CN1144060C - Battery pack, charge and discharge count and method for setting remaining capacity of battery pack - Google Patents

Abstract

The system has a heater core (14) for heating a passenger compartment, a burner (15) for burning fuel to heat a fluid that circulates through the heater core and a heat transport arrangement (18-20) between the burner and the induction side (2) of the engine to transport the heat of a high temperature combustion gas from the burner to the induction side during an engine starting process. The high temperature combustion gas is fed to the induction side before or during the heat exchange with the fluid for the heater core.

Description

Battery pack, charge and discharge count, and method of setting the remaining capacity of the battery pack

technical field

The present invention relates to a battery pack, a method for counting the number of charging/discharging times, and a method for setting the remaining power of the battery pack.

Background technique

So far, there has been provided a battery pack having a battery cell as a secondary battery, such as a lithium ion battery, a NiCd battery, or a nickel hydrogen battery.

Such battery packs generally include: a microcomputer for calculating the remaining battery power of the battery unit or communicating with an electronic device having the battery unit as a power source; peripheral equipment for the microcomputer; and a computer for calculating the remaining battery power The battery cell state detection circuit is necessary in the calculation.

The number of charge/discharge cycles of the battery pack is limited. On the other hand, the maximum number of charge/discharge cycles that can actually maintain acceptable charge/discharge characteristics is limited to a certain range depending on the type of battery cell and the like.

In conventional battery packs, it is difficult for a user to identify the maximum number of charge/discharge cycles that can realistically maintain acceptable charge/discharge characteristics, that is, to identify the service life of the battery cells. As charging/discharging is repeated, the user can only recognize that the battery cell is nearing the end of its useful life, even if the battery cell has been charged to its full capacity, only that the battery capacity is being reduced at a faster rate.

In order for the user to easily recognize the service life of the battery unit, the present applicant has proposed a battery pack and a method for displaying the state of the battery in Japanese Patent Laid-Open No. Hei 9-243718, hereinafter referred to as the first known technology.

The first known technique shown in FIG. 1 detects that the voltage of the battery cell has exceeded a first threshold voltage, and also detects that the voltage is lower than a second threshold voltage. This first known technique counts the number of charging/discharging times assuming that one charge or discharge cycle occurs when one of the voltage states is detected after another voltage state is detected.

On the other hand, in a battery pack having a plurality of battery cells, the maximum charging voltage of one battery cell is different from another battery cell. Therefore, the present applicant suggested a battery charging method and apparatus and a battery pack in Japanese Patent Laid-Open No. Hei 9-285026, hereinafter referred to as a second known art.

In the second known technique, the remaining battery power is calculated from the charge of the battery cell and the initial value stored in the battery cell.

The battery pack is loaded on an electronic device, such as a camera device, to supply electric current to the electronic device. If the power source has been exhausted, the battery pack is charged. The battery pack has: a battery cell as a chargeable and dischargeable secondary battery; and a microcomputer for detecting the voltage of the battery cell to calculate the remaining battery power.

Since the remaining battery power varies appreciably with temperature, the remaining battery power is calculated using a coefficient related to the temperature of the battery cells, as described in Japanese Patent Laid-Open No. Hei 9-297166, for example. This temperature-dependent remaining power correction factor is referred to below as a correction factor. Since the magnitude of the correction coefficient varies with temperature, the correction coefficient for each 10°C increment is stored in a non-volatile memory, such as a ROM (read only memory). The microcomputer calculates the remaining battery power using the correction coefficient stored in the nonvolatile memory and corresponding to the current temperature.

However, in the first known technique, counting up is performed only when the voltage of the battery cell drops below the second threshold, so that if the battery cell is charged before the voltage of the battery cell drops below the second threshold, Then do not count up. Therefore, there arises a problem that even if the battery cell is deteriorated due to charging/discharging, the cycle is not counted accordingly. Although one could attempt to set the second threshold to a higher value, it would occur that the count was performed while there was enough battery power left to count up correctly.

On the other hand, the conventional battery pack is designed so that once it is charged to 90%, this 90% charge is regarded as fully charged, so as to absorb errors in current detection and the like in charging. Therefore, in this battery pack, an integrated (integrated) value of the remaining battery power at the time of 90% charge is stored in the ROM in advance, and if it is confirmed that it has been charged to 90%, the battery power is set as the integrated remaining battery power value.

However, if charging/discharging is repeatedly performed, the performance of the battery cell deteriorates so that the amount of battery power that can actually be taken out is reduced. The integral remaining battery power at 90% charging is lowered due to the deterioration of the battery cell, so a difference is generated between the integral remaining battery power stored in the nonvolatile memory and the actual integral remaining battery power at 90% charging. value.

If the remaining battery power is calculated based on the initial value stored in the battery unit at the time of charging, there is a problem that the remaining battery power cannot be correctly calculated according to the second known technique.

Contents of the invention

It is therefore an object of the present invention to provide a battery pack in which if battery cell performance is degraded due to charging/discharging, the number of charging/discharging cycles is counted based on this degradation, and the remaining battery can be accurately set based on this degradation electricity.

Another object of the present invention is to provide a method for counting the number of charging/discharging in a battery pack, and a method for setting a remaining battery power of the battery pack.

According to one aspect of the present invention, the present invention provides a battery pack comprising: a rechargeable/dischargeable battery unit; a voltage detection device for detecting the voltage of the battery unit during charging/discharging; and a counter for setting a plurality of battery levels and for counting the number of times the voltage detected by the voltage detection means is converted into a different battery level in charge/discharge, wherein the counter counts the voltage detected by the voltage detection means is incremented And the number of times of switching to a different battery level, or counting the number of times the voltage detected by the voltage detection means is reduced and switched to a different battery level.

According to an aspect of the present invention, the present invention also provides a battery pack comprising: a rechargeable/dischargeable battery unit; storage means for charging to a preset ratio relative to full charge of said battery unit storing an integral remaining battery power for every preset number of cycles; a counter for counting the number of times said battery cell has been charged/discharged; and setting means for corresponding to the number of times counted by said counter, The integrated remaining battery power for a preset number of cycles stored in the storage means is set as the remaining battery power when the battery unit is fully charged.

According to one aspect of the present invention, the present invention also provides a battery pack, which includes a voltage detection device for detecting the voltage of a battery cell; a storage device for storing a correction coefficient so as to calculate the temperature for a preset temperature remaining battery power; temperature detecting means for detecting the temperature of the battery cell; and computing means. The calculating means operates in such a way that if a correction coefficient related to the temperature detected by the temperature detecting means is stored in the storage means, the calculating means reads out the correction coefficient so as to calculate the voltage from the correction coefficient and the voltage detected by the voltage detecting means Calculate remaining battery power. The calculation means also performs such work that if a correction coefficient related to the temperature detected by the temperature detection means is not stored in the storage means, the calculation means reads a correction coefficient corresponding to the one before and after the detected temperature from the storage means. temperature-related correction coefficients set in advance, so that a correction coefficient related to the detected temperature is calculated based on each read-out correction coefficient, thereby calculating the remaining battery based on the calculated correction coefficients and the voltage detected by the voltage detection means electricity.

According to another aspect, the present invention provides a method for counting the number of charging/discharging times of a battery pack, the method comprising: detecting a voltage of a rechargeable/dischargeable battery cell; setting a plurality of battery levels; and counting the detected The number of voltage transitions to different battery levels.

According to another aspect, the present invention also provides a method for setting the remaining battery capacity of a battery pack, the method comprising: when a rechargeable/dischargeable battery unit is fully charged, the battery unit has been charged to a When the ratio is preset, store the integral remaining battery power for each preset number of cycles in the storage device; count the number of times the battery cell has been charged/discharged; The integral battery power corresponding to the preset number of cycles is set as the remaining battery power when the battery unit is fully charged, wherein the accumulated remaining battery power value corresponds to the number of times counted by the counter.

According to another aspect, the present invention also provides a method for calculating the remaining battery capacity of a battery pack relative to a preset temperature, the method comprising: storing a correction factor for calculating the temperature relative to a preset temperature and detecting the temperature of the battery cell, wherein, if a correction coefficient related to the temperature detected by the temperature detecting means is stored in the storage means, the correction coefficient is read out and based on the correction coefficient and the The voltage detected by the voltage detection means calculates the remaining battery power. Also, if a correction coefficient associated with the detected temperature is not stored in the storage means, then a correction coefficient associated with a preset temperature before and after the detected temperature is read out from the storage means, so that according to each The read correction coefficient is used to calculate a correction coefficient related to the detected temperature, whereby the remaining battery power is calculated based on the calculated correction coefficient and the voltage detected by the voltage detection means.

Description of drawings

FIG. 1 shows the way of counting the number of cycles in the related art.

FIG. 2 is a graph showing a linear characteristic change of an integrated remaining battery power in the case of battery cell performance degradation.

FIG. 3 shows a state in which a battery pack according to the present invention is loaded on a camera device.

Fig. 4 is a perspective view of a battery pack.

Fig. 5 is a perspective view showing the rear side of the battery pack.

Fig. 6 is a perspective view of a battery loading unit provided in the camera device.

Fig. 7 shows the circuit structure of the battery pack.

Figure 8 shows the relationship between voltage levels and battery levels.

Fig. 9 is a flowchart for explaining the operation contents of battery level setting and cycle counting.

Figure 10 shows the calculation of the number of cycles.

FIG. 11 shows an example of the change in the integrated remaining battery power with respect to the number of cycles.

FIG. 12 shows another example of the change in the integrated remaining battery power with respect to the number of cycles.

Fig. 13 shows a circuit configuration of a battery pack.

Fig. 14 is a flowchart for explaining the main routine in calculating correction coefficients.

Fig. 15 is a flowchart for explaining a subroutine in calculating correction coefficients.

Fig. 16 shows calculation results of correction coefficients.

Fig. 17 shows the storage state of the correction coefficient for every increment of 2.5°C in a ROM.

FIG. 18 shows step widths of correction coefficients in the related art.

Detailed ways

Preferred embodiments according to the present invention will be described in detail below with reference to the accompanying drawings.

The present invention is applicable to a battery pack 1 such as that shown in FIG. 3 . This battery pack 1 is loaded, for example, in a battery loading unit 3 of a camera device 2 to supply power to the camera device 2 . On the other hand, the battery pack 1 can be loaded on a charging device (not shown) for charging.

The battery pack 1 includes a casing 19 as shown in FIG. 4 . A battery unit, which is not shown in the figure, is accommodated in the housing 19 .

The case 19 of the battery pack 1 is formed of, for example, a synthetic resin material. Guide grooves 26 , 26 for guiding the loading of the battery pack relative to the battery loading unit 3 are formed on both lateral sides in the width direction of the casing 19 . The guide grooves 26 , 26 in the respective lateral sides are open on one end in the bottom surface 24 of the housing 19 and are formed side by side along the length direction of the housing 19 .

A first input/output terminal 21 and a second input/output terminal 22 are provided on both lateral sides along the width direction of the housing 19 on the front surface 20 with respect to the loading direction of the battery loading unit 3 . A communication terminal 23 is provided on an intermediate portion along the width direction.

The first and second input/output terminals 21 , 22 supply power to a main body portion of the camera device 1 through the battery loading unit 3 . The communication terminal 23 outputs an information signal, such as a signal such as the remaining power of the battery unit, to the main body of the camera device 1 . One end of the input/output terminals 21, 22 and the outwardly facing communication terminal 23 are positioned in a substantially rectangular recess formed in the front surface 20 of the housing 19, thereby preventing contact with other than the connection terminal. Damage caused by contact with other parts of the battery loading device.

A pair of control grooves 28 , 29 are formed in the front surface side of the bottom surface 24 of the housing 19 , that is, in the front surface along the length direction. The control grooves 28 , 29 are formed line-symmetrically in the width direction with respect to a center line (not shown), as shown in FIG. 3 . During loading, the control grooves 28, 29 are engaged by control protrusions (not shown) of the battery loading unit 3 so as to limit inclination relative to the battery loading unit 3 in the width direction of the bottom surface 24 of the housing 19.

Each control groove 28, 29 is substantially an L-shape consisting of a first portion perpendicular to the bottom surface 24 of the housing 19 and a second portion perpendicular to the first portion, as shown in FIG. 5 of.

A substantially rectangular identification groove 30 is formed in the middle portion of the bottom surface 24 of the casing 19 for identifying whether the battery loading unit is a proper unit.

The identification groove 30 is positioned at a position on the center line in the width direction of the case 19 and at a position close to the front surface 20 from the midpoint of the bottom surface 24 of the case 19 . In the bottom surface inside the identification groove 30 is formed a substantially rectangular identification groove 32 extending to both longitudinal ends of the groove 30 substantially on the center line along the width direction of the casing 19 . On both sides in the width direction of the bottom surface 24 of the housing 19 , steps are formed in the identification groove 30 . The size of the identification groove 30 in the width direction is Wo.

A first guide groove 34 is formed near the communication end 23 , and the guide groove 34 extends parallel to the longitudinal direction of the housing 19 . One end of the first guide groove 34 is opened on the front surface 20 of the case 19 , and the other end thereof is formed to extend to the identification groove 30 . A step 35 having different depths in a depth direction corresponding to a direction perpendicular to the bottom surface 24 of the housing 19 is formed in the first guide groove 34 near the front surface 20 of the housing 19 . The first guide groove 34 guides the loading direction of the battery pack relative to the battery loading unit 3 .

A second guide groove 36 facing the first guide groove 34 is formed in the bottom surface 24 of the housing 19 , and the communication terminal 23 is located between the first guide groove 34 and the second guide groove 36 . The second guide groove 36 is formed parallel to the longitudinal direction of the bottom surface 24 of the housing 19 such that the second guide groove 36 has one open end in the front surface 20 of the housing 19 .

Control grooves 37 , 37 are formed in both lateral sides of the housing 19 in the width direction, which are adjacent to the first and second input/output terminals 21 , 22 . The control grooves 37 , 37 are opened on the front surface 20 and extend in a direction substantially parallel to the bottom surface 24 of the casing 19 to limit inclination in the width direction of the bottom surface 24 relative to the battery loading unit 3 .

A first locking groove 38 and a second locking groove 39 are formed in the bottom surface 24 of the casing 19, and the first locking groove 38 is engaged by the battery loading unit 3 when the battery pack is loaded on the battery loading unit 3. And the second locking groove 39. The first locking groove 38 is substantially rectangular in shape, and is located on the centerline of the width direction of the housing 19 close to the identification groove 30 . The second locking groove 39 is substantially rectangular in shape and slightly larger in size than the first locking groove 38 . The second locking groove 39 is formed on the center line in the width direction of the casing 19 near the rear side as viewed in the loading direction.

On the other hand, the battery loading unit 3 provided on the camera device 2 is slightly larger in size than the bottom surface 24 of the casing 19 . The battery loading unit 3 is provided with a pair of guide protrusions 47 engaged with the guide grooves 26 , 26 of the battery pack 1 on its two lateral sides facing the width direction of the battery pack 1 .

When the battery pack is loaded on the battery loading unit 3, the guide protrusions 47 are inserted into the guide grooves 26, 26 of the housing 19 to guide the insertion direction, keeping the bottom surface and the positioning surface of the housing 19 of the battery pack 1 45 are basically parallel.

A terminal portion 44 is formed on the side of an abutting surface 46 of the battery loading unit 3 facing the front surface 20 of the battery pack 1 . This terminal portion 44 is constituted by first to third connection terminals 51 to 53 and a cover member 60 .

First and second connection terminals 51, 52 are provided on both sides along the width direction of the battery loading unit 3 so as to be connected to the first and second input/output terminals 21, 22, respectively. The third connection terminal 53 is provided at a midpoint in the width direction of the battery loading unit 3 so as to be connected to the communication terminal 23 of the battery pack 1 . The first to third connection tabs 51 to 53 are provided on the support surface 46 of the battery loading unit 3 parallel to the bottom surface 24 of the battery pack 1 and the longitudinal direction of the battery pack 1 .

The cover member 60 is mounted on the battery loading unit 3 so as to be rotated in directions indicated by arrows a1, a2, thereby protecting the first to third connection terminals 51 to 53 from external damage.

The cover member 60 is made of, for example, a synthetic resin material, and is composed of a substantially rectangular protective member 61 and a support member 62 for supporting the protective member 61 . The surface of the protective member 61 of the cover member 60 facing the positioning surface 45 of the battery loading unit 3 is formed with a surface inclined with respect to the width direction. When the battery pack 1 is loaded on the battery loading unit 3, the case 19 presses the protective member 61 so as to allow the cover member 60 to be easily rotated in the direction indicated by the arrow a2. The support members 62, 62 of the cover member 60 are supported by the support surface 46 of the battery loading unit 3 for rotation about a pivot (not shown). On the outer periphery of the pivot of the cover member 60, a coil spring (not shown) is provided. One end of the coil spring is held by the supporting surface 46 of the battery loading unit 3 , and its other end is held by the supporting member 62 of the cover member 60 . Accordingly, the cover member 60 moves in the direction indicated by the arrow a1 under the elastic force of the coil spring so as to cover the first to third connection terminals 51 to 53 .

The battery loading unit 3 is formed with a pair of control protrusions 65, 66 that bridge the support surface 46 and the positioning surface 45, substantially symmetrically with respect to the center line, so that in the control groove 28 of the battery pack 1, 29 are engaged.

Each control projection 65, 66 is substantially an L-shape consisting of a first portion perpendicular to the positioning surface 45 and a second portion perpendicular to the first portion. The control protrusions 65 , 66 limit the inclination of the bottom surface 24 of the battery pack 1 relative to the positioning surface 45 of the battery loading unit 3 in the width direction.

The battery loading unit 3 is also formed with a first guide protrusion 68 adjacent to the third connection terminal 53 , which bridges the supporting surface 46 and the positioning surface 45 to guide the insertion of the battery pack 1 . The first guide protrusion 68 is formed parallel to the longitudinal direction of the positioning surface 45 so as to be engaged in the first guide groove 34 of the bottom surface 24 of the battery pack 1 being loaded, as shown in FIG. 4 .

The battery loading unit 3 is also formed with a second guide protrusion 54 bridging the supporting surface 46 and the positioning surface 45 for guiding the loading direction of the battery pack 1 . The second guide protrusion 54 is integrally formed with a positioning surface 45 parallel to the longitudinal direction of the second guide protrusion. The second guide protrusion 54 is engaged with the second guide groove 36 of the battery pack 1 so as to guide the loading direction.

Both lateral sides along the width direction of the battery loading unit 3 are integrally formed with control claws 55 , 55 which engage with the control grooves 37 , 37 . The control dogs 55 , 55 are parallel to the positioning surface 45 and the longitudinal direction of the battery pack 1 .

On the middle portion of the positioning surface 45 of the battery loading unit 3 is formed an identification protrusion 56 which engages with the identification groove 30 of the first battery pack 6 . The identification protrusion 56 is substantially rectangular in shape. The end of the identification protrusion 56 is formed with an identification lug 57 which engages with the identification groove 32 of the battery pack 1 . The identification protrusion 56 has a width W ₁ parallel to the width of the positioning surface 45, which is smaller than the width Wo of the identification groove 30 of the battery pack 1, so that the identification protrusion 56 can be inserted into the identification groove ₃₀ , As shown in Figure 6. The identification protrusion 56 is formed in the vertical direction at a position spaced apart from the bearing surface 46 by a distance L1.

According to the structure of the battery loading unit 3 described above, the battery pack 1 can be loaded on the battery loading unit 3 .

The charging device for charging the battery pack 1 is also provided with a battery loading unit configured similarly to the battery loading unit 3 .

The circuit configuration of the battery pack 1 will be described below.

Referring to FIG. 7, the battery pack 1 is provided with lithium ion batteries 171, 172 as two battery cells connected in series; a first input/output terminal 121, which is connected to the lithium ion battery through a resistor R101. The positive terminal of the battery 171 is connected; and a second input/output terminal 122 connected to the negative electrode of the lithium ion battery 172 .

The lithium ion batteries 171 , 172 are charged or discharged from the outside through the first and second input/output terminals 121 , 122 . Lithium ion batteries 171, 172 are connected in parallel with resistors 101, 102 connected in series. That is, the positive electrode of the lithium ion battery 171 is connected to the resistor R101 , while the negative electrode of the lithium ion battery 172 is connected to the resistor 102 .

The battery pack 1 is also provided with: a current detection circuit 173 for detecting the current flowing through the resistor 103; an A/D converter 174 for digitizing the charging/discharging current value and the battery voltage value, and a central processing A CPU (CPU) 175 for counting the number of charging/discharging, hereinafter referred to as the number of cycles, and for calculating the remaining battery power. The battery pack 1 also includes a random access memory (RAM) 176 for temporarily storing the current voltage levels of the lithium ion batteries 171, 172; and a read only memory (ROM) 177 for storing useful Based on the control program of CPU 175.

The current detection circuit 173 detects the current flowing in the resistor 103 during charging or discharging to deliver the detected current to an A/D converter 174 .

The A/D converter 174 digitizes the current value from the current detection circuit 173 to deliver the digitized current to the CPU 175. The A/D converter 174 digitizes the voltage value of one connection terminal of the resistors 101 and 102, which is hereinafter referred to as a midpoint connection terminal, that is, R102/ (R101+R102) divided voltage value, so that digitized voltage is delivered to CPU 175.

The CPU 175 is provided with a counter 175a for counting the number of cycles. The CPU 175 divides the voltage level on the midpoint connection X into four levels from battery level 0 to battery level 3, the highest battery level being battery level 3 and the lowest battery level being battery level 0. The battery level is reduced by one level at a time, and the CPU 175 counts up by one by the counter 175a.

Specifically, the CPU 175 sets the battery level to count the number of cycles according to the flowchart shown in FIG. 9 .

When the current detection circuit 173 detects the charging current or the discharging current, the CPU 175 proceeds to step ST1 to obtain the battery voltage at the neutral point connection terminal X through the A/D converter 174. Then the CPU goes to step ST2.

At step ST2, the CPU 175 checks based on a detection output of the current detection circuit 173 whether charging or discharging is in progress. If the CPU 175 confirms that charging is in progress, the CPU proceeds to step ST3. If the CPU 175 confirms that the discharge is in progress, the CPU proceeds to step ST9.

In step ST3, the CPU 175 checks whether the voltage level at the midpoint connection terminal X is higher than that of the battery level 3. If the detection result is YES, the CPU 175 proceeds to step ST4, otherwise the CPU 175 proceeds to step ST5.

In step ST4, the CPU 175 assumes that the current voltage level is the battery level 3 so as to write the level in the RAM 176 to terminate the program.

In step ST5, the CPU 175 checks whether the voltage level at the midpoint connection terminal X is higher than the battery voltage level 2. If the detection result is YES, the CPU 175 proceeds to step ST6, otherwise the CPU 175 proceeds to step ST7.

In step ST6, the CPU 175 assumes that the current voltage level is the battery level 2 to write the level in the RAM 176, thereby terminating the routine.

In step ST7, the CPU 175 checks whether the voltage level at the midpoint connection terminal X is higher than the battery voltage level 1. If the detection result is YES, the CPU 175 proceeds to step ST8, otherwise the CPU 175 assumes that the battery voltage level is battery level 0, so as to write the level into the RAM 176, thereby terminating the program.

In step ST8, the CPU 175 assumes that the current voltage level is the battery level 1 to terminate the routine.

In step ST9, where the CPU 175 proceeds to this step ST9 when it is confirmed that the discharge in step ST2 is in progress, the CPU 175 checks whether the voltage level on the midpoint connection terminal X is lower than the battery voltage level 1, that is, the battery voltage level 1. Whether the level has transitioned from 1 to 0. If the detection result is YES, the CPU 175 proceeds to step ST10, otherwise the CPU 175 proceeds to step ST11.

In step ST10, the CPU 175 assumes that the current voltage level is the battery level 0 to write the level in the RAM 176. The CPU then proceeds to step ST15.

In step ST11, the CPU 175 checks whether the voltage level at the midpoint connection terminal X is less than battery voltage level 2, that is, whether the battery level has shifted from level 2 to level 1. If the detection result is YES, the CPU proceeds to step ST12, otherwise the CPU proceeds to step ST13.

In step ST12, the CPU 175 assumes that the current voltage level is the battery level 1 to write the level in the RAM 176. The CPU then proceeds to step ST15.

In step ST13, the CPU 175 checks whether the voltage level at the midpoint connection terminal X is lower than the battery voltage level 3, that is, whether the battery level has changed from level 3 to level 2. If the detection result is YES, the CPU goes to ST14, otherwise the CPU terminates the program.

In step ST14, the CPU 175 assumes that the current voltage level is the battery level 0 to write the level in the RAM 176. The CPU then proceeds to step ST15.

In step ST15, the CPU 175 counts up the number of cycles of the counter 175a by 1/3 to terminate the processing.

That is, the CPU 175 detects which level of battery level the voltage level belongs to at the time of charging and discharging, and the count increases by 1/3 each time the voltage level is lowered due to discharging, so that any one of the three threshold values is set Exceed. Therefore, if the lithium ion secondary battery is frequently charged/discharged, the number of counted cycles can be increased in response to the actual state of deterioration of the lithium secondary battery.

Each time the battery level transitions from 3 to 2, from 2 to 1, and from 1 to 0, the number of cycles is counted up. If discharge occurs again after the battery level is 3 by charging, the cycle number is counted up each time the battery level transitions from 3 to 2 and from 2 to 1. If charging occurs again when the battery level is equal to 1, so that the battery level transitions to 3, and then discharge occurs again, the cycle number is incremented each time the battery level number is decremented. Meanwhile, 1/3 of the number of cycles shown in FIG. 10 represents the actual number of cycles.

If the number of cycles of the counter 175a of the CPU 175 exceeds the maximum number of charge/discharge counts of the lithium ion battery 171, 172, it can be considered that the lithium ion battery 171, 172 has deteriorated and its service life has ended.

The battery levels are divided into four levels in this embodiment. Alternatively, the battery level can be divided into n (>2) stages and the number of cycles can be counted up each time one of the (n-1) thresholds is exceeded.

Also, in this embodiment the number of cycles is incremented as the voltage level is lowered, ie during discharge. Alternatively, the number of cycles can be counted as the voltage level is incremented, ie during charging. It is also possible that the number of cycles can be counted during both charging and discharging.

The integrated remaining battery voltage value stored in the ROM 177 will be described below. The integrated remaining battery voltage [mAh] that can be discharged at the time of charging to 90% for each number of cycles is stored in the ROM 177, 90% charging is hereinafter referred to as the 90% integral remaining value, as shown in FIG. 11 . At this time, the 90% integral residual value is stored at intervals of 10 cycles, specifically for the intervals of cycle numbers from 0 to 10, from 11 to 20, from 21 to 30, . . . .

For example, the 90% integral residual value from 11 to 20 cycles is the 90% integral residual value from 0 to 10 cycles minus the degraded capacity of the Li-ion batteries 171, 172 resulting from 11 to 20 cycles. Similarly, the 90% integral residual from 11 to 20 cycles is the 90% integral residual from 0 to 10 cycles minus the degraded charge of the Li-ion cells 171, 172 produced by 21 to 30 cycles.

Therefore, if the remaining battery value in discharge is calculated from the initial value of the integrated remaining battery value, the battery pack 1 can perform the calculation using the 90% integrated remaining value as the set value according to the number of cycles. That is, since the 90% cumulative remaining value as an initial value for calculating the remaining battery value can be set to coincide with the deterioration value caused by charging/discharging of the lithium ion batteries 171, 172, it can be more accurate than with the conventional method. Accurately calculates the remaining battery value.

The 90% cumulative remaining value may also be stored in ROM 177 every 32 cycles, as shown in FIG. 12 . For example, if the cycle number is not less than 0 and not more than 32, then the non-corrected 90% cumulative remaining value is stored as the reference power, and if the cycle number is not less than 32 and not more than 64, then the reference power minus the correction data (constant value) If the number of cycles is not less than 64 and not more than 96, then the reference power is stored after subtracting twice the correction data, if the number of cycles is not less than 96 and not more than 128, then the reference power is minus three times the correction data stored afterwards. That is, if the degraded power is linear, then the 90% integral residual value can be stored according to the algorithm.

According to the present invention, using the battery pack described above and counting the number of charging/discharging of the battery pack in which the voltage is detected by the rechargeable/dischargeable battery cells, a plurality of battery levels are set and have been converted into different voltages. Counting the number of times a flat voltage is detected, even if the battery cell is degraded due to charging/discharging, the number of cycles can be accurately calculated according to the degree of deterioration of the battery cell.

With the battery pack and remaining battery power setting method according to the present invention, wherein the integrated remaining battery power when charged to a preset ratio is measured at intervals of a preset number of cycles with respect to full charging of the rechargeable/dischargeable battery unit Stored in the storage device, counts the number of times the battery unit has been charged/discharged, and corresponding to the count of the counter, for the preset number of cycles, the integral remaining battery power stored in the storage device is set to when the battery unit is fully charged For the remaining battery power, the integrated remaining battery power value when charged to a preset percentage corresponding to the number of cycles can be set. Since this enables the initial value at the time of charging to be set in accordance with the deterioration caused by charging/discharging of the battery cells, the remaining battery power can be calculated more accurately than with a conventional battery pack.

FIG. 13 shows a specific circuit configuration of the battery pack 1 .

The battery pack 1 is composed of a battery cell block 70 having two battery cells and a battery protection circuit block 80 for preventing the battery cell block 70 from overcharging or overdischarging.

The battery cell block 70 includes lithium ion batteries 71 , 72 as two battery cells connected in series; and a temperature sensor 76 for detecting the temperature of the lithium ion batteries 71 , 72 . The positive and negative electrodes of the lithium-ion batteries 71, 72 are connected to a positive terminal 73 and a negative terminal 74, respectively. The connection point of the lithium-ion batteries 71 , 72 is connected to a mid-point potential terminal 75 . The temperature sensor 76 detects the temperature of the batteries 71 , 72 to transmit the detection result to the battery protection circuit block 80 .

The battery protection circuit block 80 includes: a terminal V _H connected to the positive terminal 73; a terminal V _SS connected to the negative terminal 74; a terminal V _L connected to the midpoint potential terminal 75; resistors R1 to R6 for Divide the voltage on each terminal; a resistor RS and a first switch S1.

Terminals V _H , V _L are connected to each other through resistors R1 to R3 connected in series. The total resistance of the resistors R1 to R3 connected in series is the resistance Rb1, which may be 20 MΩ, for example.

Terminals V _L , V _SS are connected to each other through resistors R4 to R6 connected in series. The terminals V _L , V _SS are connected to each other through a resistor RS and a first switch S1 connected in series with each other. Meanwhile, the total resistance of the resistors R4 to R6 connected in series is Rb2, for example Rb2 may be 20MΩ. That is, the resistance value of the resistor Rb1 is equal to the resistance value of the resistor Rb2. The resistance value of the resistor RS is 390KΩ, which is much smaller than the total resistance value of the resistors Rb1 and Rb2. The first switch S1 is normally off, and the first switch S1 is turned on only during the period when the midpoint potential confirming control signal Ts is provided.

The battery protection circuit block 80 includes: first and second zener diodes 81, 82 for generating a reference voltage; first to fourth comparators 83 to 86 for detecting potential differences between respective resistors for detecting overcharging or overdischarging; a charging control circuit 89 for turning off a third switch SW _C at overcharging; and a discharging control circuit 90 for turning off a second switch SW _D at overdischarging.

The first comparator 83 has an inverting input terminal connected to the cathode of the first Zener diode 81, and the anode of the Zener diode 81 is connected to the terminal _VL . The first comparator 83 has a non-inverting input terminal connected to the connection point of the resistors R1, R2. The first comparator 83 detects whether the lithium ion battery 71 has been overcharged. The first comparator 83 outputs a logic signal H when detecting that the voltage Vb1 of the lithium ion battery 71 exceeds 4.25V, and outputs a logic signal L when detecting that the voltage Vb1 of the lithium ion battery 71 is less than 4.25V.

The second comparator 84 has an inverting input connected to the cathode of the first Zener diode 81 . The second comparator 84 has a non-inverting input terminal connected to the connection point between the resistors R2 and R3. The second comparator 84 detects whether the lithium-ion battery 71 is in an over-discharged state. Therefore, if the voltage Vb1 of the lithium-ion battery 71 is less than 2.45V, the second comparator 84 outputs a logic signal H, and if the voltage Vb1 is greater than 2.45V, outputs a logic signal L.

The third comparator 85 has an inverting input terminal connected to the cathode of the second Zener diode 82, and the anode of the Zener diode 82 is connected to the terminal V _SS . The third comparator 85 has a non-inverting input connected to the connection point between resistors R4 and R5. The third comparator 85 detects whether the lithium-ion battery 72 is in an overcharged state. Therefore, the third comparator 85 outputs a logic signal H when detecting that the voltage Vb2 of the lithium ion battery 72 exceeds 4.25V, and outputs a logic signal L if the voltage Vb2 is less than 4.25V.

The fourth comparator 86 has an inverting input connected to the cathode of the second Zener diode 82 . The fourth comparator 86 has a non-inverting input terminal connected to the connection point between the resistors R5 and R6. The fourth comparator 86 detects whether the lithium-ion battery 72 is in an over-discharged state. Specifically, if the voltage Vb2 of the lithium-ion battery 72 is less than 2.45V, the second comparator 86 outputs a logic signal H, and if the voltage Vb2 is greater than 2.45V, outputs a logic signal L.

A first OR gate 87 takes the logical sum of the outputs of the first and third comparators 83 , 85 to transfer the result to a charging control circuit 89 . An OR gate 88 takes the logical sum of the outputs of the second and fourth comparators 84 , 86 to pass the result to the discharge control circuit 90 .

The charging control circuit 89 controls the third switch SW _c , and if the logic signal H or the logic signal L is provided by the first OR gate 87 , the third switch SW _C is opened or closed. The discharge control circuit 90 controls the second switch SW _D , and if the logic signal H or the logic signal L is provided by the second OR gate 88 , the second switch SW _D is opened or closed.

It should be noted that the second and third switches SW _D and SW _C are connected in series with each other. One of the second and third switches SW _D , SW _C is connected to the second input/output terminal 22 and the other switch is connected to the terminal V _SS through a resistor R7 .

The battery pack 1 also includes: a charging/discharging current detection circuit 91 for detecting whether the battery pack is charging or discharging; a microcomputer 92 for controlling the on/off of the first switch S1 and a communication interface 93 , for data transmission/reception with the outside.

The charge/discharge current detection circuit 91 includes first and second operational amplifiers 911, 912, and resistors R11 to R16 like ring-like gaskets.

The first operational amplifier 911 has a non-inverting input terminal connected to the terminal V _SS through a resistor R13 and an inverting input terminal connected to the terminal V _SS through resistors R12 and R7. A resistor R11 is connected between the inverting input terminal and the output terminal of the first operational amplifier 911 . When the discharge current flows through the resistor R7, the first operational amplifier 911 outputs a voltage proportional to the resistance ratio of the resistor R12 to the resistor R11 to the microcomputer 92 and a third OR gate 913. If the charging current flows through the resistor R7, the second operational amplifier 912 outputs a voltage proportional to the resistance ratio of the resistor R15 to the resistor R14 to the microcomputer 92 and a third OR gate 913. The third OR gate 913 takes the logical sum to supply the result to the microcomputer 92 . That is, the charge/discharge current detection circuit 91 detects the direction of the current flowing through the resistor R7 so as to detect whether the charge/discharge is in progress, and if it is detected that the charge or discharge is in progress, the charge/discharge current detection circuit 91 provides the detection result to The microcomputer 92 also supplies the charging current value or the discharging current value to the microcomputer 92 at the same time.

If charging/discharging has been detected by the charging/discharging current detection circuit 91, or if data has been received on a communication interface 93, the microcomputer 92 is programmed to operate, otherwise enters a sleep state. The microcomputer 92 is also programmed to enter a sleep state if no charging/discharging current flows or data communication occurs within two or three seconds after activation.

The microcomputer 92 uninterruptedly detects the voltage of the terminal V _L and reads out the optimum correction coefficient stored in the ROM 94 according to the temperature of the lithium ion battery 71, 72 detected by the temperature sensor 76, so as to calculate the lithium ion battery 71, 72 remaining battery power.

As discussed above with respect to FIG. 18, not only the correction coefficients are stored at intervals of every 10°C in the ROM 94, but also a control program for perfecting the correction coefficients or a control program for calculating the remaining battery power is stored. .

The correction coefficients stored in the ROM 94 at intervals of every 10°C are five correction coefficients, that is, a correction coefficient 1 (=0.6) for a temperature of 10°C or lower; a correction coefficient 2 (=0.8) for 10°C to 20°C; a correction factor of 3 (=1.0) for 20°C to 30°C; a correction factor of 4 (=1.2) for 30°C to 40°C; and a correction factor of 5 (=1.4) for 40°C or higher temperature.

In order to calculate the correction coefficients in more detail based on these correction coefficients, the microcomputer 92 executes the procedure as shown in the flowchart in FIG. 14 from step ST101. Here, a correction coefficient for 20°C to 30°C is adopted as an example, and four correction coefficients are calculated at intervals of every 10°C.

In step ST101, the microcomputer 92 sets the correction coefficient stored in the ROM 94 as the correction coefficient 3-3 for 25.0°C to 27.5°C. That is, the correction coefficient 3-3 is set to 1.0. The microcomputer 92 then proceeds to step ST102.

In step ST102, the microcomputer 92 calculates a correction coefficient 3-1 at 20.0°C to 22.5°C from the correction coefficients 2 and 3 stored in the ROM 94. The microcomputer 92 shifts to the subroutine processing shown in FIG. 15 to calculate the intermediate value of the two correction coefficients (step ST111). Specifically, the microcomputer 92 calculates 0.9 as the median value of the correction coefficients 2 and 3 to set the correction coefficient 3-1 to 0.9. The microcomputer then proceeds to step ST103.

In step ST103, the microcomputer 92 executes the subroutine of step ST111 shown in FIG. 15 to calculate the correction coefficient 3-2 for 22.5°C to 25.0°C from the correction coefficients 3-1 to 3-3. That is, the microcomputer 92 sets the median value 0.95 of the correction coefficient 3-1 (=0.9) and the correction coefficient 3-3 (=1.0) as the correction coefficient 3-2. The microcomputer 92 then proceeds to step ST104.

In step ST104, the microcomputer 92 executes the subroutine of step ST111 in FIG. That is, the microcomputer 92 sets the median value 1.1 of the correction coefficients 3 and 4 as the correction coefficient 4-1. The microcomputer 92 then proceeds to step ST105.

In step ST105, the microcomputer 92 executes the subroutine of step ST111 in FIG. 15 to calculate the correction coefficient 3-4 for 27.5°C to 30.0°C from the correction coefficients 3-3 and 4-1. That is, the microcomputer 92 sets 1.05, which is the median value of the correction coefficients 3-3 and 4-1, as the correction coefficient 3-4. The microcomputer 92 then terminates the processing.

According to the above processing, the microcomputer 92 obtains: the correction coefficient 3-1 (=0.90) for 20.0°C to 22.5°C, the correction coefficient 3-2 (=0.95) for 22.5°C to 25.0°C, the correction coefficient 3-2 (=0.95) for 27.5°C to 27.5°C A correction factor of 3-3 for 30.0°C, and a correction factor of 4-1 (=1.1) for 30.0°C to 32.5°C, as shown in FIG. 16 .

As shown in FIG. 17, the microcomputer 92 performs similar processing for temperature ranges other than 20.0°C to 30.0°C to calculate correction coefficients at intervals of every 2.5°C.

Since the microcomputer 92 can utilize these correction coefficients with a small step width, the remaining battery power can be accurately calculated from the voltage on the terminal _VL even if the lithium ion batteries 71, 72 undergo temperature changes.

If the microcomputer 92 has calculated correction coefficients corresponding to the temperature detected by the temperature sensor 76 when the processing of step ST101 shown in FIG. battery power.

For example, if the microcomputer 92 has detected a temperature of 26°C, the microcomputer 92 can obtain a correction coefficient 3-3 (=1.0) for 25.0°C to 27.5°C when the process of step ST101 has been performed. The microcomputer 92 can therefore stop the processing from step ST102 in order to calculate the remaining battery power.

Likewise, if the microcomputer 92 has detected 23° C., the microcomputer 92 can execute the procedures of steps ST101 to ST103 to accurately calculate the remaining capacity of the lithium ion batteries 71, 72 based on the correction coefficient 3-2 and the voltage on the terminal V _L. battery power.

Meanwhile, the remaining battery power can also be calculated using a technique disclosed in Japanese Patent Laid-Open No. Hei 9-297166 without any particular limitation. However using this technique it is necessary to calculate the remaining battery charge using a temperature dependent correction factor or the voltage of the Li-ion battery 71,72.

With the battery pack 1 in which only the minimum correction coefficient needs to be stored in the ROM 94, and if the temperature of the lithium-ion batteries 71, 72 is detected, the correction coefficient is calculated only for the detected temperature range, so it is possible to Accurately calculate the correction factor.

Also, in the procedure of step ST102 to step ST105, the subroutine shown in FIG. 15 is repeatedly executed. Thus, an optimum correction coefficient can be easily calculated without performing complicated processing.

In the present embodiment, it has been explained assuming that the correction coefficients are stored at intervals of every 10° C., as shown in FIG. 18 . However, correction coefficients may be stored in advance at intervals of every 2.5° C., as shown in FIG. 17 . Also in this embodiment, it has been explained assuming that the range of 10°C is divided into four steps to calculate the correction coefficient using an interval of every 2.5(10/4)°C. However, it is also possible to separate the temperature range in finer steps in order to more accurately calculate the correction coefficient.

According to the calculation method of the battery pack and the remaining battery power of the present invention, if a correction coefficient related to the temperature detected by the temperature detection device is stored in the storage device, then according to the correction coefficient and the voltage detected by the voltage detection device, the Correction factor and calculate remaining battery power. If a correction coefficient related to the detected temperature is not stored in the storage device, a correction coefficient related to a preset temperature before and after the detected temperature is read out from the storage device to correct The coefficient is used to calculate a correction coefficient related to the detected temperature, whereby the remaining battery capacity is calculated based on the calculated correction coefficient and the voltage detected by the voltage detection means. Therefore, if a temperature change occurs in the battery cell, a correction coefficient corresponding to the change can be correctly obtained so that the remaining battery power can be accurately calculated at any time.

Claims (11)

1. A battery pack, comprising: Rechargeable/dischargeable battery unit; voltage detection means for detecting the voltage of the battery cell during charging/discharging; and a counter for setting a plurality of battery levels and for counting the number of times the voltage detected by the voltage detection means is converted to a different battery level in charging/discharging, wherein the counter counts the number of times the voltage detected by the voltage detection means The number of times the detected voltage is increased and converted to a different battery level, or the number of times the detected voltage is decreased and converted to a different battery level is counted. 2. The battery pack according to claim 1, further comprising: verification means for verifying that the service life of the battery unit has expired when the number of times counted by the counter has exceeded the maximum number of maximum charge/discharge counts. 3. A method for counting the number of charge/discharge times of a battery pack, the method comprising: Sensing the voltage of a rechargeable/dischargeable battery cell; set multiple battery levels; and Counts the number of times the detected voltage transitions to different battery levels. 4. The method according to claim 3, wherein it is verified that the service life of the battery cell has expired when the counted number of times has exceeded a maximum number of maximum charge/discharge counts. 5. The method according to claim 3, wherein the number of times is the number of times the voltage detected by the voltage detection means is increased and converted to a different battery level, or the voltage detected by the voltage detection means is decreased and is converted to the number of different battery levels. 6. A battery pack, comprising: Rechargeable/dischargeable battery unit; storage means for storing an integral remaining battery charge for each preset number of cycles when charged to a preset ratio relative to full charge of said battery cell; a counter for counting the number of times the battery cell has been charged/discharged; and setting means for setting an integrated remaining battery power for a preset number of cycles stored in said storage means as the remaining battery power when the battery unit is fully charged, corresponding to the number of times counted by said counter. 7. A method for setting the remaining battery capacity of a battery pack, the method comprising: when a rechargeable/dischargeable battery cell has been charged to a preset rate relative to full charge of the cell, storing in the storage means the integral remaining battery charge for each preset number of cycles; counting the number of times the battery cell has been charged/discharged; setting an integrated battery power corresponding to a preset number of cycles stored in the storage means as the remaining battery power when the battery unit is fully charged, wherein the accumulated remaining battery power value is the same as the number of times counted by the counter Corresponding. 8. A battery assembly, comprising: A voltage detection device for detecting the voltage of the battery unit; storage means for storing correction coefficients for calculating remaining battery power for a preset temperature; temperature detection means for detecting the temperature of the battery cell; and computing device; Said calculation means operates such that if a correction coefficient associated with the temperature detected by said temperature detection means is stored in said storage means, said calculation means reads out said correction coefficient so as to and the voltage detected by said voltage detecting means to calculate the remaining battery power; said calculating means also operates such that if a correction coefficient associated with the temperature detected by said temperature detecting means is not stored in said storage means wherein, the calculation means reads out a correction coefficient related to a preset temperature before and after the detected temperature from the storage means, so as to calculate the temperature related to the detected temperature according to each read correction coefficient A correction coefficient whereby the remaining battery power is calculated based on the calculated correction coefficient and the voltage detected by the voltage detection means. 9. The battery pack according to claim 8, further comprising: program storage means storing therein a program for calculating a correction coefficient between a given temperature and another temperature from the correction coefficient associated with said given temperature and with said other temperature Calculated by a correction factor related to temperature; The calculating means repeatedly performs the operation of calculating the correction coefficient using each correction coefficient read out from the storage means according to the program stored in the program storage means, and for the temperature detected by the temperature detecting means Before and after a temperature, a new correction coefficient is further calculated using the correction coefficient calculated according to the above procedure and the correction coefficient that has been read from the storage device, so as to calculate a correction coefficient related to the detected temperature. 10. A method for calculating remaining battery capacity of a battery pack associated with a preset temperature, the method comprising: Storing correction coefficients for calculating remaining battery power for preset temperatures; detecting the temperature of the battery cell; Wherein, if a correction coefficient related to the temperature detected by the temperature detection means is stored in the storage means, the correction coefficient is read out and the remaining battery is calculated based on the correction coefficient and the voltage detected by the voltage detection means electricity; if a correction coefficient associated with the detected temperature is not stored in said storage means, then a correction coefficient associated with a preset temperature before and after the detected temperature is read out from said storage means, so that A correction coefficient related to the detected temperature is calculated from each read correction coefficient, whereby the remaining battery power is calculated from the calculated correction coefficient and the voltage detected by the voltage detection means. 11. The method according to claim 10, comprising: A program is stored in the program storage means for calculating a correction coefficient between a given temperature and another temperature from a correction coefficient associated with said given temperature and a relation with said another temperature The relevant correction coefficients are calculated; calculating a correction coefficient using each of the correction coefficients read from said storage means according to a program stored in said program storage means; and For a temperature before and after the temperature detected by said temperature detection means, further calculate a new correction coefficient using the correction coefficient calculated according to the above procedure and the correction coefficient that has been read out from the storage means; and The operation of calculating a correction coefficient and the operation of calculating a new correction coefficient are repeatedly performed to calculate a correction coefficient related to the detected temperature.

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