How to replace the battery block in a battery pack

Abstract

To suppress erroneous determination that replacement is necessary again at relatively early timing after replacement of a battery block, while suppressing complication and increase in cost of replacement work of the battery block included in an electric pack.SOLUTION: A battery pack includes a plurality of battery blocks arranged so as to be adjacent to each other in a predetermined stacking direction. When part of the plurality of battery blocks is replaced with a pre-refreshed replacement battery block, a plurality of non-replacement battery blocks that is not replaced for the replacement battery block is adjacent in the stacking direction and a plurality of replacement battery blocks is adjacent in the stacking direction.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present disclosure relates to a battery pack including a plurality of battery blocks arranged adjacent to each other in a predetermined stacking direction, and a method for replacing battery blocks in the battery pack. [Background technology]

[0002] Conventionally, there is known a battery pack configured by electrically connecting a plurality of battery modules, each including a plurality of cells, in series or parallel, and in which each battery module can be replaced with a replacement battery module (see, for example, Patent Document 1). When replacing a battery module in this battery pack with a replacement battery module, at least one of the following procedures is performed on the replacement battery module: for example, performing cycle charging and discharging with the SOC change range limited to an intermediate range, or setting an initial SOC and then leaving the replacement battery module in an environment at a temperature higher than room temperature for a predetermined period of time. This imparts a memory effect to the replacement battery module, thereby eliminating the difference in voltage characteristics between a used non-replaceable battery module and an unused replacement battery module, resulting in uniform voltage characteristics for the entire battery pack. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-346909 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if a replacement battery module is given a memory effect in advance, the additional step of giving the memory effect complicates the battery module replacement work, which may result in increased costs. On the other hand, if a battery module to be replaced is replaced with a replacement battery module that does not have a memory effect in advance, the voltage difference between the replacement battery module and the adjacent non-replacement battery module may become large due to the presence or absence of a memory effect when the SOC is low, and it may be determined that another battery module replacement is necessary immediately after the battery module is replaced.

[0005] Therefore, the main purpose of the present disclosure is to prevent the battery block included in an electrical pack from becoming too complicated or costly to replace, while also preventing the battery block from being erroneously determined to require replacement relatively soon after replacement. [Means for solving the problem]

[0006] The battery pack of the present disclosure is a battery pack including a plurality of battery blocks arranged adjacent to each other in a predetermined stacking direction, and when some of the plurality of battery blocks are replaced with pre-refreshed replacement battery blocks, the plurality of non-replaceable battery blocks that have not been replaced with the replacement battery blocks are adjacent to each other in the stacking direction, and the plurality of replacement battery blocks are adjacent to each other in the stacking direction.

[0007] In the battery pack disclosed herein, when some of the battery blocks need to be replaced, those battery blocks are replaced with pre-refreshed replacement battery blocks. In other words, when replacing battery blocks in the battery pack disclosed herein, the replacement battery blocks are not given a memory effect, and the omission of the process of giving the memory effect reduces the complexity and cost of the work. Furthermore, in the battery pack disclosed herein, when the battery block to be replaced is replaced with the replacement battery block, the non-replaceable battery blocks that are experiencing the memory effect are appropriately rearranged so that they are adjacent to each other in the stacking direction, and the replacement battery blocks that are substantially free of the memory effect are adjacent to each other in the stacking direction. This allows battery blocks with similar amounts of voltage drop due to the memory effect to be grouped together, effectively preventing a voltage difference between two adjacent battery blocks from increasing due to a voltage drop due to the memory effect after battery block replacement. This voltage difference can be used to accurately determine whether or not a battery module needs to be replaced. As a result, the battery pack of the present disclosure can prevent the battery block from being erroneously determined to require replacement relatively soon after replacement, while minimizing the complexity and cost of the battery block replacement work. Note that the battery block of the battery pack of the present disclosure may be a battery module including multiple battery cells, may include multiple such battery modules, or may be a single battery cell.

[0008] Furthermore, when some of the battery blocks are replaced with the replacement battery blocks, the non-replaceable battery blocks may be adjacent to each other at both ends of the battery blocks in the stacking direction, and the replacement battery blocks may be adjacent to each other between the non-replaceable battery blocks at one end and the non-replaceable battery blocks at the other end. That is, the temperature of the battery blocks in the central region of the battery blocks in the stacking direction is relatively high and generally constant, whereas the temperature of the battery blocks at both ends of the battery blocks in the stacking direction, where heat dissipation is high, gradually decreases from the center to the ends. Furthermore, if a temperature difference occurs between two adjacent battery blocks, a voltage difference occurs between the two battery blocks due to the temperature difference. Therefore, if a non-replaceable battery block and a replacement battery block are adjacent to each other at both ends of the battery blocks, there is a risk that the voltage difference between them will be large due to the presence or absence of a memory effect and the temperature difference. Based on this, in this battery pack, multiple non-replaceable battery blocks that have a memory effect on both one end and the other end of the multiple battery blocks are arranged, and multiple replacement battery blocks are arranged between the multiple non-replaceable battery blocks on one end and the multiple non-replaceable battery blocks on the other end. This makes it possible to effectively prevent the voltage difference between adjacent non-replaceable battery blocks from increasing because the cause of the voltage difference is essentially the temperature difference between the two, and to effectively prevent the voltage difference between the non-replaceable battery blocks and the replacement battery blocks from increasing by arranging them adjacent to each other in an area where temperature change is small.

[0009] Furthermore, the non-replaceable battery block may be arranged closer to one of the ends of the plurality of battery blocks in the stacking direction. In this way, after some of the plurality of battery blocks are replaced with replacement battery blocks, the non-replaceable battery block is placed in or near the original position, making it possible to make the amount of voltage drop due to memory effect between the plurality of non-replaceable battery modules closer to each other at both the one end and the other end of the plurality of battery blocks.

[0010] The battery pack may be mounted on a vehicle, and the vehicle may include an electric motor that exchanges power with the battery pack and a control device that issues a warning when the voltage difference between two adjacent battery blocks is equal to or greater than a predetermined threshold. This makes it possible to properly and quickly notify a vehicle user that some battery blocks in the battery pack should be replaced.

[0011] Furthermore, the battery block to be replaced with the replacement battery block may be a battery block whose voltage difference from the maximum voltage of the plurality of battery blocks is equal to or greater than a predetermined replacement threshold, thereby enabling more accurate identification of the battery block to be replaced.

[0012] The battery block and the replacement battery block may each include a plurality of nickel-metal hydride battery cells. However, the battery block and the replacement battery block are not limited to those including nickel-metal hydride battery cells, and may include battery cells other than nickel-metal hydride battery cells that exhibit a memory effect.

[0013] The battery block replacement method in a battery pack disclosed herein is a battery block replacement method in a battery pack including a plurality of battery blocks arranged adjacent to each other in a predetermined stacking direction, in which, when some of the plurality of battery blocks are replaced with pre-refreshed replacement battery blocks, a plurality of non-replaceable battery blocks that will not be replaced with the replacement battery blocks are arranged adjacent to each other in the stacking direction, and a plurality of the replacement battery blocks are arranged adjacent to each other in the stacking direction.

[0014] This method makes it possible to prevent the battery block replacement process from becoming more complicated and costly, while also preventing the battery block from being erroneously determined to require replacement relatively soon after replacement.

[0015] Furthermore, in the method for replacing battery blocks in a battery pack according to the present disclosure, when some of the plurality of battery blocks are replaced with the replacement battery blocks, the plurality of non-replaceable battery blocks and the plurality of replacement battery blocks may be arranged so that the plurality of non-replaceable battery blocks are adjacent to each other in the stacking direction on both one end side and the other end side of the plurality of battery blocks in the stacking direction, and the plurality of replacement battery blocks are adjacent to each other in the stacking direction between the plurality of non-replaceable battery blocks on the one end side and the plurality of non-replaceable battery blocks on the other end side. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a schematic configuration diagram showing a vehicle equipped with a battery pack according to the present disclosure. [Figure 2] 1 is a schematic diagram showing a battery pack according to the present disclosure; [Figure 3] 4 is a flowchart illustrating a routine executed by the control device of the vehicle of FIG. 1 to determine whether or not a battery block included in the battery pack of the present disclosure needs to be replaced. [Figure 4] 10 is a flowchart illustrating a routine executed to identify a battery block to be replaced in a battery pack of the present disclosure. [Figure 5] 5A and 5B are schematic diagrams for explaining a procedure for replacing a battery block in a battery pack of the present disclosure. [Figure 6] 10 is an explanatory diagram showing the voltage characteristics of a non-replaceable battery block and a replacement battery block in a battery pack of the present disclosure. FIG. [Figure 7] FIG. 2 is an explanatory diagram showing the temperatures and voltages of a plurality of battery blocks of the battery pack of the present disclosure. [Figure 8] 5A and 5B are schematic diagrams for explaining a procedure for replacing a battery block in a battery pack of the present disclosure. [Figure 9] 5A and 5B are schematic diagrams for explaining a procedure for replacing a battery block in a battery pack of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0017] Next, embodiments of the present disclosure will be described with reference to the drawings.

[0018] FIG. 1 is a schematic diagram showing a vehicle V equipped with a battery pack 1 according to the present disclosure. The vehicle V shown in the figure is an electric vehicle (BEV) or hybrid vehicle (HEV, PHEV) that includes, in addition to the battery pack 1, a motor generator (three-phase AC motor) MG that is connected to the battery pack 1 via a power control device (not shown) including an inverter and the like, and that is capable of exchanging power with the battery pack 1 to output driving power and regenerative braking force. In this embodiment, power from the battery pack 1 is supplied to an air conditioning compressor and the like provided in the vehicle V, and can also be supplied to auxiliary equipment such as headlights via a DC / DC converter (not shown). The vehicle V also includes an electronic control unit 10 (hereinafter referred to as "ECU 10") that manages the battery pack 1.

[0019] 2, the battery pack 1 includes a plurality of battery modules M (for example, 28 in this embodiment) connected in series, a base member 2, and a blower 3. Each battery module M includes a relatively flat, approximately rectangular parallelepiped module case and a plurality of battery cells (single cells) (not shown) (for example, six in this embodiment) connected in series and housed in the module case. Each battery cell included in the battery module M is a nickel-metal hydride secondary battery.

[0020] A plurality of battery modules M are arranged (stacked) adjacent to each other in a predetermined stacking direction (left-right direction in FIG. 2 ) and integrated with each other to form a battery stack S. In this embodiment, the stacking direction of the plurality of battery modules M coincides with the thickness direction of the module case (extension direction of the shortest side). The plurality of battery modules M, i.e., the battery stack S, are mounted and fixed on a base member 2 and covered with a cover (not shown) fixed to the base member 2.

[0021] In the battery pack 1, as shown in FIG. 2, two adjacent battery modules M each form one battery block B1, B2, ..., B13, or B14. That is, the battery pack 1 includes a plurality of battery blocks B1-B14 (for example, 14 in this embodiment) arranged adjacent to each other in the stacking direction. In the battery pack 1, if the performance of any of the battery blocks B1-B14 deteriorates due to degradation or the like, the affected battery block B1-B14 can be individually replaced. In the following description, the battery blocks B1-B14 will be collectively referred to as "battery block B" where appropriate.

[0022] The base member 2 of the battery pack 1 has an air supply passage (not shown) that opens at one end of the base member 2, and the opening of the air supply passage is connected to the outlet of a blower 3. The blower 3 is, for example, a sirocco fan driven by a brushless motor, and as shown in FIG. 2, is fixed to the base member 2 so as to face one end (battery block B1) of the battery stack S at a distance. The blower 3 draws air in through an intake duct (not shown) and sends it out from the outlet into the air supply passage of the base member 2.

[0023] The battery stack S also has multiple air passages that each communicate with the air supply passage of the base member 2 and communicate with an exhaust duct (not shown). In this embodiment, each air passage is formed between two adjacent battery modules M. As a result, air from the blower 3 is supplied to the multiple air passages via the air supply passage of the base member 2, and the air that flows into each air passage absorbs heat from the battery modules M on both sides and is discharged to the outside through an exhaust duct (not shown). Note that a junction box (not shown) and the like are arranged between the battery stack S (battery block B1) and the blower 3.

[0024] In a vehicle V equipped with the battery pack 1 described above, the ECU 10 repeatedly executes the routine shown in FIG. 3 while the system of the vehicle V is running to determine whether or not replacement of the battery blocks B1-B14 is necessary. When the timing for executing the routine shown in FIG. 3 arrives, the ECU 10 calculates the voltages (inter-block voltages) V of the battery blocks B1-B14 detected by voltage sensors (not shown). n (where "n" indicates the number of the battery block B, and in this embodiment, n=1, 2, ..., 14) (step S100). Next, the ECU 10 sets the variable n, i.e., the number of the battery block B included in the battery pack 1, to a value of 1 (step S110). Furthermore, the ECU 10 sets the variable n, i.e., the number of the battery block B included in the battery pack 1, to a value of 1 (step S110). n and battery block B n+1 Voltage difference dV n (=V n+1 -V n ) is calculated (step S120), and the voltage difference dV n It is determined whether the absolute value of is equal to or greater than a predetermined threshold value (positive value) dVref (step S130).

[0025] Voltage difference dV n If it is determined that the absolute value of is equal to or greater than the threshold value dVref (step S130: YES), the ECU 10 increments the counter C (step S140) and then determines whether the counter C is equal to or greater than a predetermined threshold value Cref (an integer equal to or greater than 2) (step S150). If the counter C is equal to or greater than the threshold value Cref (step S150: YES), the ECU 10 n and battery block B n+1 Voltage difference dV n Since the voltage of the battery block B is continuously equal to or higher than the threshold value dVref, the ECU 10 n and battery block B n+1 and the voltage V n or V n+1The ECU 10 determines that the battery block B with the smaller value should be replaced, and stores the number n or n+1 in a storage device (not shown) (step S160). Furthermore, the ECU 10 turns on a warning light (not shown) provided on an instrument panel (not shown) of the vehicle V to notify the user of the vehicle V that there is a battery block B that needs to be replaced (step S170).

[0026] In addition, the ECU 10 detects the voltage difference dV n If it is determined that the absolute value of counter C is less than threshold value dVref (step S130: NO), the ECU 10 skips steps S140-S170, and if it is determined that counter C is less than threshold value Cref (step S150: NO), the ECU 10 skips steps S160-S170. After the processing of step S130, S150, or S170, the ECU 10 increments variable n (step S180) and determines whether variable n matches the total number N of battery blocks B1-B14 in the battery pack 1 (e.g., 14 in this embodiment) (step S190). If it is determined that variable n does not match the total number N (step S190: NO), the ECU 10 repeatedly executes the processing from step S120 onwards, and when variable n matches the total number N (step S190: YES), the ECU 10 temporarily ends the routine of FIG. 3. By executing the routine of FIG. 3, it is possible to properly and quickly notify the user of the vehicle V that some battery blocks B of the battery pack 1 should be replaced.

[0027] Next, the procedure for replacing a battery block B in the battery pack 1 will be described with reference to Figures 4 to 9. Figure 4 is a flowchart illustrating a routine executed to identify a battery block B to be replaced from among the multiple battery blocks B1-B14 in the battery pack 1. The routine in Figure 4 is executed by a diagnostic device (computer) connected to the vehicle V at a dealer, repair shop, or the like to which the vehicle V is brought.

[0028] 4, the diagnostic device first operates an air conditioning system (not shown) of the vehicle V and turns on the headlights and other lights, thereby discharging each battery cell of the battery pack 1 (step S200). The discharge process of step S200 is executed until a predetermined time has elapsed after the SOC of any battery cell has dropped to a predetermined value. After the discharge process is completed, the diagnostic device measures the voltages (inter-block voltages) V of each of the battery blocks B1-B14 detected by voltage sensors (not shown). n (Step S210). Furthermore, the diagnostic device acquires the voltages V1, V2, ..., V acquired in step S210. 14 The maximum voltage V max is acquired (step S220).

[0029] Next, the diagnostic device sets a variable n (the number of the battery block B) to the value 1 (step S230). n Voltage V n and maximum voltage V max The voltage difference ΔVn (=V max -V n ) is calculated (step S240), and the voltage difference ΔV n It is determined whether the voltage difference ΔV is equal to or greater than a predetermined replacement threshold value Vref (positive value) (step S250). n is equal to or greater than the replacement threshold Vref (step S250: YES), the diagnostic device n Voltage V n is deemed to have significantly decreased, and the battery block B n is identified as a replacement target (step S260). n If it is determined that the reference voltage Vref is equal to or greater than the replacement threshold Vref (step S250: NO), the ECU 10 skips the process of step S260.

[0030] After the processing of step S250 or S260, the ECU 10 increments the variable n (step S270) and determines whether the variable n exceeds the total number N of battery blocks B1-B14 in the battery pack 1 (step S280). If it is determined that the variable n is equal to or less than the total number N (step S280: NO), the ECU 10 repeatedly executes the processing from step S240 onwards, and when the variable n exceeds the total number N (step S280: YES), ends the routine of Fig. 4. By executing the routine of Fig. 4, it becomes possible to more accurately identify the battery block B that needs to be replaced.

[0031] When the battery block B to be replaced is identified by executing the routine of FIG. 4, the battery pack 1 is removed from the vehicle V, and the target battery block B is replaced with a replacement battery block Brp (see FIG. 9). As shown in FIG. 5, for example, if battery blocks B2, B6-B10, and B13 are identified as the replacement targets (see the shaded areas in the figure), the battery pack 1 is removed from the vehicle V, and then these battery blocks B2, B6-B10, and B13 are removed from the battery pack 1 for replacement with the replacement battery block Brp. In this embodiment, the replacement battery block Brp has been refreshed in advance by discharging it to its final voltage and then charging it, and as shown by the solid line in FIG. 6, there is essentially no memory effect in the replacement battery block Brp. In other words, when replacing the battery block B in the battery pack 1, no memory effect is imparted to the replacement battery block Brp.

[0032] Here, the non-replaceable battery blocks B1, B3-B5, B11, B12, and B14 (hereinafter referred to as "non-replaceable battery blocks Bx" as appropriate; see FIG. 9), which are battery blocks B not subject to replacement in FIG. 5, have a memory effect as shown by the dashed line in FIG. 6. If the SOC decreases without being refreshed, the memory effect will cause a decrease in voltage during discharge. Also, as shown in FIG. 7, the temperature of the stacked battery blocks B1-B14, i.e., the battery blocks B3-B12 arranged in the central region of the battery stack S, is relatively high and roughly constant. In contrast, the heat dissipation is higher at both ends of the battery stack S than at the center, so the temperature of the battery block B gradually decreases from the center toward the battery block B1 at one end, as shown in FIG. 7, and also gradually decreases from the center toward the battery block B14 at the other end. As a result, at both ends of the battery stack S, as shown in FIG. 7, the temperature of two adjacent battery blocks B n ,B n+1 A temperature difference occurs between the battery blocks B1 and B2, B2 and B3, B12 and B13, and B13 and B14. n ,B n+1 A voltage difference occurs between them.

[0033] 5, if battery blocks B2 and B13 are replaced with a replacement battery block Brp, the replacement battery block Brp will be adjacent to non-replaceable battery blocks B1 and B3 at one end of the battery stack S where the temperature difference occurs, and adjacent to non-replaceable battery blocks B12 and B14 at the other end. In this case, the voltage difference between the replacement battery block Brp and the non-replaceable battery blocks B1 and B3, and between the replacement battery block Brp and the non-replaceable battery blocks B12 and B14, may become large due to both the presence or absence of a memory effect and the temperature difference. Therefore, there is a risk that the ECU 10 of the vehicle V will again determine that battery block B needs to be replaced relatively soon after the battery block B is replaced.

[0034] Based on this, when battery blocks B2, B6-B10, and B13 are identified as those to be replaced, as illustrated in Fig. 5, battery block B2 and the like are replaced with a replacement battery block Brp as follows. That is, as shown in Fig. 8, when battery blocks B2, B6-B10, and B13 are removed from the battery pack 1, the non-replaceable battery blocks B3-B5, B11, and B12 other than the non-replaceable battery blocks B1 and B14 located at one end or the other end of the battery stack S are reassembled nearer one end or the other end of the battery stack S in the stacking direction. More specifically, the non-replaceable battery blocks B3-B5 are moved to the non-replaceable battery block B1 side (one end) while maintaining their original arrangement. Furthermore, the non-replaceable battery blocks B11 and B12 are moved to the non-replaceable battery block B14 side (the other end) while maintaining their original arrangement. Then, as shown in Figure 9, multiple (six) replacement battery blocks Brp are arranged (assembled) between the multiple non-replaceable battery blocks B1, B3-5 on one end and the multiple non-replaceable battery blocks B11, B12, B14 on the other end (the positions where the pre-replacement battery blocks B5-B11 were located).

[0035] As described above, when some of the battery blocks B1-B14 need to be replaced in the battery pack 1, the battery blocks B are replaced with pre-refreshed replacement battery blocks Brp. In other words, when replacing the battery blocks B in the battery pack 1, no memory effect is imparted to the replacement battery blocks Brp, and omitting the process of imparting the memory effect can reduce the complexity of the work and the increase in costs.

[0036] In addition, in the battery pack 1, when the battery block B to be replaced is replaced with a replacement battery block Brp (after replacement), the non-replaceable battery blocks Bx that are experiencing the memory effect are rearranged appropriately so that they are adjacent to each other in the stacking direction of the battery blocks B, and the replacement battery blocks Brp that are not substantially experiencing the memory effect are adjacent to each other in the stacking direction. This allows the battery blocks B with similar amounts of voltage drop due to the memory effect to be grouped together, so that when the SOC is low after the battery block B is replaced, the voltage drop due to the memory effect can be prevented from occurring between two adjacent battery blocks Bx. n ,B n+1 This effectively prevents the voltage difference between the battery block B from increasing, and makes it possible to accurately determine whether or not replacement of the battery block B is necessary based on the voltage difference. As a result, the battery pack 1 can prevent the battery block B from being erroneously determined to require replacement relatively soon after replacement, while preventing the battery block B from becoming complicated and costly to replace.

[0037] Furthermore, in the battery pack 1, when some of the multiple battery blocks B are replaced with replacement battery blocks Brp (after replacement), the multiple non-replaceable battery blocks Bx are adjacent in the stacking direction at both one end and the other end of the battery stack S (multiple battery blocks B1-B14) in the stacking direction, and the multiple replacement battery blocks Brp are adjacent in the stacking direction between the multiple non-replaceable battery blocks Bx at one end and the multiple non-replaceable battery blocks Bx at the other end, as shown in Fig. 9. This effectively limits the voltage difference between two adjacent non-replaceable battery blocks Bx to being caused only by the temperature difference between them, thereby effectively preventing the voltage difference from increasing, and also effectively prevents the voltage difference between the non-replaceable battery block Bx and the replacement battery block Brp from increasing by arranging them adjacent to each other in a region where temperature change is small (in this embodiment, the range from battery blocks B3 to B12). In addition, by arranging the non-replaceable battery blocks Bx at one end and the other end of the battery stack S where heat dissipation is high, it is possible to suppress a decrease in the SOC of the non-replaceable battery blocks Bx due to temperature rise and to protect the non-replaceable battery blocks Bx.

[0038] Furthermore, in the battery pack 1, when replacing a battery block B, the non-replaceable battery blocks Bx are arranged closer to one end or the other end of the battery stack S (plurality of battery blocks B1-B14) in the stacking direction. As a result, when some of the plurality of battery blocks B are replaced with replacement battery blocks Brp (after replacement), the non-replaceable battery blocks Bx are arranged in or near their original positions, which makes it possible to make the amounts of voltage drop due to the memory effect between the plurality of non-replaceable battery blocks Bx closer together at both ends of the battery stack S.

[0039] Furthermore, the battery pack 1 is mounted on a vehicle V, and the vehicle V includes a motor generator MG that exchanges power with the battery pack 1, and two adjacent battery blocks B n ,B n+1 Voltage difference dV n is equal to or greater than a predetermined threshold value dVref. This makes it possible to properly and promptly notify the user of the vehicle V that a battery block B in the battery pack 1 needs to be replaced. However, the battery pack 1 is not limited to being mounted on the vehicle V. For example, the battery pack 1 may be mounted on construction equipment, a ship, or the like, or may be installed in fixed equipment other than a mobile object.

[0040] In the above embodiment, the battery block B to be replaced with the replacement battery block Brp is determined by the maximum voltage V max Voltage difference ΔV n and the battery block B for which it is determined that the battery voltage Vref has reached or exceeded a predetermined replacement threshold Vref. This makes it possible to more appropriately determine the battery block B that should be replaced.

[0041] When the routine in FIG. 4 is executed, a single battery block B n In some cases, it may be determined that only the battery block B should be replaced. n The replacement battery block Brp and the adjacent battery block Bn-1 ,B n+1 Therefore, the routine in Figure 4 is used to n If it is determined that only battery block B should be replaced, n Battery block B adjacent to n-1 ,B n+1 Furthermore, if the number of non-replacement target blocks Bx is less than the number of battery blocks B (e.g., six in this embodiment) that are located within the range that causes the temperature difference between both ends of the battery stack S (in this embodiment, the positions of battery blocks B1-B3 and battery blocks B12-B14), the user may be recommended to replace the entire battery pack 1 instead of replacing the battery blocks B.

[0042] In the above embodiment, the battery block B and the replacement battery block Brp each include multiple battery cells that are nickel-metal hydride secondary batteries, but this is not limited to this. That is, the battery block B and the replacement battery block Brp may include battery cells that exhibit a memory effect other than nickel-metal hydride secondary batteries. Furthermore, in the above embodiment, the battery block B is formed from two battery modules M, but this is not limited to this. That is, the battery block B may be formed from a single battery module M that includes multiple battery cells, or from a single battery cell.

[0043] The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the present disclosure. Furthermore, the above-described embodiment is merely a specific form of the invention described in the Summary of the Invention, and does not limit the elements of the invention described in the Summary of the Invention. [Industrial Applicability]

[0044] The invention of the present disclosure can be used in the battery pack manufacturing industry and the like. [Explanation of symbols]

[0045] 1 battery pack, 2 base member, 3 blower, 10 electronic control unit (ECU), B1, B2, B3, B4, B5, B6, B7, B8, B9, B10, B11, B12, B13, B14 battery blocks, Br replacement battery block, Bx non-replaceable battery block, M battery module, S battery stack.

Claims

[Claim 1] A method for replacing a battery block in a battery pack including a plurality of battery blocks arranged adjacent to each other in a predetermined stacking direction, comprising: a battery pack replacing method for replacing battery blocks, the method including: arranging a plurality of non-replaceable battery blocks that will not be replaced with the replacement battery blocks adjacent to each other in the stacking direction on both one end side and the other end side of the plurality of battery blocks in the stacking direction; and arranging a plurality of the replacement battery blocks adjacent to each other in the stacking direction between the plurality of non-replaceable battery blocks on the one end side and the plurality of non-replaceable battery blocks on the other end side, when replacing some of the plurality of battery blocks whose voltage difference from the maximum voltage of the plurality of battery blocks has reached a predetermined replacement threshold or more with replacement battery blocks that have been refreshed in advance to prevent memory effect.

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