration of the battery and management unit in the energy storage section.

[0016] Figure 3 This is a 3D diagram showing an example of a battery module.

[0017] Figure 4 This is a diagram representing an example of feature mapping (SOC-OCV mapping (map)).

[0018] Figure 5 This is a conceptual diagram illustrating an example of feature mapping (map) data (SOC-OCV mapping data) received by the management unit.

[0019] Figure 6 This is a flowchart illustrating the process by which the management unit saves the received feature mapping data to the storage unit.

[0020] Figure 7 This is a flowchart illustrating the process by which the management unit reads feature mapping data from the storage unit. Detailed Implementation

[0021] The following is a summary of the implementation method.

[0022] (1) A method for manufacturing a reusable battery system includes: a management unit of a used battery receiving characteristic mapping data corresponding to the state after the start of the reuse of the used battery; the management unit using an error detection code attached to the characteristic mapping data to verify the received characteristic mapping data; and if the received characteristic mapping data is correct, the management unit storing the characteristic mapping data in a storage unit.

[0023] Used batteries can be individual battery cells, battery modules formed by connecting battery cells in series and / or in parallel, or battery packs formed by connecting battery cells or battery modules in series and / or in parallel. From the point of view of reducing the labor required for disassembly, used batteries are preferably used in reuse battery systems in a way that does not change their form (e.g., battery pack, battery module) when used for their primary purpose (e.g., vehicle battery system).

[0024] The used battery can be a lithium-ion rechargeable battery, but is not limited to this. It can also be a NaS (sodium sulfur) battery, a redox flow battery, a lithium-ion capacitor, an electric double-layer capacitor, an air battery, an all-solid-state battery, a semi-solid-state battery, a nickel-metal hydride battery, an alkaline battery, a nickel-cadmium battery, a lithium polymer battery, a lead-acid battery, and other rechargeable batteries.

[0025] The term "start of reuse" includes the manufacturing (construction) of the reused battery system and the performance testing of the used batteries. The start of reuse can be for secondary use or for use after the third time.

[0026] According to the method described in (1) above, a large amount of characteristic mapping data (e.g., state-of-charge-open-circuit voltage mapping data, hereinafter referred to as SOC-OCV mapping data) can be accurately stored in the management unit of the used battery. As a result, a reusable battery system with improved operational reliability can be manufactured.

[0027] When manufacturing a reusable battery system while minimizing changes to its original form for primary use, initial characteristic mapping data is stored in the management unit of the battery pack or module used for primary use. However, the mapping data stored here often does not correspond to the state of the used battery at the start of reuse, such as its state of health (SOH).

[0028] Figure 4 This shows the SOC-OCV mapping of batteries with different SOH values. Each profile contains a large amount of data, for example, around 100 data points.

[0029] To control the battery, in addition to the SOC-OCV mapping (an example of characteristic mapping) used to estimate the SOC based on the battery's measured voltage, charging upper limit voltage, discharging lower limit voltage, etc., are also required. The upper limit voltage and lower limit voltage are each a single data point. Compared to these values ​​(so-called setpoints), the amount of data required to form a characteristic mapping like the SOC-OCV mapping is enormous, making it prone to errors when writing to the management unit during the manufacturing of the battery system for reuse.

[0030] exist Figure 4 In the diagram, the curve representing 100% is the initial SOC-OCV mapping (when SOH is 100%) for a single use of the battery. The curve representing 70% is the SOC-OCV mapping to refer to when the SOH decreases to 70% during battery use.

[0031] If the management unit of a battery pack or battery module only stores SOC-OCV mapping data corresponding to SOH 100% during single-use, this mapping data does not correspond to the state at the start of reuse of the used battery. Therefore, it is necessary to write SOC-OCV mapping data corresponding to the state at the start of reuse of the used battery (e.g., SOH 70%) into the management unit.

[0032] Such writing is also required when a new management unit is used to manage the used battery instead of the management unit used in a single application.

[0033] If an error occurs when writing the mapping data used to form the curve corresponding to SOH 70% to the management unit, a deviation value is stored, or a curve with a different shape than the intended curve is stored. Consequently, the management unit cannot accurately estimate the battery's SOC after the reused battery system begins operation, compromising the system's reliability. The same issue may occur with other characteristic mapping data besides SOC-OCV mapping data.

[0034] The state of a used battery at the start of its reuse (e.g., SOH) is determined by measurement (e.g., based on capacity measurement from a fully charged battery to a discharged state).

[0035] In addition to State of Health (SOH), other battery states can be identified by various degradation mechanisms (isolation of active materials, reduction of charge carriers (e.g., lithium ions Li+) involved in charging and discharging, increase in resistance, decrease in electrolyte conductivity, etc.). The battery degradation state corresponding to these mechanisms can be determined and estimated through simulation based on historical usage data (current history, voltage history, temperature history, etc.) from a single application (or past applications up to the present moment).

[0036] According to the method described in (1) above, characteristic mapping data (such as SOC-OCV mapping data with a large amount of data) corresponding to the state of the used battery obtained through measurement and estimation can be accurately stored in the storage unit of the management unit after verification using error detection codes. Therefore, it is possible to manufacture a reusable battery system with improved operational reliability.

[0037] (2) In the method of (1) above, the communication unit of the reused battery system may receive the characteristic mapping data from the host device, and the multiple management units respectively set in the multiple groups of the used batteries may receive the characteristic mapping data from the communication unit.

[0038] The above method simplifies the structure of the battery reuse system, and allows multiple management units to receive the correct characteristic mapping data for the battery group they manage.

[0039] Preparing multiple used batteries with consistent remaining performance is challenging. Therefore, different characteristic mapping data can be provided to the management units of multiple battery groups via the communication unit of the battery reuse system. In secondary applications such as backup power systems and energy storage systems, it is common to connect a large number of used batteries in parallel to ensure the required capacity. It is possible to provide the management unit set up for each battery group connected in parallel with the correct characteristic mapping data for each battery group.

[0040] (3) In the method of (1) or (2) above, the host device may prepare the characteristic mapping data based on the simulation results of the measurement data of the used battery and / or historical data from past uses.

[0041] Battery measurement and simulation technologies are developing. Measurement and simulation accuracy are improving year by year, and previously unknown battery degradation phenomena are being elucidated or modeled. Applying the latest measurement data and simulation techniques to a host device allows the device to estimate the initial state of used batteries at the start of reuse and prepare characteristic mapping data, thereby further improving the operational reliability of manufactured reuse battery systems.

[0042] (4) The method of using the battery reuse system includes: a host device monitoring the state of the used battery after the reuse begins; the management unit of the used battery receiving characteristic mapping data corresponding to the state prepared by the host device; the management unit using an error detection code attached to the characteristic mapping data to verify the received characteristic mapping data; and if the received characteristic mapping data is correct, the management unit saving the characteristic mapping data in a storage unit.

[0043] According to the above application method, the host device monitors the status of the used battery after the recycling begins and prepares characteristic mapping data. The large amount of characteristic mapping data is accurately stored in the storage of the management unit, thereby improving the reliability of the application.

[0044] (5) In the method of (4) above, the host device may prepare the characteristic mapping data based on the measurement data after the start of the reuse of the used battery and / or the simulation results of the historical data after the start of the reuse.

[0045] After reuse begins, most of the charging and discharging processes are different from their previous (e.g., for primary use) operation modes. Based on the operation method described above (5), it is possible to prepare accurate characteristic mapping data based on measurement data after reuse begins and / or historical operation data after reuse begins, using, for example, simulation results applying the latest technology.

[0046] The following is a reference to the appendix. Figure 1 The embodiments will be described below. This invention is not limited to the embodiments described below.

[0047] Figure 1 This describes the structure of an energy storage system (ESS) 1, which is a reusable battery system. ESS1 includes a battery management unit (BMU) 10, an energy storage unit 11, a power conditioner (PCS) 12 (example of a charging / discharging unit), and a communication unit 13. ESS1 can also be a so-called power conditioner with an integrated battery. The reusable battery system can replace ESS1 with a backup power system, or it can be another system (e.g., a battery system for driving a mobile vehicle).

[0048] BMU10 includes a CPU (Central Processing Unit) 100, a ROM (Read Only Memory) 101, a RAM (Random Access Memory) 102, and I / O (Input / Output) 103.

[0049] CPU 100 is the execution unit, which sequentially reads the firmware stored in ROM 101 and executes control processing according to the control procedures defined by the firmware. ROM 101 is, in principle, a dedicated non-transitory memory read from CPU 100. ROM 101 is, for example, EEPROM (Electrically Erasable Programmable Read-Only Memory). The ROM 101 stores the predetermined SOC-OCV mapping 2P and the reused SOC-OCV mapping 1P. The predetermined SOC-OCV mapping 2P can also be stored in the ROM built into CPU 100.

[0050] RAM102 is a temporary memory used by CPU100 for computation. CPU100 writes the results of computation into RAM102 and reads them out while continuing processing. The data stored in RAM102 is lost when BMU10 is restarted.

[0051] The energy storage unit 11 includes a used battery. The energy storage unit 11 is connected to the system power source E via PCS 12. The energy storage unit 11 can also be connected to a power source (not shown) (e.g., a solar panel, other renewable energy generator) via PCS 12. The BMU 10 can also receive power from the energy storage unit 11.

[0052] PCS12 includes an inverter and / or converter as a power conversion unit 12a (see reference). Figure 2PCS12 is connected to the electrical load and performs functions such as supplying power from the system power source E to the electrical load, charging the energy storage unit 11 from the system power source E, and supplying power from the energy storage unit 11 to the electrical load (including assist discharge when supplying power from the system power source E to the electrical load). PCS12 can be connected to either an AC grid or a DC grid.

[0053] The communication unit 13 is a communication device used to communicate with the host device 2. The host device 2 may also be an external storage medium (e.g., a USB memory). The communication unit 13 may be, for example, a network interface card, or a structure capable of installing an external storage medium. The BMU 10 receives data from the host device 2 via the communication unit 13 (e.g., data mapped using SOC-OCV).

[0054] The host device 2 may also be a terminal device (e.g., a maintenance terminal device) that sends updated SOC-OCV mapping data to ESS1 via a local area network. Alternatively, the host device 2 may also be a server device (e.g., a remote monitoring server) that provides instructions to ESS1 or collects data from ESS1 via a communication network including the Internet.

[0055] Figure 2 This illustrates an example of the configuration of the used batteries in the energy storage unit 11 and the BMU 10. The energy storage unit 11 is configured to house multiple groups of used batteries U1, U2, ... in a battery tray or container. These multiple battery groups U are connected in parallel with a common power path Lo extending from the power conversion unit 12a of the PCS 12. In this embodiment, five groups of used batteries U1 to U5 are connected in parallel, but the number of parallel connections is not limited to this. Figure 2 As shown, PCS can also be configured outside the container.

[0056] Each battery group U includes multiple battery modules M connected in series, a current sensor 41, and a current cutoff device 45. Battery modules M can also be constructed by connecting individual battery cells (also called individual cells) in series. Hereinafter, a group formed by connecting multiple battery modules M in series is referred to as a battery bank.

[0057] In this embodiment, the energy storage unit 11 has a battery pack BMU10B in each battery pack U, and a battery domain BMU10D in a group (hereinafter referred to as a battery domain) formed by connecting multiple battery packs U in parallel. The battery domain BMU10D can communicate with the battery pack BMU10B via a communication bus (e.g., a CAN bus).

[0058] In each battery pack U, the battery module M has a cell management unit (CMU) 33 that communicates with the battery pack BMU10B, which is connected to these CMUs 33 via a serial communication interface such as RS-232C. The CMU 33 may also include a voltage sensor (not shown) for measuring the voltage of each cell, and a temperature sensor 37 (see reference 37). Figure 3 The battery pack BMU10B acquires current data measured for each battery pack, voltage data measured by the CMU33 of each battery module M, and temperature data.

[0059] The battery domain BMU10D can also aggregate the battery status data obtained from each battery pack BMU10B and store it in the storage unit 25. The storage unit 25 can also be located outside the battery domain BMU10D.

[0060] exist Figure 2 The example shown is of the battery domain BMU10D connected to the control unit 12b of PCS12, but the battery domain BMU10D can also be connected to the communication unit 13 (see reference 12b). Figure 1 Alternatively, the battery pack BMU10B can also be connected to the communication unit 13 via the CAN bus without going through the battery domain BMU10D.

[0061] like Figure 3 As shown, the battery module M in this embodiment has a housing 31 that houses multiple adjacent battery cells 60 and multiple temperature sensors 37A and 37B for measuring the temperature of the battery cells 60. The battery cell 60 is a prismatic cell that houses electrodes and a non-aqueous electrolyte within a cuboid-shaped housing. The battery cell can also be a pouch cell or a cylindrical cell. In this embodiment, the battery cell 60 is a lithium-ion rechargeable battery cell. The battery module M in this embodiment is applied to a reuse battery system while maintaining largely the same form as in its previous use (e.g., primary use). That is, the CMU 33 and temperature sensors 37 used in the previous use are not disassembled, and the battery module M is applied to the reuse battery system.

[0062] In this embodiment, in the host device 2 (refer to...) Figure 1 In the process of preparing characteristic mapping data corresponding to the state of the used batteries after the start of reuse, the data is set in each battery pack U (refer to...). Figure 2 The battery pack BMU10B receives this characteristic mapping data. In the host device 2, multiple characteristic mapping data corresponding to the envisioned states at multiple (future) time points after the start of the reuse of the used battery can also be prepared.

[0063] When batteries intended for primary use (e.g., drive battery systems in electric vehicles) are manufactured, sufficient characteristic mapping data corresponding to various battery states is not prepared. For example, preparing SOC-OCV mapping data based on various SOHs (e.g., 80%, 75%, 70%, 65%, 60%, ...) requires a long time and a large amount of labor. Furthermore, when batteries intended for primary use are manufactured, their reuse is not anticipated. Therefore, when batteries intended for primary use are manufactured, the management unit for primary use only stores a limited amount of characteristic data containing SOC-OCV mapping data corresponding to 100% SOH.

[0064] As BMU10, when using a different BMU than the one used for primary purposes (replacing the BMU), only a limited amount of characteristic data is stored in the replaced BMU10.

[0065] As the battery's SOH decreases, it is necessary to switch to the SOC-OCV mapping referenced for SOC estimation. In this embodiment, the host device 2 (referencing...) Figure 1 Prepare characteristic mapping data corresponding to the state after the start of the reuse of the used battery, and send it to the battery domain BMU10D or the battery pack BMU10B.

[0066] Figure 5 This represents SOC-OCV mapping data, an example of feature mapping data prepared by the host device 2. This mapping data includes a table management number, table data that associates SOC and OCV, and an error detection code.

[0067] Examples of error-detecting codes include checksums and cyclic redundancy codes (CRC). From the perspective of verification accuracy, CRC-16 can be used, but it is not limited to these.

[0068] The table management number only needs to be able to identify the table data. Through the table management number, it can be determined whether new mapping data is being used in battery pack BMU10B, or whether the existing mapping data continues to be used in battery pack BMU10B.

[0069] Figure 6 This illustrates the process by which the battery pack BMU10B saves the SOC-OCV mapping data received from the host device 2 into the ROM101.

[0070] The battery pack BMU10B calculates the verification data from the table management number to the table data using a calculation method corresponding to the error detection code. (Step S10).

[0071] The battery pack BMU10B determines whether the calculated check data is consistent with the error detection code (step S20). If they are consistent (S20: Yes), the received SOC-OCV mapping data is considered correct and saved in ROM101 (step S30).

[0072] If the battery pack BMU10B determines that the calculated checksum is inconsistent with the error detection code (S20: NO), the received SOC-OCV mapping data is discarded. In this case, the battery pack BMU10B continues to use the predetermined SOC-OCV mapping data.

[0073] Figure 7 This illustrates the process of reading the SOC-OCV table stored in ROM101.

[0074] The battery pack BMU10B calculates the verification data from the table management number to the table data using a calculation method corresponding to the error detection code (step S60).

[0075] The battery pack BMU10B determines whether the calculated verification data matches the error detection code (step S70). If they match (S70: YES), the newly read SOC-OCV mapping data is considered correct, and this data is used to estimate the SOC based on the measured voltage of the used battery.

[0076] When the battery pack BMU10B determines that the calculated verification data is inconsistent with the error detection code (S70: No), the battery pack BMU10B uses the predetermined SOC-OCV mapping data.

[0077] The above describes an implementation method for manufacturing a recycled battery system. Next, an implementation method for using the recycled battery system will be described.

[0078] In the application of the battery reuse system (ESS1), the host device 2 (e.g., a remote monitoring server) monitors... Figure 1 The image shows the state of the used battery (energy storage unit 11) after the recycling process has begun.

[0079] The management unit for used batteries (battery pack BMU10B) receives characteristic mapping data prepared by the host device 2, corresponding to the state after the reuse of used batteries begins (see reference). Figure 5 ).

[0080] The management unit uses error detection codes attached to the feature mapping data to verify the received feature mapping data.

[0081] If the received feature mapping data is correct, the management unit saves the feature mapping data in the storage unit (ROM101). The management unit uses the new feature mapping data to control the used battery.

[0082] In battery reuse systems, batteries deteriorate compared to their previous use, so various technologies are needed to improve the reliability of their operation.

[0083] The above-described embodiment uses the communication unit 13 provided in ESS1 and the host device 2 to achieve remote monitoring. Furthermore, in the above embodiment, the host device 2 prepares characteristic mapping data corresponding to the state of the used battery after the start of reuse. The management unit receives this characteristic mapping data, verifies it using an error detection code, and stores it. By accurately storing the large amount of characteristic mapping data in the storage unit of the management unit, the operational reliability of the reused battery system can be improved.

[0084] The host device can detect situations where the reused battery system is used under the load mode envisioned during its manufacturing process through remote monitoring. Therefore, appropriate measures can be taken as early as possible, such as reconsidering the use of the reused battery system, adding battery packs, or replacing deteriorating battery modules M and battery packs U.

[0085] Explanation of reference numerals in the attached figures

[0086] 1 ESS (Electric Storage System); 10 BMU (Bureau Management Unit); 11 Energy Storage Unit (used battery); 101 ROM (Memory Unit).

Claims

1. A method for manufacturing a reusable battery system, comprising: The management unit for used batteries receives characteristic mapping data corresponding to the state of the used batteries after the start of their reuse; The management unit uses an error detection code appended to the feature mapping data to verify the received feature mapping data; and If the received feature mapping data is correct, the management unit will save the feature mapping data in the storage unit.

2. The method for manufacturing a reusable battery system according to claim 1, wherein, The communication unit of the reused battery system receives the characteristic mapping data from the host device, and the multiple management units respectively set in the multiple groups of the used batteries receive the characteristic mapping data from the communication unit.

3. The method for manufacturing a reusable battery system according to claim 1 or claim 2, wherein, The host device prepares the characteristic mapping data based on the measurement data of the used batteries and / or simulation results from historical data from past uses.

4. A method for using a recycled battery system, comprising: The host device monitors the status of the used batteries after the recycling process begins; The management unit for the used battery receives characteristic mapping data corresponding to the state prepared by the host device; The management unit uses an error detection code appended to the feature mapping data to verify the received feature mapping data; and If the received feature mapping data is correct, the management unit will save the feature mapping data in the storage unit.

5. The method of using the recycled battery system according to claim 4, wherein, The host device prepares the characteristic mapping data based on the measurement data and / or simulation results based on the historical data after the reuse of the used battery has started.

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